Muscle activation of the torso during the modified razor curl hamstring exercise.
Oliver Gretchen D,Stone Audrey J,Wyman James W,Blazquez Ivan N
International journal of sports physical therapy
PURPOSE/BACKGROUND:The RAZOR curl has been introduced as a hamstring exercise. However, modifications to the exercise have been developed which are proposed to utilize some of the muscles of the lumbo-pelvic-hip complex. Thus, it was the purpose of this study to quantitatively examine the modified RAZOR curl using surface electromyography (sEMG), as an exercise that may recruit the trunk muscles of the lumbo-pelvic-hip complex. METHODS:Twenty-eight active male and female graduate students (24.2±1.3 years; 174.8±9.9 cm; 74.9±14.9 kg), consented to participate. Dependent variables were muscle activation of trunk musculature (dominant side gluteus medius, gluteus maximus, multifidus, longissimus, lower rectus abdominis, upper rectus abdominis, external obliques) reported as percent of maximum voluntary isometric contraction (%MVIC) during the exercise while the independent variable was the muscle selected. RESULTS:The multifidus and longissimus demonstrated moderately strong activation (35-50%MVIC) while the upper rectus abdominis demonstrated strong activation (20-35%MVIC) and the gluteus medius, gluteus maximus, lower rectus abdominis, and external obliques had minimal activation. CONCLUSIONS:These findings allow the practitioner to utilize an exercise that provides a functional training stimulus that activates not only the hamstrings but also some musculature of the trunk muscles of the lumbopelvic-hip complex at strong to moderately strong levels. LEVEL OF EVIDENCE:5.
Trunk muscle activity during trunk stabilizing exercise with isometric hip rotation using electromyography and ultrasound.
Nakai Yuki,Kawada Masayuki,Miyazaki Takasuke,Kiyama Ryoji
Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology
INTRODUCTION:The purpose of this study was to clarify the muscle activation during trunk stabilizing exercise with isometric hip rotation in healthy males by comparing that with abdominal crunch (AC) and active straight leg raise (ASLR). Electromyography and ultrasound imaging were used to simultaneously measure muscle activity and thickness of the internal oblique (IO), the external oblique (EO), transverse abdominis (TrA) and multifidus (MF) on the right side during exercise. METHODS:Twenty healthy participants performed the following exercises in supine position: isometric right or left hip internal/external rotation, AC, and ASLR. Muscle activity was normalized to maximum voluntary contraction (MVC), and muscle thickness was normalized to resting muscle thickness. RESULTS:Muscle activation and thickness of IO, MF and TrA increased significantly during the isometric hip rotation compared with other exercises. Muscle activation during the trunk stabilizing exercise with ipsilateral isometric hip internal rotation was 21% in IO, 26% in MF, and with ipsilateral hip external rotation was 12% of MVC in EO. CONCLUSION:These findings suggest that trunk stabilizing exercise with isometric hip rotation exercise may be a more safe and effective exercise to promote trunk muscle activity than AC and ASLR. These findings would be beneficial for therapists engaged in prevention and treatment of low back pain.
Can repetitive transcranial magnetic stimulation increase muscle strength in functional neurological paresis? A proof-of-principle study.
Broersma M,Koops E A,Vroomen P C,Van der Hoeven J H,Aleman A,Leenders K L,Maurits N M,van Beilen M
European journal of neurology
BACKGROUND AND PURPOSE:Therapeutic options are limited in functional neurological paresis disorder. Earlier intervention studies did not control for a placebo effect, hampering assessment of effectivity. A proof-of-principle investigation was conducted into the therapeutic potential of repetitive transcranial magnetic stimulation (rTMS), using a single-blind two-period placebo-controlled cross-over design. METHODS:Eleven patients received active 15 Hz rTMS over the contralateral motor cortex (hand area), in two periods of 5 days, for 30 min once a day at 80% of resting motor threshold, with a train length of 2 s and an intertrain interval of 4 s. Eight of these eleven patients were also included in the placebo treatment condition. Primary outcome measure was change in muscle strength as measured by dynamometry after treatment. Secondary outcome measure was the subjective change in muscle strength after treatment. RESULTS:In patients who received both treatments, active rTMS induced a significantly larger median increase in objectively measured muscle strength (24%) compared to placebo rTMS (6%; P < 0.04). Subjective ratings showed no difference due to treatment, i.e. patients did not perceive these objectively measured motor improvements (P = 0.40). CONCLUSIONS:Our findings suggest that rTMS by itself can potentially improve muscle weakness in functional neurological paresis disorder. Whereas patients' muscle strength increased as measured with dynamometry, patients did not report increased functioning of the affected hand, subjectively. The results may indicate that decreased muscle strength is not the core symptom and that rTMS should be added to behavioral approaches in functional neurological paresis.
Relationship between core stability, functional movement, and performance.
Okada Tomoko,Huxel Kellie C,Nesser Thomas W
Journal of strength and conditioning research
The purpose of this study was to determine the relationship between core stability, functional movement, and performance. Twenty-eight healthy individuals (age = 24.4 ± 3.9 yr, height = 168.8 ± 12.5 cm, mass = 70.2 ± 14.9 kg) performed several tests in 3 categories: core stability (flexion [FLEX], extension [EXT], right and left lateral [LATr/LATl]), functional movement screen (FMS) (deep squat [DS], trunk-stability push-up [PU], right and left hurdle step [HSr/HSl], in-line lunge [ILLr/ILLl], shoulder mobility [SMr/SMl], active straight leg raise [ASLRr/ASLRl], and rotary stability [RSr/RSl]), and performance tests (backward medicine ball throw [BOMB], T-run [TR], and single leg squat [SLS]). Statistical significance was set at p ≤ 0.05. There were significant correlations between SLS and FLEX (r = 0.500), LATr (r = 0.495), and LATl (r = 0.498). The TR correlated significantly with both LATr (r = 0.383) and LATl (r = 0.448). Of the FMS, BOMB was significantly correlated with HSr (r = 0.415), SMr (r = 0.388), PU (r = 0.407), and RSr (r = 0.391). The TR was significantly related with HSr (r = 0.518), ILLl (r = 0.462) and SMr (r = 0.392). The SLS only correlated significantly with SMr (r = 0.446). There were no significant correlations between core stability and FMS. Moderate to weak correlations identified suggest core stability and FMS are not strong predictors of performance. In addition, existent assessments do not satisfactorily confirm the importance of core stability on functional movement. Despite the emphasis fitness professionals have placed on functional movement and core training for increased performance, our results suggest otherwise. Although training for core and functional movement are important to include in a fitness program, especially for injury prevention, they should not be the primary emphasis of any training program.
