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The kinematics of table tennis racquet: differences between topspin strokes. Bańkosz Ziemowit,Winiarski Sławomir The Journal of sports medicine and physical fitness BACKGROUND:Studies of shot kinematics in table tennis have not been sufficiently described in the literature. The assessment of the racquet trajectory, its speed and time characteristics makes it possible to emphasize on certain technical elements in the training process in order, for example, to increase strength, speed of rotation or speed of the shot while maintaining its accuracy. The aim of this work was to measure selected kinematic parameters of table tennis racquet during forehand and backhand topspin shots, while considering the differences between these strokes in table tennis. METHODS:The measurements took place in a certified biomechanical laboratory using a motion analysis system. The study involved 12 female table tennis players in high-level sports training and performance. Each subject had to complete series of six tasks, presenting different varieties of topspin shots. RESULTS:The longest racquet trajectory was related to forehand shots, shots played against a ball with backspin and winner shots. The maximum racquet velocity was precisely in the moment of impact with the ball. The individual of velocity and distance were larger in the direction of the acting force, depending on the individual shot. CONCLUSIONS:Changing the type of topspin shot requires changes of time, velocity and primarily distance parameters as well as the direction of the playing racquet. The maximum speed of the racquet occurring at the moment of the impact is probably the most important principle in playing technique. The results can be directly used in improving training of table tennis techniques, especially in the application and use of topspin shots. 10.23736/S0022-4707.16.06104-1
Effects of different visual stimuli on postures and knee moments during sidestepping. Lee Marcus J C,Lloyd David G,Lay Brendan S,Bourke Paul D,Alderson Jacqueline A Medicine and science in sports and exercise PURPOSE:Evasive sidestepping during sports commonly results in noncontact anterior cruciate ligament injuries. Sidestepping in response to different simple visual stimuli has been studied previously but never investigated using quasi-game-realistic visual conditions. We compared the biomechanics of high-level and low-level soccer players when sidestepping in response to projected, three-dimensional defender(s) and the traditionally used planned and unplanned arrow stimuli. METHODS:A three-dimensional motion analysis system captured the trunk and lower limb kinematics and ground reaction forces of 15 high-level and 15 low-level soccer players sidestepping in response to a one-defender scenario (1DS), two-defender scenario (2DS), arrow-planned condition (AP), and arrow-unplanned condition (AUNP). The temporal constraints imposed by the stimuli conditions resulted in increasing difficulty from AP, 1DS, 2DS, to AUNP. Selected joint kinematics and three-dimensional knee moments during the weight-acceptance phase of sidestepping were analyzed. RESULTS:Hip external rotation at initial foot contact was smaller when participants sidestepped in response to the projected defenders versus arrow conditions. Hip abduction was smallest in the AP, moderate in the defender scenarios, and largest in the AUNP. Peak knee valgus moments were 25% larger in the defender scenarios and 70% larger in the AUNP compared with the AP. High-level players exhibited decreased hip abduction and knee valgus moments in the 2DS compared with the low-level players. CONCLUSIONS:Compared with the arrow conditions, sidestepping in response to the defender(s) resulted in different postures and knee moments, which further differentiated between high-level and low-level players in the complex 2DS. These findings highlight the effects of stimuli realism and complexity on the visual-perceptual-motor skill of sidestepping, which has implications for anterior cruciate ligament injury prevention. 10.1249/MSS.0b013e318290c28a
Management of sports injuries of the foot and ankle: An update. Hong C C,Pearce C J,Ballal M S,Calder J D F The bone & joint journal Injuries to the foot in athletes are often subtle and can lead to a substantial loss of function if not diagnosed and treated appropriately. For these injuries in general, even after a diagnosis is made, treatment options are controversial and become even more so in high level athletes where limiting the time away from training and competition is a significant consideration. In this review, we cover some of the common and important sporting injuries affecting the foot including updates on their management and outcomes. Cite this article: Bone Joint J 2016;98-B:1299-1311. 10.1302/0301-620X.98B10.37896
ACL reconstruction in the professional or elite athlete: state of the art. Buerba Rafael A,Zaffagnini Stefano,Kuroda Ryosuke,Musahl Volker Journal of ISAKOS : joint disorders & orthopaedic sports medicine Anterior cruciate ligament (ACL) injuries are on the rise at all levels of sport, including elite athletics. ACL injury can have implications on the athlete's sport longevity, as well as other long-term consequences, such as the development of future knee osteoarthritis. In the elite athlete, ACL injury can also have ramifications in terms of contract/scholastic obligations, sponsorships and revenue-generating potential. Although the goal of anterior cruciate ligament reconstruction (ACLR) is to return any athlete to the same preinjury level of sport, management of ACL injuries in the elite athlete come with the additional challenge of returning him or her to an extremely high level of physical performance. Despite outcome studies after ACLR in elite athletes showing a high return-to-sport rate, these studies also show that very few athletes are able to return to sport at the same level of performance. They also show that those athletes who undergo ACLR have careers that are more short-lived in comparison to those without injury. Thus, returning an elite athlete to 'near peak' performance may not be good enough for the athletic demands of elite-level sports. A possible explanation for the variability in outcomes is the great diversity seen in the management of ACL injuries in the elite athlete in terms of rehabilitation, graft choices, portal drilling and reconstruction techniques. Recently, the advent of anatomical, individualised ACLR has shown improved results in ACLR outcomes. However, larger-scale studies with long-term follow-ups are needed to better understand the outcomes of modern ACLR techniques-particularly with the rise of quadriceps tendon as an autograft choice and the addition of lateral extra-articular tenodesis procedures. The purpose of this article was thus to provide an up-to-date state-of-the-art review in the management of ACL injuries in the elite athlete. 10.1136/jisakos-2020-000456
