Shoulder strength, power, and endurance in college tennis players

Does ipsilateral and bilateral knee strength status predict lower extremity injuries of elite judokas; a prospective cohort study

The association of pre-participation knee muscle strength status with lower limb injury occurrence was investigated. Knee extensors and flexors muscle strength status including the traditional hamstrings/quadriceps (H/Q), Q/Q, H/H, and the non-dominant H/Q: dominant H/Q, HQ:HQ, ratios were recorded before the 10 month judo activity. Fifteen lower limb sport injuries were recorded for 53 judokas during the follow-up questionnaires. Significant accuracy of dominant H/Q ratio 60º/s (AUC 0.702, 95% CI 0.520 to .883, p = 0.023), as well as HQ:HQ ratios 300º/s (AUC .318, 95% CI 0.138 to 0.497, p = 0.040), and 60 º/s (AUC 0.311, 95% CI 0.130 to 0.491, p = .033) were revealed discriminating between injured and uninjured judokas. The optimum cut-off of dominant H/Q ratio associated with belonging to uninjured judokas group was 43.2% (sensitivity, 0.974; specificity, 0.533). Isokinetic knee muscle dynamometry is useful for predicting the likelihood of lower limb injuries in professional judokas during competitive activity.

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.

Reliability of isokinetic decay slope is superior to using fatigue indices for shoulder horizontal abduction

INTRODUCTION

Reliable and valid measurements for shoulder muscular endurance should be available for clinical use. The posterior shoulder endurance test offers a potential clinical assessment, but its construct validity isn't available. Since a criterion measure of muscular endurance is not available, this study's purpose was to determine a reliable method for testing shoulder muscular endurance using an isokinetic dynamometer.

METHODS

The test-retest reliability, standard error measurement, and minimal detectable change were calculated on four different paradigms to quantify muscular fatigue using two isokinetic speeds (60°sec-1,180°sec-1). Calculation paradigms included peak torque fatigue index (FI), average torque FI, area-under-the-curve FI, and peak torque decay slope. Testing occurred on two days. Repeated measures analysis of variance compared the two peak torque decay slopes across both testing days.

RESULTS

Superior reliability was found within the decay slope measurements at both 60°sec-1 (ICC = 0.941) and 180°sec-1 (ICC = 0.764) speeds, with the 60°sec-1 decay slope being the highest reliability between the two angular velocities. There was a greater amount of fatigue in the 60°sec-1 decay slope compared to the 180°sec-1 decay slope.

CONCLUSION

Using the decay slope of isokinetic shoulder horizontal abduction at 60°sec-1 is a reliable method to validate other muscular endurance clinical measures. Rehabilitation specialists should utilize the decay slope of the isokinetic dynamometry to monitor responsiveness.

Isokinetic force-power profile of the shoulder joint in males participating in CrossFit training and competing at different levels

Background

As participants who engage in CrossFit training and competition perform a large volume of high intensity overhead activities, injuries to the shoulder are one of the most common in this sport. Previous research in other sports has indicated that the isokinetic force power profile of the shoulder joint (IPSJ) rotator muscles may assist in the prediction of shoulder injury.

Aim

Therefore, the objective of this study was to determine the IPSJ in males engaged in CrossFit training at different competitive levels.

Methods

In a cross-sectional study design, participants (age, 24.1 ± 2.7 years) classified as ‘beginner’ (n = 6), ‘intermediate’ (n = 7) or ‘advanced’ (n = 9) provided informed consent to participate in this study. The IPSJ assessment involved rotational and diagonal movements, including internal and external shoulder rotator muscles, at both 180°.s⁻¹ and 300°.s⁻¹. The variables analysed were peak torque/body mass (%), mean power (W) and the external/internal peak torque/body mass ratio (%). A Kruskal–Wallis test was used to compare the IPSJ of the three groups, with Dunn’s test used for post-hoc analysis. The alpha level was set at p < 0.05.

Results

The IPSJ showed greater torque and power values in those who competed at the advanced level as compared to those at a lower competitive level (i.e. intermediate, beginner). This was observed mainly for the internal rotation and internal diagonal movements at both 180°.s⁻¹ and 300°.s⁻¹. However, such differences between competitive levels were, in general, absent for the external rotation and external diagonal movements. Moreover, the participants from the advanced competitive level exhibited an imbalance of peak torque between the muscles responsible for the external–internal rotational and external-internal diagonal movements of the shoulder (i.e. peak torque external/internal ratio <66%), particularly in the dominant shoulder.

Conclusion

These findings suggest greater development of the shoulder internal rotators and a higher probability of shoulder injury in CrossFit athletes at the advanced competitive level. Based on these results, participants engaged in CrossFit training and competition may wish to increase the volume of training for the shoulder external rotator muscles to complement the large increases in shoulder internal rotator strength that occur as a part of their regular training regimes.

Impact of Physical Performance and Anthropometric Characteristics on Serve Velocity in Elite Junior Tennis Players

Fett, J, Ulbricht, A, and Ferrauti, A. Impact of physical performance and anthropometric characteristics on serve velocity in elite junior tennis players. J Strength Cond Res 34(1): 192-202, 2020-This study aimed to investigate the impact of physical performance components and anthropometric characteristics on serve velocity (SV) in elite junior tennis players depending on the sex and age group. A sample of the best 1,019 (male = 625, female = 394) junior squad tennis players of the German Tennis Federation participated in the study involving complex anthropometric measurements (body height, body mass, sitting height, and arm span) and physical tests (e.g., SV, medicine ball throws [MBTs], hand grip strength, push-ups, back extension, countermovement jumps [CMJs], horizontal jumps, 20-m sprint, and tennis-specific endurance). Of all the anthropometric and physical characteristics analyzed, the MBTs (r = 0.49-0.60♂; r = 0.20-0.60♀), hand grip strength (r = 0.43-0.59♂; r = 0.27-0.37♀), arm span (r = 0.37-0.56♂; r = 0.24-0.36♀), body height (r = 0.31-0.52♂; r = 0.26-0.38♀), and body mass (r = 0.44-0.57♂; r = 0.35-0.39♀) were particularly closely correlated with SV. The results of the multiple regression analysis indicated that the combination of selected predictors (e.g., MBTs, grip strength, arm span, and body mass) explained 41-66% of the variance in SV of boys and 19-45%, respectively, for girls. The results reinforce that service speed is dependent on physical abilities and anthropometric characteristics but also strongly on additional factors (i.e., technical components). In particular, the upper-body power/strength is important to the junior players' service, especially in athletes with a greater body height and arm span (i.e., biomechanical advantages), whereas purely lower-body power (e.g., CMJ) is less important. To this effect, talent identification and intervention programs focusing on the specific requirements are recommended.