Effect of Lumbar Progressive Resistance Exercise on Lumbar Muscular Strength and Core Muscular Endurance in Soldiers.
Mayer John M,Childs John D,Neilson Brett D,Chen Henian,Koppenhaver Shane L,Quillen William S
OBJECTIVES:Low back pain is common, costly, and disabling for active duty military personnel and veterans. The evidence is unclear on which management approaches are most effective. The purpose of this study was to assess the effectiveness of lumbar extensor high-intensity progressive resistance exercise (HIPRE) training versus control on improving lumbar extension muscular strength and core muscular endurance in soldiers. METHODS:A randomized controlled trial was conducted with active duty U.S. Army Soldiers (n = 582) in combat medic training at Fort Sam Houston, Texas. Soldiers were randomized by platoon to receive the experimental intervention (lumbar extensor HIPRE training, n = 298) or control intervention (core stabilization exercise training, n = 284) at one set, one time per week, for 11 weeks. Lumbar extension muscular strength and core muscular endurance were assessed before and after the intervention period. RESULTS:At 11-week follow-up, lumbar extension muscular strength was 9.7% greater (p = 0.001) for HIPRE compared with control. No improvements in core muscular endurance were observed for HIPRE or control. CONCLUSIONS:Lumbar extensor HIPRE training is effective to improve isometric lumbar extension muscular strength in U.S. Army Soldiers. Research is needed to explore the clinical relevance of these gains.
Electromyographic assessment of muscle activity between genders during unilateral weight-bearing tasks using adjusted distances.
Bouillon Lucinda E,Wilhelm Jacqueline,Eisel Patricia,Wiesner Jessica,Rachow Megan,Hatteberg Lindsay
International journal of sports physical therapy
PURPOSE/BACKGROUND:Researchers have observed differences in muscle activity patterns between males and females during functional exercises. The research methods employed have used various step heights and lunge distances to assess functional exercise making gender comparisons difficult. The purpose of this study was to examine core and lower extremity muscle activity between genders during single-limb exercises using adjusted distances and step heights based on a percentage of the participant's height. METHODS:Twenty men and 20 women who were recreationally active and healthy participated in the study. Two-dimensional video and surface electromyography (SEMG) were used to assess performance during three exercise maneuvers (step down, forward lunge, and side-step lunge). Eight muscles were assessed using SEMG (rectus abdominus, external oblique, erector spinae, rectus femoris, tensor fascia latae, gluteus medius, gluteus maximus, biceps femoris). Maximal voluntary isometric contractions (MVIC) were used for each muscle and expressed as %MVIC to normalize SEMG to account for body mass differences. Exercises were randomized and distances were normalized to the participant's lower limb length. Descriptive statistics, mixed-model ANOVA, and ICCs with 95% confidence intervals were calculated. RESULTS:Males were taller, heavier, and had longer leg length when compared to the females. No differences in %MVIC activity were found between genders by task across the eight muscles. For both males and females, the step down task resulted in higher %MVIC for gluteus maximus compared to lunge, (p=0.002). Step down exercise produced higher %MVIC for gluteus medius than lunge (p=0.002) and side step (p=0.006). ICC(3,3) ranged from moderate to high (0.74 to 0.97) for the three tasks. CONCLUSIONS:Muscle activation among the eight muscles was similar between females and males during the lunge, side-step, and step down tasks, with distances adjusted to leg length. Both males and females elicited higher muscle activity for gluteus maximus and gluteus medius as compared to the trunk, hip flexors, or hamstring muscles. However these values were well below the recruitment levels necessary for strengthening in both genders. LEVEL OF EVIDENCE:4.
Single leg squat performance in physically and non-physically active individuals: a cross-sectional study.
Gianola Silvia,Castellini Greta,Stucovitz Elena,Nardo Alice,Banfi Giuseppe
BMC musculoskeletal disorders
BACKGROUND:Single-leg squat (SLS) is a functional test visually rated by clinicians for assessing lower limb function as a preventive injury strategy. SLS clinical rating is a qualitative evaluation and it does not count objective outcomes as kinematics data and surface electromyography (sEMG) assessment. Based on the SLS rating, the aims of this study were (i) to determine the clinical rating agreement among six raters and (ii) to assess kinematic and sEMG predictors of good SLS performance in physically and non-physically active individuals. METHODS:Seventy-two healthy adults, divided in physically active and non-physically active groups, performed three SLSs on their dominant leg. Clinical ratings, kinematic data and sEMG were acquired. By using a validated clinical scale, six expert clinicians rated each SLS watching a video at three different time points. Intra and inter-rater agreement of clinical ratings were undertaken and a binary logistic regression analysis was used to determine kinematic and sEMG as predictors of SLS performance. RESULTS:The weighted kappa coefficient for intra-rater reliability within each rater ranged between moderate and almost perfect agreement (0.55-0.85) whereas the weighted kappa coefficient for inter-rater reliability among raters was fair (0.34, time point 0; 0.31, time point 1; 0.30, time point 2). SLS analyses of physically active compared to non-physically active group showed a statistically significant difference in knee flexion and hip flexion (p = 0.041 and p = 0.023 respectively) and no difference in clinical ratings (p = 0.081). Greater knee flexion can predict the good SLS performance taking into account the belonging group (p = 0.019). CONCLUSIONS:Physically active individuals seemed to be at less risk to perform a non-good SLS and they had greater knee and hip flexions kinematics than non-physically active individuals. Knee flexion can predict the SLS performance quality therefore a greater knee flexion might also be considered a protective element from injuries. TRIAL REGISTRATION:ClinicalTrials.gov identifier (trial has been registred retrospectively: NCT03203083. Date registration: June 21, 2017.
Electromyographic analysis of upper body, lower body, and abdominal muscles during advanced Swiss ball exercises.