[Rehabilitation concepts and return to sport after interventions on the shoulder]. Dreinhöfer K E,Schüler S,Schäfer M,Ohly T Der Orthopade BACKGROUND:Rehabilitation of athletes following surgical interventions for shoulder injuries is of utmost importance for recovery and return to sport. OBJECTIVES:The aim was to determine adequate concepts for rehabilitation following shoulder surgery in athletes. METHODS:A selective literature search was carried out in PubMed and a review of the available concepts is given taking personal experiences as well as national and international recommendations into consideration. RESULTS:This article presents the basic principles of functional rehabilitation, the kinetic chain and the different phases in rehabilitation. Specific rehabilitation concepts and return to sport strategies following traumatic dislocation, superior labrum anterior to posterior (SLAP) lesions and rotator cuff tears are presented. There is little high-level scientific evidence available for the treatment of these patients and most concepts are based on clinical experience and expert opinion. CONCLUSION:Rehabilitation of athletes with shoulder injuries requires a broad consensus strategy with respect to the next steps. Individual concepts for rehabilitation should take surgical and patient-specific criteria into consideration. Further research is urgently required to develop evidence-based recommendations. 10.1007/s00132-013-2149-2
Core Muscle Injury: Evaluation and Treatment in the Athlete. The American journal of sports medicine BACKGROUND:Pain in the groin region, where the abdominal musculature attaches to the pubis, is referred to as a "sports hernia,""athletic pubalgia," or "core muscle injury" and has become a topic of increased interest due to its challenging diagnosis. Identifying the cause of chronic groin pain is complicated because significant symptom overlap exists between disorders of the proximal thigh musculature, intra-articular hip pathology, and disorders of the abdominal musculature. PURPOSE:To present a comprehensive review of the pathoanatomic features, history and physical examination, and imaging modalities used to make the diagnosis of core muscle injury. STUDY DESIGN:Narrative and literature review; Level of evidence, 4. METHODS:A comprehensive literature search was performed. Studies involving the diagnosis, treatment, and rehabilitation of athletes with core muscle injury were identified. In addition, the senior author's extensive experience with the care of professional, collegiate, and elite athletes was analyzed and compared with established treatment algorithms. RESULTS:The differential diagnosis of groin pain in the athlete should include core muscle injury with or without adductor longus tendinopathy. Current scientific evidence is lacking in this field; however, consensus regarding terms and treatment algorithms was facilitated with the publication of the Doha agreement in 2015. Pain localized proximal to the inguinal ligament, especially in conjunction with tenderness at the rectus abdominis insertion, is highly suggestive of core muscle injury. Concomitant adductor longus tendinopathy is not uncommon in these athletes and should be investigated. The diagnosis of core muscle injury is a clinical one, although dynamic ultrasonography is becoming increasingly used as a diagnostic modality. Magnetic resonance imaging is not always diagnostic and may underestimate the true extent of a core muscle injury. Functional rehabilitation programs can often return athletes to the same level of play. If an athlete has been diagnosed with athletic pubalgia and has persistent symptoms despite 12 weeks of nonoperative treatment, a surgical repair using mesh and a relaxing myotomy of the conjoined tendon should be considered. The most common intraoperative finding is a deficient posterior wall of the inguinal canal with injury to the distal rectus abdominis. Return to play after surgery for an isolated sports hernia is typically allowed at 4 weeks; however, if an adductor release is performed as well, return to play occurs at 12 weeks. CONCLUSION:Core muscle injury is a diagnosis that requires a high level of clinical suspicion and should be considered in any athlete with pain in the inguinal region. Concurrent adductor pathology is not uncommon. 10.1177/03635465211063890
Principles of Motor Learning to Support Neuroplasticity After ACL Injury: Implications for Optimizing Performance and Reducing Risk of Second ACL Injury. Gokeler Alli,Neuhaus Dorothee,Benjaminse Anne,Grooms Dustin R,Baumeister Jochen Sports medicine (Auckland, N.Z.) Athletes who wish to resume high-level activities after an injury to the anterior cruciate ligament (ACL) are often advised to undergo surgical reconstruction. Nevertheless, ACL reconstruction (ACLR) does not equate to normal function of the knee or reduced risk of subsequent injuries. In fact, recent evidence has shown that only around half of post-ACLR patients can expect to return to competitive level of sports. A rising concern is the high rate of second ACL injuries, particularly in young athletes, with up to 20% of those returning to sport in the first year from surgery experiencing a second ACL rupture. Aside from the increased risk of second injury, patients after ACLR have an increased risk of developing early onset of osteoarthritis. Given the recent findings, it is imperative that rehabilitation after ACLR is scrutinized so the second injury preventative strategies can be optimized. Unfortunately, current ACLR rehabilitation programs may not be optimally effective in addressing deficits related to the initial injury and the subsequent surgical intervention. Motor learning to (re-)acquire motor skills and neuroplastic capacities are not sufficiently incorporated during traditional rehabilitation, attesting to the high re-injury rates. The purpose of this article is to present novel clinically integrated motor learning principles to support neuroplasticity that can improve patient functional performance and reduce the risk of second ACL injury. The following key concepts to enhance rehabilitation and prepare the patient for re-integration to sports after an ACL injury that is as safe as possible are presented: (1) external focus of attention, (2) implicit learning, (3) differential learning, (4) self-controlled learning and contextual interference. The novel motor learning principles presented in this manuscript may optimize future rehabilitation programs to reduce second ACL injury risk and early development of osteoarthritis by targeting changes in neural networks. 10.1007/s40279-019-01058-0