The influence of hand location and handle orientation on female manual arm strength

Accurate estimations of manual arm strength (MAS) are crucial in the evaluation of occupational force demands relative to population capacity. Most current strength predictions assume force application with a vertically oriented handle, but it is unknown how uni-manual force capability changes as a function of handle orientation and hand location. This study evaluated the effect of handle orientation on MAS throughout the reach envelope. Fifteen female participants exerted maximum forces in six directions (i.e. superior, inferior, anterior, posterior, medial, lateral), at five different hand locations, and MAS was measured with the handle oriented at 0° (i.e. horizontal), 45°, 90° (i.e. vertical) and 135°. Handle orientation affected MAS in all but the anterior exertion direction, with significant interactions between hand location and grip orientation existing for the superior and inferior directions. These results suggest that handle orientation is important to consider in future predictive models of manual arm strength.

Isokinetic Characteristics of Amateur Boxer Athletes

Aim: The kinetic chain of the punch of boxers is characterized by the contribution of the shoulder; however, the isokinetic muscle strength of shoulder’s rotators muscles has not been well studied so far, especially with regards to performance. Therefore, the aim of the present study was (a) to profile the isokinetic muscle strength of rotators of the glenohumeral joint, bilateral (BL), unilateral (UL) and functional ratios in amateur boxers, and (b) to examine the variation of these muscle strength characteristics by performance level.

Methods: Forty male amateur Greek boxers from three division levels (elite, n = 22; second division, n = 11; and third division, n = 7), and 10 non-athletes (control group) were tested, using the isokinetic dynamometer Kin-Com^TM in the scapular seated position under standard conditions. We examined (i) peak torque (PT) of internal (IR) and external (ER) rotators during concentric (CON) and eccentric (ECC) contractions at low (60°/s), medium (120°/s), and high speed (180°/s), (ii) BL, (iii) UL, and (iv) functional ratios of dominant (D) and non-dominant (ND) limbs.

Results: Boxers were stronger than control group in IR and ER at all speeds, and D outscored ND limb (p < 0.05). Elite boxers were stronger than group B and C (p < 0.05); however, when peak torque was expressed in relative to body mass values, these differences were attenuated. The BL ratios for the men athletes were under 10% at 60 and 180°/s, the UL ratios were lower at 60 and higher at 180°/s and significant lower in the dominant limb at all speeds. The functional ratios of IR ECC / ER CON were higher between the control group at all speeds and the ER ECC/IR CON ratios were between 60 and 180°/s, and the two limbs with higher values at 180°/s.

Conclusion: Boxers had the strongest dominant limb and their BL ratios were normal at all speeds except of 120°/s ECC. The UL ratios of ECC at 120 and 180°/s of ND were normal, and at the other speeds abnormal due to high IR. In addition, the functional ratios may be related to the kinetic chain of the punch, which in turn correlates with the contribution of ER of both limbs.

Changes in shoulder girdle strength in 3 consecutive years in elite adolescent swimmers: a longitudinal cohort study

BACKGROUND

The shoulder complex is highly loaded during swimming. No studies were found analyzing the changes in shoulder girdle strength in young swimmers, through the years.

OBJECTIVE

To analyze the changes in strength of internal rotators and external rotators of the arm, lower trapezius and supraspinatus and in the external rotators/internal rotators ratio in young elite swimmers through 3 years.

METHODS

31 adolescent elite swimmers (14-18 years, of both sexes) participated in the study. Isometric strength of the shoulder girdle muscles was performed using a handheld dynamometer during 3 years.

RESULTS

For boys absolute data, internal rotators increased from the first to the second (p=0.0001; mean difference 45.6N; 95%CI 26.7-65.0) and third years (p=0.01; mean difference: 32.4; 95%CI: 9.3-55.5). Considering the weight-normalized data, internal rotators increased from the first to the second year (p<0.0001; mean difference: 0.52; 95%CI: 0.26-0.78), external rotators decreased from the first to the third year (p=0.003; mean difference: -0.33; 95%CI: -0.53 to -0.13) and from the second to the third year (p=0.0004; mean difference: -0.29; 95%CI: -0.46 to -0.12) and supraspinatus decreased from the second to the third year (p=0.006; mean difference: -0.17; 95%CI: -0.28 to -0.06). For girls, there were no significant differences in the absolute strength. Considering the weight-normalized data, lower trapezius decreased from the first to the third year (p=0.02; mean difference: -0.15; 95%CI: -0.27 to 0.03). Considering both sexes, the external rotators/internal rotators ratio decreased from the first to the second (p<0.0001; mean difference -0.12N; 95%CI -0.13 to -0.11) and third years (p<0.0001; mean difference -0.15N; 95%CI -0.16 to -0.14).

CONCLUSION

Muscle imbalance can occur in the shoulder girdle in young swimmers in 3 years, with increased internal rotators and decreased external rotators and supraspinatus strength in boys, and decreased strength of the lower trapezius in girls. Attention should be given in young swimmers' shoulder girdle muscle balance.

Dynamic and static shoulder strength relationship and predictive model

Static strength is typically used to standardize occupational tasks in an effort to limit over-exertion injuries; however, workplace tasks are commonly dynamic in nature. The purpose of this investigation was to assess factors influencing isokinetic shoulder strength and to develop predictive equations for isokinetic shoulder flexion and extension strength using isometric strength. Fifteen women performed a set of concentric isokinetic and isometric shoulder flexion and extension maximal exertions across a series of movement planes, angular velocities, and grip types. Data were used to generate two stepwise multiple regression models for predicting isokinetic shoulder flexion and exertion strength across the various exertion parameters. The final regression models explained a high degree of variance in predicting isokinetic shoulder flexion (R² = 0.59) and extension (R² = 0.67) with a subset of four and five inputs, respectively. The predictive equations can help establish acceptable force limits for workplace tasks requiring dynamic actions using more easily attainable static forces.

The effects of preventive rubber band training on shoulder joint imbalance and throwing performance in handball players: A randomized and prospective study

OBJECTIVES

To investigate the effects of a strength training program (STP) using rubber band exercises.

METHODS

Twenty-five athletes were divided into two groups: muscular imbalance in the dominant (D) and in the non-dominant (ND) upper limbs. Each group was subdivided into experimental and control groups. Experimental groups performed eighteen sessions of STP. Athletes were submitted to ball throwing and isokinetic strength tests to assess the muscular strength of the shoulder rotator muscles and conventional and functional balance ratios.

