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    Electrical stimulation of the thigh muscles after reconstruction of the anterior cruciate ligament. Effects of electrically elicited contraction of the quadriceps femoris and hamstring muscles on gait and on strength of the thigh muscles. Snyder-Mackler L,Ladin Z,Schepsis A A,Young J C The Journal of bone and joint surgery. American volume The effects of neuromuscular electrical stimulation on the strength of the thigh muscles and on gait were examined in ten patients after reconstruction of the anterior cruciate ligament. The patients were randomly assigned to one of two treatment groups: neuromuscular electrical stimulation and volitional exercise, or volitional exercise alone. A four-week course of electrically elicited co-contraction of the thigh muscles resulted in significant attenuation of the characteristic loss of strength of the quadriceps as compared with volitional exercise. There was no significant difference between groups in any measure of performance of the hamstring muscles. In the group that received neuromuscular electrical stimulation, the values for cadence, walking velocity, stance time of the involved limb, and flexion-excursion of the knee during stance were significantly different from those of the volitional exercise group. Flexion-excursion of the knee during stance was directly and significantly correlated with strength of the quadriceps femoris muscle. Flexion of the knee during stance was qualitatively different in the involved extremity as compared with the uninvolved extremity in all patients. There is a rapid flexion of the knee at weight acceptance that is maintained throughout stance and probably reflects stabilization of the joint by muscular coactivation to compensate for weakness of the quadriceps. The patients who received neuromuscular electrical stimulation had stronger quadriceps muscles and more normal gait patterns than those in the volitional exercise group.
    Implementation of open and closed kinetic chain quadriceps strengthening exercises after anterior cruciate ligament reconstruction. Ross M D,Denegar C R,Winzenried J A Journal of strength and conditioning research When working with athletes that have recently undergone anterior cruciate ligament (ACL) reconstructive surgery, a common goal of athletic trainers, strength and conditioning coaches, physicians, and physical therapists is to restore quadriceps strength while protecting the reconstructed ACL and patellofemoral joint from unnecessary stresses. Quadriceps strengthening exercises are often referred to as occurring in the open kinetic chain (OKC) or closed kinetic chain (CKC). Currently, there is little agreement in the literature as to whether only CKC exercises or a combination of OKC and CKC exercise should be performed after ACL reconstruction to strengthen the quadriceps. We believe that a combination of OKC and CKC exercises can be used to effectively and safely strengthen the quadriceps after ACL reconstruction. The purposes of this review are to examine the scientific literature currently available for the effects of OKC and CKC exercise on ACL strain and patellofemoral joint stress, and to present a sound rationale for using a combination of OKC and CKC exercises for quadriceps strengthening after ACL reconstruction. On the basis of our review, both OKC and CKC exercises can be modified and implemented for quadriceps strengthening after ACL reconstruction without causing excessive ACL strain or patellofemoral joint stress.
    Strength of the quadriceps femoris muscle and functional recovery after reconstruction of the anterior cruciate ligament. A prospective, randomized clinical trial of electrical stimulation. Snyder-Mackler L,Delitto A,Bailey S L,Stralka S W The Journal of bone and joint surgery. American volume Immediately after reconstruction of the anterior cruciate ligament, 110 patients were randomly assigned to treatment with high-intensity neuromuscular electrical stimulation (thirty-one patients), high-level volitional exercise (thirty-four patients), low-intensity neuromuscular electrical stimulation (twenty-five patients), or combined high and low-intensity neuromuscular electrical stimulation (twenty patients). All treatment was performed isometrically with the knee in 65 degrees of flexion. All of the patients participated in an intensive program of closed-kinetic-chain exercise. After four weeks of treatment, the strength of the quadriceps femoris muscle and the kinematics of the knee during stance phase were measured. Quadriceps strength averaged 70 per cent or more of the strength on the uninvolved side in the two groups that were treated with high-intensity electrical stimulation (either alone or combined with low-intensity electrical stimulation), 57 per cent in the group that was treated with high-level volitional exercise, and 51 per cent in the group that was treated with low-intensity electrical stimulation. The kinematics of the knee joint were directly and significantly (p < 0.05) correlated with the strength of the quadriceps. There was a clinically and statistically significant (p < 0.05) difference in the recovery of the quadriceps and the gait parameters according to the type of operation that had been performed: the patients who had had reconstruction of the anterior cruciate ligament with use of an autologous patellar-ligament graft did poorly compared with the other patients. 10.2106/00004623-199508000-00004
    Maximizing quadriceps strength after ACL reconstruction. Palmieri-Smith Riann M,Thomas Abbey C,Wojtys Edward M Clinics in sports medicine The primary objectives of ACL surgery and rehabilitation are to restore knee function to preinjury levels and promote long-term joint health. Often these goals are not achieved, however. The quadriceps is critical to dynamic joint stability, and weakness of this muscle group is related to poor functional outcomes. Because of this, identifying strategies to minimize quadriceps weakness following ACL injury and reconstruction is of great clinical interest. This article reviews the current literature and critically discusses current rehabilitation approaches to restore quadriceps muscle function after ACL reconstruction. 10.1016/j.csm.2008.02.001
    Cross-education does not accelerate the rehabilitation of neuromuscular functions after ACL reconstruction: a randomized controlled clinical trial. Zult Tjerk,Gokeler Alli,van Raay Jos J A M,Brouwer Reinoud W,Zijdewind Inge,Farthing Jonathan P,Hortobágyi Tibor European journal of applied physiology PURPOSE:Cross-education reduces quadriceps weakness 8 weeks after anterior cruciate ligament (ACL) surgery, but the long-term effects are unknown. We investigated whether cross-education, as an adjuvant to the standard rehabilitation, would accelerate recovery of quadriceps strength and neuromuscular function up to 26 weeks post-surgery. METHODS:Group allocation was randomized. The experimental (n = 22) and control (n = 21) group received standard rehabilitation. In addition, the experimental group strength trained the quadriceps of the non-injured leg in weeks 1-12 post-surgery (i.e., cross-education). Primary and secondary outcomes were measured in both legs 29 ± 23 days prior to surgery and at 5, 12, and 26 weeks post-surgery. RESULTS:The primary outcome showed time and cross-education effects. Maximal quadriceps strength in the reconstructed leg decreased 35% and 12% at, respectively, 5 and 12 weeks post-surgery and improved 11% at 26 weeks post-surgery, where strength of the non-injured leg showed a gradual increase post-surgery up to 14% (all p ≤ 0.015). Limb symmetry deteriorated 9-10% more for the experimental than control group at 5 and 12 weeks post-surgery (both p ≤ 0.030). One of 34 secondary outcomes revealed a cross-education effect: Voluntary quadriceps activation of the reconstructed leg was 6% reduced for the experimental vs. control group at 12 weeks post-surgery (p = 0.023). Both legs improved force control (22-34%) and dynamic balance (6-7%) at 26 weeks post-surgery (all p ≤ 0.043). Knee joint proprioception and static balance remained unchanged. CONCLUSION:Standard rehabilitation improved maximal quadriceps strength, force control, and dynamic balance in both legs relative to pre-surgery but adding cross-education did not accelerate recovery following ACL reconstruction. 10.1007/s00421-018-3892-1
    Safety, feasibility, and efficacy of negative work exercise via eccentric muscle activity following anterior cruciate ligament reconstruction. Gerber J Parry,Marcus Robin L,Dibble Leland E,Greis Patrick E,Burks Robert T,Lastayo Paul C The Journal of orthopaedic and sports physical therapy STUDY DESIGN:Randomized, matched design. BACKGROUND:Optimal rehabilitation following anterior cruciate ligament reconstruction (ACL-R) requires safe and effective interventions. Negative work exercise (via eccentric muscle activity) has the potential to be highly effective at producing large quadriceps size and strength gains early after ACL-R. The purpose of this investigation was to evaluate the short-term safety and efficacy of adding a progressive negative work exercise program via eccentric (ECC) ergometry early after ACL-R. METHODS AND MEASURES:Beginning 3 weeks after ACL-R, 32 participants were randomly assigned into either a 12-week traditional (TRAD) or ECC exercise program. Safety was assessed by measuring knee pain, thigh pain, knee effusion, and knee stability prior to surgery and at 3,15, and 26 weeks after surgery. Efficacy was assessed by measuring negative work output during the 12-week training program and by measuring functional ability (ie, quadriceps peak torque, hopping distance, self-reported functional ability and activity level scales) prior to surgery and 26 weeks after ACL-R. RESULTS:There were no significant differences between groups in measures of knee and thigh pain, effusion, or stability at any period after surgery. Negative work output increased systematically throughout training, while knee and thigh pain remained at relatively low levels. A significant group-by-time interaction was observed for quadriceps peak torque, hopping distance, and activity level (P< or =.02). Quadriceps strength and hopping distance of the involved limb improved by a significantly greater amount in the ECC group compared to the TRAD group (P<.01). Activity level decreased to a lesser extent in the ECC group compared to the TRAD group (P =.02). CONCLUSIONS:Negative work via an ECC intervention was implemented safely after ACL-R. The addition of negative work exercise also induced superior short-term results in strength, performance, and activity level after surgery. 10.2519/jospt.2007.2362
