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Purpose: This study aimed to determine relationships between parameters of force-production capacity in sprinting and opposition skill efficiency in rugby union games according to position. Methods: The sprint force–velocity profile of 33 professional rugby union players divided into 2 subgroups (forwards and backs) was measured on a 30-m sprint. Skill efficiencies (in percentage) of offensive duels, tackles, and rucks were assessed using objective criteria during 12 consecutive competitive games. Pearson correlation was used to determine the relationships between parameters of horizontal force-production capacity in sprinting (maximum propulsive power, theoretical maximum force [F0], theoretical maximum velocity, maximum ratio of horizontal force [RFmax], and rate of decrease of this ratio of forces with increasing velocity) and skill efficiencies. Two multiple linear regression models were used to observe whether skill efficiencies could depend on determinants of horizontal force application in low- or high-velocity conditions. A first model including F0 and theoretical maximum velocity was used as a macroscopic analysis, while a second model including RFmax and rate of decrease of this ratio of forces with increasing velocity was used as microscopic analysis to determine the most significant determinants of skill efficiency. Results: All skill efficiencies were strongly correlated with maximum propulsive power in forwards and backs. In forwards, F0 and RFmax were the key predictors of dueling, rucking, and tackling efficiency. In backs, F0 was the main predictor of dueling and rucking efficiency, whereas RFmax was the key predictor of dueling and tackling efficiency. F0 and theoretical maximum velocity equivalently contributed to tackling performance. Conclusions: In rugby union forward and back players, skill efficiency is correlated with maximum propulsive power and may be more explained by horizontal force-production capacity and mechanical effectiveness at lower velocities than at higher velocities. [ABSTRACT FROM AUTHOR]

The aim was to investigate the effects of sex, age, preferred judo technique, dominance, and injury history on the shoulder functional status of elite judo athletes. Sixty-one elite judo athletes (38 males, age: 18.1 ± 1.2 years, body mass: 69.3 ± 13.3 kg, body height: 172.2 ± 9.8 cm, brown belt to second-degree black belt) completed three questionnaires: Western Ontario Shoulder Instability, Western Ontario Rotator Cuff, and Shoulder Instability-Return to Sport after Injury. They performed four physical tests: the glenohumeral rotator isometric strength test, upper quarter Y-balance test, unilateral seated shot put test, and modified Closed Kinetic Chain Upper Extremity Stability Test. The results showed that the female athletes had less shoulder functional abilities than the male athletes (p < 0.001 to p = 0.02). The younger athletes had poorer shoulder stability and upper extremity power than the older athletes (p < 0.001 to p = 0.02), but their glenohumeral muscles were stronger in both internal (p = 0.03) and external (p = 0.005) rotations. All the judo athletes had similar bilateral differences in shoulder functional status, except for judokas who preferred throwing techniques (p = 0.01). Injury history affected self-perceived functional status (p < 0.001), as well as upper extremity muscle capacity and neuromuscular control (p = 0.01 to p = 0.05). This study provides new insight into the shoulder functional status of elite judo athletes, which may aid in the development of sports-specific injury prevention and return-to-sport programmes to reduce the risk of shoulder injury occurrence and recurrence. Highlights Normalized levels of upper extremity abilities must be sex- and age-specific in prevention programmes. Prevention programmes may focus on muscle bilateral and anteroposterior symmetry. Prevention programmes may include psychological training tailored to the sex of judo athletes. [ABSTRACT FROM AUTHOR]

Context: Tennis induces a decreased internal rotation range of motion at the dominant glenohumeral joint. The effects of self-myofascial release have not yet been investigated to restore glenohumeral range of motion. Objective: This study aimed at investigating the effects of self-myofascial release on shoulder function and perception in adolescent tennis players. Design: Test–retest design. Setting: Tennis training sport facilities. Participants: Eleven male players participated in this study (age: 15 [3] y; height: 173.1 [11.1] cm; mass: 56.0 [15.1] kg; International Tennis Number: 3). Intervention: During 5 weeks, the players performed their regular tennis training. During 5 additional weeks, self-myofascial release of the infraspinatus and pectoralis muscles was implemented 3 times per week after the warm-up of the regular training session. Main Outcome Measures: The primary outcome was glenohumeral internal rotation range of motion. The secondary outcomes were perceived shoulder instability and tennis serve accuracy and velocity. Results: Adding self-myofascial release allowed an increase of 11° (2°) of internal rotation range of motion at the dominant glenohumeral joint (P <.001) and a decreased perception of shoulder instability (P =.03), while maintaining tennis serve velocity and accuracy. Conclusions: Implementing self-myofascial release on infraspinatus and pectoralis muscles 3 times per week during 5 weeks improved dominant glenohumeral internal rotation range of motion in tennis players. It can be used as a strategy to preserve the mobility of this joint. [ABSTRACT FROM AUTHOR]

