Shoulder injuries in tennis players

Shoulder Rotational and Dynamic Stability Profiles in Elite and National-Level Tennis Players: A Pilot Study Using an Electromechanical Dynamometer for Measuring Isometric Strength

BACKGROUND/OBJECTIVE

Tennis involves repetitive overhead movements, and understanding the relationship between shoulder mobility, dynamic stability, and isometric strength could be crucial for developing targeted training programmes to enhance performance and reduce injury risk. This study aimed to assess shoulder rotational mobility, dynamic stability, and isometric strength profiles in elite and national-level tennis players.

METHODS

Twenty-four male and female athletes were grouped by competitive level: National-Level Female Group (NFG); National-Level Male Group (NMG); and Elite Male Group (EMG). Shoulder isometric strength was evaluated using an electromechanical dynamometer (Dynasystem), while rotational mobility and dynamic stability were assessed using standardised protocols.

RESULTS

Significant anthropometric differences in height, weight, and leg length were identified between NFG and the other groups (p < 0.001). NMG showed reduced external rotation compared to NFG and EMG in the dominant shoulder (p < 0.05). EMG exhibited significant asymmetries in external rotation between the dominant and non-dominant shoulders, which may be attributed to higher training volumes (p < 0.05; ES = 0.994). No significant differences were found in isometric strength across the groups, although NFG showed lower internal rotation strength and ER/IR ratio asymmetry between the dominant and non-dominant shoulder (p < 0.05). Dynamic stability scores were consistently low, with asymmetries between the dominant and non-dominant sides in most cases.

CONCLUSIONS

These findings suggest the need for targeted training to address asymmetries and enhance dynamic stability. Caution is advised when generalising these results due to the limited sample size. Future research should include more participants and explore associations with performance metrics, such as serve speed and playing style.

The efficacy of conservative management of micro-traumatic posterior shoulder instability

Background

Microtraumatic posterior shoulder instability (PSI) is characterized by symptomatic posterior translation of the glenohumeral joint. A common etiology is a gradual overload of glenohumeral joint structures. The recommend initial treatment for microtraumatic PSI is rehabilitation; however, the evidence to support this recommendation is limited. The aim of this study is to investigate the patient- reported outcome measures and return to sport success of participants with microtraumatic PSI who participate in a posterior instability rehabilitation program.

Methods

In the single-group study design, 24 shoulders in 22 sporting participants (17 male, 5 females; mean age, 21.1 years, standard deviation 10.1 years) diagnosed with microtraumatic PSI undertook the Watson Posterior Instability Program (WIP-p) over 24 weeks. Outcome measures included the Melbourne Instability Shoulder Score and Western Ontario Shoulder Instability Index at baseline, 6, 12, and 24 weeks. Failure of conservative management and time to return to sport was measured. Treatment effects were determined using linear mixed models, with 95% confidence intervals. Significance was set at 0.05.

Results

After 24 weeks of the WIP-p, participants had significant improvements at 12 (effect size or standardized mean difference (SMD): 1.1, P < .001) and 24 weeks (SMD: 1.8, P < .001) on the Western Ontario Shoulder Instability Index and significant improvements at 6 (SMD; 0.74, P = .036), 12 (SMD: 0.41, P = .007) and 24 weeks (SMD: 1.7, P < .001) on the Melbourne Instability Shoulder Score. For return to sport, 20 of the 22 (90.1%) participants returned to full activity at the 24-week time point, while two went on to have reconstructive surgery.

Discussion and Conclusion

The WIP-p resulted in a high level of return to sport and significantly improved functional outcomes in patients with microtraumatic PSI. A small proportion of sporting participations with microtraumatic PSI may fail conservative rehabilitation and require surgical consideration.

Shoulder rotation strength and overhead shooting speed associated with prior shoulder injury in water polo players

This study aimed to differentiate peak ball speed during shooting and shoulder rotation strength of the dominant arm between previously injured (PI) and uninjured (UI) water polo players. Nine PI and nine UI players performed 10 shots at 6 m from the goal mouth and three sets of three repetitions of isokinetic shoulder strength tests at 180 degrees/s on a dynamometer. Peak ball speed and shoulder concentric internal rotation (CIR) and eccentric external rotation (EER) peak torque (PT) and total work (TW) normalised to body mass were measured. EER:CIR PT and TW ratios were calculated. All PI versus UI comparisons were made using an Independent Samples T-Test. PI players shot 6% faster, produced 18% more CIR PT, and had lower EER:CIR PT (22%) and TW (34%) ratios compared with UI players. Shoulder TW compared with PT ratios could be more sensitive in differentiating PI versus UI players as TW takes into account the muscles' capacity throughout full active ROM. Practitioners could expand their foci to monitor shoulder EER:CIR TW ratios, in addition to PT ratios, to identify muscle imbalances in water polo athletes who might be at risk of injury/reinjury, and thereafter design interventions to reduce these imbalances.

Alterations to the Kinetic Chain Sequence After a Shoulder Injury in Throwing Athletes

Background

Kinetic chain (KC) sequencing is essential for efficient energy translation through the body in overhead-throwing sports. A sequencing breakdown can result in injuries to the throwing shoulder and thus the management of athlete recovery in an attempt to minimize the impact on both training and performance.

Purpose

To determine kinematic differences in KC sequencing, imperative for the prevention and rehabilitation of a shoulder injury, during maximal throwing in overhead athletes with and without a shoulder injury.

Study Design

Controlled laboratory study.

Methods

Kinematic data were collected and analyzed for 36 male overhead athletes with (symptomatic) and without (asymptomatic) a shoulder injury (18 participants per group) during maximal overhead-throwing trials using 3-dimensional motion analysis (100 Hz). Peak angular velocities and associated timing of the throwing shoulder, throwing elbow, thorax, pelvis, lead hip, and rear hip were calculated to determine the KC sequence in both groups. Kinematic data were compared using independent t tests, and relationships between variables were assessed using the Pearson correlation coefficient (both P < .05).

Results

The KC sequence in overhead athletes with or without a shoulder injury was the same, except for peak elbow extension and shoulder flexion angular velocities. These angular velocities occurred simultaneously in asymptomatic throwers (both 0.17 % before ball release [BR]) but sequentially in symptomatic throwers (0.06 % before BR and 0.67 % after BR, respectively). No differences were evident in stride length (m) or resultant ball velocity (m/s) between the groups, despite differences in key joint angular velocities across KC segments (P range, <.001-.035). Relationships between resultant ball velocity and all key joint angular velocities were evident for symptomatic but not asymptomatic throwers (P range, <.001-.026).

Conclusion

Our study demonstrated that overhead athletes, regardless of their shoulder injury history, had similar KC sequencing across the lower limb and lumbopelvic-hip complex segments before differences in the timing of peak elbow extension and shoulder flexion angular velocities of the throwing arm approaching BR. Further research investigating muscle activity changes and technique parameters during overhead throwing may present explanations as to how we can ensure that the KC sequence is not altered as a result of an injury.

Clinical Relevance

This study provides a new perspective on the KC and how an injury may not change the sequence itself in overhead-throwing performance.

Upper Extremity Musculoskeletal Profiles in Tennis Players: A Systematic Review

CONTEXT

Tennis-specific musculoskeletal (MSK) screening can assess range of motion (ROM) and muscular imbalances. Identifying normative values before implementing a MSK screen is essential in contributing to athlete performance and injury risk profiles.

OBJECTIVE

To review upper extremity MSK data in healthy tennis players across age, sex, and level of play.

DATA SOURCE

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed for this review. A search was conducted in MEDLINE, SPORTDiscus, Embase, and CINAHL.

STUDY SELECTION

This review included shoulder, elbow, and wrist ROM, isometric strength, or isokinetic strength in a tennis population. Each article was critically appraised to help identify the internal and external validity of each study.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 3.