    The use of eccentrically biased resistance exercise to mitigate muscle impairments following anterior cruciate ligament reconstruction: a short review. Gerber J Parry,Marcus Robin L,Leland E Dibble,Lastayo Paul C Sports health BACKGROUND:Novel interventions that can safely and effectively overload muscle early following anterior cruciate ligament reconstruction are needed to minimize atrophy and weakness that often becomes longstanding. EVIDENCE ACQUISITION:Eccentrically induced forces can be safely applied during the early stages of rehabilitation following surgery and serve as a potent stimulus for increasing muscle size and strength. RESULTS:Compared to a standard rehabilitation program, adding an early 12-week eccentric resistance-training program 3 weeks after anterior cruciate ligament reconstruction induces improvement in quadriceps and gluteus maximus volume at 15 weeks and at 1 year after surgery. Likewise, those who performed an eccentrically biased rehabilitation program also achieved greater improvements in quadriceps strength and hopping ability measured at 15 weeks and at 1 year after surgery. CLINICAL RELEVANCE:There is potential to safely and feasibly perform eccentric contractions as part of a formal rehabilitation program following anterior cruciate ligament reconstruction. 10.1177/1941738108327531
    Neuromuscular Electrical Stimulation Superimposed on Movement Early after ACL Surgery. Labanca Luciana,Rocchi Jacopo Emanuele,Laudani Luca,Guitaldi Rita,Virgulti Alessandro,Mariani Pier Paolo,Macaluso Andrea Medicine and science in sports and exercise PURPOSE:Quadriceps weakness and asymmetrical loading of lower limbs are two major issues after anterior cruciate ligament reconstruction (ACLR). The aim of this study was to evaluate the effectiveness of a 6-wk training protocol involving neuromuscular electrical stimulations (NMES) of the quadriceps muscle superimposed on repeated sit-to-stand-to-sit exercises (STSTS), as an additional treatment to standard rehabilitation, from the 15th to the 60th day after ACLR. METHODS:Sixty-three ACLR patients were randomly allocated to one of the three treatment groups: NMES superimposed on STSTS (NMES + STSTS), STSTS only, or no additional treatment (NAT) to standard rehabilitation. Maximal isometric strength of the knee extensor and flexor muscles was measured 60 and 180 d after surgery. Asymmetry in lower extremity loading was measured during a sit-to-stand movement at 15, 30, 60, and 180 d after surgery and during a countermovement jump 180 d after surgery by means of two adjacent force platforms placed under each foot. RESULTS:The NMES + STSTS participants showed higher muscle strength of the knee extensors, which was accompanied by lower perception of pain and higher symmetry in lower extremity loading compared with STSTS-only and NAT participants after both 60 and 180 d from surgery. Participants in the STSTS-only treatment group showed higher symmetry in lower extremity loading compared with those in the NAT group 60 d after surgery. CONCLUSIONS:These results suggest that an early intervention based on NMES superimposed to repeated STSTS exercises is effective for recovering quadriceps strength and symmetry in lower extremity loading by the time of return to sport. 10.1249/MSS.0000000000001462
    Effects of early progressive eccentric exercise on muscle structure after anterior cruciate ligament reconstruction. Gerber J Parry,Marcus Robin L,Dibble Leland E,Greis Patrick E,Burks Robert T,LaStayo Paul C The Journal of bone and joint surgery. American volume BACKGROUND:Thigh muscle atrophy is a major impairment that occurs early after reconstruction of the anterior cruciate ligament and persists for several years. Eccentric resistance training has the potential to induce considerable gains in muscle size and strength that could prove beneficial during postoperative rehabilitation. The purpose of this study was to evaluate the effects of progressive eccentric exercise on thigh muscle structure following reconstruction of the anterior cruciate ligament. METHODS:Beginning three weeks after reconstruction of the anterior cruciate ligament, forty patients were randomly assigned to a program involving either twelve weeks of eccentric exercises or a standard rehabilitation protocol. Patients were matched by surgical procedure, sex, and age. The final series consisted of two cohorts of twenty patients each who had been treated with one of two types of graft (semitendinosus-gracilis or bone-patellar tendon-bone), with ten patients treated with each of the two rehabilitation protocols in each graft cohort. To evaluate changes in muscle structure, magnetic resonance images of the involved and uninvolved thighs were acquired before and after training. The volume and peak cross-sectional area of the quadriceps, hamstrings, and gracilis and the distal portion of the gluteus maximus were calculated from these images. RESULTS:The volume and peak cross-sectional area of the quadriceps and gluteus maximus, in both the involved and the uninvolved thighs and in the patients treated with each type of graft, improved significantly more in the eccentric-exercise group (p < 0.001). The magnitude of the volume change was more than twofold greater in that group. No significant differences in any hamstring or gracilis structural measurements were observed between the rehabilitation groups. However, the volume and peak cross-sectional area of the gracilis were markedly reduced, compared with the pretraining values, in the patients who had undergone reconstruction with the semitendinosus-gracilis graft. CONCLUSIONS:Eccentric resistance training implemented three weeks after reconstruction of the anterior cruciate ligament can induce structural changes in the quadriceps and gluteus maximus that greatly exceed those achieved with a standard rehabilitation protocol. The success of this intervention can be attributed to the gradual and progressive exposure to negative work through eccentric exercise, ultimately leading to production of high muscle force. 10.2106/JBJS.F.00385
    Quadriceps function in anterior cruciate ligament-deficient knees exercising with transcutaneous electrical nerve stimulation and cryotherapy: a randomized controlled study. Hart Joseph M,Kuenze Christopher M,Pietrosimone Brian G,Ingersoll Christopher D Clinical rehabilitation OBJECTIVE:To compare strength and quadriceps muscle activation in anterior cruciate ligament-deficient patients who underwent a two-week rehabilitation exercise program using TENS or cryotherapy. DESIGN:Randomized, controlled study. SETTING:Clinical research laboratory. SUBJECTS:Thirty patients: 20 males, 10 females, 31.6 (13.0) years, 172.8 (10.0) cm, 75.8 (13.0) kg with diagnosed tear of the anterior cruciate ligament. INTERVENTIONS:All patients attended four sessions of supervised quadriceps strengthening exercises over two weeks, prior to reconstruction surgery. Patients were randomly allocated (n = 10/group) to receive exercises alone, exercise while wearing a sensory transcutaneous electrical nerve stimulation (TENS) device on the knee joint for the duration of each daily session, or 20 minutes of knee joint cryotherapy immediately prior to each daily exercise session. MAIN MEASURES:Normalized knee extension force and quadriceps central activation ratio were measured before and after the first supervised treatment session and within 24 hours of the last session. RESULTS:When accounting for differences in baseline measures, there were no statistically significant group differences immediately following the first exercise session for knee extension force (P = 0.10) or central activation ratio (P = 0.30) nor were there statistically significant group differences after the two-week intervention for knee extension force (P = 0.92) or central activation ratio (P = 0.94). Effect sizes for the change in knee extension force and central activation ratio after two weeks of therapy were all large. CONCLUSIONS:Quadriceps strength and central activation in anterior cruciate ligament deficient patients improved after two weeks of rehabilitaiton exercises, however, there were no significant differences between treatment groups. 10.1177/0269215512438272
    Quadriceps Strength Predicts Self-reported Function Post-ACL Reconstruction. Pietrosimone Brian,Lepley Adam S,Harkey Matthew S,Luc-Harkey Brittney A,Blackburn J Troy,Gribble Phillip A,Spang Jeffrey T,Sohn David H Medicine and science in sports and exercise INTRODUCTION/PURPOSE:Quadriceps strength is a useful clinical predictor of self-reported function after anterior cruciate ligament reconstruction (ACLR). However, it remains unknown if quadriceps strength normalized to body mass (QBM) or quadriceps strength limb symmetry index (QLSI) is the best predictor of self-reported function in individuals with ACLR. We sought to determine whether QBM and QLSI are able to predict individuals with ACLR who self-report high function (≥90% on the international knee documentation committee (IKDC) index). METHODS:Ninety-six individuals with a history of a primary unilateral ACLR were recruited for a multisite cross-sectional descriptive laboratory experiment. Bilateral isometric quadriceps strength was collected at 90° of knee flexion to calculate QBM and QLSI (ratio of the ACLR limb to the contralateral limb). Area under the curve (AUC) values were calculated using receiver operating characteristic curve analyses to determine the capacity of QBM and QLSI to predict individuals with high self-reported function on the IKDC index. RESULTS:QBM displayed high accuracy (AUC = 0.76; 95% confidence interval, 0.66-0.86) for identifying participants with an IKDC index ≥90%. A QBM cutoff score of 3.10 N·m·kg was found to maximize sensitivity (0.61) and specificity (0.84), and displayed 8.15 (3.09-21.55) times higher odds of reporting high function. QLSI displayed a moderate accuracy (AUC = 0.62, 0.50-0.73) for identifying participants with an IKDC index ≥90%. A QLSI cutoff score of 96.5% maximized sensitivity (0.55) and specificity (0.70), and represented 2.78 (1.16-6.64) times higher odds reporting high function. CONCLUSION:QBM is a stronger predictor of high self-reported function compared with QLSI in individuals with ACLR. Rehabilitation guidelines may benefit from incorporating the use of QBM measurements for the purpose of predicting participants that may maintain high self-reported function. 10.1249/MSS.0000000000000946
    Quadriceps function following ACL reconstruction and rehabilitation: implications for optimisation of current practices. Gokeler Alli,Bisschop Marsha,Benjaminse Anne,Myer Greg D,Eppinga Peter,Otten Egbert Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA PURPOSE:To determine the most effective practices for quadriceps strengthening after ACL reconstruction. METHODS:An electronic search has been performed for the literature appearing from January 1990 to January 2012. Inclusion criteria were articles written in English, German or Dutch with unilateral ACL-reconstructed patients older than 13 years, RCT rehabilitation programmes containing muscle strengthening, protocol described in detail and time frame of measurements reported. Quadriceps muscle strength and patient-reported outcomes were the endpoints. Included studies were assessed on their methodological quality using the CONSORT Checklist. RESULTS:From 645 identified studies, 10 met the inclusion criteria. Seven studies found an increase in quadriceps strength after intervention programmes regardless of type of training. An eccentric exercise programme showed significantly better values for isometric quadriceps strength compared to a concentric exercise programme. The Tegner activity scale showed a significant increase in activity level for all training programmes. The Cincinnati Knee Rating System showed significant improvements in particular for the neuromuscular training group. CONCLUSIONS:The evidence from this review indicates that eccentric training may be most effective to restore quadriceps strength, but full recovery may not be achieved with current rehabilitation practices. Neuromuscular training incorporating motor learning principles should be added to strengthening training to optimise outcome measurements. LEVEL OF EVIDENCE:II. 10.1007/s00167-013-2577-x