Marshall Paul W M,Desai Imtiaz
Journal of strength and conditioning research
Although there is now some evidence examining the use of a Swiss ball during core stability and resistance exercises, this has commonly been performed using basic or isometric exercises. There is currently no evidence examining more advanced Swiss ball exercises. The purpose of this study was to determine whether or not muscle activity measured during advanced Swiss ball exercises was at an approximate intensity recommended for strength or endurance training in advanced, or novice individuals. After a familiarization session, 14 recreationally active subjects performed 6 different "advanced" Swiss ball exercises in a randomized order. The primary dependent variables in this study were the activity levels collected from anterior deltoid, pectoralis major, rectus abdominis (RA), external obliques, lumbar erector spinae, vastus lateralis (VL), and biceps femoris using surface electromyography. All signals were normalized to maximal voluntary isometric contractions performed before testing for each muscle. The results of this study showed that the Swiss ball roll elicited muscle activity in triceps brachii (72.5+/-32.4%) and VL (83.6+/-44.2%) commensurate with the intensity recommended for strength exercises in advanced trainers. Rectus abdominis activity was greatest during the bridge exercise (61.3+/-28.5%, p<or=0.01). This was the only exercise to elicit RA muscle activity commensurate with a strength training effect. The remainder of the exercises elicited abdominal activity that would require a higher number of repetitions to be performed for an endurance training adaptation. Although this study has provided evidence for one advanced Swiss ball exercise providing a significant whole-body stimulus, the practical difficulty and risks of performing these more complicated Swiss ball exercises may outweigh potential benefits.
The use of instability to train the core musculature.
Behm David G,Drinkwater Eric J,Willardson Jeffrey M,Cowley Patrick M
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme
Training of the trunk or core muscles for enhanced health, rehabilitation, and athletic performance has received renewed emphasis. Instability resistance exercises have become a popular means of training the core and improving balance. Whether instability resistance training is as, more, or less effective than traditional ground-based resistance training is not fully resolved. The purpose of this review is to address the effectiveness of instability resistance training for athletic, nonathletic, and rehabilitation conditioning. The anatomical core is defined as the axial skeleton and all soft tissues with a proximal attachment on the axial skeleton. Spinal stability is an interaction of passive and active muscle and neural subsystems. Training programs must prepare athletes for a wide variety of postures and external forces, and should include exercises with a destabilizing component. While unstable devices have been shown to be effective in decreasing the incidence of low back pain and increasing the sensory efficiency of soft tissues, they are not recommended as the primary exercises for hypertrophy, absolute strength, or power, especially in trained athletes. For athletes, ground-based free-weight exercises with moderate levels of instability should form the foundation of exercises to train the core musculature. Instability resistance exercises can play an important role in periodization and rehabilitation, and as alternative exercises for the recreationally active individual with less interest or access to ground-based free-weight exercises. Based on the relatively high proportion of type I fibers, the core musculature might respond well to multiple sets with high repetitions (e.g., >15 per set); however, a particular sport may necessitate fewer repetitions.
Relationship Between Body Positioning, Muscle Activity, and Spinal Kinematics in Cyclists With and Without Low Back Pain: A Systematic Review.
Streisfeld Gabriel M,Bartoszek Caitlin,Creran Emily,Inge Brianna,McShane Marc D,Johnston Therese
CONTEXT:Low back pain is reported by more than half of cyclists. The pathomechanics and association of risk factors of lumbar spine overuse injuries in cycling are not clearly understood. OBJECTIVE:To determine whether relationships exist between body positioning, spinal kinematics, and muscle activity in active cyclists with nontraumatic low back pain. DATA SOURCES:In August of 2015 and April of 2016, a comprehensive search of the PubMed, CINAHL, Ovid MEDLINE, and Scopus databases was performed independently by 5 reviewers. STUDY SELECTION:Included articles consisted of biomechanical studies examining factors relating to low back pain in cyclists as agreed upon by group consensus. STUDY DESIGN:Systematic review. LEVEL OF EVIDENCE:Level 4. DATA EXTRACTION:Five reviewers appraised by consensus each article using the Downs and Black checklist. RESULTS:Eight studies met criteria for this review. There is evidence that cyclists with lower handlebar heights displayed increased lumbosacral flexion angles during cycling. Core muscle activation imbalances, back extensor endurance deficits, and increased lumbar flexion while cycling were found to be present in cyclists with low back pain. CONCLUSION:Spinal and core muscle activation imbalances in a prolonged flexed posture associated with cycling may lead to maladaptive spinal kinematics and increased spinal stresses contributing to overuse low back pain.
An evaluation of upper-body muscle activation during coupled and uncoupled instability resistance training.
Campbell Brian M,Kutz Matt R,Morgan Amy L,Fullenkamp Adam M,Ballenger Ryan
Journal of strength and conditioning research
Recently, there has been a growth in the popularity of resistance exercises performed on unstable surfaces. However, the relationship between unstable surface training and load coupling on muscle activation is unclear. The purpose of this study was to evaluate changes in muscle activation during a barbell (BB) (coupled) and dumbbell (DB) (uncoupled) chest press exercise performed on an unstable surface. The 3 specific chest press conditions included 50% 1 repetition maximum (RM) with BB (50% BB), 50% 1RM with DBs (50% DB), and 25% 1RM with DBs (25% DB). Ten male subjects participated in the study (age, 23.9 ± 2.6 years; body weight, 82.8 ± 10.2 kg). During testing, mean electromyographic activity was assessed for pectoralis major (PM), triceps brachii, anterior deltoid (AD), and rectus abdominis (RA) and was presented as a percent change across the lifting conditions. It was observed that muscle activation increased by 15% in both the PM and RA from the 50% BB condition to the 50% DB condition. Also, the greatest percent difference in muscle activation between the 50 and 25% DB conditions occurred for PM and AD (+54% during 50% DB). These results suggest that demands on the core musculature to provide stability are increased with the use of DBs (uncoupled) as opposed to a BB (coupled). Where instability training provides a sufficient hypertrophy stimulus in prime mover muscle groups, there may be the added benefit of core stability training. Specifically, this type of training may benefit both untrained persons and those engaged in active rehabilitation.
Muscle Activity Patterns do not Differ Between Push-Up and Bench Press Exercises.
Gottschall Jinger S,Hastings Bryce,Becker Zachary
Journal of applied biomechanics
Popular topics for upper-body resistance training involve the differences between hand positions, open versus closed chain exercises, and movement variations for the novice to the advanced. It was hypothesized that there will be no difference between closed (push-up) versus open (bench press) chain exercises for the primary muscle group activity nor would there be a difference between push-ups on the toes versus knees with respect to the percent contribution of each muscle. Surface muscle activity was measured for 8 upper-body and core muscles during a sequence of push-up and bench press variations with a normalized weight for 12 active men. Each participant completed push-ups and bench press exercises at each of 3 hand positions. The results demonstrated that there were few differences between closed versus open chain exercises for the primary muscle groups with the exception of core activation. In addition, in general, narrow hand positions yielded greater activation, and there were no significant differences between push-ups on the toes versus knees with respect to the percent contribution for the primary muscle groups. In conclusion, closed chain exercises may be preferred for functional training, and knee push-ups may be ideal as a novice push-up variation.