Rehabilitation of Soft Tissue Injuries of the Hip and Pelvis. Hammond Kyle E,Kneer Lee,Cicinelli Pete Clinics in sports medicine The athlete's hip is complex when it comes to the surrounding musculature-approximately 21 different muscles can cross the hip and pelvis region, all synchronously working to maintain pelvic stability and functional hip activities. Commonly injured muscle groups for high-level athletes include flexors, adductors, abductors, and/or proximal hamstring musculotendinous complex. These muscle groups work in harmony; however, each has an independent function and propensity for injury. Rehabilitation phases for each injury group can be broken down into 3 phases: acute management, strengthening, and return-to-sport or return-to-competition phase. Specific rehabilitation principles and modalities are described for each injury group. 10.1016/j.csm.2021.01.002
Risk of Secondary Injury in Younger Athletes After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis. Wiggins Amelia J,Grandhi Ravi K,Schneider Daniel K,Stanfield Denver,Webster Kate E,Myer Gregory D The American journal of sports medicine BACKGROUND:Injury to the ipsilateral graft used for reconstruction of the anterior cruciate ligament (ACL) or a new injury to the contralateral ACL are disastrous outcomes after successful ACL reconstruction (ACLR), rehabilitation, and return to activity. Studies reporting ACL reinjury rates in younger active populations are emerging in the literature, but these data have not yet been comprehensively synthesized. PURPOSE:To provide a current review of the literature to evaluate age and activity level as the primary risk factors in reinjury after ACLR. STUDY DESIGN:Systematic review and meta-analysis. METHODS:A systematic review of the literature was conducted via searches in PubMed (1966 to July 2015) and EBSCO host (CINAHL, Medline, SPORTDiscus [1987 to July 2015]). After the search and consultation with experts and rating of study quality, 19 articles met inclusion for review and aggregation. Population demographic data and total reinjury (ipsilateral and contralateral) rate data were recorded from each individual study and combined using random-effects meta-analyses. Separate meta-analyses were conducted for the total population data as well as the following subsets: young age, return to sport, and young age + return to sport. RESULTS:Overall, the total second ACL reinjury rate was 15%, with an ipsilateral reinjury rate of 7% and contralateral injury rate of 8%. The secondary ACL injury rate (ipsilateral + contralateral) for patients younger than 25 years was 21%. The secondary ACL injury rate for athletes who return to a sport was also 20%. Combining these risk factors, athletes younger than 25 years who return to sport have a secondary ACL injury rate of 23%. CONCLUSION:This systematic review and meta-analysis demonstrates that younger age and a return to high level of activity are salient factors associated with secondary ACL injury. These combined data indicate that nearly 1 in 4 young athletic patients who sustain an ACL injury and return to high-risk sport will go on to sustain another ACL injury at some point in their career, and they will likely sustain it early in the return-to-play period. The high rate of secondary injury in young athletes who return to sport after ACLR equates to a 30 to 40 times greater risk of an ACL injury compared with uninjured adolescents. These data indicate that activity modification, improved rehabilitation and return-to-play guidelines, and the use of integrative neuromuscular training may help athletes more safely reintegrate into sport and reduce second injury in this at-risk population. 10.1177/0363546515621554
Anterior cruciate ligament- specialized post-operative return-to-sports (ACL-SPORTS) training: a randomized control trial. White Kathleen,Di Stasi Stephanie L,Smith Angela H,Snyder-Mackler Lynn BMC musculoskeletal disorders BACKGROUND:Anterior cruciate ligament reconstruction (ACLR) is standard practice for athletes that wish to return to high-level activities; however functional outcomes after ACLR are poor. Quadriceps strength weakness, abnormal movement patterns and below normal knee function is reported in the months and years after ACLR. Second ACL injuries are common with even worse outcomes than primary ACLR. Modifiable limb-to-limb asymmetries have been identified in individuals who re-injure after primary ACLR, suggesting a neuromuscular training program is needed to improve post-operative outcomes. Pre-operative perturbation training, a neuromuscular training program, has been successful at improving limb symmetry prior to surgery, though benefits are not lasting after surgery. Implementing perturbation training after surgery may be successful in addressing post-operative deficits that contribute to poor functional outcomes and second ACL injury risk. METHODS/DESIGN:80 athletes that have undergone a unilateral ACLR and wish to return to level 1 or 2 activities will be recruited for this study and randomized to one of two treatment groups. A standard care group will receive prevention exercises, quadriceps strengthening and agility exercises, while the perturbation group will receive the same exercise program with the addition of perturbation training. The primary outcomes measures will include gait biomechanics, clinical and functional measures, and knee joint loading. Return to sport rates, return to pre-injury level of activity rates, and second injury rates will be secondary measures. DISCUSSION:The results of this ACL-Specialized Post-Operative Return To Sports (ACL-SPORTS) Training program will help clinicians to better determine an effective post-operative treatment program that will improve modifiable impairments that influence outcomes after ACLR. TRIAL REGISTRATION:Randomized Control Trial NIH 5R01AR048212-07. ClinicalTrials.gov: NCT01773317. 10.1186/1471-2474-14-108