    Effects of neuromuscular electrical stimulation after anterior cruciate ligament reconstruction on quadriceps strength, function, and patient-oriented outcomes: a systematic review. Kim Kyung-Min,Croy Ted,Hertel Jay,Saliba Susan The Journal of orthopaedic and sports physical therapy STUDY DESIGN:Systematic literature review. OBJECTIVE:To perform a systematic review of randomized controlled trials assessing the effects of neuromuscular electrical stimulation (NMES) on quadriceps strength, functional performance, and self-reported function after anterior cruciate ligament reconstruction. BACKGROUND:Conflicting evidence exists regarding the effectiveness of NMES following anterior cruciate ligament reconstruction. METHODS:Searches were performed for randomized controlled trials using electronic databases from 1966 through October 2008. Methodological quality was assessed using the Physiotherapy Evidence Database Scale. Between-group effect sizes and 95% confidence intervals (CIs) were calculated. RESULTS:Eight randomized controlled trials were included. The average Physiotherapy Evidence Database Scale score was 4 out of possible maximum 10. The effect sizes for quadriceps strength measures (isometric or isokinetic torque) from 7 studies ranged from -0.74 to 3.81 at approximately 6 weeks postoperatively; 6 of 11 comparisons were statistically significant, with strength benefits favoring NMES treatment. The effect sizes for functional performance measures from 1 study ranged from 0.07 to 0.64 at 6 weeks postoperatively; none of 3 comparisons were statistically significant, and the effect sizes for self-reported function measures from 1 study were 0.66 and 0.72 at 12 to 16 weeks postoperatively; both comparisons were statistically significant, with benefits favoring NMES treatment. CONCLUSION:NMES combined with exercise may be more effective in improving quadriceps strength than exercise alone, whereas its effect on functional performance and patient-oriented outcomes is inconclusive. Inconsistencies were noted in the NMES parameters and application of NMES. LEVEL OF EVIDENCE:Therapy, level 1a-. 10.2519/jospt.2010.3184
    Neuromuscular Electrical Stimulation Therapy to Restore Quadriceps Muscle Function in Patients After Orthopaedic Surgery: A Novel Structured Approach. Spector Paul,Laufer Yocheved,Elboim Gabyzon Michal,Kittelson Andrew,Stevens Lapsley Jennifer,Maffiuletti Nicola A The Journal of bone and joint surgery. American volume 10.2106/JBJS.16.00192
    Strength Training Effects on Muscular Regeneration after ACL Reconstruction. Friedmann-Bette Birgit,Profit Francesca,Gwechenberger Thomas,Weiberg Nadine,Parstorfer Mario,Weber Marc-André,Streich Nikolaus,Barié Alexander Medicine and science in sports and exercise PURPOSE:Protracted quadriceps muscle atrophy is observed after anterior cruciate ligament reconstruction (ACL-R). The aim of this study was to assess if quadriceps strength training with eccentric overload (CON/ECC) is more efficient to induce muscle regeneration after ACL-R than conventional concentric/eccentric (CON/ECC) strength training. METHODS:Biopsies from the vastus lateralis muscle were obtained from 37 recreational athletes after 12 wk of regular rehabilitation after ACL-R and again after 12 wk with twice a week of either conventional CON/ECC (n = 16) or CON/ECC (n = 21) one-legged supervised leg-press training. Immunohistochemical analyses were used to determine satellite cell (SC) number (Pax7); activated SC number (Pax7/MyoD); fibers expressing myosin heavy-chain (MHC) I and II, MHC neonatal, and fiber cross-sectional area. Magnetic resonance imaging was performed to measure quadriceps cross-sectional area and isokinetic testing for the measurement of quadriceps strength. RESULTS:CON/ECC induced a significantly (P = 0.002) greater increase in quadriceps cross-sectional area than did CON/ECC. There also was a significant increase in the fiber cross-sectional areas of all fiber types and in quadriceps strength, but without significant difference between training groups. Only CON/ECC training led to a significant (P < 0.05) increase in percent type I fibers. After training, the number of MHC I/MHCneo fibers was significantly (P < 0.05) greater in the CON/ECC than after in the CON/ECC group. The proportion of hybrid fibers tended to decrease in both groups; percent type II fibers, SC number, and activated SC number remained unchanged. CONCLUSIONS:CON/ECC leads to significantly greater muscle hypertrophy compared with CON/ECC, but without the hypothesized enhancing effect on SC activation. At the same time, CON/ECC+ induces a less favorable slower muscle phenotype for strong and fast movements. 10.1249/MSS.0000000000001564
    Open kinetic chain exercises in a restricted range of motion after anterior cruciate ligament reconstruction: a randomized controlled clinical trial. Fukuda Thiago Yukio,Fingerhut Deborah,Moreira Viviane Coimbra,Camarini Paula Maria Ferreira,Scodeller Nathalia Folco,Duarte Aires,Martinelli Mauro,Bryk Flavio Fernandes The American journal of sports medicine BACKGROUND:Recent studies have shown that an early start of open kinetic chain (OKC) exercises for quadriceps strengthening in a full range of motion (ROM) could increase anterior knee laxity after anterior cruciate ligament (ACL) reconstruction with flexor tendons. However, there are no clinical trials that evaluated outcomes of OKC exercises in a restricted ROM for pain, function, muscle strength, and anterior knee laxity at 1 year after surgery. PURPOSE:To determine if an early start of OKC exercises for quadriceps strength in a restricted ROM would promote a clinical improvement without causing increased anterior knee laxity in patients after ACL reconstruction. STUDY DESIGN:Randomized controlled clinical trial; Level of evidence, 1. METHODS:A total of 49 patients between 16 and 50 years of age who underwent ACL reconstruction with semitendinosus and gracilis autografts were randomly assigned to an early start OKC (EOKC) exercise group or a late start OKC (LOKC) exercise group. The EOKC group (n = 25; mean age, 26 years) received a rehabilitation protocol with an early start of OKC (fourth week postoperatively) within a restricted ROM between 45° and 90°. The LOKC group (n = 24; mean age, 24 years) performed the same protocol with a late start of OKC exercises between 0° and 90° (12th week postoperatively). Quadriceps and hamstring muscle strength, 11-point numerical pain rating scale (NPRS), Lysholm knee scoring scale, single-legged and crossover hop tests, and anterior knee laxity were measured to assess outcomes at the 12-week, 19-week, 25-week, and 17-month postoperative follow-up (range, 13-24 months). RESULTS:No difference (P < .05) was noted between groups with respect to demographic data. Both groups (EOKC and LOKC) had a higher level of function and less pain at the 19-week, 25-week, and 17-month assessments when compared with 12 weeks postoperatively (P < .05). The EOKC group had improved quadriceps muscle strength at the 19-week, 25-week, and 17-month follow-up when compared with 12 weeks postoperatively (P < .05); the LOKC group showed improvement only at the 17-month postoperative assessment. However, the analysis between groups showed no difference for all pain and functional assessments, including anterior knee laxity (P > .05). CONCLUSION:An early start of OKC exercises for quadriceps strengthening in a restricted ROM did not differ from a late start in terms of anterior knee laxity. The EOKC group reached the same findings in relation to pain decrease and functional improvement when compared with the LOKC group but showed a faster recovery in quadriceps strength. The nonweightbearing exercises seem appropriate for patients who have undergone ACL reconstruction, when utilized in a specific ROM. The magnitude of difference in quadriceps strength between the 2 rehabilitation protocols was around 5%; however, this difference was not clinically significant, especially because both groups had equal function on the hop tests. 10.1177/0363546513476482
    Isokinetic eccentric training is more effective than constant load eccentric training for quadriceps rehabilitation following anterior cruciate ligament reconstruction: a randomized controlled trial. Vidmar Marlon Francys,Baroni Bruno Manfredini,Michelin Alexandre Fróes,Mezzomo Márcio,Lugokenski Ricardo,Pimentel Gilnei Lopes,Silva Marcelo Faria Brazilian journal of physical therapy OBJECTIVE:To compare the effects of conventional (constant load) eccentric training and isokinetic eccentric training on quadriceps muscle mass, strength and functional performance in recreational athletes following anterior cruciate ligament (ACL) reconstruction. METHODS:Thirty recreational male athletes (25 years old) undergoing ACL reconstruction received a standard rehabilitation program. Volunteers were randomized to conventional group (CG; n = 15) or isokinetic group (IG; n = 15) to be engaged in a 6-week (2 sessions/week) quadriceps eccentric training program at the extensor chair or at the isokinetic dynamometer, respectively. Assessments of quadriceps muscle mass (through magnetic resonance imaging), strength (through isokinetic dynamometry) and self-aware functionality (through questionnaire) were performed before and after the training programs. Single leg hop test performance was assessed only at post-training evaluation. RESULTS:IG had significantly higher improvements than CG (p < 0.05) for all muscle mass outcomes (+17-23% vs. +5-9%), as well as for isometric (+34% vs. +20%) and eccentric (+85% vs. +23%) peak torques. There was no between-group difference (p > 0.05) for concentric peak torque, Lysholm score, and single leg hop test. CONCLUSION:Isokinetic eccentric training promotes greater responses than conventional eccentric training on quadriceps muscle mass and strength of recreational athletes following ACL reconstruction. 10.1016/j.bjpt.2019.07.003