DATA EXTRACTION

A total of 41 studies met the search criteria. Each contributor organized the data elements of interest into data tables, with a second contributor assigned for review. Data elements of interest included player and study characteristics: ROM, isometric dynamometry, and isokinetic strength.

RESULTS

A total of 3174 players were included in the final studies. Most of the players included were competitive adolescents and young adults; 15 studies included ROM data. Male tennis players consistently had more external rotation (ER) gain (range, 1.8º to 8.8º) and internal rotation (IR) loss (range, -15.3º to -3.0º) when compared with their female counterparts (ER range, -2.5º to 5.8º; IR range, -10.4º to -3º). Shoulder IR and ER strength were measured in the majority of all the strength studies, with the external rotators generating at least two-thirds the strength of the internal rotators.

CONCLUSION

Overall MSK data of tennis players indicate that shoulder strength values are often larger than nontennis players, but equal to or slightly lower than comparable athletes in other overhead sports. Adaptive changes of the glenohumeral joint and subsequent rotational motion are similar to those of other overhead athletes.

Musculoskeletal Disorder Risk Assessment during the Tennis Serve: Performance and Prevention

Addressing the risk of musculoskeletal disorders (MSDs) during a tennis serve is a challenge for both protecting athletes and maintaining performance. The aim of this study was to investigate the risk of MSD occurrence using the rapid whole-body assessment (REBA) ergonomic tool at each time step, using 3D kinematic analysis of joint angles for slow and fast serves. Two force platforms (750 Hz) and an optoelectronic system including 10 infrared cameras (150 Hz, 82 markers located on the whole body and on the racket) were used to capture the kinematics of the six REBA joint areas over five services in two young male and two young female ranked players. The mean REBA score was 9.66 ± 1.11 (ranging from 7.75 to 11.85) with the maximum value observed for the loading and cocking stage (REBA score > 11). The intermediate scores for each of the six joint areas ranged between 2 and 3 and the maximum value of their respective scales. The lowest scores were observed for the shoulder. Neck rotation and shoulder flexion are parameters that could be taken into account when analyzing performance in the context of MSD prevention.

Role of kinetic chain in sports performance and injury risk: a narrative review

The kinetic chain refers to the body's intricate coordination of various segments to perform a specific activity involving precise positioning, timing, and speed. This process is based on task-oriented and activity-specific pre-programmed muscle activation patterns enhanced by repeated practice. It demands muscular eccentric strength, joint flexibility, and musculotendinous elastic energy storage. The body core (lumbopelvic-hip complex) forms the kinetic chains' central point of activities in most sports because it facilitates load transfers to and from the limbs. The kinetic chain relationship with fascia, peripheral nerves, and tensegrity is fundamental to holistic human body movements. The kinetic chain function demands neuromuscular, sensorimotor, and neurocognitive control. Any blockage or defect in the kinetic chain can develop compensatory patterns, high demands on distal parts, and overuse and overload injuries. Taking a holistic approach and evaluating the integrity of the kinetic chain in athletes can significantly enhance efforts to improve sports performance and mitigate injury risk.

Scapular Resting Posture and Scapulohumeral Rhythm Adaptations in Volleyball Players: Implications for Clinical Shoulder Assessment in Athletes

Volleyball players develop shoulder sports-related adaptations due to repetitive overhead motions. It is essential to differentiate between these sports-related adaptations and pathological patterns in clinical assessments, particularly on scapular resting posture and scapulohumeral rhythm. Using an electromagnetic tracking system, the 3D shoulder kinematics of 30 male elite asymptomatic volleyball players and a matching control group were recorded at rest and in eight humeral elevation positions, in 15-degree increments from 15 to 120 degrees. The results indicated that the dominant scapular resting posture of the volleyball group was more anteriorly tilted than the control group (Volleyball: mean = -12.02°, STD = 4.16°; Control: mean = -7.45°, STD = 5.42°; Mean difference = 4.57°; STD = 6.85°; CI95% = 2.1° to 7.1°). The scapulohumeral rhythm in the volleyball group showed greater scapular internal rotation (Volleyball: mean = 41.60°, STD = 9.14°; Control: mean = 35.60°, STD = 6.03°; mean difference = 6.02°, STD = 1.47°; CI95% = 4.80° to 7.25°) and anterior tilt (Volleyball: mean = -9.10°, STD = 5.87°; mean = -2.3°, STD = 9.18°; mean difference = 6.88°, STD = 0.66°; CI95% = 6.34° to 7.43°). These findings suggest that volleyball players have developed a sports-related scapular adaptive pattern. This information may be valuable for clinical assessment and rehabilitation planning in injured volleyball players and may aid in the decision-making process for determining a safe return-to-play after a shoulder injury.

Posterior Shoulder Instability in Tennis Players: Aetiology, Classification, Assessment and Management

Background

Micro-traumatic posterior shoulder instability (PSI) is an often missed and misdiagnosed pathology presenting in tennis players. The aetiology of micro-traumatic PSI in tennis players is multifactorial, including congenital factors, loss of strength and motor control, and sport-specific repetitive microtrauma. Repetitive forces placed on the dominant shoulder, particularly combinations of flexion, horizontal adduction, and internal rotation contribute to the microtrauma. These positions are characteristic for kick serves, backhand volleys, and the follow-through phase of forehands and serves. The aim of this clinical commentary is to present an overview of the aetiology, classification, clinical presentation, and treatment of micro-traumatic PSI, with a particular focus on tennis players.

Level of Evidence

5.

The Effect of McGill Core Stability Training on Movement Patterns, Shooting Accuracy, and Throwing Performance in Male Basketball Players: A Randomized Controlled Trial

CONTEXT

Core stability training has been recommended as a vital element in improving movement's pattern and athletic performance. The main objective of this study was to investigate the effect of 12-week McGill core stability training on movement patterns, shooting accuracy, and throwing performance.

DESIGN

Randomized controlled clinical trial.

SETTING

University research laboratory.

METHODS

Forty male basketball players were randomly assigned to experimental and control groups. The experimental group completed 12-week McGill core stability training, while the control group completed routine exercise training. Patterns of functional movements was measured through functional movement screen (FMS), shooting accuracy measured by static 3-point shooting (S3P) and dynamic 60-second 3-point shooting test, and throwing performance measured by Functional Throwing Performance Index.

RESULTS

Comparison revealed that regardless of received training, after 12 weeks both groups showed significant improvement in all outcome measures. However, experimental group had significantly higher post test scores in FMS (P = .02), S3P (P = .007), and dynamic 60-second 3-point shooting test (P = .01). For Functional Throwing Performance Index, there was no group differences (P = .96). The results of follow-up assessments showed for all measurements including FMS (P = .03), S3P (P = .004), dynamic 60-second 3-point shooting test (P < .001), and Functional Throwing Performance Index (P = .005); experimental group had higher scores than the control group.

CONCLUSIONS

According to the results, implementing McGill core stability training in basketball routine training would be advisable since significant improvement can be obtained in the measured parameters.

Professional tennis players suffer high prevalence of shoulder alterations during the season: a possible tennis shoulder syndrome

PURPOSE

To analyze the shoulder alterations of professional tennis players during the competition season and to compare the differences between their dominant vs. non-dominant shoulders, as well as gender and age differences.

METHODS

Two-hundred and seventy shoulders of (78 men and 57 women) professional active tennis players were assessed during 3 ATP and WTA tournaments.

MAIN VARIABLES STUDIED

long head of biceps (LHB) tenderness and synovitis; glenohumeral internal rotation deficit (GIRD), total range of motion (TRM), external rotation (ER) and scapular dyskinesis (DK). Secondary variables: shoulder dominance, gender, age, training hours, ranking, type of backhand. LHB tenderness and synovitis were assessed by clinical and ultrasound examination, TRM with goniometer and DK by dynamic observation.