RESULTS

STP improved external rotator peak torque (18.0 ± 0.8 to 21.3 ± 1.0 Nm, p < 0.01) and total work (29.3 ± 0.9 to 34.5 ± 1.5 J, p < 0.01) in the D experimental group, while only total work (34.8 ± 2.5 to 37.6 ± 3.1 J, p < 0.03) improved in the D control group. The ND experimental group also presented significant improvement in external rotator peak torque (18.8 ± 0.8 to 21.1 ± 1.3 Nm, p < 0.01) and total work values (29.0 ± 1.4 to 34.6 to 1.6 J, p < 0.01) while there was no strength improvement in the ND control group. The ND experimental group showed an improvement in conventional (61.5 ± 3.5 to 72.7 ± 3.0%, p = 0.03) and functional (1.0 ± 0.1 to 1.6 ± 0.08, p < 0.01) ratios. STP did not improve the conventional ratio in the D experimental group. However, STP produced a large effect size. The D experimental group presented an improvement in ball velocity (49.0 ± 2.4 to 52.5 ± 2.2 km/h, p = 0.04) in standing position throwing.

CONCLUSIONS

STP improves muscular strength of external rotator muscles and muscular balance.

Shoulder-Rotator Strength, Range of Motion, and Acromiohumeral Distance in Asymptomatic Adolescent Volleyball Attackers

CONTEXT

Sport-specific adaptations at the glenohumeral joint could occur in adolescent athletes because they start participating in high-performance sports in early childhood.

OBJECTIVE

To investigate shoulder-rotator strength, internal-rotation (IR) and external-rotation (ER) range of motion (ROM), and acromiohumeral distance (AHD) in asymptomatic adolescent volleyball attackers to determine if they have risk factors for injury.

DESIGN

Cross-sectional study.

SETTING

University laboratory.

PARTICIPANTS

Thirty-nine adolescent high school-aged volleyball attackers (22 boys, 17 girls; age = 16.0 ± 1.4 years, height = 179.2 ± 9.0 cm, mass = 67.1 ± 10.9 kg, body mass index = 20.7 ± 2.6 kg/m²).

MAIN OUTCOME MEASURE(S)

Shoulder IR and ER ROM, total-rotation ROM, glenohumeral IR deficit, AHD, and concentric and eccentric strength of the shoulder internal and external rotators were tested bilaterally.

RESULTS

External-rotation ROM was greater (t₃₈ = 4.92, P < .001), but IR ROM (t₃₈ = -8.61, P < .001) and total ROM (t₃₈ = -3.55, P = .01) were less in the dominant shoulder, and 15 athletes had a glenohumeral IR deficit (IR ROM loss > 18°). We observed greater concentric internal-rotator (t₃₈ = 2.89, P = .006) and eccentric external-rotator (t₃₈ = 2.65, P = .01) strength in the dominant than in the nondominant shoulder. The AHD was less in the dominant shoulder (t₃₈ = -3.60, P < .001).

CONCLUSIONS

Adolescent volleyball attackers demonstrated decreased IR ROM, total ROM, and AHD and increased ER ROM in their dominant shoulder. Therefore, routine screening of adolescent athletes and designing training programs for hazardous adaptive changes could be important in preventing shoulder injuries.

Influence of Playing a Prolonged Tennis Match on Shoulder Internal Range of Motion

BACKGROUND

Shoulder range of motion (ROM) deficits have been identified as an injury risk factor among tennis players. It is well known that shoulder internal rotation deficit increases with age and years of play, but there is a lack of knowledge regarding the influence of a prolonged tennis match on shoulder ROM.

PURPOSE

To examine changes in shoulder ROM during a prolonged tennis match.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Shoulder passive internal and external rotation ROM were measured on 8 male tennis players before, every 30 minutes during, and just after a 3-hour tennis match. Total ROM was calculated as the combination of shoulder internal and external rotations. Ball velocity on the serve was measured with a radar gun before, at midmatch, and just after the match.

RESULTS

Decreases in shoulder internal rotation (-20.8°; P = .005), total ROM (-24.6°; P = .001), and serve velocity (-1.8 m/s; P = .002) were observed at the end of the match. No statistically significant difference was observed for shoulder external rotation after the match (P = .460).

CONCLUSION

Passive shoulder internal rotation and total ROM are significantly decreased during a 3-hour tennis match.

CLINICAL RELEVANCE

The results show that a prolonged tennis match play can modify values of shoulder ROM.

Structural and biomechanical changes in shoulders of junior javelin throwers: a comprehensive evaluation as a proof of concept for a preventive exercise protocol

PURPOSE

The purpose of this study was to develop a preventive exercise protocol based on structural and functional changes present in shoulder joints of young throwing athletes. As a proof of concept, these changes were previously evaluated in a cross-section of high-performance junior javelin throwers.

METHODS

Thirteen members of the German and Bavarian junior javelin squad (mean age 17.5 ± 0.8 years) completed a systematic clinical examination, shoulder range of motion (ROM) measurement, and were scored with standardized clinical tools. 3.0 tesla magnetic resonance imaging (MRI) was conducted on both shoulders. Bilateral three-dimensional analysis of the scapulothoracic motion during multiplanar humeral elevation and isokinetic strength testing of the shoulder internal and external rotators was accomplished. Based on the findings, a preventive exercise protocol was confirmed.

RESULTS

Dominant internal ROM was significantly decreased (dominant 48° ± 20° vs. non-dominant 57° ± 19°; P = 0.006) and dominant external ROM increased (dominant 117° ± 15° vs. non-dominant 107° ± 10°; P = 0.008). MRI revealed posterosuperior intraosseous cysts of the humeral head with a size larger than >3 mm in 69 % of the dominant shoulders and only in 15 % in the non-dominant shoulders. Motion analysis of the static scapular resting position was significantly different between dominant and non-dominant sides regarding anterior tilt (dominant > non-dominant, mean difference 4.2°, P = 0.010) and retraction (dominant > non-dominant, mean difference 2.4°, P = 0.038). Dominant scapular anterior tilt during flexion and abduction was significantly increased (-4.3°, P = 0.006; -3.4°, P = 0.046). Dominant retraction was significantly increased during abduction (-2.3°, P = 0.040). Isokinetic outcome parameters presented nonsignificant bilateral differences.

CONCLUSIONS

Elite junior javelin throwers already present structural (humeral intraosseous cysts) and biomechanical changes (ROM deficits and asymmetric scapulothoracic motion patterns), even if they have no history of major shoulder pain or injury. A novel exercise protocol was developed in order to address the complex of alterations in a comprehensive way. Preventive diagnostics in combination with a systematic all-year preventive exercise intervention might be one option to detect and control risk factors of a symptomatic throwing shoulder at an early stage.