    Effects of early progressive eccentric exercise on muscle size and function after anterior cruciate ligament reconstruction: a 1-year follow-up study of a randomized clinical trial. Gerber J Parry,Marcus Robin L,Dibble Leland E,Greis Patrick E,Burks Robert T,LaStayo Paul C Physical therapy BACKGROUND AND PURPOSE:The authors previously reported that focused eccentric resistance training during the first 15 weeks following anterior cruciate ligament reconstruction (ACL-R) induced greater short-term increases in muscle volume, strength, and measures of function relative to standard rehabilitation. The purpose of this study was to evaluate the effects of early progressive eccentric exercise on muscle volume and function at 1 year after ACL-R. PARTICIPANTS AND METHODS:Forty patients who had undergone an ACL-R were randomly assigned to 1 of 2 groups: a group that received early progressive eccentric exercise (n=20) and a group that received standard rehabilitation (n=20). Seventeen participants in the eccentric exercise group and 15 participants in the standard rehabilitation group completed a 1-year follow-up. Magnetic resonance images of the thighs were acquired 1 year after ACL-R and compared with images acquired 3 weeks after surgery. Likewise, routine knee examinations, self-report assessments, and strength and functional testing were completed 1 year after surgery and compared with previous evaluations. A 2-factor analysis of variance for repeated measures (group x time) was used to analyze the data. RESULTS:Compared with the standard rehabilitation group, improvements in quadriceps femoris and gluteus maximus muscle volume in the involved lower extremity from 3 weeks to 1 year following ACL-R were significantly greater in the eccentric exercise group. Improvements in quadriceps femoris and gluteus maximus muscle volume were 23.3% (SD=14.1%) and 20.6% (SD=12.9%), respectively, in the eccentric exercise group and 13.4% (SD=10.3%) and 11.6% (SD=10.4%), respectively, in the standard rehabilitation group. Improvements in quadriceps femoris muscle strength and hopping distance also were significantly greater in the eccentric exercise group 1 year postsurgery. DISCUSSION AND CONCLUSION:A 12-week focused eccentric resistance training program, implemented 3 weeks after ACL-R, resulted in greater increases in quadriceps femoris and gluteus maximus muscle volume and function compared with standard rehabilitation at 1 year following ACL-R. 10.2522/ptj.20070189
    Young Athletes Who Return to Sport Before 9 Months After Anterior Cruciate Ligament Reconstruction Have a Rate of New Injury 7 Times That of Those Who Delay Return. Beischer Susanne,Gustavsson Linnéa,Senorski Eric Hamrin,Karlsson Jón,Thomeé Christoffer,Samuelsson Kristian,Thomeé Roland The Journal of orthopaedic and sports physical therapy OBJECTIVE:To investigate the association between sustaining a second anterior cruciate ligament (ACL) injury and (1) time to return to sport, (2) symmetrical muscle function, and (3) symmetrical quadriceps strength at the time of return to sport in young athletes after primary ACL reconstruction. DESIGN:Prospective cohort study. METHODS:Patient demographics and results from 5 tests of muscle function (2 strength tests and 3 hop tests) were extracted from a rehabilitation registry. A questionnaire was sent to athletes (15-30 years old) who were involved in knee-strenuous sport before the injury and had undergone primary ACL reconstruction to determine time of return to knee-strenuous sport (preinjury Tegner Activity Scale score of 6 or greater). We used the Cox proportional hazard regression model to analyze time to event. RESULTS:One hundred fifty-nine (32% of the initial sample) athletes (mean ± SD age, 21.5 ± 4.4 years; 64% female) were included. Athletes with a higher preinjury Tegner Activity Scale score had a higher rate of second ACL injury (hazard ratio = 2.1; 95% confidence interval: 1.2, 3.6; <.01). Athletes who returned to knee-strenuous sport before 9 months after reconstruction had a higher rate of second ACL injury (hazard ratio = 6.7; 95% confidence interval: 2.6, 16.7; <.001). There was no association between symmetrical muscle function or quadriceps strength and second ACL injury. CONCLUSION:Returning to knee-strenuous sport before 9 months after ACL reconstruction was associated with an approximately 7-fold increased rate of sustaining a second ACL injury. Achieving symmetrical muscle function or quadriceps strength was not associated with new ACL injury in young athletes. . 10.2519/jospt.2020.9071
    Exercise with Blood Flow Restriction to Improve Quadriceps Function Long After ACL Reconstruction. Kilgas Matthew A,Lytle Lydia L M,Drum Scott N,Elmer Steven J International journal of sports medicine Quadriceps atrophy and weakness can persist for years after anterior cruciate ligament reconstruction (ACLR). We evaluated the effectiveness of a home-based blood flow restriction (BFR) exercise program to increase quadriceps size and strength several years after ACLR. Nine adults with ACLR (5±2 yrs post-surgery, ≤90% symmetry in quadriceps size and strength) and nine uninjured controls volunteered. ACLR participants exercised at home for 25 min, 5×/wk for 4 wks (single-leg knee extension, bodyweight half-squats, walking). Blood flow in only the involved leg was restricted using a thigh cuff inflated to 50% of limb occlusion pressure. Rectus femoris and vastus lateralis thickness and knee extensor strength were measured before and after training. Baseline and post-training symmetry (involved leg/uninvolved leg) indices were compared to uninjured controls. Rectus femoris and vastus lateralis thickness and knee extensor strength in the involved leg increased by 11±5%, 10±6%, and 20±14%, respectively (all P<0.01). Compared to baseline, post-training knee extensor strength symmetry increased from 88±4 to 99±5% (P<0.01) and did not differ from uninjured controls (99±5%, P=0.95). Implementation of BFR exercise at home was feasible, safe and effective. Results extend upon early post-operative application of BFR exercise for ACLR recovery and demonstrate that BFR can improve quadriceps function long after ACLR. 10.1055/a-0961-1434
    Cross-education improves quadriceps strength recovery after ACL reconstruction: a randomized controlled trial. Harput Gulcan,Ulusoy Burak,Yildiz Taha Ibrahim,Demirci Serdar,Eraslan Leyla,Turhan Egemen,Tunay Volga Bayrakci Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA PURPOSE:The aim of this study was to investigate the effects of concentric and eccentric cross-education (CE) on quadriceps strength and knee function recoveries after anterior cruciate ligament (ACL) reconstruction. METHODS:Forty-eight patients (age: 29.5 ± 6.8 years, body mass index: 26.1 ± 3.2 kg/m) who had undergone ACL reconstruction with hamstring tendon autograft were included in the study. The patients were randomly divided into three groups when they reached four weeks post surgery: (1) concentric CE (n = 16); (2) eccentric CE (n = 16); and (3) control (n = 16). All groups followed the same post-surgical rehabilitation program for their reconstructed limb. Additionally, the two experimental groups followed eight weeks of isokinetic training for the uninjured knee at 60°/s for 3 days per week. Quadriceps maximum voluntary isometric strength (MVIC) was measured during the 4th week (pre-training), 12th week (post training), and 24th week post surgery. The single-leg hop distance and International Knee Documentary Committee (IKDC) scores were also evaluated during the 24th week post surgery. Analysis of variance was used for statistical analysis. RESULTS:Group-by-time interaction was significant for quadriceps MVICs for reconstructed and healthy limbs (p = 0.02). Quadriceps strength of both knees was greater in concentric and eccentric CE groups compared to control group during the 12th- and 24th weeks post surgery (p < 0.05). Strength gain was 28% and 31% in concentric and eccentric CE groups, respectively, when compared with the control group. Concentric and eccentric CE had similar effects on quadriceps strength recovery (n.s.). IKDC score, and single-leg hop distances were not significantly different among groups (n.s.). CONCLUSIONS:Concentric and eccentric quadricep strengthening of healthy limbs in early phases of ACL rehabilitation improved post-surgical quadriceps strength recovery of the reconstructed limb. CE should be integrated into ACL reconstruction rehabilitation, especially in the early rehabilitative phases to restore quadriceps strength. LEVEL OF EVIDENCE:Randomized controlled trial, Level I. 10.1007/s00167-018-5040-1
    Immediate effects of Kinesio Taping(®) on neuromuscular performance of quadriceps and balance in individuals submitted to anterior cruciate ligament reconstruction: A randomized clinical trial. Oliveira Araken K A,Borges Daniel T,Lins Caio A A,Cavalcanti Rafael L,Macedo Liane B,Brasileiro Jamilson S Journal of science and medicine in sport OBJECTIVES:Investigate the immediate effects of Kinesio Taping(®) on neuromuscular performance of femoral quadriceps and balance in individuals submitted to anterior cruciate ligament reconstruction. DESIGN:This is a randomized clinical trial. METHODS:Forty-seven male participants, between 12 and 17 weeks after anterior cruciate ligament reconstruction, underwent initial assessment consisting of postural balance analysis using baropodometry, followed by eccentric and concentric isokinetic assessment at 60°/s of knee extensors, concomitant to electromyographic signals captured from the vastus lateralis muscle. They were then randomly allocated to one of the following groups: control, placebo and Kinesio Taping(®). Kinesio Taping(®) group participants were submitted to Kinesio Taping(®) on the femoral quadriceps of the affected limb, while placebo group subjects used the same procedure without the tension proposed by the method. The control group remained at rest for 10min. All participants were reassessed following the same procedure as the initial evaluation. The following variables were analyzed: peak torque/body weight and muscle potential using dynamometry; amplitude of antero-posterior and latero-lateral displacement from the center of pressure using baropodometry; and amplitude of muscle activation (root mean square) applying surface electromyography. RESULTS:None of the variables analyzed showed significant intergroup or intragroup differences. CONCLUSIONS:Kinesio Taping(®) does not alter the neuromuscular performance of femoral quadriceps or balance of subjects submitted to anterior cruciate ligament reconstruction, for any of the variables analyzed. 10.1016/j.jsams.2014.12.002
    Femoral Nerve Block versus Intra-Articular Infiltration: A Preliminary Study of Analgesic Effects and Quadriceps Strength in Patients Undergoing Arthroscopic Anterior Cruciate Ligament Reconstruction. Iamaroon Arissara,Tamrongchote Suwitcha,Sirivanasandha Busara,Halilamien Pathom,Lertwanich Pisit,Surachetpong Sudkanoung,Rungwattanakit Paweenus Journal of the Medical Association of Thailand = Chotmaihet thangphaet BACKGROUND:Adequate analgesia and early rehabilitation is necessary for arthroscopic anterior cruciate ligament reconstruction (A CLR) surgery. OBJECTIVE:To compare analgesia and quadriceps strength after femoral nerve block (FNB) with intra-articular infiltration (IA) using 0.25% bupivacaine for ACLR with patella tendon graft. MATERIAL AND METHOD:Forty patients were randomized to receive FNB under ultrasound guidance with 20 mL of bupivacaine or IA with 15 mL of bupivacaine into the knee joint and 5 mL infiltrated along the incision sites including portal sites at the end of surgery. All patients received intravenous ketorolac at wound closure. Data regarding demographic, time to first pain, time to first morphine requirement, morphine usage, pain scores and quadriceps strength were recorded. RESULTS:Significant difference in quadriceps strength was shown. Ninety percent of patients in Group IA and fifty-five percent of patients in Group FNB had good ability to extend knee at 24 hours after surgery (p = 0.013). No differences were found in demographic data, time to first pain, time to first morphine requirement, post operative pain scores and morphine consumption, CONCLUSION:The preliminary results demonstrated that IA has an effect on quadriceps strength less than FNB while provide comparable postoperative analgesia after patellar tendon graft ACLR.