RESULTS

LHB tenderness of the dominant shoulder was present in 35% of all players, being more prevalent in women (47.4%) than men (26.9%) p = 0.023. LHB synovitis of the dominant shoulder was present in 20.2% of all players without difference between genders (n.s). High prevalence of GIRD was found in both dominant (87.4%) and non-dominant (56.3%) shoulders, being more prevalent in the dominant shoulder p = 0.00005. TRM was decreased in both dominant (144.5° ± 20.2°) and non-dominant shoulders (161.2° ± 18.9°) p = 0.00005. ER was normal in dominant (93.8° + /9.3°) and non-dominant shoulders (93.4° + /8.4°) (n.s). DK was present in 57.7% of dominant and 45.9% of non-dominant shoulders (n.s). The combination of LHB alterations, GIRD and DK in the dominant shoulder was present in 13.3% of the participants. There were no significant differences between younger (< 22 years) vs older players (≥ 22 years).

CONCLUSION

Professional tennis players actively playing suffer a high prevalence of LHB inflammation, GIRD, scapular dyskinesis and decreased TRM in their dominant and non-dominant shoulders. The LHB is a significant cause for anterior shoulder pain in this population. Women suffer more LHB tenderness than men. Young players are as affected as older players.

LEVEL OF EVIDENCE

Level IV.

Fastball pitching performance only slightly decreases after mobility impediment of the pelvis and trunk-Do (catch-up) compensation strategies come into play?

Background

Baseball pitching performance can be mechanically explained by the summation of speed principle and the principle of optimal coordination of partial momenta. Impeding optimal energy generation or transfer by or between the pelvis and trunk segments could provide valuable insight into possible compensation or catch-up mechanisms that may manifest themselves based on these principles.

Aim

The aim of the present study was to explore the effects of experimentally impeding the mobility of and between the pelvis and trunk segments (1) on ball speed and mechanical peak joint power, and (2) on mechanical peak load of the elbow and shoulder joints at maximal external rotation (MER) during fastball pitching.

Methods

Eleven elite baseball pitchers (mean age 17.4, SD 2.2 years; mean pitching experience 8.9, SD 3.0 years) were instructed to throw at least 15 fastballs as fast and accurately as possible under two conditions. One condition involved impeding the mobility of the pelvis and trunk segments to hamper their ability to rotate independently, which consequently should affect the separation time, defined as the time interval between the pelvis and trunk peak angular velocities. In the other condition, pitchers threw unimpeded. Ball speed, mechanical peak joint power and peak net moment of the elbow and shoulder at MER were compared between conditions using Generalized Estimating Equations (GEE).

Results

In the impeded pitching condition, the mean difference of the separation time was 12.4 milliseconds [95% CI (4.0, 20.7)] and for ball speed 0.6 mph [95% CI (0.2, 0.9)] lower compared to the unimpeded condition. Only the peak pelvic angular velocity, in addition to the trunk, upper arm and forearm, was 45 deg/s [95% CI (24, 66)] higher impeded condition. The mean differences of the joint power and net moments at the shoulder and elbow did not reach statistical significance.

Conclusion

In elite adolescent baseball, the observed pitching performance after experimentally impeding pelvic and trunk mobility undermines a potential distal catch-up strategy based on the summation of speed principle. The increased peak pelvic angular velocity may indicate a compensation strategy following the optimal coordination of partial momenta principle to practically maintain pitching performance.

Upper Body Injuries in Golfers

PURPOSE OF REVIEW

Golf is a sport that can be played by an athlete of any age, which enhances its popularity. Each golfer's swing is unique, and there is no "right" way to swing the golf club; however, the professional golfer often has more of a consistent swing as opposed to an amateur golfer. A collaborative, team approach involving the golfer with a swing coach, physical therapist, and physician often can be informative on how to prevent golf injury, but also how to treat golf injury if it occurs.

RECENT FINDINGS

As a rotational sport, the golfer needs to be trained and treated with respect for how the body works as a linkage system or kinetic chain. A warm-up is recommended for every golfer before practicing or playing, and this warm-up should account for every segment of the linkage system. Though it has been thought of as a relatively safe sport, injuries can be seen with golfers of any age or skill level, and upper body injuries involving the cervical and thoracic spine, shoulder, elbow, and wrist are common. A narrative review is provided here of the epidemiology of golf injury and common injuries involving each of these upper body regions. In addition, treatment and injury prevention recommendations are discussed.

Throwing Injury Prevention Strategies with a Whole Kinetic Chain-Focused Approach

Purpose of Review

This review examines the relationship between the baseball pitching motion and the kinetic chain. The goal was to determine the underlying causes of a deficiency in throwing mechanics throughout a throwing motion, and to provide an evidence-based approach on how to prevent injuries caused by a lack of proper mechanics. In doing so, we sought to provide a warm-up strategy that can be added to every baseball player’s daily on-field routine that is tailored to each phase of the throwing motion.

Recent Findings

To help minimize the risk of injury to overhead throwing athletes, a thorough understanding of the throwing motion is critical. Throwing a ball places extreme stress on the body, notably the shoulder and elbow joints. With a clear understanding of the biomechanics of throwing, we can develop an injury prevention routine to minimize unnecessary stresses throughout the kinetic chain.

Summary

The throwing cycle is a complex motion that places various stresses throughout the thrower’s body, from the ankle to the core, and from the back to the shoulder and elbow. A thorough understanding of the mechanics of this motion, along with specific exercises to target the specific actions of each phase, may allow for throwers, regardless of their age and experience, to minimize injury risk.

A Scoping Review on Shoulder Injuries of Wheelchair Tennis Players: Potential Risk-Factors and Musculoskeletal Adaptations

Wheelchair tennis players are prone to develop shoulder injuries, due to the combination of wheelchair propulsion, overhead activities and daily wheelchair activities. A methodical literature search was conducted to identify articles on shoulder complaints in wheelchair tennis, wheelchair sports and tennis. The aims were to identify (1) type of shoulder complaints; (2) possible risk factors for the development of shoulder injuries; (3) musculoskeletal adaptations in the shoulder joint in wheelchair tennis players. Fifteen papers were included in this review, five on wheelchair tennis, three on wheelchair sports and seven on tennis. Type of shoulder complaints were acromioclavicular pathology, osteoarthritic changes, joint effusion and rotator cuff tears. Possible risk factors for the development of shoulder injuries in wheelchair tennis are overhead movements, repetitive activation of the anterior muscle chain and internal rotators, as well as a higher spinal cord injury level. Muscular imbalance with higher values for the internal rotators, increase in external range of motion, decrease in internal range of motion and reduced total arc of motion were the most common proposed musculoskeletal adaptations due to an unbalanced load. These presented risk factors and musculoskeletal adaptations might help researchers, coaches and wheelchair tennis players to prevent shoulder injuries.

Match Analysis, Physical Training, Risk of Injury and Rehabilitation in Padel: Overview of the Literature

Padel is a racket sport that has been gaining great popularity and scientific interest in recent years. It could be considered to be a high-intensity intermittent sport with valuable cardiovascular and neuromuscular benefits; however, the risk of injury cannot be neglected. To date, there is still a gap of knowledge in the scientific literature on this emergent sport. Therefore, the present review aims to synthetize the current knowledge on padel game dynamics to better characterize the main risk factors, the injury rate and characteristics, and the most effective rehabilitative treatment strategies. PubMed, Scopus, Cochrane, and PEDro were screened up to January 2022 to identify eligible studies focusing on padel players as participants. Out of 160 records, we included 19 studies, which were focused on match analysis, anthropometric and physical training, the risk of injury, and rehabilitative interventions. The results showed that the high action velocity and the sudden changes in direction during a padel match could represent a risk factor for injuries, especially in untrained players. However, the high heterogeneity of the studies in the literature hinders our ability to draw any strong conclusions, and the results should be carefully considered. Future research should address the lack of knowledge on injury mechanisms and type to implement a tailored rehabilitation program.

