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To assess the reliability and the validity of a modified version of the Athletic Shoulder Test (M-AST), using a handheld dynamometer instead of a force plate.Test-retest reliability and concordance between tools.University Motion Lab.Twenty healthy volunteers who practiced an upper limb sport for at least 5 h per week were recruited for the study.The concordance between the Athletic Shoulder Test (AST) and the Modified-Athletic Shoulder Test (M-AST) was assessed with intra-class correlation coefficients (ICC), paired T-Test and Bland-Altman plots. The inter-session reliability was assessed with intra-class correlation coefficients (ICC), SEM, MDC and paired T-Test.A strong concordance was found between AST and M-AST values (ICC = 0.86-0.97; p 0.05) in all the positions considered and for both sessions. Bland-Altman plots confirmed these results. However, the inter-session reliability was more variable for both AST and M-AST (ICC = 0.643-0.923; p 0.05).The M-AST seems to be a reliable, cheaper and easier to implement alternative to the AST to measure recovery status following matches or training sessions in upper limb athletes. As for the AST, familiarization trials will have to be performed before the assessment to have accurate measurements.NCT05112380.

Purpose To date, the relationship between footstrike pattern and performance, as well as with injury incidence in endurance running remains unclear. For these reasons, it is currently not recommended to modify footstrike pattern in an uninjured long-distance runner. The purpose of this study was to analyse whether athletic coaches apply these current scientific recommendations with their endurance runners on the field. Methods A Delphi method study was used to develop an online survey that was administered to French-speaking athletic coaches in Belgium. The survey comprised three sections: 1) coaches’ profile, 2) coaches’ perception of footstrike patterns, 3) practices pertaining to footstrike patterns. Results One hundred and fourteen respondents completed the entire questionnaire. Ninety-six (84%) athletic coaches reported modifying the footstrike pattern of their endurance runners. They reported that they modify their runners’ rearfoot and forefoot strike more often than a midfoot strike (P < 0.0001) to prevent injury (83%) and to improve performance (66%). According to them, midfoot strike is considered as the best landing pattern for endurance performance (47%) and injury prevention (36%) whereas rearfoot strike is considered as the worst (respectively, 50% and 52%). Summary and conclusion This study highlights the disparities between scientific recommendations and athletic coaches’ field practices for modifying footstrike patterns in endurance runners. Contrary to current scientific literature recommendations, a large proportion of coaches modify the natural footstrike pattern of their endurance runners towards a midfoot strike pattern to improve performance and prevent injury.

Tennis practice requires a lot of technical, physical and mental qualities that have to be trained from the youngest age. The important number of hours spent on the court can lead, medium-to-long term to strength or flexibility adaptations, even in the youngest players. The current study aimed to explore the developmental consequences of repetitively playing tennis on shoulder range of motion and shoulder rotators' strength in elite male and female tennis players.Eigthy four painfree elite tennis players were assessed during preseason between 2009 and 2019. Clinical assessment included internal and external rotation range of motion and forward shoulder posture while maximal internal and external rotators strength were assessed with an isokinetic dynamometer in concentric and in eccentric modes (at 60°/s and 240°/s).In male players, growth and maturation induced an increase in forward shoulder posture. Absolute peak torque and bodyweight peak torque of internal and external rotators in concentric and eccentric mode were also significantly increased during with age while ER/IR concentric ratios were significantly decreased. In the female players, only absolute peak torque of internal and external rotators in concentric mode and eccentric strength of external rotators were significantly influenced by the development.Specific adaptations were found in male and female players with age and practice. The important variability in the results within the different age categories and the gender strengthens the importance of regular screening (and isokinetic evaluations) in young tennis players in order to highlight potential atypical profiles, which could have a negative influence on performance or increase the risk of injuries during the development of the player.