Recovery and Performance in Sport: Consensus Statement. Kellmann Michael,Bertollo Maurizio,Bosquet Laurent,Brink Michel,Coutts Aaron J,Duffield Rob,Erlacher Daniel,Halson Shona L,Hecksteden Anne,Heidari Jahan,Kallus K Wolfgang,Meeusen Romain,Mujika Iñigo,Robazza Claudio,Skorski Sabrina,Venter Ranel,Beckmann Jürgen International journal of sports physiology and performance The relationship between recovery and fatigue and its impact on performance has attracted the interest of sport science for many years. An adequate balance between stress (training and competition load, other life demands) and recovery is essential for athletes to achieve continuous high-level performance. Research has focused on the examination of physiological and psychological recovery strategies to compensate external and internal training and competition loads. A systematic monitoring of recovery and the subsequent implementation of recovery routines aims at maximizing performance and preventing negative developments such as underrecovery, nonfunctional overreaching, the overtraining syndrome, injuries, or illnesses. Due to the inter- and intraindividual variability of responses to training, competition, and recovery strategies, a diverse set of expertise is required to address the multifaceted phenomena of recovery, performance, and their interactions to transfer knowledge from sport science to sport practice. For this purpose, a symposium on Recovery and Performance was organized at the Technical University Munich Science and Study Center Raitenhaslach (Germany) in September 2016. Various international experts from many disciplines and research areas gathered to discuss and share their knowledge of recovery for performance enhancement in a variety of settings. The results of this meeting are outlined in this consensus statement that provides central definitions, theoretical frameworks, and practical implications as a synopsis of the current knowledge of recovery and performance. While our understanding of the complex relationship between recovery and performance has significantly increased through research, some important issues for future investigations are also elaborated. 10.1123/ijspp.2017-0759
Osteochondritis dissecans of the lateral humeral condyle in a table tennis player. Pintore E,Maffulli N Medicine and science in sports and exercise The case of a table tennis player suffering from intra-articular loose bodies of the elbow is reported. The patient developed the first signs of osteochondritis dissecans of the right lateral humeral condyle at age 16 but underwent surgery only 6 yr later. He has now resumed training and competition, despite some residual stiffness due to early osteoarthritis. This is the first case of osteochondritis dissecans of the elbow ascribed to this sport. It was probably due to repetitive valgus compressive stresses at the radiocapitellar joint during the forced movements imposed by high-level table tennis in a young athlete.
Elite Athletes' In-event Competitive Anxiety Responses and Psychological Skills Usage under Differing Conditions. Frontiers in psychology Even though the assessment of competitive anxiety responses (intensity, interpretation, and frequency) using the time-to-event paradigm has gained much attention, literature on the account of these same experiences in-event and their corresponding psychological skills adopted under differing conditions is limited. This is a follow up investigation to establish the extent to which associated anxiety responses are stable or dynamic and whether this pattern could be related to reported psychological skills under low or high stressful conditions across gender. Twenty-three high level ( = 13 males and 10 females) Ghanaian Table Tennis players provided data through completion of modified versions of Competitive State Anxiety Inventory-2, incorporated with directional and frequency of intrusion scales and the Test of Performance Strategies inventory during breaks within competitive fixtures. MANCOVAs (gender × stress condition) with follow-up analyses revealed no significant interactions and no main effect for gender but significant main effects were realized for all anxiety dimensions and psychological skills for only the second factor. Specifically, the intensity and frequency of cognitive and somatic state anxiety symptoms increased and were interpreted as debilitative under the high stress condition, although self-confidence and other array of psychological skills were highly displayed under the same stressful condition. Findings highlight the dynamic characteristics of in-event associated anxiety responses and ineffectiveness of deployed psychological skills regardless of gender. These perhaps show the exceptionality of affective experiences in an African setting, suggesting a culturally diversified approach to psychological skills application, if desirable effects are to be attained. 10.3389/fpsyg.2017.02280
Catecholamine excretion and heart rate as factors of psychophysical stress in table tennis. Baron R,Petschnig R,Bachl N,Raberger G,Smekal G,Kastner P International journal of sports medicine Table tennis, like tennis, squash and badminton, is a racket sport. All these sports have in common a rapid succession of mostly short-term maximal or submaximal efforts and short recovery phases. The goal of this paper is to investigate the psychophysical stress in table tennis by means of the stress hormones epinephrine and norepinephrine. The catecholamines were determined from urine samples. 16 Austrian top-level table tennis players were examined. There were 8 female and 8 male players in this group. The catecholamine excretion at rest (R), training (TR), practice competition (PC), competition (C) and treadmill ergometry (TE) are indicated in ng/min of collecting time. When the group is divided according to sex, we find marked differences in the catecholamine release. While the epinephrine excretion during and after training and practice competition is basically the same, it is lower during and after treadmill ergometry and higher after competition. The same result was found with respect to norepinephrine excretion. The ratio between norepinephrine and epinephrine was 4:1 at rest and during and after treadmill ergometry, 6:1 during and after training, 5:1 during and after the practice competition and 2:1 during and after the competition. The investigation showed that a table tennis competition puts high stress on the player. The mental component should therefore receive much more importance in order to keep the stress low. 10.1055/s-2007-1021306
