Eccentric and Isometric Shoulder Rotation Strength and Range of Motion: Normative Values for Adolescent Competitive Tennis Players

Shoulder range of motion in competitive tennis players: systematic review and meta-analysis

Background

To compare shoulder range of motion (ROM) in dominant vs. nondominant shoulder of competitive tennis players, and to determine whether shoulder ROM is different between younger and older players, or males and females.

Methods

A search was performed on PubMed, Embase, and Epistemonikos on December 18, 2023. This study conforms to the principles of the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. Clinical studies or case reports on shoulder ROM including external rotation (ER; shoulder at 90° of abduction) and internal rotation (IR) in competitive, elite, or professional tennis players.

Results

We found 25 eligible studies that reported on a total of 18,534 tennis players, of which 20 studies reported the ROM for the dominant and nondominant side. Comparing dominant vs. nondominant shoulders revealed that dominant shoulders had significantly smaller IR (53.0° vs. 62.6°; P < .001). Comparing adults vs. children revealed that adults have significantly smaller IR (44.5° vs. 57.1°; P < .001) and ER (95.3° vs. 110.3°; P < .001). Comparing females vs. males revealed no significant differences in ER (113.4° vs. 104.9°; P = .360) or IR (54.3° vs. 56.4°; P = .710).

Conclusion

IR in shoulders of tennis players is significantly smaller in dominant vs. nondominant sides (53.0° vs. 62.6°, P < .001), and significantly smaller in adults vs. children (44.5° vs. 57.1°, P < .001). These findings could be relevant in the context of physical preparation and training of tennis players, to monitor evolution of IR as a result of their sport and/or as they transition from childhood to adulthood.

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.

Injury, Training, Biomechanical, and Physiological Profiles of Professional Breakdancers

Background

Breakdancing or breaking will enter the Olympics in 2024, however, there is a paucity of literature exploring the epidemiology, demands, and performance.

Purpose

The purpose of this study was to describe injury and training profiles, along with the results of a short performance test battery, in a group of elite breakers.

Study Design

Cross-sectional study (retrospective).

Methods

Fourteen breakdancers (breakers) (4 Bgirls, 10 Bboys) participated in an interview regarding their injury and training history, endurance test (cycle VO2max testing), counter movement jump, squat jump, drop jump, isometric hip abduction, adduction, shoulder external and internal rotation strength testing on a fixed-frame dynamometer. Breakers were divided into elite (n=10) and developing (n=4) based on their qualification for a world finals competition; Wilcoxen rank sums were used to compare the two groups, or in the case of strength testing between those with and without an injury history.

Results

The breakers had a median 11.0 [10.0 - 14.0] years breaking experience and trained 24.4 [20.5 - 30.0] hours per week. The knee was the most commonly injured body part and most frequently injured joint, with the thigh being the most common site for muscle injuries. There were no differences in endurance testing or jump height testing results between elite and developing breakers. There was no difference in shoulder external or internal rotation strength between athletes with a history of shoulder injury and those without. Similarly, there was no difference in hip abduction or adduction strength in those with a history of hip injury and those without.

Conclusion

The results of this study should be viewed with caution due to the small sample size. However, this study is the first to publish functional and physiological descriptives on breakers. The authors hope these results support clinicians treating breakers as well as encourages future research related to breaking.

Level of Evidence

2b.

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 dynamic control ratio and its equilibrium point: A preliminary study of isokinetic fatiguing internal-external rotational effort of the shoulder joint in healthy subjects

The shoulder joint-related dynamic control ratio (DCR) is derived by dividing the peak eccentric moment of the external rotators (ER) by the peak concentric moment of the internal rotators (IR). However, given the inherent limitation associated with a single value DCR, an alternative approach is to calculate it at fixed angular intervals. This preliminary study aimed at exploring the variation in the DCR at a resolution of 1° and under fatiguing external and internal rotation exertions. Eighteen young men, 10 experienced and 8 without experience in overhead sporting activities completed two separate series of 45 ER eccentric and 45 IR concentric isokinetic repetitions at 120°/s. The analysis focused on repetitions 1-3 (TR1), 21-23 (TR2) and 41-43 (TR3). The relative fatigue values for both muscle groups and for both E and NE participants were 25-40% with significantly higher fatigue resistance in eccentric compared with concentric exertions. The DCR traces varied substantially linearly for most of the internal rotation range of motion while significant differences (p < 0.001) were found in their values within group between TR1, TR2 and TR3 and between experienced and non-experienced participants. An antagonistic moment equilibrium (DCR = 1) was reached in all instances and for both groups only during TR3 with a significant progressive reduction in this moment as fatigue increased. Thus, considering the DCR as an angle-based variable rather than a single value isokinetic parameter, may add new insight regarding the interplay between the rotatory muscles of the shoulder joint.

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.