BACKGROUND: Isokinetic evaluation is considered the gold standard in muscle strength measurement due to its sensitivity, intra-dynamometer reproducibility and usefulness in the injury prevention screening and follow up of subjects with musculoskeletal pathologies, neurological disease or after surgical operation. However, can one switch among different isokinetic dynamometers for the purpose of knee muscles evaluation? OBJECTIVES: To comprehensively evaluate the compatibility of the isokinetic short concentric and eccentric strength evaluation protocol and of the fatigability resistance evaluation between three different isokinetic devices. METHODS: Eighteen recreationally active men underwent three isokinetic knee testing sessions on three different isokinetic devices with 7–10 days of rest between each session. Relative (Pearson’s r product-moment correlation coefficient – PCC) and absolute (standard error of measurement – SEM, Cohen effect sizes (d) and probabilistic inferences – MBI) parameters of reproducibility were determined to assess the inter-dynamometer agreement. RESULTS: For the short concentric and eccentric strength evaluation protocol, the extensors in concentric mode and the flexors in eccentric mode can be compared (eventually with transposition formulas provided) between Biodex, Con-Trex and Cybex (almost all PCC ⩾ 0.80). The DCR could be compared between Con-Trex and Cybex and between Biodex and Cybex pairs (eventually with transposition formula provided). For the fatigability resistance evaluation protocol, the total sum can be compared for extensors (eventually with transposition formulas provided) for PM for all dynamometer pairs considered and, in the case of MW, only for Biodex and Con-Trex (PCC ⩾ 0.80). CONCLUSIONS: Only some of the parameters derived either from the short concentric and eccentric strength evaluation protocol or the fatigability resistance evaluation protocol may be interchangeable providing transposition formulas are applied. Otherwise, isokinetic findings are largely system-dependent save some specific instances.

Summary The Wingate Anaerobic Test (WAnT) and isokinetic fatigability protocols are mainly used to evaluate the anaerobic power of athletes for whom jumping is a predominant action in their sport. Nevertheless, the testing protocol must be as close as possible to the activity pattern of the sport to be valid. Therefore, for these athletes, the test should consist of repetitions of jumps that are task-specific. Our aim was to propose a new jumping protocol allowing for specific assessment of fatigue, to examine its absolute and relative reliability and to determine its ideal duration. Twenty male volleyball performed fifty countermovement jumps (CMJ) at a rate of 33 jumps per minute on two occasions, with seven days recovery between each session. Jump height was computed for each CMJ using a 3D optoelectronic system, which was subsequently added to determine cumulative performance after 10, 15, 20, 25, 30, 35, 40, 45 and 50 repetitions. Reliability of the average jump height was not affected by the lengthening of the protocol and was high for all considered durations (ICC > 0.94; SEM

Context: Shoulder injuries are highly prevalent in sports involving the upper extremity. Some risk factors have been identified in the literature, but consensus is still lacking. Objectives: To identify risk factors of overuse shoulder injury in overhead athletes, as described in the literature. Data Sources: A systematic review of the literature from the years 1970 to 2018 was performed using 2 electronic databases: PubMed and Scopus. Study Selection: Prospective studies, written in English, that described at least 1 risk factor associated with overuse shoulder injuries in overhead sports (volleyball, handball, basketball, swimming, water polo, badminton, baseball, and tennis) were considered for analysis. Study Design: Systematic review. Level of Evidence: Level 3. Data Extraction: Data were extracted from 25 studies. Study methodology quality was evaluated using the Modified Coleman Methodology Score. Results: Intrinsic factors, previous injury, range of motion (lack or excess), and rotator cuff weakness (isometric and isokinetic) highly increase the risk of future injuries. Additionally, years of athletic practice, body mass index, sex, age, and level of play seem to have modest influence. As for the effect of scapular dysfunction on shoulder injuries, it is still controversial, though these are typically linked. Extrinsic factors, field position, condition of practice (match/training), time of season, and training load also have influence on the occurrence of shoulder injuries. Conclusion: Range of motion, rotator cuff muscle weakness, and training load are important modifiable factors associated with shoulder injuries. Scapular dysfunction may also have influence. The preventive approach for shoulder injury should focus on these factors.

The objective of this study was to assess the influence of scapular kinesiotaping and scapular muscle fatigue on tennis performance in dyskinetic players, with regard to racket velocity and the acc...