The Role of Diets and Dietitians for Para-Athletes: A Pilot Study Based on Interviews. Nutrients Efforts to provide nutrition support to para-athletes have not been established to date, and are far behind those established for athletes without disabilities. In the present study, we attempted to clarify the actual situation regarding dietary challenges of para-athletes. The aim of this study was to obtain clues to effective intervention methods that encourage the practice of sports nutrition. Six active elite para-athletes (30-70 years, four males) and a female physical therapist without physical disability participated in semi-structured interviews. All para-athletes had lower-limb disabilities and participated in the international wheelchair sports competitions (tennis, softball, and table tennis, with 2-26 years of player history). The interview items were on the ideal diet for improving competitive performance, evaluation of their typical diets, and the role of the dietitian as support. Responses obtained from participants were analyzed using quantitative content analysis by language analysis software. There are differences in the ideal diet based on the characteristics of the sport, but most participants believed that a nutritionally well-balanced diet with abundant vegetables was ideal for improving competitive performance. Para-athletes who use a wheelchair daily pay attention to their total calorie intake, because gaining weight is a critical issue for operating their wheelchairs and transferring themselves to and from their wheelchairs. Despite their world-class competition levels, none of them received routine dietary advice from dietitians. Some para-athletes did not even feel the need to engage with dietitians. Even for these para-athletes at a high level of competition, the "ideal diet" they considered was not always the optimal diet for improving their competitive performance. In addition, there are various barriers to practicing their optimal diet due to disability characteristics. Dietitians need to understand these barriers, their concerns and conflicts, and how to help them plan the optimal diet to improve their performance and maintain overall health. 10.3390/nu14183720
A Multidisciplinary Investigation of the Effects of Competitive State Anxiety on Serve Kinematics in Table Tennis. Ngo Vuong,Richards Hugh,Kondric Miran Journal of human kinetics Displays of anxiety in table tennis were assessed through subjective (a self-report questionnaire), physiological (heart-rate variability) and kinematic variables. Using a within-group crossover design, 9 university-level table tennis players completed a series of serves under low- and high-anxiety conditions. Anxiety manipulation was achieved through the introduction of a national standard table tennis player, known to the participants, to receive serves in the high-anxiety condition, whilst serves were received by no opponent in the low-anxiety condition. Automated motion capture systems consisting of high-speed 3D motion cameras and analytical software (QUALISYS) determined the subject's movement kinematics: bat face angle (degrees) and serve routine duration (s). Self-reported state anxiety (MRF-Likert) and heart rate measurements were collected to examine changes between conditions. Contrary to the hypothesis, bat face angles did not change significantly between anxiety conditions (F (1.8) = 2.791, p = 0.133) and movement times were faster in the high-anxiety condition. In light of these findings, research into other facets of movement behaviour must be analysed to gain further understanding of the effects of anxiety on performance, which remain unclear. 10.1515/hukin-2017-0008
Comparative Study of Kinematics and Muscle Activity Between Elite and Amateur Table Tennis Players During Topspin Loop Against Backspin Movements. Wang Meizi,Fu Lin,Gu Yaodong,Mei Qichang,Fu Fengqin,Fernandez Justin Journal of human kinetics This study investigated differences of lower limb kinematics and muscle activity during table tennis topspin loop against backspin movements between elite players (EPs) and amateur players (APs). Ten EPs and ten APs performed crosscourt backhand loop movements against the backspin ball with maximal power. Vicon motion analysis and a MEGA ME6000 system was used to capture kinematics and surface EMG data. The motion was divided into two phases, including the backswing and swing. The joints' flexion and extension angle tendency between EPs and APs differed significantly. The coefficient of multiple correlation (CMC) values for EPs were all beyond 0.9, indicating high similarity of joint angles change. APs presented moderate similarity with CMC values from 0.5 to 0.75. Compared to APs, EPs presented larger ankle eversion, knee and hip flexion at the beginning moment of the backswing. In the sEMG test, EPs presented smaller standardized AEMG (average electromyography) of the lower limb muscles in the rectus femoris and tibia anterior on both sides. Additionally, the maximum activation of each muscle for EPs was smaller and MPF (mean power frequency) of the lower limb was greater during the whole movement. The present study revealed that EPs could complete this technical motion more economically than APs, meanwhile, EPs were more efficient in muscle usage and showed better balance ability. 10.1515/hukin-2017-0182
Developing a tool to assess technical skills in talented youth table tennis players-a multi-method approach combining professional and scientific literature and coaches' perspectives. Faber Irene R,Koopmann Till,Büsch Dirk,Schorer Jörg Sports medicine - open BACKGROUND:The assessment of technical skills as part of a multidimensional approach for talent identification and development in sports seems promising, especially in a technique-based sport like table tennis. However, current instruments mostly focus on a single element of technical skills, mainly use quantitative outcomes, and/or are not developed for talent purposes. Practice would benefit from a new instrument using a more ecologically valid approach. Thus, the purpose of this study was to identify the essential elements of technical skills in young table tennis players and to establish a first tool while using a multi-methods study design including an archive search for professional literature, a systematic search for scientific literature, as well as ten in-depth