Abdominal muscle feedforward activation in patients with chronic low back pain is largely unaffected by 8 weeks of core stability training.
Allison Garry T
Journal of physiotherapy
QUESTION:Does timing of abdominal muscle activation in response to rapid shoulder flexion change after 8 weeks with low-load core stability exercises (CSE), high-load sling exercises (SE), or general exercises (GE) in chronic nonspecific low back pain (LBP) patients? DESIGN:A randomised, controlled trial with concealed allocation. SETTING:Patients were recruited from general practitioners, physiotherapists, or by advertising at a regional hospital in Norway. PARTICIPANTS:Men and women, aged 18-60 years, with chronic nonspecific LBP for 3 months or more, and pain score of 2 or more on a 0-10 numeric rating scale were included. Key exclusion criteria included radiating pain below the knee or neurological signs from nerve root compression, and former back surgery. Randomisation of 109 participants allocated 36 to CSE, 36 to SE, and 37 to GE. INTERVENTIONS:Patients in the three groups attended treatment once a week for 8 weeks, supervised by a physiotherapist. All were encouraged to stay active and received an information booklet with general information on LBP. The CSE were individualised according to protocols focusing on isolated activation of transversus abdominis during an abdominal drawing-in manoeuver in supine hook-lying position with ultrasound feedback. Written instructions to carry out the drawing-in exercise (10 × 10 seconds 2-3 times per day) at home were also provided. The SE maintained the lumbar spine stable in neutral position throughout a range of leg/arm positions and movements, using elastic bands attached to the pelvis to help the patient maintain a neutral spine position. The SE was performed for 40 minutes in a physiotherapy clinic. The GE group received generalised trunk strengthening and stretching exercises supervised by a physiotherapist at a fitness centre. OUTCOME MEASURES:Primary outcome was change in onset of the deep abdominal muscles in response to rapid shoulder flexion. RESULTS:102 participants completed the study. No or small changes were found in onset after treatment. Baseline adjusted between-group differences showed a 15 milliseconds (95% CI 1 to 28) and a 19 millisecond (95% CI 5 to 33) improvement with SE relative to CSE and GE, respectively, but on one side only. There was no association between changes in pain and onset over the intervention period (R(2)≤0.02). CONCLUSION:Abdominal muscle onset was largely unaffected by 8 weeks of exercises in chronic LBP patients with changes in onset of less than 20 milliseconds between groups.
Muscle activation in suspension training: a systematic review.
Aguilera-Castells Joan,Buscà Bernat,Fort-Vanmeerhaeghe Azahara,Montalvo Alicia M,Peña Javier
Suspension training is an adjunct to traditional strength and conditioning. The effect of added instability on muscle activation during traditional exercises is unclear and depends on the exercise and type of instability. The purpose of this review was to compare the activations of different muscles in suspension training exercises and their traditional counterparts. A search of the current literature was performed without language restrictions using the electronic databases PubMed (1969-12 January 2017), SPORTDiscus (1969-12 January 2017) and Scopus (1969-12 January 2017). The inclusion criteria were: (1) descriptive studies; (2) physically active participants; and (3) studies that analysed muscle activation using normalised electromyographic signals during different suspension training exercises. Eighteen studies met the inclusion criteria. For the push-up, inverted row, prone bridge and hamstring curl in suspension, the activation of upper-body and core muscles ranged between moderate (21-40% maximum voluntary isometric contraction (MVIC)) and very high (>60% MVIC). Muscle activation in these same muscle groups was greater with suspension exercises relative to comparable traditional exercises, except for the inverted row. Muscle activation in the upper extremity and core muscles varied greatly amongst studies.
Effect of two different exercise regimens on trunk muscle morphometry and endurance in soldiers in training.
Teyhen Deydre S,Childs John D,Dugan Jessica L,Wright Alison C,Sorge Joshua A,Mello Jeremy L,Marmolejo Michael G,Taylor Adam Y,Wu Samuel S,George Steven Z
BACKGROUND:Limited evidence exists on how strength and endurance exercises commonly used to prevent low back pain affect muscle morphometry and endurance. OBJECTIVE:The purpose of this study was to analyze the effects of 2 exercise regimens on the morphometry and endurance of key trunk musculature in a healthy population. DESIGN:The study was designed as a randomized controlled trial. SETTING:The study was conducted in a military training setting. PARTICIPANTS:A random subsample (n=340; 72% men, 28% women; mean [±SD] age=21.9±4.2 years; mean [±SD] body mass index=24.8±2.8 kg/m2) from the larger Prevention of Low Back Pain in the Military trial (N=4,325) was included. INTERVENTION:The core stabilization exercise program (CSEP) included low-load/low-repetition motor control exercises, whereas the traditional exercise program (TEP) included exercises conducted at a fast pace, with the use of high-load, high-repetition trunk strengthening exercises. MEASUREMENTS:Baseline and follow-up examinations included ultrasound imaging of the trunk muscles and endurance tests. Linear mixed models were fitted to study the group and time effect and their interactions, accounting for the clustering effect. RESULTS:Symmetry generally improved in the rest and contracted states, but there were no differences suggestive of muscle hypertrophy or improved ability to contract the trunk muscles between soldiers receiving the CSEP or the TEP. Total trunk endurance time decreased over the 12-week period, but endurance performance favored soldiers in the CSEP group. Endurance time was not associated with future episodes of low back pain. LIMITATIONS:The lack of morphological changes may not be detectable in an already-active cohort, or a more intensive dose was needed. CONCLUSIONS:Although improved symmetry was noted, neither the CSEP nor the TEP resulted in muscle hypertrophy. Longer endurance times were noted in individuals who completed the CSEP but were not strongly predictive of future low back pain episodes.
The development and reliability of a simple field based screening tool to assess core stability in athletes.