LEVEL OF EVIDENCE

IV.

Effect of Resistance Training Maintaining the Joint Angle-torque Profile Using a Haptic-based Machine on Shoulder Internal and External Rotation

[Purpose] The aim of this study was to present an individualized resistance training method to enable exercise while maintaining an exercise load that is set according to an individual’s joint angle-torque using a haptic-based resistance training machine. [Methods] Five participants (machine group) performed individualized shoulder internal and external rotation training with a haptic resistance training machine, while another five participants performed general dumbbell-based shoulder internal and external rotation training for eight weeks. Internal and external rotation powers of subjects were measured using an isokinetic machine before and after training. [Results] The average powers of both shoulder internal and external rotation has been improved after training (25.72%, 13.62%). The improvement in power of external rotation in the machine group was significantly higher than that in the control group. [Conclusion] This study proposes a haptic-based individualized rotator cuff muscle training method. The training protocol maintaining the joint angle-torque profile showed better improvement of shoulder internal/external rotation than dumbbell training.

Profiling the isokinetic shoulder rotator muscle strength in 13- to 36-year-old male and female handball players

OBJECTIVES

To evaluate the external (ER) and internal rotator (IR) muscles' isokinetic peak torque and conventional and functional strength ratios in handball players and controls of different ages.

DESIGN

Cross-sectional and descriptive analysis.

SETTING

Exercise Physiology Laboratory.

PARTICIPANTS

A total of 228 participants (108 athletes and 120 controls) were divided into five groups according to age, ranging from 13 to 36 years old.

MAIN OUTCOME MEASURES

Isokinetic tests were performed concentrically at 60 and 300 deg s(-1) and eccentrically at 300 deg s(-1).

RESULTS

The differences between the athletes and controls regarding the peak torque of the ER and IR muscles were significant in males older than 18 years. The peak torque of the IR and ER muscles increased significantly across age in male athletes, but not in female athletes, except in the case of ER peak torque, which differed significantly between 13 and 16 years old. The female athletes presented higher conventional ratios (0.81 ± 0.07) than males (0.66 ± 0.08). Values represent means and standard deviations. Athletes and controls showed mean functional strength ratios below 1.0.

CONCLUSIONS

Although there were no muscular ratio differences between the athletes and the controls, their ratio values were below the literature-recommended reference values to prevent shoulder injuries.

Rotator cuff strength in recurrent anterior shoulder instability

BACKGROUND

Although rotator-cuff muscle contraction plays an important role in stabilizing the glenohumeral joint, little is known about the role of these muscles in the pathophysiology of recurrent anterior instability. We intended to analyze the association between isokinetic internal rotator and external rotator muscle strength and glenohumeral joint instability in patients with recurrent anterior instability that was not previously treated surgically.

METHODS

We enrolled thirty-seven patients with unilateral recurrent anterior posttraumatic shoulder dislocation and eleven healthy nonathletic subjects in this controlled study. The association between internal rotator and external rotator strength and shoulder instability was analyzed by side-to-side comparisons and comparisons with a control group. Isokinetic internal rotator and external rotator strength was evaluated with a Con-Trex dynamometer, with the subject seated and the shoulder abducted 45° in the scapular plane. Tests were performed at 180°/s, 120°/s, and 60°/s in concentric mode for both sides. Peak torque normalized to body weight and external rotator to internal rotator ratio were calculated for each angular velocity. Clinical and isokinetic evaluation was done by the same rehabilitation physician.

RESULTS

The association between shoulder instability and internal rotator and external rotator strength was associated with side-to-side differences (p < 0.05). Compared with a control group, strength values were lower on the pathological shoulder side of the patients with shoulder instability than on the healthy contralateral shoulder of control subjects at 180°/s and 120°/s (p < 0.05). The side-to-side differences were increased when the nondominant upper-extremity side was involved and were decreased when the dominant side was involved. There was no association between glenohumeral joint instability and external rotator to internal rotator ratio.

CONCLUSIONS

Internal rotator and external rotator weakness was associated with recurrent anterior instability, and side-to-side differences depended on the side of hand dominance. Use of a control group may help in the analysis of the influence of constraints on shoulder strength. Further prospective studies are necessary to determine whether the weakness is a cause or an effect of the instability.

Avaliação muscular isocinética da articulação do ombro em atletas da Seleção Brasileira de voleibol sub-19 e sub-21 masculino

INTRODUÇÃO E OBJETIVO: A musculatura do complexo do ombro possui um papel importante na produção de força e potência articular no voleibol, permitindo a realização do gesto esportivo de maneira coordenada. A documentação objetiva produzida pela avaliação isocinética auxilia no diagnóstico e na prevenção de lesões do complexo do ombro, além de ser uma ferramenta útil no prognóstico do retorno rápido e seguro para a prática esportiva do atleta lesionado. O objetivo deste estudo foi avaliar o desempenho muscular isocinético dos músculos rotadores laterais e mediais da articulação glenoumeral em atletas de voleibol da Seleção Brasileira Masculina sub-19 e sub-21. MÉTODOS: O protocolo realizado durante o teste foi de cinco repetições máximas de rotação lateral e medial de ombro no modo concêntrico-concêntrico na velocidade de 60º/s e 30 repetições na velocidade de 360º/s. Análise de variância (ANOVA) mista foi utilizada para avaliar as variáveis dependentes: trabalho máximo e torque máximo normalizados pela massa corporal dos músculos rotadores laterais e mediais do ombro, razão agonista/antagonista nas duas velocidades e índice de fadiga muscular. RESULTADOS: A análise dos dados demonstrou haver um desequilíbrio entre os rotadores laterais e mediais (razão agonista/antagonista) da articulação do ombro em atletas brasileiros de voleibol da categoria sub-21, revelando menor força relativa dos rotadores laterais. CONCLUSÃO: Foi possível identificar alterações em atletas de voleibol que, associadas a demandas específicas do esporte, podem levar à sintomatologia no complexo do ombro e/ou queda da performance.

Shoulder functional ratio in elite junior tennis players

OBJECTIVE

To evaluate shoulder rotation strength and compare the functional ratio between shoulders of elite junior tennis players.

DESIGN

This cross-sectional study evaluated muscular rotation performance of 40 junior tennis players (26 male and 14 female) with an isokinetic dynamometer.

MAIN OUTCOME MEASURES

Strength variables of external (ER) and internal rotators (IR) in concentric and eccentric modes were considered. For the peak torque functional ratio, the eccentric strength of the ER and the concentric strength of the IR were calculated.