interviews with expert coaches. RESULTS:This approach taken ensured empirical findings to be combined with knowledge and experiences from the practical field and detailed explications by high-level expert coaches. Results for the literature searches yielded 23 professional and 21 scientific articles while data saturation was reached through all ten interviews. The triangulation process resulted in two general (i.e., individuality, interconnection between elements) and five specific (i.e., bat grip, ready position, footwork/body positioning, service, stroke) elements of technical skills in young table tennis players. In addition, criteria for both flawed and excellent executions were identified for each of the five specific elements. Finally, these results were used to create an observation sheet usable for an assessment during competition. CONCLUSIONS:This study revealed the crucial elements of technical skills that should be taken into account when assessing sport-specific technical skills of youth table tennis players (8-12 years). Moreover, it provided concise descriptions of what is considered to be flawed or excellent executions of technical skills. Based on these findings, a first observation sheet, the Oldenburg observation sheet for Table Tennis Technique (O3T), was created to be used for the assessment of the current technical skill level within a competitive context at the early stage of a table tennis player's career. Future research should focus on its measurement properties and its value within a multidimensional assessment for talent purposes. 10.1186/s40798-021-00327-5
Design of a Tennis-Specific Agility Test (TAT) for Monitoring Tennis Players. Jansen Marleen G T,Elferink-Gemser Marije T,Hoekstra Aldo E,Faber Irene R,Huijgen Barbara C H Journal of human kinetics Agility is an important ability for tennis players. To be successful in the rallies, players must perform rapid, multidirectional movements in response to the ball and/or the position of the opponent. For a test to be representative in monitoring agility performance, it should capture a combination of the physical and cognitive agility performance. Considering that literature reports no reliable and valid sport-specific agility test for tennis, the aim of this article was to design and evaluate the measurement properties of a Tennis-specific Agility Test (TAT). To evaluate the TAT, test-retest reliability, concurrent validity, and feasibility were assessed. For reproducibility, a two-way mixed ANOVA was performed. Concurrent validity was assessed using Pearson correlations. A total of 69 tennis players participated in this study of whom 16 competed at the international (22 ± 3.7 years, playing level (Dynamic Rating System): .8 ± .3), 43 at the national (14 ± 1.4 years, playing level: 4.6 ± 1.4), and 10 at the regional level (15 ± 0.8 years, playing level: 4.9 ± 1.1). Test-retest reliability was found to be moderate with an Intra-Class Correlation coefficient (ICC) of .74 (p < .01) and a percentual minimal detectable change (%MDC) of 6.2%. Concurrent validity was found to be moderate by comparison with a recognised agility test, the Spider Drill, which measures only the physical component (.70; p < .01), and by comparison with tennis performance for both boys (r = .67; p < .01) and girls (r = .72; p < .01). The feasibility was high with short time for preparation (five to ten minutes) and time per participant (<5 minutes). In conclusion, the TAT shows promising results for assessing sport-specific agility performance in tennis making it likely to be used in the practical setting. 10.2478/hukin-2021-0094
Correlation analysis of national elite Chinese male table tennis players' shoulder proprioception and muscle strength. World journal of clinical cases BACKGROUND:Shoulder is the most injured part in table tennis players, and it takes multiple roles in transmitting power and striking the center of the ball during the stroke. Proprioception is strongly correlated with high level of athletic performance. It is customary to assume that there is a correlation between proprioception and muscle strength and therefore proprioceptive assessment and rehabilitation is often neglected. AIM:To investigate the correlation between isokinetic muscle strength and proprioception in the internal and external rotation muscle groups of elite Chinese male table tennis players, to provide reference for physical training and rehabilitation of elite table tennis players. METHODS:A total of 19 national elite table tennis players from the Chinese National Table Tennis Team were recruited in this research. All of them had more than 10 years training experience and had participated major competitions such as the National Games and World Youth Championships. IsoMed 2000 was used to test the peak torque of internal and external rotation isokinetic concentric contraction of the athletes' bilateral shoulder joints at low speed (60°/s) and high speed (180°/s) respectively; IsoMed 2000 was used to conduct the Joint Position Reproduction test to evaluate the athletes' proprioceptive ability capacity at low speed (60°/s) and high speed (180°/s) respectively. If the data satisfied the normal distribution, the correlation between the differences in peak torque s and angles in different directions was analyzed using a Pearson simple linear model; otherwise, Spearman correlation analysis was used. The comparison of proprioceptive ability between the table tennis racket-holding hand and non-racket-holding hands was performed using independent samples -test if the data satisfied a normal distribution; otherwise, the Mann-Whitney test was used. RESULTS:There was no direct linear correlation between the strength and proprioceptive correlation analysis at slow speed (60°/s) and fast speed (180°/s) in the racket-holding hand; At the slow speed (60°/s) and fast speed (180°/s), there was no correlation between muscle strength and proprioception in the non-racket-holding hand except for the internal rotation variable error (VE) and external rotation relative peak torque, which showed a moderate positive correlation ( = 0.477, < 0.05), ( = 0.554, < 0.05). The internal rotation's constant error (CE) and VE were 1.06 ± 3.99 and 2.94 ± 2.16, respectively, for the racket-holding hand, and -3.36 ± 2.39 and 1.22 ± 0.93, respectively, for the non-racket-holding hand; the internal rotation's CE, VE of the racket-holding hand was lower than that of the non-racket-holding hand, and there was a highly significant difference ( < 0.01). CONCLUSION:There was no correlation between muscle strength and proprioceptive function in the internal and external rotation of the racket-holding hand's shoulder in elite Chinese male table tennis players. These results may be useful for interventions for shoulder injuries and for the inclusion of proprioceptive training in rehabilitation programs. 10.12998/wjcc.v10.i24.8514