The Thrower's Shoulder

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The thrower's shoulder has been a subject of great interest for many decades. Different theories have been proposed to clarify the pathophysiology, clinical presentation, and treatment options for this condition. In this review article, we summarize the relevant anatomy and pathophysiology and how these translate into signs, symptoms, and imaging findings. Also, a historical review of the treatment methodologies in the setting of an evolving concept is presented.

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The initial event in the cascade is thickening and contracture of the posteroinferior capsule resulting from repetitive tensile forces during the deceleration phase of throwing. This is known as "the essential lesion" and is clinically perceived as glenohumeral internal rotation deficit (GIRD), and a Bennett lesion may be found on radiographs.

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Change in the glenohumeral contact point leads to a series of adaptations that are beneficial for the mechanics of throwing, specifically in achieving the so-called "slot," which will maximize throwing performance.

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The complexity of the throwing shoulder is the result of an interplay of the different elements described in the cascade, as well as other factors such as pectoralis minor tightness and scapular dyskinesis. However, it is still unclear which event is the tipping point that breaks the balance between these adaptations and triggers the shift from an asymptomatic shoulder to a painful disabled joint that can jeopardize the career of a throwing athlete. Consequences are rotator cuff impingement and tear, labral injury, and scapular dyskinesis, which are seen both clinically and radiographically.

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A thorough understanding of the pathologic cascade is paramount for professionals who care for throwing athletes. The successful treatment of this condition depends on correct identification of the point in the cascade that is disturbed. The typical injuries described in the throwing shoulder rarely occur in isolation; thus, an overlap of symptoms and clinical findings is common.

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The rationale for treatment is based on the pathophysiologic biomechanics and should involve stretching, scapular stabilization, and core and lower-body strengthening, as well as correction of throwing mechanics, integrating the entire kinetic chain. When nonoperative treatment is unsuccessful, surgical options should be tailored for the specific changes within the pathologic cascade that are causing a dysfunctional throwing shoulder.

The Effect of Crutch Gait Pattern on Shoulder Reaction Force when Walking with Lower Limb Exoskeletons

Lower limb exoskeleton robots have shown great potential in assistive and rehabilitative applications, allowing individuals with motor impairment, such as spinal cord injury (SCI) patients, to perform overground gait. Most assistive lower limb exoskeletons require users to use crutches to balance themselves during standing and walking. However, long-term crutch usage has been demonstrated to be potentially harmful to the shoulder joints, due to the repetitive high shoulder reaction forces. Investigations into the shoulder loads experienced during exoskeleton use are needed to understand the extent of this harm and, if required, to reduce the risk of injury. In this preliminary study, the effects of different gait patterns on the shoulder load are investigated in an experiment involving three able-bodied individuals. Specifically, the differences in shoulder load during exoskeleton walking are studied with two commonlyobserved gait patterns: (1) the four-point parallel crutch gait and (2) the four-point reciprocal crutch gait. Contact forces between the ground and the human-exoskeleton system were recorded and used to indicate shoulder reaction force. The results suggested no significant differences in maximum force and maximum rate of loading between the two crutch gait patterns, and only minor differences in force time integral. This indicates that shoulder reaction force may not be a significant factor when choosing between crutch gaits during exoskeleton use.

Sensors for Wheelchair Tennis: Measuring Trunk and Shoulder Biomechanics and Upper Extremity Vibration during Backhand Stroke

This study was the first to compare the differences in trunk/shoulder kinematics and impact vibration of the upper extremity during backhand strokes in wheelchair tennis players and the able-bodied players relative to standing and sitting positions, adopting an electromagnetic system along with wearable tri-axial accelerometers upon target body segments. A total of 15 wheelchair tennis players and 15 able-bodied tennis players enrolled. Compared to players in standing positions, wheelchair players demonstrated significant larger forward trunk rotation in the pre-preparation, acceleration, and deceleration phase. Significant higher trunk angular velocity/acceleration and shoulder flexion/internal rotation angular velocity/acceleration were also found. When able-bodied players changed from standing to sitting positions, significant changes were observed in the degree of forward rotation of the trunk and shoulder external rotation. These indicated that when the functions of the lower limbs and trunk are lacking or cannot be used effectively, “biomechanical solutions” such as considerable reinforcing movements need to be made before the hitting movement. The differences between wheelchair tennis players and able-bodied players in sitting positions could represent the progress made as the wheelchair players evolve from novices to experts. Knowledge about how sport biomechanics change regarding specific disabilities can facilitate safe and inclusive participation in disability sports such as wheelchair tennis.

Validity and reliability of a novel monitoring sensor for the quantification of the hitting load in tennis

Wearable sensor systems are a emerging tools for the evaluation of the sport's activity and can be used to quantify the external workload of the athlete. The main goal of this paper was to evaluate the validity and reliability of the "Armbeep inertial measurement unit" (IMU) sensor both in a closed tennis exercise and in open matchplay. Twentyfour junior tennis players performed a baseline drill and played matches, during which they wore a combined accelerometer and gyroscope sensor. Video footage was concomitantly recorded using a digital video camera. The agreement between the measurements was assessed with the intraclass correlation coefficient (ICC) and the standard error of measurement (SEM). A simple linear regression was used to predict the number of shots registered from the video and from the Armbeep IMU sensor's data. The number of total forehand and backhand shots during the drill repetitions showed an excellent test and re-test reproducibility (ICC≥0.90). There was a significant relationship between the Armbeep IMU sensor's number of contacts and the total number of shots (R2 = 0.938) which indicated the excellent reliability of the tested Armbeep IMU sensor for those parameters. Considering the accuracy of the total tennis shots and the small magnitude of error for wrist speed and acceleration, the Armbeep IMU sensor appears to be an appropriate on-court tool that can be used to monitor the hitting load during tennis practice and matches.

The Biomechanics of Shoulder Movement with Implications for Shoulder Injury in Table Tennis: A Minireview

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.

Effects of exercise therapy plus manual therapy on muscle activity, latency timing and SPADI score in shoulder impingement syndrome

PURPOSE

The study aimed to compare the effects of exercise therapy plus manual therapy (ET plus MT) and exercise therapy (ET) alone on muscle activity, muscle onset latency timing and shoulder pain and disability index-Hindi (SPADI-H) score in athletes with shoulder impingement syndrome (SIS).

MATERIALS AND METHOD

Overhead male athletes diagnosed with SIS were randomly allocated into ET plus MT group(n = 40) and ET group(n = 40). Muscle activity, muscle onset latency timings and SPADI-H score were assessed. Both the groups performed 8 weeks of intervention and were evaluated at baseline, 4th and 8th weeks.

RESULT

ET plus MT group was more effective in increasing muscle activity, optimising latency timings and decreasing SPADI score when compared to ET group alone(p < 0.05). After treatment muscle activity and SPADI-H improved in both groups (p < 0.05).

CONCLUSION

ET plus MT was superior for improving muscle activity, muscle onset latency timing and SPADI score compared to ET alone.

Tennis overuse injuries in the upper extremity

OBJECTIVE

Tennis is a popular sport with high levels of participation. This article aims to describe how upper extremity overuse injuries occur in relation to tennis biomechanics and to review their imaging characteristics and implications for management. In particular, we will review the imaging patterns of internal impingement, scapular dyskinesis, lateral and medial epicondylitis, ulnar collateral ligament insufficiency, valgus extension overload, capitellar osteochondritis dissecans, extensor carpi ulnaris tendinosis and instability, tenosynovitis, triangular fibrocartilage complex injuries, and carpal stress injuries.

CONCLUSION

Tennis is a complex and physically demanding sport with a wide range of associated injuries. Repetitive overloading commonly leads to injuries of the upper extremity. An understanding of the underlying mechanisms of injury and knowledge of these injury patterns will aid the radiologist in generating the correct diagnosis in both the professional and recreational tennis athlete.