O'Connor S,McCaffrey N,Whyte E,Moran K
Physical therapy in sport : official journal of the Association of Chartered Physiotherapists in Sports Medicine
OBJECTIVES:To adapt the trunk stability test to facilitate further sub-classification of higher levels of core stability in athletes for use as a screening tool. To establish the inter-tester and intra-tester reliability of this adapted core stability test. DESIGN:Reliability study. SETTING:Collegiate athletic therapy facilities. PARTICIPANTS:Fifteen physically active male subjects (19.46 ± 0.63) free from any orthopaedic or neurological disorders were recruited from a convenience sample of collegiate students. MAIN OUTCOME MEASURES:The intraclass correlation coefficients (ICC) and 95% Confidence Intervals (CI) were computed to establish inter-tester and intra-tester reliability. RESULTS:Excellent ICC values were observed in the adapted core stability test for inter-tester reliability (0.97) and good to excellent intra-tester reliability (0.73-0.90). While the 95% CI were narrow for inter-tester reliability, Tester A and C 95% CI's were widely distributed compared to Tester B. CONCLUSIONS:The adapted core stability test developed in this study is a quick and simple field based test to administer that can further subdivide athletes with high levels of core stability. The test demonstrated high inter-tester and intra-tester reliability.
The effect of a novel core stabilization technique on managing patients with chronic low back pain: a randomized, controlled, experimenter-blinded study.
You Joshua H,Kim Suhn-Yeop,Oh Duck-Won,Chon Seung-Chul
OBJECTIVE:To identify the effect of a novel augmented core stabilization exercise technique on physical function, pain and core stability in patients with chronic low back pain. DESIGN:A block randomized controlled trial with two groups. SETTING:A sports rehabilitation clinic. PARTICIPANTS:Forty patients with low back pain (20 experimental, mean (SD) age 50.35 (9.26) years and 20 control, 51.30 (7.01)), 19 men and 21 women. INTERVENTIONS:In the experimental group ankle dorsiflexion was used in addition to drawing in the abdominal wall; the control group involved drawing in the abdominal wall alone. Both groups received the same conventional physical therapy training three days a week for eight weeks. MAIN OUTCOME MEASURES:Physical disability instruments; Oswestry Disability Index and Roland Morris Disability Questionnaire; pain intensity assessments; visual analogue scale, Pain Disability Index, and a pain rating scale; and core stability measures, such as the active straight leg raise, were determined at pretest, posttest and two-month follow-up. RESULTS:After the intervention, the experimental group showed significant greater improvement at two months compared with the control group. Physical disability results included Oswestry Disability Index (P = 0.001, from 24.25 (7.08) to 13.35 (4.17)) and Roland Morris Disability Questionnaire (P = 0.001, from 15.55 (1.99) to 8.15 (1.69)), pain intensity including visual analogue scale (P = 0.001, from 6.30 (1.03) to 3.35 (0.59)), Pain Disability Index (P = 0.001, 31.25 (5.44) to 19.00 (3.58)) and pain rating scale (P = 0.001, from 72.25 (18.73) to 50.10 (15.47)), and the core stability test such as active straight leg raise (P = 0.001, from 7.40 (0.75) to 2.15 (0.49)). CONCLUSIONS:This study provides the clinical evidence that adding ankle dorsiflexion to drawing in the abdominal wall gave increased benefit in terms of physical disability, pain and core stability in patients with chronic low back pain.
Muscle activation patterns of the lumbo-pelvic-hip complex during walking gait before and after exercise.
Chang Mihyang,Slater Lindsay V,Corbett Revay O,Hart Joseph M,Hertel Jay
Gait & posture
The lumbo-pelvic-hip core complex consists of musculoskeletal structures that stabilize the spine and pelvis, however fatigue may affect muscle recruitment, active muscle stiffness and trunk kinematics, compromising trunk stability. The purpose of this study was to compare trunk muscle activation patterns, and trunk and lower extremity kinematics during walking gait before and after exercise. Surface electrodes were placed over the rectus abdominis, external oblique, erector spinae, gluteus medius, vastus lateralis, and vastus medialis of twenty-five healthy inidviduals. Means and 95% confidence intervals for muscle amplitude, muscle onsent and kinematics for 0-100% of the gait cycle were compared before and after exercise. Mean differences (MD) and standard deviations were calculated for all significant differences. The amplitude increased in the rectus abdominis during loading (MD=0.67±0.11), midstance (MD=0.75±0.04), terminal stance (MD=0.58±0.04), and late swing (MD=0.75±0.07) after exercise. Amplitude also increased during swing phase in the erector spinae (MD=0.92±0.11), vastus lateralis (MD=1.12±0.30), and vastus medialis (MD=1.80±0.19) after exercise. There was less trunk and hip rotation from initial contact to midstance after exercise. Neuromuscular fatigue significantly influenced the activation patterns of superficial musculature and kinematics of the lumbo-pelvic-hip complex during walking. Increased muscle activation with decreased movement in a fatigued state may represent an effort to increase trunk stiffness to protect lumbo-pelvic-hip structures from overload.
The Activity of Surface Electromyographic Signal of Selected Muscles during Classic Rehabilitation Exercise.
Xiao Jinzhuang,Sun Jinli,Gao Junmin,Wang Hongrui,Yang Xincai
Rehabilitation research and practice
Objectives. Prone bridge, unilateral bridge, supine bridge, and bird-dog are classic rehabilitation exercises, which have been advocated as effective ways to improve core stability among healthy individuals and patients with low back pain. The aim of this study was to investigate the activity of seven selected muscles during rehabilitation exercises through the signal of surface electromyographic. Approaches. We measured the surface electromyographic signals of four lower limb muscles, two abdominal muscles, and one back muscle during rehabilitation exercises of 30 healthy students and then analyzed its activity level using the median frequency method. Results. Different levels of muscle activity during the four rehabilitation exercises were observed. The prone bridge and unilateral bridge caused the greatest muscle fatigue; however, the supine bridge generated the lowest muscle activity. There was no significant difference (P > 0.05) between left and right body side muscles in the median frequency slope during the four rehabilitation exercises of seven muscles. Conclusions. The prone bridge can affect the low back and lower limb muscles of most people. The unilateral bridge was found to stimulate muscles much more active than the supine bridge. The bird-dog does not cause much fatigue to muscles but can make most selected muscles active.
The Activation Pattern of Trunk and Lower Limb Muscles in an Electromyographic Assessment; Comparison Between Ground and Treadmill Walking.