    Whole-Body Vibration on Performance of Quadriceps After ACL Reconstruction: A Blinded Randomized Controlled Trial. da Costa Karinna Sonálya Aires,Borges Daniel Tezoni,de Brito Macedo Liane,de Almeida Lins Caio Alano,Brasileiro Jamilson Simões Journal of sport rehabilitation CONTEXT:Whole-body vibration (WBV) has been widely used in clinical and sport practice. These devices produce constant vibrations, originating symmetrical waves that move along the vertical axis. It is suggested that mechanical stimuli produced by high vibration can be an alternative to improve neuromuscular performance and balance in different populations. However, there is still a lack of consensus in the literature regarding neurophysiological responses in the skeletal muscle immediately after the use of WBV, specifically in individuals subjected to anterior cruciate ligament reconstruction. OBJECTIVE:To investigate the immediate effects of WBV on neuromuscular performance of the quadriceps femoris and postural oscillation of individuals subjected to anterior cruciate ligament reconstruction. DESIGN:This is a blinded randomized controlled trial. SETTING:University laboratory. PARTICIPANTS:Forty-four men. INTERVENTION:Participants were randomized into 2 groups: control group (n = 22, exercise protocol on the vibrating platform turned off) and WBV group (n = 22, exercises on the vibrating platform turned on, at a frequency of 50 Hz and amplitude of 4 mm). MAIN OUTCOME MEASURES:The volunteers underwent a dynamometric evaluation of the quadriceps femoris and electromyographic activity of vastus lateralis and vastus medialis muscles, in addition to oscillation of the center of pressure at 2 different moments: before and immediately after the intervention protocol. RESULTS:The intragroup comparison evidenced differences between preassessments and postassessments for the variables of laterolateral amplitude, peak torque, and total work. However, no significant difference was observed in the intergroup comparison after WBV protocol. CONCLUSION:The use of WBV did not immediately alter the performance of the quadriceps femoris and the electromyographic activity of vastus lateralis and vastus medialis muscles. In addition, it also did not interfere with pressure center oscillation of individuals subjected to anterior cruciate ligament reconstruction. 10.1123/jsr.2017-0063
    [Effect of isokinetic training of thigh muscle group on graft remodeling after anterior cruciate ligament reconstruction]. Liu Haifeng,Lu Wei,Liang Daqiang,Geng Hongli,Zhu Weimin,Ouyang Kan,Li Hao,Peng Liangquan,Feng Wenzhe,Zhong Mingjin,Chen Kang,Li Ying,Deng Zhenhan,Wang Daping Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery Objective:To investigate the effect of isokinetic training of thigh muscle group on graft remodeling after anterior cruciate ligament (ACL) reconstruction, and summarize the relevant rules to guide the clinic. Methods:Between August 2016 and December 2016, forty patients underwent arthroscopic ACL reconstruction using hamstring tendon were randomly divided into isokinetic group and control group ( =20). The two groups of patients underwent staged rehabilitation treatment. The isokinetic group replaced the traditional intervention with the corresponding isokinetic strength training from 3 to 6 months after operation, and the traditional rehabilitation intervention was used in the control group. Finally, 12 cases of isokinetic group and 12 cases of control group with complete follow-up were enrolled in study. There was no significant difference in gender, age, body mass index, side of injury, the interval between injury and operation, and preoperative International Knee Documentation Committee (IKDC) score between the two groups ( >0.05). The peak torque (PT) of knee extension and flexion and hamstring quadriceps ratio (H/Q) were measured at 3 months, 6 months, 12 months, and the second-look arthroscopy. The MRI examination was performed at the same time to evaluate graft remodeling. The shape, tension, and degree of vascularization of grafts were observed under arthroscopy. The grafts were harvested and observed by HE staining. Results:The invertal between ACL reconstruction and the second-look arthroscopy was (23.57±3.23) months in isokinetic group and (23.22±3.56) months in control group, showing no significant difference between the two groups ( >0.05). At the second-look arthroscopy, the IKDC score was 90.45±4.73 in isokinetic group and 89.32±4.54 in control group, showing significant differences when compared with preoperative scores in the two groups ( <0.05). But there was no significant difference between the two groups ( =0.868, =0.404). At 3 months after operation, there was no significant difference in the PT of knee extension and flexion between the two groups ( >0.05). At 6 months, 12 months, and the second-look arthroscopy, the PT of knee extension and flexion in isokinetic group were higher than those in control group ( <0.05). The H/Q at 6 months and 12 months were higher in isokinetic group than in control group, and the differences were significant ( <0.05). There was no significant difference in MRI score between the two groups at 3 months, 6 months, and the second-look arthroscopy ( >0.05). The MRI score at 12 months was significantly higher in isokinetic group than in control group ( <0.05). At the second-look arthroscopy, there was no significant difference in the arthroscopic score between the two groups ( >0.05), and the histological score of the isokinetic group was superior to the control group ( <0.05). Conclusion:On the basis of regular rehabilitation training, using the isokinetic training system to develop a suitable post-surgical isokinetic rehabilitation training program is helpful in early muscle strength recovery, early graft remodeling, and even long-term histological results after ACL reconstruction. 10.7507/1002-1892.201902059
    Unilateral Quadriceps Strengthening With Disinhibitory Cryotherapy and Quadriceps Symmetry After Anterior Cruciate Ligament Reconstruction. Kuenze Christopher M,Kelly Adam R,Jun Hyung-Pil,Eltoukhy Moataz Journal of athletic training CONTEXT:  The effect of unilateral cryotherapy-facilitated rehabilitation exercise on involved-limb quadriceps function and limb symmetry in individuals with quadriceps dysfunction after anterior cruciate ligament reconstruction (ACLR) remains unclear. OBJECTIVE:  To measure the effect of a 2-week unilateral cryotherapy-facilitated quadriceps-strengthening program on knee-extension strength and quadriceps central activation ratio (CAR) in participants with ACLR. DESIGN:  Controlled laboratory study. SETTING:  Laboratory. PATIENTS OR OTHER PARTICIPANTS:  A total of 10 volunteers with unilateral ACLR (1 man, 9 women; age = 21.0 ± 2.8 years, height = 164.6 ± 5.0 cm, mass = 64.0 ± 6.1 kg, body mass index = 23.7 ± 2.7 kg/m) and 10 healthy volunteers serving as control participants (1 man, 9 women; age = 20.8 ± 2.5 years, height = 169.1 ± 6.2 cm, mass = 61.1 ± 6.4 kg, body mass index = 21.4 ± 2.3 kg/m) participated. INTERVENTION(S):  Participants with ACLR completed a 2-week unilateral cryotherapy-facilitated quadriceps-strengthening intervention. MAIN OUTCOME MEASURE(S):  Bilateral normalized knee-extension maximal voluntary isometric contraction (MVIC) torque (Nm/kg) and quadriceps CAR (%) were assessed preintervention and postintervention. Limb symmetry index (LSI) was calculated at preintervention and postintervention testing. Preintervention between-groups differences in unilateral quadriceps function and LSI were evaluated using independent-samples t tests. Preintervention-to-postintervention differences in quadriceps function were evaluated using paired-samples t tests. Cohen d effect sizes (95% confidence interval [CI]) were calculated for each comparison. RESULTS:  Preintervention between-groups comparisons revealed less knee-extension MVIC torque and quadriceps CAR for the ACLR limb (MVIC: P = .01, Cohen d = -1.31 [95% CI = -2.28, -0.34]; CAR: P = .004, Cohen d = -1.48 [95% CI = -2.47, -0.49]) and uninvolved limb (MVIC: P = .03, Cohen d = -1.05 [95% CI = -1.99, -0.11]; CAR: P = .01, Cohen d = -1.27 [95% CI = -2.23, -0.31]) but not for the LSI (MVIC: P = .46, Cohen d = -0.34 [95% CI = -1.22, 0.54]; CAR: P = .60, Cohen d = 0.24 [95% CI = -0.64, 1.12]). In the ACLR group, participants had improved knee-extension MVIC torque in the involved limb ( P = .04, Cohen d = 0.32 [95% CI = -0.56, 1.20]) and uninvolved limb ( P = .03, Cohen d = 0.29 [95% CI = -0.59, 1.17]); however, the improvement in quadriceps CAR was limited to the involved limb ( P = .02, Cohen d = 1.16 [95% CI = 0.21, 2.11]). We observed no change in the LSI with the intervention for knee-extension MVIC torque ( P = .74, Cohen d = 0.09 [95% CI = -0.79, 0.97]) or quadriceps CAR ( P = .61, Cohen d = 0.26 [95% CI = -0.62, 1.14]). CONCLUSIONS:  Two weeks of cryotherapy-facilitated exercise may improve involved-limb quadriceps function while preserving between-limbs symmetry in patients with a history of ACLR. 10.4085/1062-6050-52.10.13
    Effect of eccentric strengthening after anterior cruciate ligament reconstruction on quadriceps strength. Lepley Lindsey K,Palmieri-Smith Riann Journal of sport rehabilitation CLINICAL SCENARIO:Interventions aimed at safely overloading the quadriceps muscle after anterior cruciate ligament (ACL) reconstruction are essential to reducing quadriceps muscle weakness that often persists long after the rehabilitation period. Despite the best efforts of clinicians and researchers to improve ACL rehabilitation techniques, a universally effective intervention to restore preinjury quadriceps strength has yet to be identified. A muscle's force-producing capacity is most optimal when an external force exceeds that of the muscle while the muscle lengthens. Hence, the potential to improve muscle strength by overloading the tissue is greater with eccentric strengthening than with concentric strengthening. Traditionally, the application of early postoperative high-intensity eccentric resistance training to the ACL-reconstructed limb has been contraindicated, as there is potential for injury to the ACL graft, articular cartilage, or surrounding soft-tissue structures. However, recent evidence suggests that the application of early, progressive, high-force eccentric resistance exercises to the involved limb can be used to safely increase muscle volume and strength in ACL-reconstructed individuals. As a result, eccentric strengthening may be another attractive alternative to traditional concentric strengthening to improve quadriceps strength after ACL reconstruction. FOCUSED CLINICAL QUESTION:In patients who have undergone ACL reconstruction, is there evidence to suggest that eccentric exercise positively affects postoperative quadriceps strength? 10.1123/jsr.22.2.150