Epidemiology and pain in elementary school-aged players: a survey of Japanese badminton players participating in the national tournament

Pain is common in athletes which should be well managed. To identify risk factors for shoulder pain, and the association between shoulder pain, lower back pain and knee pain among elementary school-aged badminton players, we conducted a cross-sectional study to collect data of the past year among 611 elementary school age (7-12 years old) badminton players belonging to the Japan Schoolchildren Badminton Federation using a questionnaire. Odds ratio (OR) and 95% confidence interval (CI) were estimated by multivariate logistic regression analysis. The overall incidence rate of shoulder injuries, lower back injuries and knee injuries was 0.38 injuries per 1000 h of badminton training. Players with training time per day > 2.5 h were 2.64 times (95% CI 1.03-6.78, p = 0.043) more likely to sustain shoulder pain than those with training time per day ≤ 2.5 h. A significant association was revealed between shoulder pain and knee pain as well as between lower back pain and knee pain as training hours per day > 2.5 h. Moreover, lower back pain was significantly associated with shoulder pain independent of training hours per day (≤ 2.5 h: p = 0.001; > 2.5 h: p < 0.001). These findings indicate that training time per day is risk factor, and shoulder pain, lower back pain and knee pain were associated with each other in elementary school-aged badminton players.

Shadow pitching deviates ball release position: kinematic analysis in high school baseball pitchers

Background

Although shadow pitching, commonly called “towel drill,” is recommended to improve the throwing motion for the rehabilitation of pitching disorders before the initiation of a throwing program aimed at returning to throwing using a ball, the motion differs from that of normal throwing. Learning improper motion during ball release (BR) may increase shoulder joint forces. Abnormal throwing biomechanics leads to injures. However, there has been no study of shadow pitching focusing on the BR position. The purpose of the present study was to evaluate the BR position and kinematic differences between shadow pitching and normal throwing. In addition, the effect of setting a target guide for BR position on throwing motion was examined in shadow pitching.

Methods

The participants included in this study were 20 healthy male students who were overhand right-handed pitchers with no pain induced by a throwing motion. Participants performed normal throwing (task 1), shadow pitching using a hand towel (task 2), and shadow pitching by setting a target of the BR position (task 3). A motion capture system was used to evaluate kinematic differences in throwing motions, respectively. Examination items comprised joint angles and the differences in BR position.

Results

BR position of task 2 shifted significantly toward the anterior, leftward, and downward directions compared with task 1. The distance of BR position between tasks 1 and 2 was 24 ± 10%. However, task 3 had decreased BR deviation compared with task 2 (the distance between 3 and 1 was 14 ± 7%). Kinematic differences were observed among groups at BR. For shoulder joint, task 2 showed the highest value in abduction and horizontal adduction among groups. In spine flexion, left rotation and thorax flexion, task 2 was significantly higher than task 1. Task 3 showed small differences compared with task 1.

Conclusions

The BR position of shadow pitching deviated significantly in the anterior, leftward, and downward directions compared with normal throwing. Furthermore, we demonstrated that the setting of BR target reduces this deviation. Thus, the target of BR position should be set accurately during shadow pitching exercises in the process of rehabilitation.

Common and Less Well-known Upper-limb Injuries in Elite Tennis Players

A recent increase in epidemiology studies on injuries in elite tennis players has helped to shed light on the types of injuries these athletes sustain. This article reviews the common upper-limb injuries in elite players and includes less well known, but important, injuries. A search was conducted to identify current relevant studies involving elite tennis players. Injury frequency rates, injuries by regions, and types of injuries together with a list of commonly reported injuries in the upper limb were established. This list was then reviewed and refined by a sports medicine physician who cares for elite tennis players to include both those injuries of the upper limb that are common and those that are less well known but still important and frequently encountered. Common injuries include internal shoulder impingement, rotator cuff pathology, labral tears, elbow tendinopathies, as well as extensor carpi ulnaris tendinopathies and subluxation. Posterior shoulder instability, distal humeral bone stress, elbow medial collateral ligament, and nondominant wrist ulnar collateral ligament injuries are not commonly reported injuries, but they are of significant clinical importance.

Return to sport following reverse shoulder arthroplasty: a systematic review

BACKGROUND

The purpose of this study is to systematically review the evidence in the literature to ascertain the rate and timing of return to sport following reverse shoulder arthroplasty (RSA).

METHODS

A systematic literature search based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, using the Embase, MEDLINE, and Cochrane Library Databases. Eligible for inclusion were clinical studies reporting on return to sport following RSA. Statistical analysis was performed using SPSS.

RESULTS

Overall, 8 studies including 455 patients (464 shoulders) met our inclusion criteria. The majority of patients were female (77.7%), with an average age of 74.2 years. The overall rate of return to sport was 79.1%; with 66.7% of golfers, 74.3% of swimmers, 50.0%, of tennis players, 94.4% of joggers, and 69.7% of cyclists returning. In addition, 71.4% of patients returned to the same level of sporting activity. The average time to return to sport was 3.4 months with a mean follow-up of 34.0 months.

DISCUSSION AND CONCLUSION

The results from our systematic review show that the majority of patients are able to return to sport following RSA, with a large number returning to the same level of sport. However, results were modest in overhead athletes, with a concerning number unable to return to tennis post-RSA.

Scapular Dyskinesis and the Kinetic Chain: Recognizing Dysfunction and Treating Injury in the Tennis Athlete

PURPOSE OF REVIEW

This article aims to provide a comprehensive understanding of the evaluation, diagnosis, and management of scapular dyskinesis and its impact on the kinetic chain in tennis athletes.

RECENT FINDINGS

Optimal glenohumeral biomechanics are intimately associated with proper scapular motion and function. The tennis serve requires the scapula to act as a force transducer in the kinetic chain to convert potential energy generated in the lower extremities to kinetic energy in the upper extremity. Any aberration within this complex kinetic chain will result in force uncoupling and increases the potential for injury through compensatory mechanisms. Specifically, scapular dyskinesis has been associated with an increased risk of shoulder pain of up to 43% in overhead athletes. These pathologies include rotator cuff disease, subacromial and posterior impingement, labral injuries, and SLAP tears. Although the direct causality of these injuries remains controversial, multiple kinematic studies have demonstrated altered scapular positioning increasing the predilection for soft tissue pathology. The diagnosis of scapular dyskinesis is predicated upon a thorough history, physical examination, and observational analysis of key nodes in the kinetic chain during tennis activity. Conservative management remains the mainstay of treatment and consists of a graduated physical therapy regimen. Although shoulder pain in the overhead athletes is often multifactorial, early recognition and treatment of scapular dyskinesis generally carry a favorable prognosis and result in improved patient outcomes.

Injury and training history are associated with glenohumeral internal rotation deficit in youth tennis athletes

A glenohumeral internal rotation deficit (GIRD) of the shoulder, is associated with an increased risk of shoulder injuries in tennis athletes. The aim of the present study was to reveal the impact of 1) age, sex, specific training data (i.e. training volume, years of tennis practice, years of competitive play) and 2) upper extremity injuries on GIRD in youth competitive tennis athletes.

A cross-sectional retrospective study design was adopted. Youth tennis players (n = 27, 12.6 ± 1.80 yrs., 18 male) belonging to an elite tennis squad were included. After documenting the independent variables (anthropometric data, tennis specific data and history of injury), the players were tested for internal (IR) and external (ER) shoulder rotation range of motion (RoM, [°]). From these raw values, the GIRD parameters ER/IR ratio and side differences and TRoM side differences were calculated. Pearson’s correlation analyses were performed to find potential associations of the independent variables with the GIRD outcomes.

A significant positive linear correlation between the years of tennis training and IR side asymmetry occurred (p < .05). A significant negative linear relation between the years of tennis training and the ratio of ER to IR range of motion (RoM) in the dominant side (p < .05) was found. The analysis of covariance showed a significant influence of the history of injuries on IR RoM (p < .05).