Muscle strength imbalances and poor flexibility are frequently described as risk factors for hamstring injury. Preventive strategies include eccentric exercises, but the influence of field eccentric exercises on these risk factors remains unclear. We investigated the influence of a field hamstring eccentric program on hamstring strength and flexibility. Twenty-seven amateur athletes were randomly assigned to an intervention (n=13) or control group (n=14). In the intervention group, participants were involved in 15 sessions of four eccentric exercises. Peak torque, hamstring-to-quadriceps ratios, passive and active flexibility were analyzed. No significant modifications of strength, passive or active flexibility were observed in the control group (p>0.05). Hamstring eccentric peak torque (+7.1%) and functional hamstring-to-quadriceps ratios (9.3%) were significantly increased (p0.05). In conclusion, a 6-week eccentric program, including four field exercises for hamstring muscles, is an effective method of improving eccentric strength, functional ratios and, especially, passive flexibility. As this program may be easily implemented in a real-world context, this association of multiple eccentric exercises might be useful in an injury prevention strategy.

Given the potential consequences of falls among older adults, a major challenge is to identify people at risk before the first event. In this context, gait parameters have been suggested as markers of fall risk. To examine, among older people, the prospective relationship between gait patterns assessed in comfortable and challenging walking conditions, and future fall(s). A total of 105 adults older than 65 years, living independently at home and without a recent fall history were included in a 2-year, longitudinal, observational study. All underwent physical and functional assessment. Gait speed, stride length, frequency, symmetry and regularity and Minimum Toe Clearance (MTC) were recorded in comfortable (CW), fast (FW) and dual task walking (DTW) conditions. Gait parameter changes occurring between CW and FW and between CW and DTW were calculated and expressed in percent. DTW cost was calculated as the change of DTW relative to CW. Fall events were recorded using fall diaries. Comparisons according to fall occurrence were performed by means of univariate analysis and multivariate binary logistic regression analysis. Two-year follow-up was available for 96 participants, of whom 35 (36.5%) fell at least once. Comparative analysis showed that future fallers had shorter FW stride length and higher symmetry DTW cost than non-fallers (p

Background Recommendations are available for assessment criteria for safe return-to-play (RTP) after a lateral ankle sprain. However, their current use among physicians is unknown. Methods French-speaking physicians in Belgium, France and Switzerland were asked to complete an online survey and report their clinical assessment of selected RTP criteria. Results The respondent sample (n = 109) included physicians with and without Sports Medicine education, varied level of experience and proportion of athletes in their practice population. Pain was the most selected criterion for safe RTP (90% of physicians), followed by ability to engage in functional tasks (82%), functional instability (73%), range of motion (61%), proprioception (47%), mechanical instability (39%), strength (38%) and swelling (31%). A low proportion of physicians use quantitative measures to assess these criteria (between 4% and 53%). Conclusions A large proportion of physicians consider the recommended criteria for RTP decisions. However, physicians do not frequently use quantitative measures.

A tightness of the posterior structures of the throwing shoulder has been hypothesised to be associated with injuries and pain because of alterations of the scapular kinematics and muscular imbalances. The aims of this study were to identify the clinical and biomechanical profile of symptomatic and asymptomatic overhead athletes with a tight shoulder and to evaluate the efficiency of a self-applied stretching program. Twenty male overhead athletes were recruited. Half of them reported a painful shoulder at the beginning of the study. For four weeks, the volunteers performed daily stretching exercises. Before and after the stretching program, gleno-humeral mobility, scapular kinematics, rotator muscles strength and pain were evaluated. Before stretching, the main difference between the groups was more impingement syndrome and rotator cuff tendon lesion positive tests in the symptomatic group (

The trophy position is a coaching cue for the tennis serve that usually corresponds to the racquet high point (RHP) during the preparatory action for the stroke. Mastering this position and its time of occurrence seems essential in overarm movements like in the tennis serve. Clinicians and coaches have a real interest in understanding the trophy position and its evolution during the development of the elite players at different ages. A 3D motion system was used to measure the kinematics of the serve. A group of high-level tennis players were selected for three different age groups: 8 adults (ITN 1), 8 teenagers (ITN 3) and 8 children (ITN 5-6). Results show a modified pattern sequence of the tennis serve between children and adult players. RHP appears earlier relative to impact for children (-0.54 ± 0.10 s) than for adults (-0.36 ± 0.11 s) and teenagers (-0.33 ± 0.05 s) (p = 0.007). At RHP, children present lower trunk transverse plane rotation (p < 0.003) and higher shoulder external rotation (p < 0.003). These positions for the child players may represent an increased risk of shoulder and trunk injury than for older players and contribute to a lower racquet resultant velocity at impact.