Mazaheri Reza,Sanjari Mohammad Ali,Radmehr Gelareh,Halabchi Farzin,Angoorani Hooman
Asian journal of sports medicine
BACKGROUND:Due to biomechanical differences, various patterns of muscle contraction are expected to occur while walking over ground versus when walking on a treadmill. OBJECTIVES:This study aimed to compare amplitude and duration of activation of selected trunk and lower extremity muscles during over-ground and treadmill walking. MATERIALS AND METHODS:Through a simple sampling method, 19 sedentary healthy men within the age range of 20 - 40 were selected. Surface electromyography of rectus abdominis, external oblique, longissimus and multifidus muscles as the selected trunk muscles and vastus medialis, vastus lateralis and hamstrings as the selected lower limb muscles were recorded. RESULTS:In each gait cycle, there were no statistically significant differences in duration of selected trunk as well as lower limb muscles activity between treadmill and over-ground walking. However the mean amplitude of rectus abdominis (P = 0.005), longissimus (P = 0.018) and multifidus (P = 0.044) as the selected trunk muscles as well as the mean amplitude of vastus lateralis (P = 0.005) and vastus medialis (P < 0.001) as the lower limb muscles was greater on treadmill compared with over ground. CONCLUSIONS:Due to the stabilizing role of trunk and lower limb muscles during walking, these muscles seem to be active throughout the entire gait cycle. The increased muscle amplitude on treadmill can demonstrate that more motor units may be recruited during the contraction, which can be helpful in prescribing the appropriate type of exercise especially for patients with core muscle weakness.
Core stability training for injury prevention.
Huxel Bliven Kellie C,Anderson Barton E
CONTEXT:Enhancing core stability through exercise is common to musculoskeletal injury prevention programs. Definitive evidence demonstrating an association between core instability and injury is lacking; however, multifaceted prevention programs including core stabilization exercises appear to be effective at reducing lower extremity injury rates. EVIDENCE ACQUISITION:PUBMED WAS SEARCHED FOR EPIDEMIOLOGIC, BIOMECHANIC, AND CLINICAL STUDIES OF CORE STABILITY FOR INJURY PREVENTION (KEYWORDS: "core OR trunk" AND "training OR prevention OR exercise OR rehabilitation" AND "risk OR prevalence") published between January 1980 and October 2012. Articles with relevance to core stability risk factors, assessment, and training were reviewed. Relevant sources from articles were also retrieved and reviewed. RESULTS:Stabilizer, mobilizer, and load transfer core muscles assist in understanding injury risk, assessing core muscle function, and developing injury prevention programs. Moderate evidence of alterations in core muscle recruitment and injury risk exists. Assessment tools to identify deficits in volitional muscle contraction, isometric muscle endurance, stabilization, and movement patterns are available. Exercise programs to improve core stability should focus on muscle activation, neuromuscular control, static stabilization, and dynamic stability. CONCLUSION:Core stabilization relies on instantaneous integration among passive, active, and neural control subsystems. Core muscles are often categorized functionally on the basis of stabilizing or mobilizing roles. Neuromuscular control is critical in coordinating this complex system for dynamic stabilization. Comprehensive assessment and training require a multifaceted approach to address core muscle strength, endurance, and recruitment requirements for functional demands associated with daily activities, exercise, and sport.
Analysis of muscle activity during active pelvic tilting in sagittal plane.
Takaki Sho,Kaneoka Koji,Okubo Yu,Otsuka Satoru,Tatsumura Masaki,Shiina Itsuo,Miyakawa Shumpei
Physical therapy research
BACKGROUND:Pelvic tilting is performed to improve lumbopelvic flexibility or retrain the motor control of local muscles. However, few studies investigated the activity of local muscles during pelvic tilting. PURPOSE:The purpose of this study was to investigate muscle activity during anterior and posterior pelvic tilting. METHOD:Twelve healthy males (age, 22.6 ± 1.4 years) participated. Fine-wire electrodes were inserted into the bilateral lumbar multifidus (MF) and transversus abdominis (TrA). Surface electrodes were used to record activity of the bilateral rectus abdominis, external oblique, and erector spinae (ES), and the unilateral right latissimus dorsi, gluteus maximus, semitendinosus, and rectus femoris muscles. The electromyographic activities during anterior and posterior pelvic tilting in a standing position were recorded and expressed as a percentage of the maximum voluntary contraction (%MVC) for each muscle. RESULTS:The activities of the bilateral MF (right: 23.9 ± 15.9 %MVC, left: 23.9 ± 15.1 %MVC) and right ES (19.0 ± 13.3 %MVC) were significantly greater than those of the other muscles during anterior pelvic tilting. The activity of the left TrA (14.8 ± 16.4 %MVC) was significantly greater than that of the other muscles during posterior pelvic tilting. CONCLUSIONS:The results suggested that the MF and ES are related to anterior pelvic tilting. The activity of the TrA, which was classified as a local muscle, was greater during posterior pelvic tilting. This study indicated that local muscles such as the MF and TrA may be related to pelvic tilting.
Muscle, skin and core temperature after -110°c cold air and 8°c water treatment.
Costello Joseph Thomas,Culligan Kevin,Selfe James,Donnelly Alan Edward
The aim of this investigation was to elucidate the reductions in muscle, skin and core temperature following exposure to -110°C whole body cryotherapy (WBC), and compare these to 8°C cold water immersion (CWI). Twenty active male subjects were randomly assigned to a 4-min exposure of WBC or CWI. A minimum of 7 days later subjects were exposed to the other treatment. Muscle temperature in the right vastus lateralis (n=10); thigh skin (average, maximum and minimum) and rectal temperature (n=10) were recorded before and 60 min after treatment. The greatest reduction (P<0.05) in muscle (mean ± SD; 1 cm: WBC, 1.6 ± 1.2°C; CWI, 2.0 ± 1.0°C; 2 cm: WBC, 1.2 ± 0.7°C; CWI, 1.7 ± 0.9°C; 3 cm: WBC, 1.6 ± 0.6°C; CWI, 1.7 ± 0.5°C) and rectal temperature (WBC, 0.3 ± 0.2°C; CWI, 0.4 ± 0.2°C) were observed 60 min after treatment. The largest reductions in average (WBC, 12.1 ± 1.0°C; CWI, 8.4 ± 0.7°C), minimum (WBC, 13.2 ± 1.4°C; CWI, 8.7 ± 0.7°C) and maximum (WBC, 8.8 ± 2.0°C; CWI, 7.2 ± 1.9°C) skin temperature occurred immediately after both CWI and WBC (P<0.05). Skin temperature was significantly lower (P<0.05) immediately after WBC compared to CWI. The present study demonstrates that a single WBC exposure decreases muscle and core temperature to a similar level of those experienced after CWI. Although both treatments significantly reduced skin temperature, WBC elicited a greater decrease compared to CWI. These data may provide information to clinicians and researchers attempting to optimise WBC and CWI protocols in a clinical or sporting setting.