Context: Tennis playing generates specific adaptations, particularly at the dominant shoulder. It remains to be established whether shoulder-strength balance can be restored by sling-based training for adolescent recreational tennis players. Objective: To investigate the effects of a sling-based exercise for shoulder external rotators on external rotator muscle strength, internal rotator muscle strength, glenohumeral range of motion, and tennis serve performance. Design: Test-retest design. Setting: Tennis training sports facilities. Participants: Twelve adolescent male players volunteered to participate in this study (age: 13.3 ±0.5 y; height: 1.64 ± 0.07 m, mass: 51.7 ± 5.8 kg, International Tennis Number: 8). Intervention: The procedure spanned 10 wk. For the first 5 wk, players performed their regular training (RT) twice a week. For the last 5 wk, a sling-based exercise (SE) for strengthening the shoulder external rotator muscles was added to their RT. Main Outcome Measures: Maximal isometric strength of shoulder external and internal rotator muscles and glenohumeral range of motion in external and internal rotation were assessed in both shoulders. Serve performance was also evaluated by accuracy and postimpact ball velocity using a radar gun. Results: No change was found in any measurement after the RT period. Significant increases in external (~+5%; P < .001) and internal (~+2%; P < .05) rotator muscle strength and in external/internal strength ratio (~+4%; P < .001) were observed after the SE period. Serve velocity and accuracy were significantly improved after SE (~+2% and ~+24%, respectively; P < .05 for both), while no clinically meaningful alterations in range of motion were observed. Conclusions: Prophylactic intervention through SE for strengthening shoulder external rotator muscles appears effective in restoring strength balance at the dominant shoulder and may prevent adolescent tennis players from sustaining degenerative shoulder problems, which could later impair their performance of daily and work-related tasks. [ABSTRACT FROM AUTHOR]

Background: To reduce the rate of anterior cruciate ligament (ACL) graft rupture, recent surgeries have involved anterolateral ligament reconstruction (ALLR). This reconstruction procedure harvests more knee flexor muscle tendons than isolated ACL reconstruction (ACLR), but its influence on knee muscle strength recovery remains unknown. This study aimed to assess the influence of ALLR with a gracilis graft on the strength of the knee extensor and flexor muscles at 6 months postoperatively. Hypothesis: The additional amount of knee flexor harvest for ALLR would result in impairment in knee flexor muscle strength at 6 months postoperatively. Study Design: Retrospective cohort study. Level of Evidence: Level 2. Methods: A total of 186 patients were assigned to 2 groups according to the type of surgery: ACL + ALLR (graft: semitendinosus + gracilis, n = 119) or isolated ACLR (graft: semitendinosus, n = 67). The strength of the knee extensor and flexor muscles was assessed using an isokinetic dynamometer at 90, 180, and 240 deg/s for concentric and 30 deg/s for eccentric contractions and compared between groups using analysis of variance statistical parametric mapping. Results: Regardless of the surgery and the muscle, the injured leg produced significantly less strength than the uninjured leg throughout knee flexion and extension from 30° to 90° for each angular velocity (30, 90, 180, and 240 deg/s). However, the knee muscle strength was similar between the ACL + ALLR and ACLR groups. Conclusion: The addition of ALLR using the gracilis tendon during ACLR does not alter the muscle recovery observed at 6 months postoperatively. Clinical Relevance: Although more knee flexor muscle tendons were harvested in ACL + ALLR, the postoperative strength recovery was similar to that of isolated ACLR. [ABSTRACT FROM AUTHOR]