RESULTS

All variables related to IR were significantly higher on the dominant compared to the non-dominant side in males and females (p<0.05), but only boys exhibited this dominance effect in ER (p<0.05 and p<0.001). Regarding functional ratios, they were significantly lower for the dominant shoulder (p<0.001) and below 1.00 for both groups, indicating that the eccentric strength of the ER was not greater than the concentric strength of the IR.

CONCLUSION

Elite junior tennis players without shoulder injury have shoulder rotation muscle strength imbalances that alter the normal functional ratio between rotator cuff muscles. Although these differences do not seem to affect the athletic performance, detection and prevention with exercise programs at an early age are recommended.

Data-based interval hitting program for female college volleyball players

CONTEXT

Interval sports programs are a critical rehabilitation element when preparing the injured athlete for a return to preinjury activities. There is currently no published interval hitting program to guide a return to unrestricted play for the volleyball athlete. Therefore, data-based, position-specific overhead hitting programs that control for intensity, time, and number of ball strikes were developed for female college volleyball players.

EVIDENCE ACQUISITION

Records from a single Division I varsity women's volleyball team were examined for all matches during 7 consecutive years of team play. Data were collected for number of hitting and service attempts per game for each position and the number of games per match.

RESULTS

Per game, middle hitters averaged 4.51 attacks and 2.77 service attempts; right-side hitters, 3.58 attacks and 1.26 service attempts; outside hitters, 6.37 attacks and 3.44 service attempts; and setters and defensive specialists, 0.17 attacks and 1.78 service attempts.

CONCLUSION

The interval hitting program can provide rehabilitation specialists with a data-based approach that may facilitate a return to play and minimize the risk of reinjury for volleyball athletes.

Isokinetic peak torque ratios and shoulder injury history in adolescent female volleyball athletes

CONTEXT

Few researchers have examined shoulder strength in adolescent volleyball athletes despite increasing levels of participation in this age group.

OBJECTIVE

To compare medial and lateral isokinetic peak torque of the rotator cuff among skill levels and between athletes with and without a history of shoulder injury.

DESIGN

Cross-sectional design.

SETTING

The Human Performance Lab and Athletic Training Lab.

PATIENTS OR OTHER PARTICIPANTS

Thirty-eight female adolescent club volleyball athletes from 10 to 15 years of age (mean = 13.02 +/- 1.60 years).

MAIN OUTCOME MEASURE(S)

We measured concentric and eccentric peak torque of the medial and lateral rotators of the shoulder and calculated resultant cocking and spiking ratios based on peak torque values.

RESULTS

Athletes at higher skill levels had higher peak torque measurements in concentric and eccentric medial and lateral rotation compared with the athletes at lower skill levels. No differences in peak torque existed between participants with or without an injury history 6 months before the study. Strength ratios did not differ across skill levels, but previously injured participants produced lower eccentric medial rotation to concentric lateral rotation ratios compared with participants without a history of injury (P = .02). At the highest skill level, previously injured participants produced lower eccentric lateral rotation to concentric medial rotation ratios compared with participants without an injury history (P = .04).

CONCLUSIONS

Differences in medial and lateral shoulder rotator strength ratios appear to be related more to injury prevalence than to absolute strength. Shoulder dysfunction related to strength ratio deficits also may exist in adolescent female volleyball athletes. Preventive shoulder strengthening programs focused on improving eccentric strength and correcting imbalances between medial and lateral rotators may be warranted for all female adolescent volleyball athletes.

A descriptive profile of age-specific knee extension flexion strength in elite junior tennis players

BACKGROUND

Tennis requires repetitive multidirectional movement patterns that can lead to lower extremity injury. Knowledge of population and age-specific strength parameters can be used during performance enhancement training and rehabilitation of tennis players.

OBJECTIVES

The purpose of this study was to generate population and age-specific descriptive profiles of concentric isokinetic knee extension and flexion strength in elite junior tennis players, and determine whether bilateral differences exist between extremities and across age ranges.

METHODS

A total of 103 elite male tennis players (mean (SD) 15.92 (2.14), range 11-21) and 53 female tennis players (mean (SD) 15.0 (2.30, range 11-21) were isokinetically tested on a Cybex 6000 isokinetic dynamometer at 180 and 300 degrees/s to assess bilateral concentric knee extension and flexion strength using a standard bilateral testing protocol.

RESULTS

No significant bilateral difference between the dominant (racquet side) lower extremity and the contralateral non-dominant side were measured in lower extremity knee extension or flexion strength normalised to body weight, or in the hamstring quadriceps strength ratios in male and female subjects. Male subjects did show significant (p<0.001) increases in knee extension and flexion strength across the age ranges from 11-15 years of age to 16-21 years. Female subjects did not show any significant change in the normalised knee extension or flexion strength across age ranges. Hamstring/quadriceps strength ratios were bilaterally symmetric and remained clinically and statistically constant across age ranges for the male and female elite tennis players.

CONCLUSIONS

Population and age-specific isokinetic descriptive data from elite tennis players can provide guidance in the development and monitoring of performance enhancement and rehabilitation programs for elite tennis players. The changes identified in normalised knee extension and flexion strength in elite male tennis players necessitate the use of population and age-specific descriptive data.

Morphology of the deltoid muscles in elite tennis players

The aim of this study was to examine the deltoid muscle properties of the dominant and non-dominant arm of Greek professional male tennis players. Eight male tennis players (mean age 22.0 years, s = 3.2) were subjected to biopsy of the deltoid muscle of both arms. Adenosine triphosphate (ATPase) histochemistry and myosin heavy chain (MHC) composition were performed on the samples with homogenate electrophoresis. No significant differences were observed in the percentage of types I, IIa, IIab, and IIb muscle fibres between the deltoid muscles of the two arms. Types I, IIa, and IIx muscle fibres of the dominant and non-dominant deltoid muscles did not differ significantly for MHC isoform composition. Type IIab muscle fibres showed a similar cross-sectional area (CSA) percentage distribution between the two arms. The CSA percentage for types I, IIa, and IIb muscle fibers did not differ significantly between the dominant and the non-dominant arm. We conclude therefore that regular tennis training probably does not lead to any significant changes in the muscle fibre types of the dominant and non-dominant arms of elite tennis players.

Validation of a new test that assesses functional performance of the upper extremity and neck (FIT-HaNSA) in patients with shoulder pathology

Background

There is a lack of standardized tests that assess functional performance for sustained upper extremity activity. This study describes development of a new test for measuring functional performance of the upper extremity and neck and assesses reliability and concurrent validity in patients with shoulder pathology.