Injury and training history but not age or training volume may impact on glenohumeral internal rotation deficit in youth tennis athletes. We showed that GIRD in the dominant side in youth tennis players is progressive with increasing years of tennis practice and independent of years of practice associated with the history of injuries. Early detection of decreased glenohumeral RoM (specifically IR), as well as injury prevention training programs, may be useful to reduce GIRD and its negative consequences.

Bone asymmetries in the limbs of children tennis players: testing the combined effects of age, sex, training time, and maturity status

This study estimated upper and lower limb bone mineral content (BMC) and bone area (BA) in 48 children tennis players (24 boys, 24 girls) aged 7-13 years. The sample comprised four age groups (8.2 ± 0.44, 9.5 ± 0.13, 10.5 ± 0.33, 12.2 ± 0.58). BMC and BA were measured via DXA, and sexual maturity by the Tanner scale, then used as a binary: prepubertal vs peripubertal. Total training time (TTT) included all playing years. Arms were asymmetric and legs symmetric. Boys were more asymmetric than girls in BMC (18% vs 13%) and BA (11% vs 8%). Pre-pubertal children were less asymmetric than peri-pubertal in BMC (14% vs 18%) and in BA (9.4% vs 10%). Bone growth changed with age and TTT markedly better in the dominant arm. The linear combination of TTT, sex, and maturity binary extracted 59% of BMC asymmetry and only 21% of BA asymmetry. For both bone parameters the sex effect was significant only for the pre-pubertal children. Training time constitutes the best predictor of bone asymmetry compared to age, sex, and maturity; when adequate, playing arm bone hypertrophy may be detectable at the age of 7-8 years. These results have health and performance implications.

Hand-Arm Vibration Assessment and Changes in the Thermal Map of the Skin in Tennis Athletes during the Service

During recent years the number of tennis athletes has increased significantly. When playing tennis, the human body is exposed to many situations which can lead to human injuries, such as the so-called tennis elbow (lateral epicondylitis). In this work a biomechanical analysis of tennis athletes, particularly during the service, was performed, considering three different types of over-grip and the presence of one anti-vibrator device. One part of the study evaluates the exposure to hand-arm vibration of the athlete, based on the European Directive 2002/44/EC concerning the minimum health and safety requirements, regarding the exposure of workers to risks from physical agents. The second part of the study considers an infrared thermography analysis in order to identify signs of risk of injury, particularly tennis elbow, one of the most common injuries in this sport. The results show that the presence of the anti-vibrator influences the vibration values greatly in the case of athletes with more experience and also for athletes with less performance. The presence of the Cork and/or Tourna on the racket grip does not have any significant effect on the hand-arm vibration (HAV), similarly in the case of athletes with the best performance and athletes with less technique. The results indicated that the infrared thermography technique may be used to identify the risk of injuries in tennis players.

Acute effects of a single tennis match on passive shoulder rotation range of motion, isometric strength and serve speed in professional tennis players

Shoulder pain has been associated with glenohumeral internal rotation deficit (GIRD) and a reduction in external rotation (ER) strength; however, in tennis players, there is scarce evidence regarding the impact of a single match on shoulder range of motion (ROM), strength and serve speed. The aim of this study was to determine the acute effect of a single tennis match on shoulder rotation ROM, isometric strength and serve speed. Twenty-six professional tennis players participated in the study (20.4±4.4 years; 10.5±3.2 years tennis expertise; 20.5±5.4 h/week training). Passive shoulder external (ER-ROM) and internal rotation ROM (IR-ROM), ER and IR isometric strength were measured before and after a single tennis match (80.3±21.3 min) in both shoulder´s. Moreover, the total arc of motion (TAM) and ER/IR strength ratio were calculated. Video analysis was used to assess the number of serves and groundstrokes, while a radar gun was utilized to measure maximal ball speed. In the dominant shoulder, compared to pre-match levels, IR-ROM was significantly reduced (-1.3%; p = 0.042), while ER-ROM (5.3%; p = 0.037) and TAM (3.1%; p = 0.050) were significantly increased. In the non-dominant shoulder, ER-ROM (3.7%; p = 0.006) was increased. Furthermore, in the dominant shoulder, the isometric ER strength was significantly reduced after the match (-4.8%; p = 0.012), whereas serve speed was not significantly reduced after match (-1.16%; p = 0.197). A single tennis match leads to significant reductions in shoulder ROM (e.g., IR of the dominant shoulder) and isometric strength (e.g., ER of the dominant shoulder). This study reveals the importance of recovery strategies prescription aiming at minimize post-match alteration in the shoulders.

Evolution of the trophy position along the tennis serve player's development

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.

Assessment of ultrasonography as a diagnostic tool in shoulder pain and alterations in glenohumeral range of motion in tennis players

INTRODUCTION

Shoulder pain and alterations in the range of motion are common disorders in tennis players. However, the relation between shoulder structures and these conditions is unknown.

AIM

To evaluate whether, using ultrasonography, one can identify tennis players with shoulder pain and those having specific changes of the range of rotation of the glenohumeral joint.

MATERIAL AND METHODS

A total of 66 subjects were assessed through examination of the range of rotation of the glenohumeral joint and ultrasonography.

RESULTS

The study group consisted of 37 people with shoulder pain (24.2 ±8.6 years) and the control group included 29 subjects without shoulder pain (21.9 ±10.8 years). The prevalence of pathologies of the supraspinatus (SSP), infraspinatus (ISP) or subscapularis (SSC) was significantly higher in the study group than in the control group (p = 0.044) but solely for the combined pathologies. The incidence rate of pathological shoulder changes (the SSP, ISP, SSC and the subacromial bursa) was not correlated with the ranges of rotations or intensity of pain. Glenohumeral internal rotation deficit (GIRD), total rotational motion (TROM) deficit and external rotation deficiency (ERD) were independent of pathological shoulder changes, except the significantly higher prevalence of SSP pathologies among subjects with ERD.

CONCLUSIONS

Ultrasonography could be helpful in identifying tennis players with painful shoulder having rotator cuff pathologies. However, the ability of the method to identify players having specific changes of the range of rotation of the glenohumeral joint is limited, with the exception of tennis players with ERD having SSP pathologies.

Quantifying hitting activity in tennis with racket sensors: new dawn or false dawn?

The non-invasive measurement of movement through sensor technologies is common in elite sport, yet only recently become possible in tennis. This study validated two commercial tennis racquet sensors compared to gold standards in VICON and expert notational analysis. One national-level male tennis player hit 24 shots (9 forehands and 9 backhands, hit with heavy topspin, flat and slice; 6 serves) using a Babolat Play racket with a Zepp sensor. Measures of shot type, impact location and racket speed were compared against those captured by a 500-Hz 12 camera VICON system. Cohen's kappa (κ) and a weighted kappa (κ _w) assessed the accuracy of stroke classification and impact location, respectively, and intraclass correlation coefficients (ICC) validated sensor-derived racket speed. Both sensors recorded the same total stroke volume as VICON, while Zepp racket speed displayed near perfect agreement with VICON (ICC = 0.983; p < 0.001). They exhibited moderate agreement with true stroke classification (Babolat: κ = 0.730; Zepp: κ = 0.612) and minimal agreement with true impact location (Babolat: κ _w = 0.412; Zepp: κ _w = 0.217). During match play, both sensors achieved near perfect accuracy for stroke volume but experienced difficulty discriminating the different stroke types. In sum, the Babolat Play and Zepp determined stroke volume and intensity accurately but were less effective in identifying specific strokes and impact locations.

The epidemiology of MRI detected shoulder injuries in athletes participating in the Rio de Janeiro 2016 Summer Olympics

BACKGROUND

To use Magnetic Resonance Imaging (MRI) to characterize the severity, location, prevalence, and demographics of shoulder injuries in athletes at the Rio de Janeiro 2016 Summer Olympic Games.