Background: The time elapsed since surgery is the primary criterion for allowing athletes to return to sport after shoulder stabilization surgery using the Latarjet procedure. The objective assessment of shoulder functional status through the return-to-sport continuum demands a scoring instrument that includes psychological and physical dimensions. This study aimed to statistically validate the Shoulder-SanTy Athletic Return To Sport (S-STARTS) score in patients who have undergone primary shoulder stabilization surgery. Hypothesis: The S-STARTS score fulfils the criteria for statistical validation for assessing return-to-sport readiness after shoulder stabilization surgery. Study Design: Diagnostic study. Level of Evidence: Level 4. Methods: Fifty patients and 50 controls completed the Shoulder Instability-Return to Sport after Injury questionnaire and performed 4 physical performance tests, from which 8 outcome measures were extracted to provide a composite score, named S-STARTS, according to a scoring procedure. The statistical validation of the S-STARTS score was based on construct validity, discriminant validity, sensitivity to change, internal consistency, reliability, agreement, and feasibility. Results: The 8 components of the S-STARTS score provided additional information (0.01 ≤ | r | ≤ 0.59). The S-STARTS score exhibited good reliability (intraclass coefficient of correlation [3,k] = 0.74), no ceiling or floor effects, and high discrimination and sensitivity to change. The S-STARTS score was significantly lower in patients than in controls (13.5 ± 3.8 points vs 16.1 ± 2.7 points, respectively; P < 0.001). A significant increase was reported between 4.5 and 6.5 months postoperatively (12.8 ± 2.3 points vs 17.2 ± 2.4 points, respectively; P < 0.001). Conclusions: The S-STARTS score meets statistical validation criteria for the assessment of shoulder functional status after shoulder stabilization surgery using the Latarjet procedure. Clinical Relevance: Using an S-STARTS score–based assessment to monitor an athlete's progression through the return-to-sport continuum may help clinicians and strength and conditioning coaches in return-to-sport decision-making. [ABSTRACT FROM AUTHOR]

The tennis serve generates high musculoskeletal loads at the shoulder complex, making athletes particularly vulnerable to chronic injuries, especially adolescent players. Chronic injuries are commonly related to altered scapular kinematics. This study explored the effects of a history of shoulder problems involving humerothoracic and scapulothoracic kinematics during the tennis serve at low speed in adolescent competitive players with and without a history of dominant shoulder problems. Totally, 28 adolescent tennis players were split into two groups, those with and those without a history of shoulder problems. Data on humeral and scapular kinematics relative to the thorax were collected using an electromagnetic system during slow velocity serves. The two groups's humerothoracic and scapulothoracic 3D joint angles were compared both at the end of the cocking phase and at the end of the acceleration phase of the tennis serve. At the end of the cocking phase, the players with a 30 history of shoulder problems showed less humeral abduction and external rotation and more scapular upward rotation. This group also showed less humeral abduction at the end of the acceleration phase. Players with a history of shoulder problems adapted their humerothoracic and scapulothoracic orientations to preserve shoulder integrity during the tennis serve. [ABSTRACT FROM AUTHOR]

CONTEXT: In women's handball, the large numbers of throws and passes make the shoulder region vulnerable to overuse injuries. Repetitive throwing motions generate imbalance between shoulder internal- and external-rotator muscles. It has not yet been established whether sling-based training can improve shoulder external-rotator muscle strength. OBJECTIVE: This study investigated the effectiveness of a 6-wk strengthening program in improving shoulder functional profile in elite female high school handball players. DESIGN: Crossover study. SETTING: National elite handball training center. PARTICIPANTS: 25 elite female high school handball players. INTERVENTIONS: The program, completed twice per week for 6 wk, included sling-based strengthening exercises using a suspension trainer for external rotation with scapular retraction and scapular retraction alone. MAIN OUTCOMES: Maximal shoulder external- and internal-rotation strength, shoulder external- and internal-rotation range of motion (ROM), and maximal throwing velocity were assessed preintervention and postintervention for dominant and nondominant sides. RESULTS: After sling training, external- and internal-rotation strength increased significantly for both sides (P ≤ .001, and P = .004, respectively), with the result that there was no significant change in external- and internal-rotation strength ratios for either the dominant or the nondominant shoulder. No significant differences were observed for external-rotation ROM, while internal-rotation ROM decreased moderately, in particular in the dominant shoulder (P = .005). Maximal throwing velocity remained constant for the dominant arm, whereas a significant increase was found for the nondominant arm (P = .017). CONCLUSIONS: This 6-wk strengthening program was effective in improving shoulder external-rotator muscle strength but resulted in a decrease in the ROM in shoulder internal rotation, while throwing velocity remained stable. Adding a stretching program to this type of sling-based training program might help avoid potential detrimental effects on shoulder ROM [ABSTRACT FROM AUTHOR]