    Quadriceps Muscle Size Following ACL Injury and Reconstruction: A Systematic Review. Birchmeier Thomas,Lisee Caroline,Kane Kevin,Brazier Brett,Triplett Ashley,Kuenze Christopher Journal of orthopaedic research : official publication of the Orthopaedic Research Society Image-based assessments of quadriceps muscle size facilitate examination of structural changes after anterior cruciate ligament (ACL) injury and reconstruction (ACLR). Understanding the effects of ACLR on muscle size measures may aid in clarifying the contribution of quadriceps atrophy toward quadriceps strength. The purpose of this study was to systematically review the literature examining the effects of ACLR on quadriceps muscle volume and cross-sectional area (CSA). An online database search was conducted using Web of Science, SportDISCUS, PubMed (Medline), CINHAL (EBSCO), and Cochrane Library limited to articles published after January 1, 1980. Means and standard deviations were extracted for the ACLR limb and the contralateral limb, and sample characteristics from relevant articles. Magnitude of between limb differences were assessed using pooled effect sizes (Hedge's g) and 95% confidence intervals. Eleven articles (five CSA, six muscle volume) were included in this systematic review. Included studies reported negative effective sizes, indicating that the ACLR limb was smaller in CSA or muscle volume compared with the contralateral limb; however, 36% of the included articles reported meaningful difference between the limbs. Quadriceps atrophy may occur following ACL injury and persist after rehabilitation, however, the magnitude of these reductions may not be clinically meaningful and may only partially explain the persistent quadriceps weakness that is ubiquitous among this patient population. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:598-608, 2020. 10.1002/jor.24489
    Quadriceps Function, Knee Pain, and Self-Reported Outcomes in Patients With Anterior Cruciate Ligament Reconstruction. Lepley Adam S,Pietrosimone Brian,Cormier Marc L Journal of athletic training CONTEXT:  Interactions among muscle strength, pain, and self-reported outcomes in patients with anterior cruciate ligament reconstruction (ACLR) are not well understood. Clarifying these interactions is of clinical importance because improving physical and psychological function is thought to optimize outcomes after ACLR. OBJECTIVE:  To examine the relationships among neuromuscular quadriceps function, pain, self-reported knee function, readiness to return to activity, and emotional response to injury both before and after ACLR. DESIGN:  Descriptive laboratory study. PATIENTS OR OTHER PARTICIPANTS:  Twenty patients (11 females and 9 males; age = 20.9 ± 4.4 years, height = 172.4 ± 7.5 cm, weight = 76.2 ± 11.8 kg) who were scheduled to undergo unilateral ACLR. MAIN OUTCOME MEASURE(S):  Quadriceps strength, voluntary activation, and pain were measured at presurgery and return to activity, quantified using maximal voluntary isometric contractions (MVICs), central activation ratio, and the Knee Injury and Osteoarthritis Outcome Score pain subscale, respectively. Self-reported knee function, readiness to return to activity, and emotional responses to injury were evaluated at return to activity using the International Knee Documentation Committee questionnaire (IKDC), ACL Return to Sport After Injury scale (ACL-RSI), and Psychological Response to Sport Injury Inventory (PRSII), respectively. Pearson product moment correlations and linear regressions were performed using raw values and percentage change scores. RESULTS:  Presurgical levels of pain significantly predicted 31% of the variance in the ACL-RSI and 29% in the PRSII scores at return to activity. The MVIC and pain collected at return to activity significantly predicted 74% of the variance in the IKDC, whereas only MVIC significantly predicted 36% of the variance in the ACL-RSI and 39% in the PRSII scores. Greater increases in MVIC from presurgery to return to activity significantly predicted 49% of the variance in the ACL-RSI and 59% of the variance in the IKDC scores. CONCLUSION:  Decreased quadriceps strength and higher levels of pain were associated with psychological responses in patients with ACLR. A comprehensive approach using traditional rehabilitation that includes attention to psychological barriers may be an effective strategy to improve outcomes in ACLR patients. 10.4085/1062-6050-245-16
    Functional electrical stimulation following anterior cruciate ligament reconstruction: a randomized controlled pilot study. Moran Uria,Gottlieb Uri,Gam Arnon,Springer Shmuel Journal of neuroengineering and rehabilitation BACKGROUND:Inadequate quadriceps strength following anterior cruciate ligament reconstruction (ACLR) often results in alterations in gait pattern that are usually reported during loading response. Neuro-muscular electrical stimulation (NMES) is frequently used to overcome this quadriceps weakness. Despite the beneficial effects of NMES, persistent deficits in strength and gait are reported. The aim of this study was to investigate the feasibility of applying quadriceps functional electrical stimulation (FES) during walking in addition to standard rehabilitation, in the initial stage of ACLR rehabilitation. METHODS:Subjects were randomized to quadriceps FES synchronized with walking group (n = 10) or quadriceps NMES (duty cycle of 10 s on/10 s off) group (n = 13). Both interventions were performed for 10 min three days a week, in addition to a standard rehabilitation program. Assessments were performed up to 2 weeks before the ACLR (pre-ACLR), and 4 weeks postoperatively. Outcomes measured were gait speed, single limb stance gait symmetry, quadriceps isometric peak strength ratio (peak strength at 4 weeks/peak strength pre-ACLR) and peak strength inter-limb symmetry. Gait outcomes were also assessed 1-week post-surgery. RESULTS:Subjects in both groups regained pre-ACLR gait speed and symmetry after 4 weeks of rehabilitation, with no difference between groups. However, although pre-ACLR quadriceps peak strength was similar between groups (FES - 205 Nm, NMES - 225 Nm, p = 0.605), subjects in the FES group regained 82% of their pre-quadriceps strength compared to 47% in the NMES group (p = 0.02). In addition, after 4 weeks, the FES group had significantly better inter-limb strength symmetry 0.63 ± 0.15 vs. 0.39 ± 0.18 in the NMES group (p = 0.01). CONCLUSIONS:Quadriceps FES combined with traditional rehabilitation is a feasible, early intervention treatment option, post-ACLR. Furthermore, at 4 weeks post-surgery, FES was more effective in recovering quadriceps muscle strength than was NMES. While spatiotemporal gait parameters did not differ between groups, kinetic and kinematic studies may be useful to further understand the effects of quadriceps FES post-ACLR. The promising results of this preliminary investigation suggest that such studies are warranted. TRIAL REGISTRATION:ISRCTN 02817399 . First posted June 29, 2016. 10.1186/s12984-019-0566-0
    The Use of Recombinant Human Growth Hormone to Protect Against Muscle Weakness in Patients Undergoing Anterior Cruciate Ligament Reconstruction: A Pilot, Randomized Placebo-Controlled Trial. Mendias Christopher L,Enselman Elizabeth R Sibilsky,Olszewski Adam M,Gumucio Jonathan P,Edon Daniel L,Konnaris Maxwell A,Carpenter James E,Awan Tariq M,Jacobson Jon A,Gagnier Joel J,Barkan Ariel L,Bedi Asheesh The American journal of sports medicine BACKGROUND:Anterior cruciate ligament (ACL) tears are common knee injuries. Despite undergoing extensive rehabilitation after ACL reconstruction (ACLR), many patients have persistent quadriceps muscle weakness that limits their successful return to play and are also at an increased risk of developing knee osteoarthritis (OA). Human growth hormone (HGH) has been shown to prevent muscle atrophy and weakness in various models of disuse and disease but has not been evaluated in patients undergoing ACLR. HYPOTHESIS:Compared with placebo treatment, a 6-week perioperative treatment course of HGH would protect against muscle atrophy and weakness in patients undergoing ACLR. STUDY DESIGN:Randomized controlled trial; Level of evidence, 2. METHODS:A total of 19 male patients (aged 18-35 years) scheduled to undergo ACLR were randomly assigned to the placebo (n = 9) or HGH (n = 10) group. Patients began placebo or HGH treatment twice daily 1 week before surgery and continued through 5 weeks after surgery. Knee muscle strength and volume, patient-reported outcome scores, and circulating biomarkers were measured at several time points through 6 months after surgery. Mixed-effects models were used to evaluate differences between treatment groups and time points, and as this was a pilot study, significance was set at < .10. The Cohen was calculated to determine the effect size. RESULTS:HGH was well-tolerated, and no differences in adverse events between the groups were observed. The HGH group had a 2.1-fold increase in circulating insulin-like growth factor 1 over the course of the treatment period ( < .05; = 2.93). The primary outcome measure was knee extension strength, and HGH treatment increased normalized peak isokinetic knee extension torque by 29% compared with the placebo group ( = .05; = 0.80). Matrix metalloproteinase-3 (MMP3), which was used as an indirect biomarker of cartilage degradation, was 36% lower in the HGH group ( = .05; = -1.34). HGH did not appear to be associated with changes in muscle volume or patient-reported outcome scores. CONCLUSION:HGH improved quadriceps strength and reduced MMP3 levels in patients undergoing ACLR. On the basis of this pilot study, further trials to more comprehensively evaluate the ability of HGH to improve muscle function and potentially protect against OA in patients undergoing ACLR are warranted. REGISTRATION:NCT02420353 ( ClinicalTrials.gov identifier). 10.1177/0363546520920591
    Neuromuscular electrical stimulation is effective in strengthening the quadriceps muscle after anterior cruciate ligament surgery. Hauger Annette V,Reiman M P,Bjordal J M,Sheets C,Ledbetter L,Goode A P Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA PURPOSE:Reduced ability to contract the quadriceps muscles is often found immediately following anterior cruciate ligament (ACL) surgery. This can lead to muscle atrophy and decreased function. Application of neuromuscular electrical stimulation (NMES) may be a useful adjunct intervention to ameliorate these deficits following ACL surgery. The purpose of this review was to determine whether NMES in addition to standard physical therapy is superior to standard physical therapy alone in improving quadriceps strength or physical function following ACL surgery. METHODS:A computer-assisted literature search was conducted utilizing PubMed, CINAHL, PEDro and Cochrane Library databases for randomized clinical trials where patients after ACL surgery received NMES with the outcome of muscle strength and/or physical function. Random effect models were used to pool summary estimates using standardized mean differences (SMD) for strength outcomes. Physical function outcomes were assessed qualitatively. Methodological quality was assessed from the Physiotherapy Evidence Database (PEDro)-score. RESULTS:Eleven studies met our inclusion criteria; results from six of these were pooled in the meta-analysis showing a statistically significant short-term effect of NMES (4-12 weeks) after surgery compared to standard physical therapy [SMD = 0.73 (95% CI 0.29, 1.16)]. Physical function also improved significantly more in the NMES groups. PEDro scores ranged from 3/10 to 7/10 points. CONCLUSION:NMES in addition to standard physical therapy appears to significantly improve quadriceps strength and physical function in the early post-operative period compared to standard physical therapy alone. LEVEL OF EVIDENCE:I. 10.1007/s00167-017-4669-5