Methods

A series of developmental tests were conducted to develop a protocol for assessing upper extremity tasks that required multi-level movement and sustained elevation. Kinematics of movement were investigated to inform subtask structure. Tasks and test composition were refined to fit clinical applicability criteria and pilot tested on 5 patients awaiting surgery for shoulder impingement and age-sex matched controls. Test-retest reliability was assessed on 10 subjects. Then a cohort of patients with mild to moderate (n = 17) shoulder pathology and 19 controls (17 were age-sex matched to patients) were tested to further validate the Functional Impairment Test-Hand, and Neck/Shoulder/Arm (FIT-HaNSA) by comparing it to self-reported function and measured strength. The FIT-HaNSA, DASH and SPADI were tested on a single occasion. Impairments in isometric strength were measured using hand-held dynamometry. Discriminative validity was determined by comparing scores to those of age-sex matched controls (n = 34), using ANOVA. Pearson correlations between outcome measures (n = 41) were examined to establish criterion and convergent validity.

Results

A test protocol based on three five-minute subtasks, each either comprised of moving objects to waist-height shelves, eye-level shelves, or sustained manipulation of overhead nuts/bolts, was developed. Test scores for the latter 2 subtasks (or total scores) were different between controls as compared to either surgical-list patients with shoulder impingement or a variety of milder shoulder pathologies (p < 0.01). Test 1 correlated the highest with the DASH (r = -0.83), whereas Test 2 correlated highest with the SPADI (r = -0.76).

Conclusion

Initial data suggest the FIT-HaNSA provides valid assessment of impaired functional performance in patients with shoulder pathology. It discriminates between patients and controls, is related to self-reported function, and yet provides distinct information. Longitudinal testing is warranted.

Tennis Physiology

The game of tennis has evolved from the wooden-racket era of long, crafty points based on style and finesse, to the current fast paced, explosive sport based on power, strength and speed, where 210 km/h serves are common. This evolution over the last 20 years has led to an increased interest in tennis research. Competitive tennis athletes need a mixture of anaerobic skills, such as speed, agility and power, combined with high aerobic capabilities. The work-to-rest ratios of competitive tennis athletes range between 1 : 3 and 1 : 5, and fatigue has been shown to greatly reduce the hitting accuracy. Competitive male tennis athletes maintain body fat <12% and have maximal oxygen uptake values >50 mL/kg/min, and as high as 70 mL/kg/min. Results from lactate testing in tennis players are inconclusive as some studies have shown increased levels, whilst other studies have shown little or no change. Further investigation is required to determine the production and utilisation effects of lactate from playing tennis. The average length of time to play a point in tennis is <10 seconds and this has declined substantially in the last 20 years. Further research is needed to investigate tournament performance and its effect on fatigue, recovery, hormonal and injury levels. As the game of tennis continues to change, the physiological parameters must be continually investigated to help provide athletes, coaches and trainers with information that will aid in the development of efficient and productive tennis performance and injury prevention programmes.

Phenotypic plasticity and functional asymmetry in response to grip forces exerted by intercollegiate tennis players

This study examined phenotypic and functional responses to extreme asymmetry in hand use, and recorded the grip forces that occur during the tennis serve to assess the forces that contribute to asymmetry. Compressive grip performance was measured for Division I collegiate tennis players (24 female, 24 male) and nonathlete college students (18 females, 17 males) during three experiments: single-repetition maximum voluntary contraction, 30 consecutive repetitions, and a 30-s static hold. Tennis players had significant asymmetry in both forearm circumference and grip strength. The dominant hand of female tennis players produced 25% more force than the opposite hand, while the difference between hands of male tennis players was 18%. However, endurance over 30-repetitions and during the 30-s hold did not significantly differ between the limbs of tennis players. No significant asymmetry in forearm measurements, grip strength, or endurance was detected between the limbs of nonathletes. Grip forces generated during the tennis serve were recorded for 4 male tennis players, using a racket with a dynamometer incorporated into the handle. Peak handgrip forces generated during the serve (150-250 N) averaged 31-44% of the maximum grip force of the participant. Tennis players have increased muscle mass and strength of the dominant limb. Moderate forces, occurring hundreds of times each match and practice, are likely the primary forces contributing to this morphological and functional asymmetry.

Isokinetic profile of wrist and forearm strength in elite female junior tennis players

BACKGROUND

In tennis, injuries to the elbow and wrist occur secondary to the repetitive nature of play and are seen at increasingly young ages. Isokinetic testing can be used to determine muscular strength levels, but dominant/non-dominant and agonist/antagonist relations are needed for meaningful interpretation of the results.

OBJECTIVES

To determine whether there are laterality differences in wrist extension/flexion (E/F) and forearm supination/pronation (S/P) strength in elite female tennis players.

METHODS

32 elite female tennis players (age 12 to 16 years) with no history of upper extremity injury underwent bilateral isokinetic testing using a Cybex 6000 dynamometer. Peak torque and single repetition work values for wrist E/F and forearm S/P were measured at speeds of 90 degrees/s and 210 degrees/s, with random determination of the starting extremity. Repeated measures analysis of variance was used to determine differences between extremities for peak torque and single repetition work values.

RESULTS

Significantly greater (p<0.01) dominant arm wrist E/F and forearm pronation strength was measured at both testing speeds. Significantly less (p<0.01) dominant side forearm supination strength was measured at both testing speeds.

CONCLUSIONS

Greater dominant arm wrist E/F and forearm pronation strength is common and normal in young elite level female tennis players. These strength relations indicate sport specific muscular adaptations in the dominant tennis playing extremity. The results of this study can guide clinicians who work with young athletes from this population. Restoring greater dominant side wrist and forearm strength is indicated after an injury to the dominant upper extremity in such players.

Shoulder terminal range eccentric antagonist/concentric agonist strength ratios in overhead athletes

OBJECTIVE

The agonist-antagonist strength relationship for shoulder external rotation and internal rotation was formerly described by the relatively more functional ratios of eccentric external rotator to concentric internal rotator moments, and eccentric internal rotator to concentric external rotator moments for the entire range of motion. The aim of this study was to provide descriptive data for terminal range eccentric antagonist/concentric agonist rotator cuff strength in overhead athletes.

METHOD

The dominant and non-dominant shoulders of 40 asymptomatic military overhead athletes were tested through a range of 20 degrees of external rotation to 90 degrees of internal rotation using the Cybex NORM isokinetic dynamometer at a speed of 90 degrees /s. Differences between the dominant and non-dominant shoulders were assessed using the paired samples t-test.