Analysis of Technical-Tactical Actions in High-Level Table Tennis Players: Differences between Sexes. Sports (Basel, Switzerland) Table tennis is a sport played at a high speed; therefore, the technical-tactical variables are very important. The objective of the research is to analyze the technical and tactical characteristics of high-level TT players according to sex. A total of 48 high-level players (24 women and 24 men) participated in the present study. The investigation was carried out during two championships. The matches were recorded and subsequently analyzed by notational analysis. The results indicate that women stroke the ball more times during the rallies. In the men's competition, the forehand technique predominates over the backhand technique. The flip was the most used in the male sex ( < 0.05). At the tactical level, more winning actions were performed in the men's competition than in the women's, both with the forehand and backhand game. Men performed more losing technical actions when using the forehand and backhand flips. The pivot footwork tactical action was higher in the men's competition. The analysis of the technical-tactical actions highlighted important differences between the sexes. The predominant losing techniques among players are forehand and backhand flip. Female players use more defensive strokes, while male players use more offensive strokes, in particular the flip technique. The potential biomechanical progress of the male player characterized by a larger wingspan biotype could facilitate a better technical-tactical performance. The results obtained are of interest to improve the performance of the players as they must train at a technical-tactical level differently depending on the sex and style of play. 10.3390/sports11110225
Analysis of Specific Physical Fitness in High-Level Table Tennis Players-Sex Differences. International journal of environmental research and public health Table tennis performance depends on multiple factors such as technique, tactics and fitness. Several studies have focused on investigating different technical-tactical variables. However, research analysing the specific physical qualities of this sport is scarce, particularly in the female sex. The aim of the present study was to assess the physical fitness variables associated with individual performance in elite table tennis players according to sex. Forty-eight elite players divided into males (n = 24; 25.38 ± 4.01 years) and females (n = 24; 22.33 ± 3.83 years) participated in the study. To determine physical fitness, participants performed vertical jump, hand grip strength, ergospirometry and lateral displacement tests (reaction time, displacement time and lateral acceleration). Male players showed higher values in vertical jump, hand grip strength and maximum oxygen consumption (p < 0.001). Likewise, male players moved laterally faster (p < 0.001). On the other hand, female players had a better reaction time towards the dominant side (p < 0.01). Elite male table tennis players showed better physical fitness compared to female players. Due to the scarcity of data on elite table tennis players, these results can serve as reference values for different table tennis practitioners. 10.3390/ijerph19095119
Joint and plantar loading in table tennis topspin forehand with different footwork. Lam Wing-Kai,Fan Jia-Xing,Zheng Yi,Lee Winson Chiu-Chun European journal of sport science Table tennis players often execute one-step, side-step or cross-step to move to an appropriate position for topspin forehand. However, to our knowledge, no studies have investigated the footwork effects on lower-limb kinetics and kinematics, which are related to playing performance and injury prevention. This study examined the ground reaction forces, joint kinetics and in-shoe plantar pressure distribution during topspin forehand with three typical footwork patterns. Fifteen male table tennis players performed cross-court topspin forehands in one-step, side-step and cross-step. Force plate, motion capturing, and instrumented insole systems were used to measure ground reaction force, joint moments and plantar pressure variables. One-way ANONA with repeated measures was performed to determine any significant differences between footwork. Results indicated that participants exhibited significantly higher ground reaction force loadings, knee flexion angle, knee moment, ankle inversion and moment during side-step and cross-step compared with one-step footwork condition (p < .01). Plantar pressure data indicated that the significantly higher peak pressure were observed in the total foot, toe, 1st, 2nd and 5th metatarsal regions during side-step and cross-step (p < .01). Additionally, cross-step had induced higher peak pressure in medial midfoot and heel regions than one-step and higher peak pressure in total and 1st metatarsal regions than side-step (p < .01). These results suggest that foot orthotic designs should consider the stronger emphasis on those high-pressured areas and that the differential joint and plantar loadings in side-step and cross-step may provide useful insights to injury mechanism and training protocol development. 10.1080/17461391.2018.1534993