    Quadriceps Neuromuscular and Physical Function After Anterior Cruciate Ligament Reconstruction. Hunnicutt Jennifer L,McLeod Michelle M,Slone Harris S,Gregory Chris M Journal of athletic training CONTEXT:Persistent neuromuscular deficits in the surgical limb after anterior cruciate ligament reconstruction (ACLR) have been repeatedly described in the literature, yet little is known regarding their association with physical performance and patient-reported function. OBJECTIVE:To describe (1) interlimb differences in neuromuscular and functional outcomes and (2) the associations of neuromuscular outcomes with measures of physical and knee-related patient-reported function. DESIGN:Cross-sectional study. SETTING:Laboratory. PATIENTS OR OTHER PARTICIPANTS:Thirty individuals after primary, unilateral ACLR (19 males; age = 21.5 years [range, 14-41 years]; 8 months [range = 6-23 months] postsurgery). MAIN OUTCOME MEASURE(S):Knee-extensor isometric and isokinetic peak torque was measured with an isokinetic dynamometer. Cross-sectional area (CSA) was measured bilaterally for each of the quadriceps muscles via magnetic resonance imaging. We measured quadriceps central activation bilaterally via the superimposed-burst technique. Physical performance (single-legged hop tests, step length via spatiotemporal gait analysis) and patient-reported outcomes (International Knee Documentation Committee questionnaire and Knee Injury and Osteoarthritis Outcome Score Sport and Recreation subscale) were also recorded. We conducted Wilcoxon signed rank tests to identify interlimb differences. Spearman ρ correlation analyses revealed associations between limb symmetry and neuromuscular and functional outcomes, as well as with patient-reported function. RESULTS:Deficits in the surgical limb as compared with the nonsurgical limb were present for all outcomes ( values < .05). Greater single-legged hop-test symmetry (83%) was significantly correlated with greater symmetry in knee-extensor isometric (63%; = 0.567, = .002) and isokinetic (68%; = 0.540, = .003) strength, as well as greater cross-sectional area of the vastus medialis (78%; = 0.519, = .006) and vastus lateralis (82%; = 0.752, < .001). A higher International Knee Documentation Committee questionnaire score (82.2) was significantly correlated with greater symmetry in knee-extensor isokinetic strength ( = 0.379, = .039). CONCLUSIONS:Although deficits were observed in the surgical limb for all neuromuscular measures, greater symmetry in the size and strength of the quadriceps, rather than activation, was more strongly associated with physical performance after ACLR. Greater symmetry in strength was also more strongly associated with patient-reported function. 10.4085/1062-6050-516-18
    Functional Resistance Training to Improve Knee Strength and Function After Acute Anterior Cruciate Ligament Reconstruction: A Case Study. Brown Scott R,Washabaugh Edward P,Dutt-Mazumder Aviroop,Wojtys Edward M,Palmieri-Smith Riann M,Krishnan Chandramouli Sports health BACKGROUND:Thigh muscle weakness after anterior cruciate ligament reconstruction (ACLR) can persist after returning to activity. While resistance training can improve muscle function, "nonfunctional" training methods are not optimal for inducing transfer of benefits to activities such as walking. Here, we tested the feasibility of a novel functional resistance training (FRT) approach to restore strength and function in an individual with ACLR. HYPOTHESIS:FRT would improve knee strength and function after ACLR. STUDY DESIGN:Case report. LEVEL OF EVIDENCE:Level 5. METHODS:A 15-year-old male patient volunteered for an 8-week intervention where he performed 30 minutes of treadmill walking, 3 times per week, while wearing a custom-designed knee brace that provided resistance to the thigh muscles of his ACLR leg. Thigh strength, gait mechanics, and corticospinal and spinal excitability were assessed before and immediately after the 8-week intervention. Voluntary muscle activation was evaluated immediately after the intervention. RESULTS:Knee extensor and flexor strength increased in the ACLR leg from pre- to posttraining (130 to 225 N·m [+74%] and 44 to 88 N·m [+99%], respectively) and increases in between-limb extensor and flexor strength symmetry (45% to 92% [+74%] and 47% to 72% [+65%], respectively) were also noted. After the intervention, voluntary muscle activation in the ACLR leg was 72%, compared with the non-ACLR leg at 75%. Knee angle and moment during late stance phase decreased (ie, improved) in the ACLR leg and appeared more similar to the non-ACLR leg after FRT training (18° to 14° [-23.4] and 0.07 to -0.02 N·m·kg·m [-122.8%], respectively). Corticospinal and spinal excitability in the ACLR leg decreased (3511 to 2511 [-28.5%] and 0.42 to 0.24 [-43.7%], respectively) from pre- to posttraining. CONCLUSION:A full 8 weeks of FRT that targeted both quadriceps and hamstring muscles lead to improvements in strength and gait, suggesting that FRT may constitute a promising and practical alternative to traditional methods of resistance training. CLINICAL RELEVANCE:FRT may serve as a viable approach to improve knee strength and function after ACL reconstruction. 10.1177/1941738120955184
    Conditioning Brain Responses to Improve Quadriceps Function in an Individual With Anterior Cruciate Ligament Reconstruction. Krishnan Chandramouli,Washabaugh Edward P,Dutt-Mazumder Aviroop,Brown Scott R,Wojtys Edward M,Palmieri-Smith Riann M Sports health BACKGROUND:Persistent quadriceps weakness and activation failure are common in individuals with anterior cruciate ligament (ACL) reconstruction. A growing body of evidence indicates that this chronic quadriceps dysfunction could be partly mediated due to reduced corticospinal excitability. However, current rehabilitation approaches do not directly target corticospinal deficits, which may be critical for restoring optimal clinical outcomes after the surgery. This case study tested the feasibility of operant conditioning of torque responses evoked by transcranial magnetic stimulation (TMS) to improve quadriceps function after ACL reconstruction. HYPOTHESIS:Operant conditioning of motor evoked torque responses would improve quadriceps strength, voluntary activation, and corticospinal excitability. STUDY DESIGN:Case study and research report. LEVEL OF EVIDENCE:Level 5. METHODS:A 24-year-old male with an ACL reconstruction (6 months postsurgery) trained for 20 sessions (2-3 times per week for 8 weeks) to increase his TMS-induced motor evoked torque response (MEP torque) of the quadriceps muscles using operant conditioning principles. Knee extensor strength, voluntary quadriceps muscle activation, and quadriceps corticospinal excitability were evaluated at 3 time points: preintervention (pre), 4 weeks (mid), and immediately after the intervention (post). RESULTS:The participant was able to successfully condition (ie, increase) the quadriceps MEP torque after 1 training session, and the conditioned MEP torque gradually increased over the course of 20 training sessions to reach about 500% of the initial value at the end of training. The participant's control MEP torque values and corticospinal excitability, which were measured outside of the conditioning paradigm, also increased with training. These changes were paralleled by improvements in knee extensor strength and voluntary quadriceps muscle activation. CONCLUSION:This study shows that operant conditioning of MEP torque is a feasible approach to improving quadriceps corticospinal excitability and quadriceps function after ACL reconstruction and encourages further testing in a larger cohort of ACL-reconstructed individuals. CLINICAL RELEVANCE:Operant conditioning may serve as a potential therapeutic adjuvant for ACL rehabilitation. 10.1177/1941738119835163
    Knee extensor and flexor strength before and after anterior cruciate ligament reconstruction in a large sample of patients: influence of graft type. Huber Raphael,Viecelli Claudio,Bizzini Mario,Friesenbichler Bernd,Dohm-Acker Markus,Rosenheck Thomas,Harder Laurent,Maffiuletti Nicola A The Physician and sportsmedicine OBJECTIVE:Hamstring and patellar tendon autografts are the most frequently-used graft types for anterior cruciate ligament (ACL) reconstruction, with no consensus on their respective effects on thigh muscle strength. The objective of this study was to re-examine isokinetic knee extensor and flexor strength before and after ACL reconstruction with patellar and hamstring tendon grafts using a single-center and a relatively large database, where surgical, rehabilitation and testing procedures were strictly standardized for all patients. METHODS:A total of 464 patients with a unilateral ACL rupture underwent arthroscopic ACL reconstruction with either patellar or hamstring tendon grafts. Isokinetic concentric strength was evaluated prior to surgery and at 5- and 9-month postoperative follow-ups in different patient subgroups (n = 140, 464 and 215, respectively). RESULTS:Knee extensor strength was lower in patients operated with the patellar tendon graft at the 5-month (p < 0.05) but not at the 9-month follow-up. Knee flexor strength was lower in patients operated with the hamstring tendon graft at both postoperative time points (p < 0.05). The prevalence of quadriceps weakness was high (66-91%) in both patient groups at both follow-ups. CONCLUSION:Overall, postoperative recovery of thigh muscle function seems to be better with the patellar than with the hamstring tendon graft due to the fact that both, knee extensor and flexor strength, were more impaired after ACL reconstruction with the hamstring tendon autograft. 10.1080/00913847.2018.1526627
    Progressive strength training restores quadriceps and hamstring muscle strength within 7 months after ACL reconstruction in amateur male soccer players. Welling Wouter,Benjaminse Anne,Lemmink Koen,Dingenen Bart,Gokeler Alli Physical therapy in sport : official journal of the Association of Chartered Physiotherapists in Sports Medicine OBJECTIVES:The purpose of the current study was to compare the results of a progressive strength training protocol for soccer players after anterior cruciate ligament reconstruction (ACLR) with healthy controls, and to investigate the effects of the strength training protocol on peak quadriceps and hamstring muscle strength. DESIGN:Between subjects design. SETTING:Outpatient physical therapy facility. PARTICIPANTS:Thirty-eight amateur male soccer players after ACLR were included. Thirty age-matched amateur male soccer players served as control group. MAIN OUTCOME MEASURES:Quadriceps and hamstring muscle strength was measured at three time points during the rehabilitation. Limb symmetry index (LSI) > 90% was used as cut-off criteria. RESULTS:Soccer players after ACLR had no significant differences in peak quadriceps and hamstring muscle strength in the injured leg at 7 months after ACLR compared to the dominant leg of the control group. Furthermore, 65.8% of soccer players after ACLR passed LSI >90% at 10 months for quadriceps muscle strength. CONCLUSION:Amateur male soccer players after ACLR can achieve similar quadriceps and hamstring muscle strength at 7 months compared to healthy controls. These findings highlight the potential of progressive strength training in rehabilitation after ACLR that may mitigate commonly reported strength deficits. 10.1016/j.ptsp.2019.08.004