RESULTS

The terminal range ratios during external rotation (20 degrees of internal rotation - 10 degrees of external rotation) were found to be 2.09 and 1.58 for the dominant and non-dominant shoulders, respectively, whereas the terminal range ratios during internal rotation (60-90 degrees of internal rotation) were 1.03 and 1.19 for the dominant and non-dominant shoulders, respectively. These ratio differences between the dominant and non-dominant shoulders were significant (P<0.01 for external and internal rotation).

CONCLUSION

The muscle torque ratios of eccentric antagonist/concentric agonist are different between dominant and non-dominant shoulders of skilled overhead athletes at terminal ranges. This functional assessment of strength testing that reflects dynamic shoulder joint stability during the throwing activity at these specific ranges may provide valuable information either during preventive exercise programs or in the evaluation of the injured shoulder of the overhead athlete. We recommended functional exercises that improve eccentric external rotation strength on the dominant shoulder during the rehabilitation and prevention programs in overhead athletes.

Glenoid Labrum Lesion in an Elite Tennis Player: A Clinical Challenge in Diagnosis

Shoulder pain among overhead-sport athletes is common and often presents a challenge to clinicians in making an accurate diagnosis. A case report of a young college tennis player is presented, with emphasis on the clinical examination process leading to the diagnosis of a superior labrum anteroposterior lesion. The current literature regarding the clinical diagnosis of glenoid labrum lesion in the shoulder with respect to specific clinical tests was reviewed. It is recommended that clinicians consider glenoid labral lesions in the context of shoulder instability. Glenohumeral internal-rotation deficit should be routinely evaluated and corrected in high-performance tennis players.

Shoulder strength profile in elite junior tennis players: horizontal adduction and abduction isokinetic evaluation

OBJECTIVE

To establish normative data for muscle performance during isokinetic horizontal abduction and adduction of the shoulder in elite junior tennis players.

METHODS

Thirty six tennis players were evaluated (23 male, 13 female; mean age 14 years (range 12-18)). An isokinetic dynamometer was used to test the shoulder horizontal abductors and adductors at 60 and 180 degrees/s. Absolute and relative peak torque (PT and PT/BW), total work (TW), endurance ratio (ER), and the ratio of the peak torque between horizontal abductors and adductors (HAB/HAD ratio) were recorded. Data were compared for the dominant and non-dominant shoulders, horizontal abductor and adductor muscles, and between players grouped according to age.

RESULTS

The dominant shoulder was significantly (p<0.05) stronger than the non-dominant shoulder in all variables except ER and HAB/HAD ratio. The abductors were significantly (p<0.05) weaker than the adductors in all subjects. The type of backhand (one handed or two handed) did not influence the strength of the shoulder horizontal abductors on the dominant side. The number of years of tennis practice had an effect on muscle strength as evaluated by absolute data (PT and TW) but not relative measurements (PT/BW and TW/BW).

CONCLUSION

The findings confirm that horizontal abduction and adduction are stronger in the dominant shoulder of junior tennis players. The clinical relevance of these findings is not established, and more studies are needed to compare tennis players with athletes from other sports and non-athletes.

Mesure de la force des muscles rotateurs de l'épaule chez des sportifs sains de haut niveau (natation, volley-ball, tennis) par dynamomètre isocinétique : comparaison entre épaule dominante et non dominante

OBJECTIVE

To compare lateral rotator (LR) and medial rotator (MR) muscle strength of both shoulders in a sport involving asymmetrical movements (tennis), symmetrical movements (swimming), and symmetrical and asymmetrical movements (volley-ball).

MATERIALS AND METHODS

Retrospective study of 42 healthy elite athletes (18 women: 14 tennis players, 19 swimmers and 9 volleyball players. We evaluated the strength of LR and MR of both shoulders by Cybex Norm isokinetic dynamometer, in the concentric mode, in the modified Davies position, at 2 different speeds (60 degrees and 180 degrees s(-1)) and analysed peak torque of LR and MR and LR/MR ratios.

RESULTS

TENNIS: The MR peak torque of the dominant shoulder was significantly higher than that of the non-dominant shoulder. The LR/MR ratio of the dominant shoulder was significantly lower than the non dominant shoulder in women. SWIMMING: The LR strength and LR/MR ratio of the dominant shoulder was higher than the non dominant side in men at 60 degrees/second. Both shoulders showed comparable strength in women. VOLLEYBALL: Shoulder muscular strength was symmetrical.

CONCLUSION

The higher strength of MR muscles in the dominant shoulder of tennis players (asymmetrical movements) has been reported in the literature. Athletes show asymmetrical shoulder strength in swimming, a symmetrical sport and similar LR and MR strength in both shoulders in volleyball, a sport with asymmetrical movements. To our knowledge, these results have never been reported before.

An isokinetic profile of trunk rotation strength in elite tennis players

PURPOSE

The changes in stroke production in the modern game of tennis have increased the demands on trunk rotation in elite tennis players. Unlike the shoulder, where unilateral strength adaptations have been identified, no study to date has objectively quantified side to side rotational trunk strength in elite tennis players.

METHODS

One hundred nine elite tennis players were tested using a Cybex isokinetic torso rotation unit at 60 and 120 degrees x s(-1) to measure left and right rotation while stabilized in a seated position. A repeated-measures ANOVA was used with post hoc dependent t-tests where main effect differences were identified to determine side to side rotational differences.

RESULTS

No significant difference in trunk rotation strength was measured in the elite male players. Peak torque to body weight ratios averaged 63.7 and 57.5% for forehand rotation (left rotation in right-handed player) and 64.4 and 59.2% for backhand rotation at 60 and 120 degrees x s(-1), respectively. In females, slightly greater (P < 0.001) backhand rotation strength (right rotation in a right-handed player) was measured at both testing speeds with peak torque to body weight ratios ranging between 47.7 and 45.1% for left rotation and 50.8 and 48.3% for right rotation at 60 and 120 degrees x s(-1), respectively. Left rotation/right rotation ratios ranged from 95 to 98% for males and from 94 to 96% for females.

CONCLUSIONS

Elite-level male tennis players have symmetric trunk rotation strength. Elite female tennis players have slightly greater backhand rotation strength (by 4-8%) than forehand rotation. Conditioning programs for elite tennis players should include exercises to facilitate and develop bilateral trunk rotation.