The topspin tennis forehand drive has become a feature of modern game; yet, as compared to the serve, there has been little research analysing its kinematics. This is surprising given that there is considerably more variation in the execution of the topspin forehand. Our study is the first to examine the amplitude of upper limb joint rotations that produce topspin in the forehand drives of 14 male competitive tennis players using video-based motion analysis. Humerothoracic abduction (-)/adduction (+), extension (-) /flexion (+), and external (-)/internal (+) rotation, elbow extension (-) /flexion (+) and forearm supination (-)/pronation (+), wrist extension (-)/flexion (+) and ulnar (-)/radial (-) deviation were computed. Our findings revealed that the generation of topspin demanded more humeral extension and forearm pronation but less humeral internal rotation angular displacement during the forwardswing. The follow-through phase of the topspin shot was characterised by greater humeral internal rotation and forearm pronation, and reduced humeral horizontal adduction when compared to the flat shot. This study provides practitioners with a better understanding of the upper limb kinematics associated with the topspin tennis forehand drive production to help guide skill acquisition interventions and physical training. [ABSTRACT FROM AUTHOR]

This study compared EMG activity of young tennis players' muscles during forehand drives in two groups, GD--those able to raise by more than 150% the vertical velocity of racket-face at impact from flat to topspin forehand drives, and GND, those not able to increase their vertical velocity to the same extent. Upper limb joint angles, racket-face velocities, and average EMGrms values, were studied. At similar joint angles, a fall in horizontal velocity and a rise in racket-face vertical velocity from flat to topspin forehand drives were observed. Shoulder muscle activity rose from flat to topspin forehand drives in GND, but not for drives in GD. Forearm muscle activity reduced from flat to topspin forehand drives in GD, but muscle activation was similar in GND. The results show that radial deviation increased racket-face vertical velocity more at impact from the flat to topspin forehand drives than shoulder abduction. [ABSTRACT FROM AUTHOR]

This study aimed at demonstrating the asymmetry in volume between the dominant and nondominant upper limbs in tennis players, controlled for maturity status. Upper limb volumes on both sides were calculated in 72 tennis players and 84 control subjects, using the truncated cone method. The participants' maturity status was determined using the predicted age at peak height velocity (PHV). The results showed significant larger side-to-side asymmetry in volume in tennis groups than in control groups. These findings suggested that, even before PHV, specific-sport adaptations occurred in the dominant upper limb in tennis players. [ABSTRACT FROM AUTHOR]

This study investigated the influence of the covering swimsuit and the fabric surface properties on the butterfly stroke kinematics. Surface properties were evaluated by wetting measurements of two fabric samples: one for training suits and one for competition suits. The surface of the second one was coated by mechanochemical treatment in order to modify its surface properties. Nine national level swimmers performed a 50-m butterfly at submaximal velocity in three swimsuit conditions: conventional, long, and coated long swimsuits. From video recording, the hip was digitized at the entry and exit of the swimmer's hand in order to calculate the duration, hip displacement, and hip linear velocity during underwater and recovery phases and during stroke. The results for wetting show that competition fabric was more water-repellent than training fabric, but both were isotropic. Moreover, the mechanochemical treatment increased water repellency and anisotropy. The swimming results indicated that, when compared to a conventional swimsuit, wearing a coated long swimsuit increased hip linear velocity during stroke, and particularly during the recovery phase which had a shorter duration. These results suggest that the covering swimsuit should be coupled with the water repellent and anisotropic properties of the fabric surface in order to improve swimming performance. [ABSTRACT FROM AUTHOR]