The aim of the study was to assess the activation profile of scapular stabilizing muscles in dyskinetic asymptomatic people.This is a noninterventional observational study. Two groups of 20 people were included in the study. The first group involved asymptomatic athletes with scapular dyskinesis. The second one included athletes without scapular dysfunction. Muscle activation of upper trapezius, lower trapezius, and serratus anterior were recorded by a surface electromyography during shoulder flexion and shoulder abduction, in unloaded and loaded conditions.A significant increase of the activity of the upper trapezius (between 23% and 31%) and a significant decrease of the activity of the lower trapezius (between 32% and 65%) were observed in the dyskinetic group in comparison with the nondyskinetic group in asymptomatic athletes. A significant increase between 17% and 31% of the activity of the serratus anterior was also observed in dyskinetic people. Likewise, a significant increase approximately 24%-61% and 23%-70% was noted respectively in upper trapezius/lower trapezius and upper trapezius/serratus anterior ratio's in the dyskinetic group.An alteration of periscapular muscular activation exists in dyskinetic asymptomatic people. Future studies will be needed to know whether those alterations increase the risk of shoulder injuries.

Background Even though most studies normalize the surface EMG signal of the gastrocnemius muscle using a single position of maximum voluntary isometric contraction (MVIC), several studies tend to indicate that several positions are in fact needed to obtain a maximal voluntary activation (MVA) for most of the subjects. However, no combination of positions has already been described. Research question A combination of MVIC positions to normalize the EMG signal of the gastrocnemius muscle is investigated. the influence of using several positions on the reproducibility of the normalization process is evaluated. Methods Twenty healthy volunteers (45 % female – 55 % male, 25.4 years (SD 4.3), 72.6 kg (SD 13.9), 1.78 m (SD 0.12)) were recruited. Six positions for MVIC were compared and the effect of several normalization combinations on a functional task (gait) was evaluated. Results Several positions are needed to obtain at least 90 % of the MVA for 90 % of the volunteers even though the use of a single well-chosen position (unipodal standing position with knee fully extended and ankle fully plantar-flexed) will lead to no statistically significant differences of the gait evaluation during stance phase. For each position, five repetitions of the MVIC are recommended to obtain a valid MVA. Significance This study confirms that using several MVIC positions is recommended when possible to normalize the gastrocnemius muscle EMG signal. However, in the situation of a patient where limited MVIC attempts are possible, using a single well-chosen position should not significantly influence the amplitude and the reproducibility of the measures.

Background Functional testing has recently become more and more popular to assess athletes, both for injury prevention, as well as in an objective of performance. However, the relationship between the results of these tests and performances (or injuries) or their interpretation remains unclear. Objective The aim of this study is to explore the usefulness, the characteristics, and the interpretation of the most frequently used upper-limb functional test. Methods Twenty-two experts with an excellent knowledge of upper limb functional tests and an expertise in sports medicine and/or sports training of at least 5 years were recruited. They answered to qualitative and quantitative questions about functional testing trough structured questionnaires (online). Results Four rounds were needed to reach a consensus about the usefulness as well as the characteristics of each test. Different sports-specific batteries of tests were also suggested by the experts and reached consensus. However, concerning the interpretation of the test, a consensus was only found for half of the tests considered. Conclusion The current study summarizes the characteristics and the usefulness of the most popular upper-limb functional tests. However, the interpretation of some tests will have to be further explored since no consensus was found for them.

Resume Le role joue par la scapula dans la gestuelle sportive d’arme-lancer ou de frappe d’un projectile apparait fondamental ; il concerne le placement et la mobilisation scapulaire adequate pour faciliter la fonctionnalite de l’epaule. A l’inverse, une position ou une mobilisation inappropriee de la scapula lors de la gestuelle pourrait limiter la performance ou exacerber une lesion. La dysfonction scapulothoracique, appelee dyskinesie, s’avere frequente dans l’epaule sportive incluant le membre superieur ; elle s’observe chez des athletes pathologiques, mais aussi dans l’epaule sportive asymptomatique. En presence d’une pathologie d’epaule, un bilan oriente doit permettre d’identifier une eventuelle dyskinesie. Le suivi reeducatif comprend alors une prise en charge specifique dediee aux causes fonctionnelles de cette dysfonction scapulothoracique. L’approche preventive s’avere egalement indispensable etant donne les liens mis en evidence par des etudes prospectives entre la presence d’une dyskinesie et la survenue lesionnelle. De plus, le benefice de l’intervention preventive apparait demontre lors d’un suivi longitudinal de sportif integrant un programme preventif par rapport a un groupe controle.

