Comparison of scapular position in elite tennis players with and without shoulder impingement: A case-control study.

BACKGROUND: To maximize the ball velocity in the tennis sever, the shoulder plays a key role in the kinetic chain. But shoulder inefficiency leads to shoulder injuries such as shoulder impingement syndrome (SIS). Thus, to verify the scapular movements during the tennis serve could help prevent shoulder injury in tennis players. OBJECTIVE: This case-control study aimed to verify the scapular movements during flat first serve for elite tennis players with shoulder impingement syndrome compared to those without it. METHODS: Eight elite tennis players (4 males and 4 females) with SIS and 8 elite healthy players (4 males and 4 females) performed flat first serves, and the three-dimensional scapular kinematic data was recorded using the Qualisys motion capture system through spherical reflective markers including the acromion marker cluster. RESULTS: The scapula was more internally rotated (median difference: 10.40∘) in the male players with SIS than in those without it at the maximally externally rotated humerothoracic joint during flat first serve, and female players with SIS (median difference: 7.16∘ and 11.28∘, respectively) had more internally rotated scapula at the maximally externally rotated humerothoracic joint and ball impact. CONCLUSION: Increased scapular internal rotation may be something that affects shoulder injuries in the overhead sports, and it may help to prevent and rehabilitate overhead injuries including SIS.

The short-term effectiveness of scapular focused taping on scapular movement in tennis players with shoulder pain: A within-subject comparison.

This study aimed to investigate the short-term effectiveness of scapular focused taping (SFT) on scapular position and kinematics during the tennis serve among professional players with and without shoulder pain. The cohort included 7 players who had no history of non-shoulder pain (NSP) and 6 players with shoulder pain (SP). All participants performed tennis flat serves while the Qualisys motion capture system recorded three-dimensional scapular kinematic data according to the International Society of Biomechanics recommendations. SFT was applied to the participants' torso aligned with the lower trapezius, and the same movements were repeated. In the SP group, the scapula was tilted more posteriorly after the application of SFT as compared to before at ball release and maximally externally rotated humerothoracic joint during tennis serve (t = -5.081, P = .004 and t = -2.623, P = .047, respectively). In the NSP group, the scapula was tilted more posteriorly with SFT as compared to without at first 75% timing of the cocking phase and maximally externally rotated humerothoracic joint (t = -3.733, P = .010 and t = -2.510, P = .046, respectively). And the SP group exhibited a more rotated scapula externally after the application of SFT as compared to before at Ball impact (t = 5.283, P = .003). SFT had a positive immediate effect on the scapular posterior tilting and external rotation during certain phases of the tennis serve among tennis athletes with and without shoulder pain. These findings may help clinicians and sports practitioners to prevent and rehabilitate shoulder injuries for overhead athletes. Level of evidence: Level III; Case-Control Design; Comparative Study.

Optimal relative workload for managing low-injury risk in lower extremities of female field hockey players: A retrospective observational study.

ABSTRACT: Our study aimed to investigate the relative workload that is related to the injury in lower extremities of female field hockey players and to identify the optimal ratio of acute to chronic workloads (ACWR) depending on the playing position to manage low risk of sports-related injuries.Data were collected using a global positioning systems unit on a full-time basis and during competition among 52 players who were enrolled in Korea National Team. The ACWR was calculated by dividing the most recent 1 week workload by the prior 4 weeks workload. Injury risk was calculated for each category from very low to very high based on a z-score.In striker and midfielder, the injury risk was the lowest in the moderate-low category of total distance covered, meters per minute (MpM), repeated high-intensity effort bouts, and acceleration bouts, and the moderate-high category of high-intensity running distance (HID). The injury risk of a defender was the lowest in the moderate-low category of HID and MpM.The ACWR in total distance covered, MpM, repeated high-intensity effort bouts, and acceleration bouts should stay within the moderate-low category in striker and midfielder positions and HID and MpM in defender positions in order to manage low-risk of non-contact and soft tissue injuries in female field hockey players.

Effects of Neuromuscular Training on the Rear-foot Angle Kinematics in Elite Women Field Hockey Players with Chronic Ankle Instability.

The aims of this study were to investigate the ankle position, the changes and persistence of ankle kinematics after neuromuscular training in athletes with chronic ankle instability (CAI). A total of 21 national women's field hockey players participated (CAI = 12, control = 9). Ankle position at heel strike (HS), midstance (MS), and toe touch (TT) in the frontal plane during walking, running and landing were measured using 3D motion analysis. A 6-week neuromuscular training program was undertaken by the CAI group. Measurements of kinematic data for both groups were measured at baseline and the changes in kinematic data for CAI group were measured at 6 and 24 weeks. The kinematic data at HS during walking and running demonstrated that the magnitude of the eversion in the CAI group (-5.00° and -4.21°) was less than in the control group (-13.45°and -9.62°). The kinematic data at MS also exhibited less ankle eversion in the CAI group (-9.36° and -8.18°) than in the control group (-18.52° and -15.88°). Ankle positions at TT during landing were comparable between groups. Following the 6-week training, the CAI participants demonstrated a less everted ankle at HS during walking and running (-1.77° and -1.76°) compared to the previous positions. They also showed less ankle eversion at MS (-5.14° and -4.19°). Ankle orientation at TT changed significantly to an inverted ankle position (from -0.26° to 4.11°). The ankle kinematics were restored back to the previous positions at 24 weeks except for landing. It appeared that athletes with unstable ankle had a relatively inverted ankle position, and that 6-week neuromuscular training had an immediate effect on changing ankle orientation toward a less everted direction. The changed ankle kinematics seemed to persist during landing but not during walking and running.

Effects of a 6-Week Neuromuscular Rehabilitation Program on Ankle-Evertor Strength and Postural Stability in Elite Women Field Hockey Players With Chronic Ankle Instability.

OBJECTIVE: To determine whether a neuromuscular rehabilitation program can improve postural stability and ankle-evertor strength and to examine the temporal changes and persistence of the rehabilitation effects in athletes with chronic ankle instability (CAI). DESIGN: A total of 21 national women field hockey players participated in this study (CAI, n = 12; control, n = 9). MAIN OUTCOME MEASURES: Isokinetic ankle-evertor strength (peak torque [PT], total work [TW]) at 30°/s, 60°/s, 90°/s, and 120°/s, mediolateral stability index (MSI), and dynamic stability test (TCT). Data were recorded at baseline, 6 wk, and 24 wk. RESULTS: At baseline, isokinetic evertor strength was comparable between groups. At 6 wk, the CAI group demonstrated significantly increased eccentric PT and TW at 30°/s and 60°/s and increased concentric/eccentric TW at 90°/s. The control group showed significantly increased concentric TW at 30°/s and increased concentric PT and TW at 90°/s. At 24 wk, except for eccentric PT at 60°/s and 120°/s, concentric/eccentric PT and TW were significantly increased in the CAI group. The control group showed significantly increased TW at all angular velocities regardless of contraction mode. The CAI group exhibited significant increases in concentric/eccentric evertor PT and TW at 120°/s in comparison with the control group. MSI and TCT decreased in both groups at 6 wk; however, the CAI group demonstrated significant increases in both measures at 24 wk, whereas the control group showed no significant change. CONCLUSIONS: The results suggest that the neuromuscular rehabilitation program had an immediate effect on gaining eccentric evertor strength and improving postural control and appeared to contribute to enhancing the evertor strength of unstable ankles in the longer term. On the other hand, improved postural stability did not seem to persist.