The effect of short-term isometric training on core/torso stiffness.
Lee Benjamin,McGill Stuart
Journal of sports sciences
"Core" exercise is a basic part of many physical training regimens with goals ranging from rehabilitation of spine and knee injuries to improving athletic performance. Core stiffness has been proposed to perform several functions including reducing pain by minimising joint micro-movements, and enhancing strength and speed performance. This study probes the links between a training approach and immediate but temporary changes in stiffness. Passive and active stiffness was measured on 24 participants; 12 having little to no experience in core training (inexperienced), and the other 12 being athletes experienced to core training methods; before and after a 15 min bout of isometric core exercises. Passive stiffness was assessed on a "frictionless" bending apparatus and active stiffness assessed via a quick release mechanism. Short-term isometric core training increased passive and active stiffness in most directions for both inexperienced and experienced participants, passive left lateral bend among experienced participants being the exception (P < 0.05). There was no difference between the inexperienced and experienced groups. The results confirm that the specific isometric training exercise approach tested here can induce immediate changes in core stiffness, in this case following a single session. This may influence performance and injury resilience for a brief period.
Effect of Core Stability Training on Trunk Function, Standing Balance, and Mobility in Stroke Patients.
Haruyama Koshiro,Kawakami Michiyuki,Otsuka Tomoyoshi
Neurorehabilitation and neural repair
BACKGROUND:Trunk function is important for standing balance, mobility, and functional outcome after stroke, but few studies have evaluated the effects of exercises aimed at improving core stability in stroke patients. OBJECTIVE:To investigate the effectiveness of core stability training on trunk function, standing balance, and mobility in stroke patients. METHODS:An assessor-blinded, randomized controlled trial was undertaken in a stroke rehabilitation ward, with 32 participants randomly assigned to an experimental group or a control group (n = 16 each). The experimental group received 400 minutes of core stability training in place of conventional programs within total training time, while the control group received only conventional programs. Primary outcome measures were evaluated using the Trunk Impairment Scale (TIS), which reflects trunk function. Secondary outcome measures were evaluated by pelvic tilt active range of motion in the sagittal plane, the Balance Evaluation Systems Test-brief version (Brief-BESTest), Functional Reach test, Timed Up-and-Go test (TUG), and Functional Ambulation Categories (FAC). A general linear repeated-measures model was used to analyze the results. RESULTS:A treatment effect was found for the experimental group on the dynamic balance subscale and total score of the TIS ( P = .002 and P < .001, respectively), pelvic tilt active range of motion ( P < .001), Brief-BESTest ( P < .001), TUG ( P = .008), and FAC ( P = .022). CONCLUSIONS:Core stability training has beneficial effects on trunk function, standing balance, and mobility in stroke patients. Our findings might provide support for introducing core stability training in stroke rehabilitation.
Electromyographic activity of selected trunk, core, and thigh muscles in commonly used exercises for ACL rehabilitation.
Khaiyat Omid A,Norris Jessica
Journal of physical therapy science
[Purpose] Most of rehabilitation programmes for Anterior Cruciate Ligament (ACL) injury focus on quadriceps-hamstrings activation imbalances and less is known about kinetically linked muscles. This study investigated electromyographic activity of selected trunk, core, and thigh muscles during common rehabilitation exercises for ACL injury. [Subjects and Methods] Twelve active female volunteers participated in this cross-sectional laboratory study. Surface EMG was used to compare activation of eight trunk, hip/core, and lower limb muscles: Erector Spinae (ES), Rectus Abdominis (RA), Gluteus Maximus (GM), Vastus Lateralis (VL), Rectus Femoris (RF), Vastus Medialis (VM), Biceps Femoris (BF), and Semitendinosus (ST) during Forward Lunge, Double Leg Raise, Glute Bridge, Sit-Up, and Squat. [Results] Forward lunge produced significantly higher activation in the VM (61.1 ± 19.4), VL (59.2 ± 12.9), and RF (32.0 ± 2.6). Double leg raise generated highest activity in the RF (26.6 ± 2.8) and RA (43.3 ± 4.4); and Glute Bridge in the GM (44.5 ± 19.0) and BF (22.4 ± 4.3). Sit-up produced the highest activation in the RF (36.6 ± 4.7) followed by RA (18.9 ± 3.8). Squat produced a higher activation in VL (55.0 ± 12.9), VM (51.5 ± 18.2), and ES (40.4 ± 18.3). [Conclusion] This study provide further evidence for developing training programmes for ACL injury prevention and rehabilitation. A combination of exercises to reinstate quadriceps-hamstrings activation balance and enhance core stability is recommended.
The use of electromyography and magnetic resonance imaging to evaluate a core strengthening exercise programme.
Rutkowska-Kucharska Alicja,Szpala Agnieszka
Journal of back and musculoskeletal rehabilitation
BACKGROUND:The question that was asked in the study was whether a training routine based on curl-up exercises with a load provided by body mass of the person increases local muscle strength or local muscle endurance. OBJECTIVE:The aim of this study was to evaluate the effect of 4 weeks training based on a small load and low movement velocity on electrical activity (EMG), cross-sectional area (CSA) of core stabilisers. METHODS:The EMG activity was measured in the rectus abdominis (RA), obliquus abdominis externus and erector spinae (ES) muscles. CSA of the muscles: RA, anterolateral abdominal, psoas major, quadratus lumborum, ES, and multifidus at the level of L3-L4 were measured too. RESULTS:The training increased the CSA and thickness in most of the muscles studied. Statistically significant correlation was found only for the ES circumference (left side) and EMG activity for the right side (r= 0.627, p= 0.022) and left side (r= 0.624, p= 0.023). CONCLUSIONS:The training programme resulted in a increase in the number of curl-up repetitions revealing an endurance increase in abdominal muscles. Furthermore, there was a increase in the EMG activity of the RA. An increase of the CSA of all tested muscles showed an increase of muscle active force.
The Training Effects of Foam Rolling on Core Strength Endurance, Balance, Muscle Performance and Range of Motion: A Randomized Controlled Trial.