Running biomechanics and its evolution that occurs over intensive trials are widely studied, but few studies have focused on the reproducibility of stride evolution in these runs. The purpose of this investigation was to assess the reproducibility of changes in eight biomechanical variables during exhaustive runs, using three-dimensional analysis. Ten male athletes (age: 23 ± 4 years; maximal oxygen uptake: 57.5 ± 4.4 ml02·min-1·kg-1; maximal aerobic speed: 19.3 ± 0.8 km·h-1) performed a maximal treadmill test. Between 3 to 10 days later, they started a series of three time-to-exhaustion trials at 90% of the individual maximal aerobic speed, seven days apart. During these trials eight biomechanical variables were recorded over a 20-s period every 4 min until exhaustion. The evolution of a variable over a trial was represented as the slope of the linear regression of these variables over time. Reproducibility was assessed with intraclass correlation coefficients and variability was quantified as standard error of measurement. Changes in five variables (swing duration, stride frequency, step length, centre of gravity vertical and lateral amplitude) showed moderate to good reproducibility (0.48 ≤ ICC ≤ 0.72), while changes in stance duration, reactivity and foot orientation showed poor reproducibility (-0.71 ≤ ICC ≤ 0.04). Fatigue-induced changes in stride biomechanics do not follow a reproducible course across the board; however, several variables do show satisfactory stability: swing duration, stride frequency, step length and centre of gravity shift.

Resume Le suivi du risque lesionnel des sportifs implique l’utilisation d’outils valides. Sous le terme d’outils, nous privilegierons la notion de protocole d’evaluation qui englobe des dimensions variees tels que les outils de mesures, les conditions de passation du test, l’expertise des operateurs… En effet, c’est la somme de ces aspects qui determinera, in fine, la qualite d’un test. Les protocoles d’evaluation impliquent au prealable l’identification de facteurs de risque, puis l’evaluation du caractere predictif de ces facteurs. En outre, le protocole utilise devra etre reproductible entre les sessions pour permettre un suivi longitudinal du sportif mais aussi, si possible, entre les operateurs et entre les centres d’evaluation. Le developpement d’outils de prevention represente donc un travail considerable mais absolument necessaire pour s’assurer de l’efficacite de la prise en charge des sportifs.

BACKGROUND Adequate motor control is considered important for spinal stability and the prevention of low back pain in adulthood and in childhood. OBJECTIVE Given that the sitting position can affect proprioception, this study aimed to evaluate the influence of using at school a triangular and dynamic cushion on schoolchildren's trunk motor control. METHODS Thirty 8-year-old schoolchildren were randomized into a control group (n= 15) and a "cushion group" (n= 15), in which the children used the cushion for one year and a half. At the end of this period, a 3D-analysis was used to assess lumbar spine proprioception by means of a trunk repositioning task performed blindfolded in a seated position in two conditions (on a stable and on an unstable surface). RESULTS The schoolchildren in the cushion group performed better at the trunk repositioning task (p= 0.02) and hold their lumbar lordosis (p= 0.03) better than the control children, in both conditions (stable and unstable). CONCLUSIONS This preliminary study suggests that daily use of a triangular dynamic cushion has a beneficial impact on children's lumbar proprioception. Further studies are needed to confirm these results and investigate the effectiveness of its use to prevent low back pain in adulthood.

This paper studies the dynamics of tape springs which are characterised by a highly geometrical nonlinear behaviour including buckling, the formation of folds and hysteresis. An experimental set-up is designed to capture these complex nonlinear phenomena. The experimental data are acquired by the means of a 3D motion analysis system combined with a synchronised force plate. Deployment tests show that the motion can be divided into three phases characterised by different types of folds, frequencies of oscillation and damping behaviours. Furthermore, the reproducibility quality of the dynamic and quasi-static results is validated by performing a large number of tests. In parallel, a nonlinear finite element model is developed. The required model parameters are identified based on simple experimental tests such as static deformed configurations and small amplitude vibration tests. In the end, the model proves to be well correlated with the experimental results in opposite sense bending, while in equal sense, both the experimental set-up and the numerical model are particularly sensitive to the initial conditions.