METHODS

This was a retrospective analysis of all routine shoulder MRIs obtained from the Olympic Village Polyclinic during the Rio 2016 Summer Olympics. Imaging was performed on 1.5 T and 3 T MRI, and interpretation was centrally performed by a board-certified musculoskeletal radiologist. Images were assessed for tendon, muscle, bone, bursal, joint capsule, labral, and chondral abnormality.

RESULTS

A total of 11,274 athletes participated in the Games, of which 55 (5%) were referred for a routine shoulder MRI. Fifty-three (96%) had at least two abnormal findings. Seven (13%) had evidence of an acute or chronic anterior shoulder dislocation. Forty-nine (89%) had a rotator cuff partial tear and / or tendinosis. Subacromial / subdeltoid bursitis was present in 29 (40%). Thirty (55%) had a tear of the superior labrum anterior posterior (SLAP).

CONCLUSION

Our study demonstrated a high prevalence of both acute and chronic shoulder injuries in the Olympic athletes receiving shoulder MRI. The high rates of bursal, rotator cuff, and labral pathology found in these patients implies that some degree of glenohumeral instability and impingement is occurring, likely due to fatigue and overuse of the dynamic stabilizers. Future studies are needed to better evaluate sport-specific trends of injury.

What is the reliability of clinical measurement tests for humeral head position? A systematic review

STUDY DESIGN

Systematic review.

INTRODUCTION

Physiotherapists routinely assess the position of the humeral head (HH) in patients with shoulder pain.

PURPOSE OF THE STUDY

To conduct a systematic review to determine the quality and content of studies that evaluated the reliability of clinical measurement methods for assessing the HH position.

METHODS

Five databases and gray literature were searched for studies fitting the eligibility criteria. After abstract and full-text review, the included studies were appraised using the Quality Appraisal of Reliability Studies checklist. Articles were considered of high quality if 8 was achieved on the checklist, and the overall quality of evidence was classified using prespecified criteria. Multiple raters extracted and performed quality ratings; a consensus process was used to finalize the reliability data that were synthesized and presented in a narrative synthesis. Reliability was classified as excellent if the intracorrelation coefficients or intercorrelation coefficients (ICCs) reported exceeded 0.75.

RESULTS

Fifteen studies on the reliability of ultrasound (US) and 3 studies on palpation were included. The methodologic quality was moderate in 17 of 18 studies. The intrarater reliability for all studies was excellent (ICC, 0.76-0.99) with the exception of the 90° abduction in internal rotation position (ICC, 0.48) for palpation. The inter-rater reliability tended to be lower (ICC, 0.48-0.68) for palpation and higher (ICC, 0.66-0.99) for US. Physiotherapists demonstrated excellent intrarater reliability across different levels of training in ultrasonography.

DISCUSSION

Our study found a moderate overall level of evidence to support the use of US for assessing HH position in symptomatic or asymptomatic subjects.

CONCLUSION

A moderate overall level of evidence exists for the use of US to reliably assess the HH position. Limited research supports the methods used for palpation within a clinical setting.

LEVEL OF EVIDENCE

2a.

An Accurate and Rapid System to Identify Play Patterns in Tennis using Video Recording Material: Break Point Situations as a Case Study

The goal of this study was to present an accurate and rapid detection system to identify patterns in tennis, based on t-pattern analysis. As a case study, the break point situations in the final matches of the clay court tournaments played during the seasons 2011 and 2012 between the tennis players Novak Djokovic and Rafael Nadal were chosen. The results show that Nadal achieves a higher conversion rate with respect to Djokovic in the break point situations, independent of the outcome of the match. Some repetitive patterns of both players were revealed in break point circumstances. In long rally sequences (higher than seven hits), the Spanish player won more break points, both serving and receiving, as a result of unforced errors of his opponent’s backhand. In medium rally sequences (between four and seven hits), other factors such as the type, direction or serve location have shown to play an important role in the outcome of the point. The study also reveals that Djokovic frequently commits double faults in these critical situations of the match. This is the first time that t-patterns have been used to analyze the sport of tennis. The technique is based on computer vision algorithms and video recording material to detect particular relationships between events and helps to discover the hidden mechanistic sequences of tennis players.

Os Acromiale in Professional Tennis Players

Background:

Os acromiale is a rare condition mostly reported in the literature through case reports, imaging studies, or reports of surgical treatment. This condition is the result of nonunion of growth plates of the acromion during the natural developmental process that occurs between 15 and 25 years of age. Its incidence is low, and few studies are available in the literature on athletes with high functional demands, and particularly on athletes within a specific sport.

Purpose:

To collect epidemiological data and to report the amount of time out of play as well as the type of treatment and its efficiency in professional tennis players.

Study Design:

Case series; Level of evidence, 4.

Methods:

We performed a retrospective study using the medical data of athletes within our national tennis league who complained about their shoulder between 2011 and 2016. Nine professional tennis players (mean age, 20 years) with painful shoulders were diagnosed with os acromiale; 3 of them played at an international level, with the other 6 playing at a national level. The diagnosis was confirmed using radiography, including the axillary view, and magnetic resonance imaging (MRI). One female player had associated subacromial bursitis.

Results:

All cases of os acromiale were classified as involving the mesoacromion, following the Lieberson classification. No patient underwent surgery, and no patient was treated with local or subacromial infiltration. Patients stopped competition and training throughout the rehabilitation period. All patients received medical treatment with nonsteroidal anti-inflammatory drugs (NSAIDs), ice, and physical therapy with a specific rehabilitation program. All athletes returned to their former level of play after a mean of 37 days. No patient suffered from recurrent pain. One patient underwent MRI after 2 years, showing a normal bone signal and complete healing of the acromion.

Conclusion:

Conservative treatment including NSAIDs, rest, ice, and physical therapy allowed for good recovery and return to the former level of play. Surgical treatment is usually not indicated for os acromiale in the professional tennis player.

REFERENCE VALUES FOR GLENOHUMERAL JOINT ROTATIONAL RANGE OF MOTION IN ELITE TENNIS PLAYERS

BACKGROUND

Due to the repetitive overhead activity involved in playing tennis and the physical demands of the game, shoulder joint injury is common. There is limited research available describing sport specific risk factors for injury in tennis, however, changes in shoulder rotational range of motion (ROM) have been associated with injury in other overhead 'throwing' type sports.

PURPOSE

This study had two purposes: i) to identify reference values for passive glenohumeral joint rotational ROM in elite tennis players, and, ii) to investigate differences in ROM between various age groups of players.

STUDY DESIGN

Cross-sectional analysis.

METHODS

Data was collected at national performance camps held at a National Tennis Centre between September 2012 and July 2015. One hundred and eighty-four tennis players aged between 11 and 24 years took part. All had a top eight national ranking within their respective age group. Participants were divided into three age groups; under 14 years, 14-15 years, and 16 years and over. The main outcome measures were dominant and non-dominant internal and external rotation as well as total glenohumeral joint passive ROM.

RESULTS

Reduced internal, and greater external rotation passive ROM were identified on the dominant side (p < 0.05), however, no side-to-side differences in total rotation ROM were found (p > 0.05). A glenohumeral joint internal rotation deficit (GIRD) was prevalent on the dominant side, which increased in magnitude with rising player age. Differences in dominant side internal and external rotation ROM were identified between age groups with the 14-15-year olds having less internal and greater external rotation than the under 14-year olds and the over 16-year old athletes (p < 0.05). The total range of motion values were not found to differ between age groups (p > 0.05).

CONCLUSIONS

This study provides reference values for glenohumeral joint rotational ROM in elite tennis players and demonstrates age specific differences. Future studies should investigate links between changes in ROM and injury risk.

LEVEL OF EVIDENCE

3.