Junker Daniel,Stöggl Thomas
Journal of sports science & medicine
Self myofascial therapy via foam roller is a common technique used by many athletes and patients to aid recovery, improve range of motion (ROM) and prevent injury. Further, it is suggested that foam rolling improves core stability. However, research about the training effects of foam rolling on measures of core "strength endurance", muscle performance, balance and flexibility is limited. Forty recreationally active females and males (age: 18-48 yrs) were randomly assigned to a foam roll (FOAM, n = 14), a core stabilization (CORE; n = 12) and a control group (CG, n = 12). FOAM massaged their lower leg muscles (5 exercises) with the foam roll 2 times per week for 8 weeks while CORE was assigned to core stability training including 5 exercises. CG underwent no intervention. Applied tests for outcome measurements were the Bourban trunk muscle strength test (TMS), standing long jump (SLJ), single leg triple hop for distance (SLTH) test, Y-Balance test and stand and reach test. There was an interaction effect (time x treatment) for the dorsal TMS (p = 0.043), demonstrating greater improvements in CORE compared with FOAM and CG with no difference between FOAM and CG. For the stand and reach test a main effect for time (p < 0.001) and time x treatment interaction (p = 0.005) were found, indicating an increase in ROM in FOAM compared with CORE and CG with no difference between the latter. No significant effects were found for balance and muscle performance. An 8-week training with the foam roll is effective in increasing ROM in the stand and reach test without concomitant decreases in core "strength endurance", muscle performance and balance parameters. The core stabilization training was sufficient to improve performance in dorsal TMS test.
Evaluating Abdominal and Lower-Back Muscle Activity While Performing Core Exercises on a Stability Ball and a Dynamic Office Chair.
Holmes Michael W R,De Carvalho Diana E,Karakolis Thomas,Callaghan Jack P
OBJECTIVE:The purpose of this study was to evaluate the ability of a dynamic office chair to activate the core muscles while participants performed exercises sitting on the chair compared to a stability ball. BACKGROUND:Prolonged sitting has become an accepted part of the modern office. However, epidemiological evidence suggests that sedentary postures are linked to many adverse effects on health. The concept of dynamic or active sitting is intended to promote movement while sitting to reduce the time spent in prolonged, static postures. METHODS:Sixteen participants performed four pelvic rotation exercises (front-back, side-side, circular, and leg lift) on both a dynamic office chair and a stability ball. Muscle activity from 12 torso muscles were evaluated with surface electromyography. RESULTS:For all exercises, trunk muscle activity on the chair was comparable to that on a stability ball. The right external oblique was the only muscle to produce greater peak activity (p = .019) when using the ball compared to the chair (21.4 ± 14.0 percent maximal voluntary excitations (%MVE) and 14.7 ± 10.8 %MVE for the ball and chair, respectively). The left thoracic erector spinae produced greater average activity (p = .044) on the chair than on the ball. CONCLUSION:These findings suggest that this dynamic sitting approach could be an effective tool for core muscle activation while promoting movement and exercise while sitting at work. APPLICATION:Muscle activations on the dynamic chair are comparable to those on a stability ball, and dynamic office chairs can promote movement and exercise while sitting at work.
Core Muscle Activation in Suspension Training Exercises.
Cugliari Giovanni,Boccia Gennaro
Journal of human kinetics
A quantitative observational laboratory study was conducted to characterize and classify core training exercises executed in a suspension modality on the base of muscle activation. In a prospective single-group repeated measures design, seventeen active male participants performed four suspension exercises typically associated with core training (roll-out, bodysaw, pike and knee-tuck). Surface electromyographic signals were recorded from lower and upper parts of rectus abdominis, external oblique, internal oblique, lower and upper parts of erector spinae muscles using concentric bipolar electrodes. The average rectified values of electromyographic signals were normalized with respect to individual maximum voluntary isometric contraction of each muscle. Roll-out exercise showed the highest activation of rectus abdominis and oblique muscles compared to the other exercises. The rectus abdominis and external oblique reached an activation higher than 60% of the maximal voluntary contraction (or very close to that threshold, 55%) in roll-out and bodysaw exercises. Findings from this study allow the selection of suspension core training exercises on the basis of quantitative information about the activation of muscles of interest. Roll-out and bodysaw exercises can be considered as suitable for strength training of rectus abdominis and external oblique muscles.
The Relationship of Core Strength and Activation and Performance on Three Functional Movement Screens.
Johnson Caleb D,Whitehead Paul N,Pletcher Erin R,Faherty Mallory S,Lovalekar Mita T,Eagle Shawn R,Keenan Karen A
Journal of strength and conditioning research
Johnson, CD, Whitehead, PN, Pletcher, ER, Faherty, MS, Lovalekar, MT, Eagle, SR, and Keenan, KA. The relationship of core strength and activation and performance on three functional movement screens. J Strength Cond Res 32(4): 1166-1173, 2018-Current measures of core stability used by clinicians and researchers suffer from several shortcomings. Three functional movement screens appear, at face-value, to be dependent on the ability to activate and control core musculature. These 3 screens may present a viable alternative to current measures of core stability. Thirty-nine subjects completed a deep squat, trunk stability push-up, and rotary stability screen. Scores on the 3 screens were summed to calculate a composite score (COMP). During the screens, muscle activity was collected to determine the length of time that the bilateral erector spinae, rectus abdominis, external oblique, and gluteus medius muscles were active. Strength was assessed for core muscles (trunk flexion and extension, trunk rotation, and hip abduction and adduction) and accessory muscles (knee flexion and extension and pectoralis major). Two ordinal logistic regression equations were calculated with COMP as the outcome variable, and: (a) core strength and accessory strength, (b) only core strength. The first model was significant in predicting COMP (p = 0.004) (Pearson's Chi-Square = 149.132, p = 0.435; Nagelkerke's R-Squared = 0.369). The second model was significant in predicting COMP (p = 0.001) (Pearson's Chi-Square = 148.837, p = 0.488; Nagelkerke's R-Squared = 0.362). The core muscles were found to be active for most screens, with percentages of "time active" for each muscle ranging from 54-86%. In conclusion, performance on the 3 screens is predicted by core strength, even when accounting for "accessory" strength variables. Furthermore, it seems the screens elicit wide-ranging activation of core muscles. Although more investigation is needed, these screens, collectively, seem to be a good assessment of core strength.