For coaches, the most common and easiest way to analyse the tennis serve is to refer to their own vision. However, human vision is insufficient to observe high-speed motion with great precision. With the improvement of technology, it is now possible to study the gesture from a quantitative point of view. The quantitative evaluation of the tennis serve focuses on the kinematics and kinetics of the player but also on the stroke result, which includes the ball speed and the ball trajectory. This review aims to highlight the current tools available for players, coaches, medical staffs and biomechanical researchers, to evaluate the tennis serve. This overview will provide information to the player’s entourage in order to choose the right tools depending on their specific purposes. All of these tools can be applied in performance improvement and injury prevention.

Scapular dyskinesis is observed in 61% of overhead athletes (Burn et al., 2016). For most of them, it remains asymptomatic. However, scapular dyskinesis is considered a risk factor for shoulder injury by some authors (Clarsen et al., 2014). The aim of this study is to explore the effectiveness of kinesiotaping in modifying scapular kinematics and peri-scapular muscle activity in dyskinetic athletes. The 3-dimensional position and orientation of the scapula as well as the activation of upper trapezius, lower trapezius and serratus anterior were recorded in twenty asymptomatic athletes during shoulder movements (flexion and abduction), in loaded and unloaded conditions and in three circumstances (standard, kinesiotaping 1, kinesiotaping 2). A significant decrease between 9 and 12% in upper trapezius activity was observed with kinesiotaping 1 and 2. Lower trapezius activity was slightly increased with kinesiotaping 1 while it was significantly decreased about 15-20% with kinesiotaping 2. No change was observed in serratus anterior activity, for either kinesiotaping 1 or 2. Considering scapular kinematics, both kinesiotaping 1 and 2 significantly increased posterior tilt and upward rotation. External rotation was decreased with kinesiotaping 2, in comparison to standard condition. Kinesiotaping, and especially taping 1, seems to be an effective method for changing periscapular muscle activity and scapular kinematics.

To meet the demand of a player’s entourage (e.g., coaches and medical staff), it is important for the biomechanics specialist to perform repeatable measures. To the best of our knowledge, to date, it has not been demonstrated whether similar results are obtained between two sessions of testing or between laboratory and field sport kinematic protocols with regard to the tennis serve. This study had two primary aims. First, the inter-session repeatability of biomechanical variables of a tennis serve was evaluated. Second, the differences between laboratory and field evaluations were studied. Thirteen national tennis players (ITN 3) performed the same 28 markers’ set laboratory test twice two weeks apart, and other thirteen national players (ITN 3) performed two 4 markers’ set tests both in the laboratory and on an official tennis court one week apart. A 3D motion system was used to measure lower-limb, pelvis, trunk, dominant arm and racket kinematics. A force plate was used to evaluate kinetics of legs’ drive in the laboratory. A personal method based on a point scoring system was developed to evaluate the ball landing location accuracy. We observed that the majority of the studied variables were acceptable for excellent relative reliability for the inter-session analysis. We also showed that the impact of the laboratory versus field context on the player’s serve was limited

Gait patterns of healthy aging are needed to allow a comparison with pathological situations. However, little data is available. To present gait pattern of healthy older specially selected to be “healthy walkers”. Fifty-seven older people benefited from a geriatric assessment including clinical and functional evaluations to include only those without gait disorders. Gait data were simultaneously recorded using a tri-axial accelerometer placed on the waist and four 3D position markers placed on the feet at the level of the heel and the toe. Volunteers walked at comfortable self-selected speed (CW), fast self-selected speed (FW), and finally in dual task walking condition (DTW). The extracted gait parameters were: gait speed, stride length, stride frequency, regularity and symmetry, swing, stance and double support time and ratio and minimum toe clearance. Gait speed and stride length were normalized to the right leg length. Fifty-seven older people with a mean age of 69.7 ± 4.2 years old (range from 65 to 82 years) were included. Data were analyzed according to the gender and according to the age (