Wearable knee joint fatigue estimating system based on curvature and pressure sensing. Technology and health care : official journal of the European Society for Engineering and Medicine BACKGROUND:The injury of the knee joint is found to be directly related to the fatigue caused by excessive exercise. Many previous studies used wearable devices to measure the angle of knee joint during activities, but did not pay enough attention to the load of knee joint related to the fatigue degree of it. OBJECTIVE:A wearable embedded system was designed to sense the motion state and load of knee joint and uses the sensoring data to estimate and predict the fatigue degree of knee joint during exercise in real time, so as to prevent it from being injured. METHODS:An economical wearable system is designed to measure the parameters of the knee joint during exercises. Then the warning message and recommended healthy lasting time are able to be sent to users to avoid excessive exercise. 24 healthy volunteers aged 20-25 years were involved in the experiments. Two famous evaluation scales for knee joint from Department of Orthopedics (Lysholm score and IKDC score) were adopted to evaluate the protective effect. RESULTS:After 14 days of the first stage testing, all the participants with wearable devices reported healthy knee joint state to verify the effectiveness of the system. For the second stage, the testing group equipped with wearable warning devices did not receive obvious change in the two scales. However, Lysholm score of control group dropped by at least 7.4 and IKDC score dropped by at least 11.1 which were significantly reduced. CONCLUSION:Only using human perception to prevent knee joint fatigue had a risk of failure while the designed wearable system could protect the knee successfully from injuries during exercises, such as running, badminton, table tennis and basketball. Moreover, female gender and a high BMI value may be two factors that increase the risk of knee injuries during sports. 10.3233/THC-213579
Lower Limb Biomechanics during the Topspin Forehand in Table Tennis: A Systemic Review. Bioengineering (Basel, Switzerland) The aim of this study is to review the valuable lower limb biomechanical contribution to table tennis topspin forehand. Databases included Scopus, PubMed, and Web of science. In this case, 19 articles were selected for the systematic review. The mechanics of the plantar, lower limb joints kinematics and kinetics, muscle activity, and racket-joint relationship are described through gender, performance level, and footwork. The study found that the hip movement characteristics and the hip muscle group activity following a proximal-to-distal sequence strategy significantly contributed to the maximum acceleration of the racket. Optimizing the motion strategy of the ankle and plantar as well as the ankle muscle group activity is beneficial for the transmission of energy in the kinetic chain. Muscle groups around the ankle and subtalar joints are heavily activated during landing to maintain foot stability during the landing phase. Lower limb muscle development plays an important role in movement control and stability as well as sports injury prevention in table tennis footwork during the performance of the topspin forehand. Furthermore, physical development levels and anatomical differences (such as hip and lower trunk muscle strength differences), maybe the main reasons for gender differences observed during the topspin forehand. Systematically summarizing this valuable information can contribute to athletes' and coaches' knowledge to enhance topspin forehand performance and training regimes. We suggest that future research could consider the joint contact forces, ball movement, and ball-racket impact during a performance of topspin forehand. 10.3390/bioengineering9080336
The Biomechanics of Shoulder Movement with Implications for Shoulder Injury in Table Tennis: A Minireview. Li Liang,Ren Feng,Baker Julien S Applied bionics and biomechanics A high proportion of shoulder injuries in table tennis players are common, which is both a diagnostic and therapeutic challenge. An understanding of the interaction between biomechanical function of the shoulder and mechanisms of shoulder injuries in table tennis players is necessary to prevent injury and to conduct clinical treatment of the shoulder as soon as possible. The purpose of this minireview was to select the available evidence on the biomechanical characteristics of shoulder movement and potential relationships with various shoulder injuries that are common in table tennis players. Five studies revealed interesting biomechanical characteristics of shoulder movement patterns in table tennis players: large internal rotation torque, an increased torsion-rotation movement, and a greater angular velocity of internal rotation were found. Two studies were noted that were related to specific shoulder injury: glenohumeral internal rotation deficit (GIRD) and impingement syndrome. Unfortunately, it is difficult to draw conclusions on the mechanisms of shoulder injury in table tennis players due to the little evidence available that has investigated shoulder injury mechanisms based on biomechanical characteristics. Future studies should focus on the potential relationship between the biomechanical characteristics of the shoulder and injury prevalence to provide valuable reference data for clinical treatment. 10.1155/2021/9988857
The ischemic model of chronic muscle spasm and pain. European journal of translational myology This article was not intended to be a complete review of the electromyography of pathological muscle states, but it was written to illustrate how the "Coletti Method of EMG ChemoDenervation" (CMECD®) protocol for the treatment of chronic pain resulting from chronic muscle spasm was developed and established. That process led to an unexpected understanding of the underlying pathophysiology of chronic muscle spasm, which represents a paradigm shift in our understanding and ultimately in our treatment of muscle spasm-induced chronic pain. Other investigators had brought to light the presence of spontaneous electrical activity (SEA) in states of muscle spasm. Those findings were all but ignored by standard EMG/Nerve conduction studies in clinical practice. Starting with a simple EMG device I experimented with various medications to treat patients with chronic pain associated with chronic muscle spasm. Suppression of SEA with long-acting medications resolved both the chronic spasm and chronic pain. A successful protocol using phenoxybenzamine was established and clinical outcomes were followed. More than 200 patients were successfully treated during last 12 years. Correlating known exercise muscle physiology with the development of the pathological state of chronic muscle spasm as seen by electromyography led to the postulation of the ischemic model of chronic muscle spasm. Light microscopy pathophysiologic supportive findings are presented and discussed. Predictions from this model to various aspects of treatment were supportive. Implications regarding treatment by the CMECD procedure, as well as other standard therapies, are discussed. Application of the ischemic model to other pain conditions was explored with implications of therapeutic modification. Recommendations for changes in rehabilitation therapy are discussed. 10.4081/ejtm.2022.10323