    Quadriceps muscle function after rehabilitation with cryotherapy in patients with anterior cruciate ligament reconstruction. Hart Joseph M,Kuenze Christopher M,Diduch David R,Ingersoll Christopher D Journal of athletic training CONTEXT:Persistent muscle weakness after anterior cruciate ligament (ACL) reconstruction may be due to underlying activation failure and arthrogenic muscle inhibition (AMI). Knee-joint cryotherapy has been shown to improve quadriceps function transiently in those with AMI, thereby providing an opportunity to improve quadriceps muscle activation and strength in patients with a reconstructed ACL. OBJECTIVE:To compare quadriceps muscle function in patients with a reconstructed ACL who completed a 2-week intervention including daily cryotherapy (ice bag), daily exercises, or both. DESIGN:Cross-sectional study. SETTING:Laboratory. PATIENTS OR OTHER PARTICIPANTS:A total of 30 patients with reconstructed ACLs who were at least 6 months post-index surgery and had measurable quadriceps AMI. INTERVENTION(S):The patients attended 4 supervised visits over a 2-week period. They were randomly assigned to receive 20 minutes of knee-joint cryotherapy, 1 hour of therapeutic rehabilitation exercises, or cryotherapy followed by exercises. MAIN OUTCOME MEASURE(S):We measured quadriceps Hoffmann reflex, normalized maximal voluntary isometric contraction torque, central activation ratio using the superimposed-burst technique, and patient-reported outcomes before and after the intervention period. RESULTS:After the 2-week intervention period, patients who performed rehabilitation exercises immediately after cryotherapy had higher normalized maximal voluntary isometric contraction torques (P = .002, Cohen d effect size = 1.4) compared with those who received cryotherapy alone (P = .16, d = 0.58) or performed exercise alone (P = .16, d = 0.30). CONCLUSIONS:After ACL reconstruction, patients with AMI who performed rehabilitation exercises immediately after cryotherapy experienced greater strength gains than those who performed cryotherapy or exercises alone. 10.4085/1062-6050-49.3.39
    Utility of Neuromuscular Electrical Stimulation to Preserve Quadriceps Muscle Fiber Size and Contractility After Anterior Cruciate Ligament Injuries and Reconstruction: A Randomized, Sham-Controlled, Blinded Trial. Toth Michael J,Tourville Timothy W,Voigt Thomas B,Choquette Rebecca H,Anair Bradley M,Falcone Michael J,Failla Mathew J,Stevens-Lapslaey Jennifer E,Endres Nathan K,Slauterbeck James R,Beynnon Bruce D The American journal of sports medicine BACKGROUND:Anterior cruciate ligament (ACL) injuries and reconstruction (ACLR) promote quadriceps muscle atrophy and weakness that can persist for years, suggesting the need for more effective rehabilitation programs. Whether neuromuscular electrical stimulation (NMES) can be used to prevent maladaptations in skeletal muscle size and function is unclear. PURPOSE:To examine whether early NMES use, started soon after an injury and maintained through 3 weeks after surgery, can preserve quadriceps muscle size and contractile function at the cellular (ie, fiber) level in the injured versus noninjured leg of patients undergoing ACLR. STUDY DESIGN:Randomized controlled trial; Level of evidence, 1. METHODS:Patients (n = 25; 12 men/13 women) with an acute, first-time ACL rupture were randomized to NMES (5 d/wk) or sham (simulated microcurrent electrical nerve stimulation; 5 d/wk) treatment to the quadriceps muscles of their injured leg. Bilateral biopsies of the vastus lateralis were performed 3 weeks after surgery to measure skeletal muscle fiber size and contractility. Quadriceps muscle size and strength were assessed 6 months after surgery. RESULTS:A total of 21 patients (9 men/12 women) completed the trial. ACLR reduced single muscle fiber size and contractility across all fiber types ( < .01 to < .001) in the injured compared with noninjured leg 3 weeks after surgery. NMES reduced muscle fiber atrophy ( < .01) through effects on fast-twitch myosin heavy chain (MHC) II fibers ( < .01 to < .001). NMES preserved contractility in slow-twitch MHC I fibers ( < .01 to < .001), increasing maximal contractile velocity ( < .01) and preserving power output ( < .01), but not in MHC II fibers. Differences in whole muscle strength between groups were not discerned 6 months after surgery. CONCLUSION:Early NMES use reduced skeletal muscle fiber atrophy in MHC II fibers and preserved contractility in MHC I fibers. These results provide seminal, cellular-level data demonstrating the utility of the early use of NMES to beneficially modify skeletal muscle maladaptations to ACLR. CLINICAL RELEVANCE:Our results provide the first comprehensive, cellular-level evidence to show that the early use of NMES mitigates early skeletal muscle maladaptations to ACLR. REGISTRATION:NCT02945553 (ClinicalTrials.gov identifier). 10.1177/0363546520933622
    Factors correlating with recovery of quadriceps strength after double-bundle anterior cruciate ligament reconstruction with hamstring tendon autografts. Iwame Toshiyuki,Matsuura Tetsuya,Okahisa Tetsuya,Iwase Joji,Uemura Hirokazu,Sairyo Koichi European journal of orthopaedic surgery & traumatology : orthopedie traumatologie PURPOSE:Recovery of quadriceps strength after anterior cruciate ligament (ACL) reconstruction is one of the criteria used to promote rehabilitation and return to play. The purpose of this study was to investigate the factors associated with recovery of quadriceps strength after ACL reconstruction with hamstring tendon autografts. METHODS:Isokinetic quadriceps strength at 60°/s was measured preoperatively and 6 months after surgery in 101 patients (54 males and 47 females) who underwent double-bundle ACL reconstruction with hamstring tendon autografts. The quadriceps strength index (%) was calculated by normalizing the peak torque of the operated leg with that of the contralateral leg. Details on age, sex, body mass index, time from injury to surgery, pre-injury Tegner activity scale score, previous meniscus repair, and preoperative quadriceps strength index were recorded. The factors associated with the postoperative quadriceps strength index were investigated in univariate and multivariate regression analyses. RESULTS:Multivariate regression analysis showed that preoperative quadriceps strength index (p = 0.001) was independently associated with the quadriceps strength index at 6 months after surgery. There was a marginally significant inverse association between age and postoperative quadriceps strength, but no statistically significant association was found for any of the other factors investigated. CONCLUSIONS:Postoperative quadriceps strength index at 6 months after double-bundle ACL reconstruction with hamstring tendon autografts was affected by preoperative quadriceps strength index. Adequate preoperative quadriceps strength may need to be considered in order to facilitate better recovery of quadriceps strength after ACL reconstruction and to support an earlier return to sports activities. 10.1007/s00590-019-02580-7
    Effect of Blood Flow Restriction Training on Quadriceps Muscle Strength, Morphology, Physiology, and Knee Biomechanics Before and After Anterior Cruciate Ligament Reconstruction: Protocol for a Randomized Clinical Trial. Erickson Lauren N,Lucas Kathryn C Hickey,Davis Kylie A,Jacobs Cale A,Thompson Katherine L,Hardy Peter A,Andersen Anders H,Fry Christopher S,Noehren Brian W Physical therapy BACKGROUND:Despite best practice, quadriceps strength deficits often persist for years after anterior cruciate ligament reconstruction. Blood flow restriction training (BFRT) is a possible new intervention that applies a pressurized cuff to the proximal thigh that partially occludes blood flow as the patient exercises, which enables patients to train at reduced loads. This training is believed to result in the same benefits as if the patients were training under high loads. OBJECTIVE:The objective is to evaluate the effect of BFRT on quadriceps strength and knee biomechanics and to identify the potential mechanism(s) of action of BFRT at the cellular and morphological levels of the quadriceps. DESIGN:This will be a randomized, double-blind, placebo-controlled clinical trial. SETTING:The study will take place at the University of Kentucky and University of Texas Medical Branch. PARTICIPANTS:Sixty participants between the ages of 15 to 40 years with an ACL tear will be included. INTERVENTION:Participants will be randomly assigned to (1) physical therapy plus active BFRT (BFRT group) or (2) physical therapy plus placebo BFRT (standard of care group). Presurgical BFRT will involve sessions 3 times per week for 4 weeks, and postsurgical BFRT will involve sessions 3 times per week for 4 to 5 months. MEASUREMENTS:The primary outcome measure was quadriceps strength (peak quadriceps torque, rate of torque development). Secondary outcome measures included knee biomechanics (knee extensor moment, knee flexion excursion, knee flexion angle), quadriceps muscle morphology (physiological cross-sectional area, fibrosis), and quadriceps muscle physiology (muscle fiber type, muscle fiber size, muscle pennation angle, satellite cell proliferation, fibrogenic/adipogenic progenitor cells, extracellular matrix composition). LIMITATIONS:Therapists will not be blinded. CONCLUSIONS:The results of this study may contribute to an improved targeted treatment for the protracted quadriceps strength loss associated with anterior cruciate ligament injury and reconstruction. 10.1093/ptj/pzz062
    Blood Flow Restriction Training Applied With High-Intensity Exercise Does Not Improve Quadriceps Muscle Function After Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial. Curran Michael T,Bedi Asheesh,Mendias Christopher L,Wojtys Edward M,Kujawa Megan V,Palmieri-Smith Riann M The American journal of sports medicine BACKGROUND:A major goal of rehabilitation after anterior cruciate ligament reconstruction (ACLR) is restoring quadriceps muscle strength. Unfortunately, current rehabilitation paradigms fall short of this goal, such that substantial quadriceps muscle strength deficits can limit return to play and increase the risk of recurrent injuries. Blood flow restriction training (BFRT) involves the obstruction of venous return to working muscles during exercise and may lead to better recovery of quadriceps muscle strength after ACLR. PURPOSE:To examine the efficacy of BFRT with high-intensity exercise on the recovery of quadriceps muscle function in patients undergoing ACLR. STUDY DESIGN:Randomized controlled trial; Level of evidence, 2. METHODS:A total of 34 patients (19 female, 15 male; mean age, 16.5 ± 2.7 years; mean height, 169.0 ± 19.7 cm; mean weight, 73.2 ± 17.7 kg) scheduled to undergo ACLR were randomly assigned to 1 of 4 groups: concentric (n = 8), eccentric (n = 8), concentric with BFRT (n = 9), and eccentric with BFRT (n = 9). The exercise component of the intervention consisted of patients performing a single-leg isokinetic leg press, at an intensity of 70% of the patients' 1-repetition maximum during either the concentric or eccentric action, for 4 sets of 10 repetitions 2 times per week for 8 weeks beginning at 10 weeks postoperatively. Patients randomized to the BFRT groups performed the leg-press exercise with a cuff applied to the thigh, set to a limb occlusion pressure of 80%. Isometric and isokinetic (60 deg/s) quadriceps peak torque, quadriceps muscle activation, and rectus femoris muscle volume were assessed before ACLR, after BFRT, and at the time that patients returned to activity and were converted to the change in values from baseline for analysis. Also, 1-way analyses of covariance were used to compare the change in values for each dependent variable between groups after BFRT and at return to activity ( ≤ .05). RESULTS:No significant differences were found between groups for any outcome measures at either time point ( > .05). CONCLUSION:An 8-week BFRT plus high-intensity exercise intervention did not significantly improve quadriceps muscle strength, activation, or volume. On the basis of our findings, the use of BFRT in conjunction with high-intensity resistance exercise in patients undergoing ACLR to improve quadriceps muscle function may not be warranted. REGISTRATION:NCT03141801 ( ClinicalTrials.gov identifier). 10.1177/0363546520904008