Tennis

Isokinetic dynamometry is used in the assessment and rehabilitation of shoulder function in tennis players. The aim of this study was to validate a newly installed Biodex III Isokinetic Dynamometer for internal and external shoulder rotation. A non-injured male performed this movement which replicates an integral section of the tennis service action (Cohen et al., 1994). Three maximal trials were performed at six randomly assigned angular velocities (0.52, 1.05, 1.57, 2.09, 2.62 and 3.14 rad x s(-1)) with 90 s rest between each set. Trials were recorded using an on-line motion analysis system and kinematic data were obtained. Kinematic angular displacement of the lever arm was slightly greater (> or = 0.01 rad x s(-1)) than for the isokinetic dynamometer at all test angular velocities. Mean angular velocities from the kinematic data were almost identical to those from the isokinetic dynamometer but less than the target values, and this difference (e.g. 2.55 rad x s(-1) at 3.14 rad x s(-1)) was greater at higher angular velocities owing to the greater acceleration phases required. Peak angular velocity was similar on the isokinetic dynamometer to the target values, but substantially less than those from the kinematic data (e.g. 0.68 rad x s(-1) at 0.52 rad x s(-1)). This suggests that the isokinetic data are over-smoothed and may mask important information. In summary, criterion validity of this isokinetic dynamometer is supported for displacement and mean angular velocity, but not for peak angular velocity. Shoulder rotations in tennis are often at angular velocities greater than the Biodex can reproduce, but for the purpose of monitoring the shoulder strength and range of motion of tennis players and providing safe functional rehabilitation, the use of slower angular velocities is acceptable.

Velocity of a tennis serve and measurement of isokinetic muscular performance: brief review and comment

Isokinetic strength testing provides objective and reliable muscular performance data on elite tennis players; however, such data are not highly correlated with performance on a multiple-joint kinetic chain activity such as the tennis serve. In this brief review, an overview of the muscular performance characteristics generated through isokinetic testing for elite tennis players is presented. Application of population specific isokinetic strength profiles in specific populations for rehabilitation and performance enhancement is recommended.

Return to play for rotator cuff injuries and superior labrum anterior posterior (SLAP) lesions

The shoulder is a frequently injured joint in athletes, and the most common injuries in active patients include instability, rotator cuff injuries, and superior labrum lesions. These three types of injuries often involve different mechanisms of injury, variable methods of surgical repair, and different considerations in rehabilitation and return to play. This article focuses upon rotator cuff injuries and superior labrum lesions, treated nonoperatively and operatively. Return to play with these injuries depends upon many factors including upon the age of the patient, the severity of the pathology,the type of treatment rendered, and the expectations of the patient.

Isokinetic performance at diagonal pattern and shoulder mobility in elite overhead athletes

The purpose of this study was to measure isokinetically glenohumeral joint movement peak torque and work in professional basketball, volleyball, handball and baseball players and determine whether significant differences exist between the dominant and non-dominant extremity in athletes and controls. Eighty healthy professional overhead athletes (basketball, volleyball, handball and baseball players) and 20 controls were tested bilaterally on a CYBEX 6000 isokinetic dynamometer at 60 degrees and 180 degrees s(-1) for diagonal pattern of the glenohumeral joint. A standardized protocol and testing guidelines were strictly followed. The range of motion of internal rotation (IR) on the dominant side of baseball players was significantly smaller than those on the dominant side of basketball, handball and volleyball players, and controls (P<0.01). Flexion/abduction/external rotation were consistently higher on the dominant arm (8.5%) for peak torque at 60 degrees s(-1) in baseball players, and bilateral ratios were lower on the dominant arm (14.8%) for peak torque at 180 degrees s(-1) in basketball players. The results of this study are important for the application and interpretation of isokinetic data and flexibility and mobility characteristics on unilaterally dominant overhead athletes. Functional weakness in external rotators, mobility impairments in IR and muscle imbalance have been shown in the dominant arm of these overhead athletes.

Shoulder strength and range of motion in female amateur-league tennis players

STUDY DESIGN

Cross sectional.

OBJECTIVES

To compare the strength and range of motion of the dominant and nondominant shoulders of adult female amateur tennis players. The secondary purpose of the study was to examine whether there were any differences in the observed relationships between women with a past history of shoulder pain and those with no history of shoulder pathology.

BACKGROUND

Information on characteristics of the shoulder in amateur female tennis players is scarce, as research has concentrated on highly skilled or male players, despite the cumulative prevalence of shoulder pain in this group.

METHODS AND MEASURES

Fifty-one female competitive, amateur tennis players (average age, 45 years) were tested bilaterally for shoulder internal/external rotation passive range of motion and isokinetic concentric strength.

RESULTS

Shoulder range of motion and strength ratios were comparable between sides. In the dominant arm, the total rotational range of motion was 221 degrees, with an internal to external rotator peak torque ratio of 1.05. External rotator strength was significantly greater in the dominant arm of individuals with no history of pain.

CONCLUSIONS

Range of motion and strength adaptations widely reported in highly skilled tennis players were not apparent in amateur female players. In assessment and management, clinicians should regard the amateur female tennis player as a separate entity from the highly skilled player.

Isokinetic shoulder rotator muscles in wheelchair athletes

OBJECTIVES

To assess the influence of wheelchair propulsion and neurological level on isokinetic shoulder rotational strength.

SETTING

University of Montpellier, France

METHODS

Data were evaluated in three groups of subjects as follows: 12 nonathletes, 15 tennis players and 21 wheelchair athletes. We then compared 12 high paraplegic athletes (HPA) and nine low paraplegic athletes (LPA) within the group of 21 wheelchair athletes: The isokinetic tests were performed in the seated 45 degrees abducted test position in the scapular plane at 60, 180 and 300 degrees s(-1) for both shoulders. Peak torque and mean power values were gathered and, from these values, the internal/external rotation ratios were calculated.

RESULTS

Intergroup comparison showed an influence of lesion and sport on peak torque at 180 and 300 degrees s(-1) for the internal rotators and significantly higher values of the internal/external ratios in the wheelchair athlete group. For mean power, we observed significant differences under all test conditions and significant differences for ratio only on the dominant side at 180 degrees s(-1) and on the dominant side at 300 degrees s(-1). Comparison of the two groups of paraplegic athletes showed significantly higher values of peak torque and mean power of the external rotators in the LPA for all test conditions.

CONCLUSIONS

Neurological level of lesion does not systematically influence the development of internal rotator muscles; in contrast, the participation of the external rotators appears strongly correlated to neurological level. The comparison of the two sides in the two paraplegic groups showed that in two-thirds of the cases the values of the external rotators were significantly higher than those of the internal rotators on the nondominant side for peak torque and mean power. Ratios on the dominant side were systematically higher than on the nondominant side, with significant differences also noted in two-thirds of the cases. These results raise questions about the influence of neurological level and wheelchair propulsion on the muscular adaptations of the shoulder in wheelchair athletes.