Shoulder Injuries in the Overhead-Throwing Athlete: Epidemiology, Mechanisms of Injury, and Imaging Findings

The unparalleled velocity achieved by overhead throwers subjects the shoulder to extreme forces, resulting in both adaptive changes and pathologic findings that can be detected at imaging. A key biomechanical principle of throwing is achieving maximum external rotation, which initially leads to adaptive changes that may result in a pathologic cascade of injuries. In addition to the well-established concepts of glenohumeral internal rotation deficit and internal impingement, osseous and soft-tissue injuries of the shoulder unique to overhead athletes are illustrated. The epidemiology and biomechanics of throwing injuries are reviewed, and examples from the authors' institutional experience with competitive, collegiate, and professional baseball players are provided to demonstrate the constellation of unique imaging findings seen in overhead throwing athletes. Given the widespread popularity of baseball, and other sports relying on overhead throwing motions at all playing levels from recreational to professional, it is important for radiologists in various practice settings to be familiar with the special mechanisms, locations, and types of shoulder injuries seen in the overhead throwing population. ^© RSNA, 2018.

Scapular motion adaptations in junior overhead athletes: a three-dimensional kinematic analysis in tennis players and non-overhead athletes

Adult overhead athletes without a history of shoulder injury show scapular adaptations. There is a lack of detailed assessment of scapular kinematics in junior overhead athletes. This study aims to investigate three-dimensional scapular kinematics in junior overhead athletes. We recruited a total of 20 junior tennis players and 20 healthy children without participation in any overhead sports in this study. Bilateral scapular kinematic data were recorded using an electromagnetic tracking device for scapular plane glenohumeral elevation. The data were further analysed at 30°, 45°, 60°, 90° and 120° during glenohumeral elevation and lowering. Statistical comparisons of the data between groups (junior overhead athletes and non-overhead athletes) and sides (serve dominant and non-dominant shoulders of the overhead athletes) were analysed with the ANOVA. Comparisons showed that, in general, the scapula was more upwardly rotated and anteriorly tilted in overhead athletes when compared to non-overhead athletes, however there was no side-to-side differences when serve dominant and non-dominant shoulders compared in junior overhead athletes. The serve dominant arm of junior overhead athletes had alternations in scapular kinematics when compared with the non-overhead athletes. These findings provide clinical evaluation implications and the need for clinicians to assess for potential adaptations in junior overhead athletes.

Classification of lumbopelvic-hip complex instability on kinematics amongst female team handball athletes

OBJECTIVES

The purpose of this study was to examine how lumbopelvic-hip complex (LPHC) stability, via knee valgus, affects throwing kinematics during a team handball jump shot.

DESIGN

LPHC stability was classified using the value of knee valgus at the instant of landing from the jump shot. If a participant displayed knee valgus of 17° or greater, they were classified as LPHC unstable. Stable and unstable athletes' throwing mechanics were compared.

METHODS

Twenty female team handball athletes (26.5±4.7years; 1.75±0.04m; 74.4±6.4kg; experience level: 4.8±4.1 years) participated. An electromagnetic tracking system was used to collect kinematic data while participants performed three 9-m jump shots. The variables considered were kinematics of the pelvis, trunk, and shoulder; and segmental speeds of the pelvis, torso, humeral, forearm, and ball velocities. Data were analyzed across four events: foot contact, maximum shoulder external rotation, ball release, and maximum shoulder internal rotation.

RESULTS

Statistically significant differences were found between groups in pelvis, trunk, humerus, and forearm velocities at all events (p≤0.05). Specifically, the unstable group displayed significantly slower speeds.

CONCLUSIONS

These findings suggest the difference in throwing mechanics are affected by LPHC instability for this select group of female team handball athletes. These differences infer an increased risk of injury in the upper and lower extremities when landing from a jump shot because of the energy losses throughout the kinetic chain and lack of utilization of the entire chain. It is recommended that further investigations also consider muscle activation throughout the throwing motion.

Arthroscopic Shoulder Surgery in Female Professional Tennis Players: Ability and Timing to Return to Play

OBJECTIVE

To assess the outcome and time to return to previous level of competitive play after shoulder surgery in professional tennis players.

DESIGN

Retrospective case series.

SETTING

Tertiary academic centre.

PATIENTS AND INTERVENTIONS

The records of all female tennis players on the Women's Tennis Association (WTA) professional circuit between January 2008 and June 2010 were reviewed to identify players who underwent shoulder surgery on their dominant (serving) shoulder.

MAIN OUTCOME MEASURES

Primary outcomes were the ability and time to return to professional play and if they were able to return to their previous level of function as determined by singles ranking. Preoperative and postoperative singles rankings were used to determine rate and completeness of return to preoperative function.

RESULTS

During the study period, 8 professional women tennis players from the WTA tour underwent shoulder surgery on their dominant arm. Indications included rotator cuff debridement or repair, labral reconstruction for instability or superior labral anterior posterior lesion, and neurolysis of the suprascapular nerve. Seven players (88%) returned to professional play. The mean time to return to play was 7 months after surgery. However, only 25% (2 of 8) players achieved their preinjury singles rank or better by 18 months postoperatively. In total, 4 players returned to their preinjury singles ranking, with their peak singles ranking being attained at a mean of 2.4 years postoperatively.

CONCLUSIONS

In professional female tennis players, a high return to play rate after arthroscopic shoulder surgery is associated with a prolonged and often incomplete return to previous level of performance. Thus, counseling the patient to this fact is important to manage expectations.

LEVEL OF EVIDENCE

Level IV-Case Series.

Influence of Posture-Cuing Shirt on Tennis Serve Kinematics in Division III Tennis Players

OBJECTIVE

The purpose of this study was to evaluate the influence of a posture-cuing shirt on internal rotation velocity of the shoulder during a tennis swing and to determine this influence on shoulder external rotation position.

METHODS

Nine healthy competitive college tennis players from a Division III college participated in this study. High-speed motion capture allowed for 3-dimensional analysis of shoulder kinematics during a tennis serve. Two conditions were evaluated while the athletes performed a high-velocity tennis serve: a standard tennis shirt and a posture-cuing shirt.

RESULTS

Shoulder internal rotation velocity increased when wearing the posture-cuing shirt. Peak internal rotation velocity increased from 960.61°/s ± 93.24°/s to 1217.96°/s ± 155.01°/s (t = -1.76, P = .058). Internal rotation velocity at the time of impact increased from 765.18°/s ± 95.48°/s to 900.54°/s ± 105.33°/s (t = -1.50, P = .086). Shoulder maximum external rotation did not differ between the 2 conditions, at 172.00° ± 2.92° and 170.89° ± 3.70° (t = 0.325, P = .754).

CONCLUSIONS

Wearing a posture-cuing shirt may possibly alter shoulder kinematics during an overhead sport activity such as tennis. Internal rotation velocity seemed to improve while wearing this shirt, although shoulder external rotation position did not change. It is not known if these improvements can influence injury risk.

The Kinetic Chain Revisited: New Concepts on Throwing Mechanics and Injury

The overhead throwing motion is a complex activity that is achieved through activation of the kinetic chain. The kinetic chain refers to the linkage of multiple segments of the body that allows for transfer of forces and motion. The lower extremities and core provide a base of support, generating energy that is transferred eventually through the throwing arm and hand, resulting in release of the ball. The kinetic chain requires optimal anatomy, physiology, and mechanics and is involved in all 6 phases of overhead throwing: windup, stride, arm cocking, acceleration, deceleration, and follow-through. Breaks or deficits in the kinetic chain can lead to injury or decreased performance. Through an understanding of the mechanics and pathomechanics seen in each phase of throwing, the clinician can better evaluate and screen for potential kinetic chain deficits in the overhead throwing athlete. The purpose of this article is to review the biomechanics of the overhead throwing motion, the role of the kinetic chain in throwing, and the clinical evaluation and management of abnormal throwing mechanics and related injuries.