Isokinetic concentric versus eccentric training of shoulder rotators with functional evaluation of performance enhancement in elite tennis players

Development and Performance Evaluation of a Smart Upper-Limb Rehabilitation Exercise Device

User-friendly rehabilitation medical devices can enhance health and the quality of life through the convergence of information communication and medical technology. Muscle contraction enables bodily movement, and the assessment of muscle strength is crucial. Muscle contraction includes isometric, isotonic, and isokinetic types. Many individuals with physical disabilities rely on wheelchairs due to lower-limb paralysis. There is a substantial correlation between the level of upper-limb functional recovery and the quality of daily life. This study aimed to design and evaluate a device that utilizes various muscle contractions to enhance the effectiveness of upper-limb rehabilitation exercises. The results from the isometric performance assessment showed percentage error rates of >30% for 5-30 kg. Correction equations were employed, and the isometric performance assessment resulted in error rates below 2.1% for 5-30 kg. Isokinetic performance assessment using video analysis evaluated a consistent wire speed from 10 cm/s to 70 cm/s with an average error rate of 0.91% across all speeds. This study demonstrates the ability to accurately measure various muscle contractions and showcases the potential for real-time feedback. This highlights how such a device could be helpful for target groups, including older adults and individuals with disabilities, during upper-limb rehabilitation exercises.

Effects of athletic training on physical fitness and stroke velocity in healthy youth and adult tennis players: A systematic review and meta-analysis

Better physical fitness and stroke velocity in healthy elite compared to sub-elite tennis players have been shown in previous studies. However, evidence-based knowledge regarding the effectiveness of athletic training on physical fitness and stroke velocity is currently lacking. Thus, the objective of this systematic review with meta-analysis was to characterize, aggregate, and quantify athletic training effects on measures of physical fitness and stroke velocity in healthy youth and adult tennis players. A computerized systematic literature search was performed in the databases PubMed, Web of Science, and SportDiscus from their inception date to August 2022. Studies were included, among others, if the intervention period lasted a minimum of four weeks and if at least one parameter of physical fitness (i.e., speed, agility, lower-extremity muscle power, upper-extremity muscle power/strength, endurance, balance, flexibility) or stroke performance (i.e., stroke velocity) was tested. Initially, 11,511 articles were identified, after removing duplicates and assessing abstracts and full texts, 24 articles were used to calculate weighted standardized mean differences (SMD). For measures of physical fitness, athletic training resulted in small (speed: SMD = 0.44), moderate (endurance: SMD = 0.61, upper-extremity muscle power: SMD = 0.72; flexibility: SMD = 0.63), and large (agility: SMD = 0.93, lower-extremity muscle power: SMD = 0.88; upper-extremity muscle strength: SMD = 0.90; balance: SMD = 0.88) effects. Further, a large effect (SMD = 0.90) on stroke velocity was detected. The additionally performed sub-analyses showed differences in the effectiveness of athletic training on variables of physical fitness and stroke speed when considering players' age (i.e., youth players: <18 years; adult players: ≥18 years). Precisely, there was a high potential for training-related adaptations in adult players with respect to lower-extremity muscle power, upper-extremity muscle strength, and stroke velocity and in youth players with respect to endurance. Interventions to promote physical fitness and stroke velocity in healthy tennis players revealed varying levels of effectiveness ranging from small to large and these were additionally affected by players' age. Therefore, future studies should investigate modalities to increase training efficacy in youth and adult tennis players, especially for fitness components that showed small- to moderate-sized changes.

The Influence of Growth, Maturation and Resistance Training on Muscle-Tendon and Neuromuscular Adaptations: A Narrative Review

The purpose of this article is to provide an overview of the growth, maturation and resistance training-related changes in muscle-tendon and neuromuscular mechanisms in youth, and the subsequent effect on performance. Sprinting, jumping, kicking, and throwing are common movements in sport that have been shown to develop naturally with age, with improvements in performance being attributed to growth and maturity-related changes in neuromuscular mechanisms. These changes include moderate to very large increases in muscle physiological cross-sectional area (CSA), muscle volume and thickness, tendon CSA and stiffness, fascicle length, muscle activation, pre-activation, stretch reflex control accompanied by large reductions in electro-mechanical delay and co-contraction. Furthermore, a limited number of training studies examining neuromuscular changes following four to 20 weeks of resistance training have reported trivial to moderate differences in tendon stiffness, muscle CSA, muscle thickness, and motor unit activation accompanied by reductions in electromechanical delay (EMD) in pre-pubertal children. However, the interaction of maturity- and training-related neuromuscular adaptions remains unclear. An understanding of how different neuromuscular mechanisms adapt in response to growth, maturation and training is important in order to optimise training responsiveness in youth populations. Additionally, the impact that these muscle-tendon and neuromuscular changes have on force producing capabilities underpinning performance is unclear.

The Effect of Shoulder Injury Prevention Program on Shoulder Isokinetic Strength in Young Male Volleyball Players

The purpose of this study was to examine the effects of an eight-week 11 + S programme on isokinetic shoulder strength in young male volleyball players. Twenty-eight top-level young male volleyball players were recruited for this study. The players were randomly assigned into intervention (14 players) and control (14 players) groups. The intervention group performed the 11 + S as a warm-up before training at least three times a week for eight weeks. Dominant shoulder strength was measured using an isokinetic dynamometer at 60°/s and 180°/s. The functional deceleration ratio (FDR) was calculated as a functional strength profile. 20% FDR improvement after eight weeks of 11 + S at 180°/s (p = 0.003) were observed. No other statistically significant effects for shoulder strength improvement was observed (p > 0.05). Eight weeks of 11 + S warm-up programme improved the glenohumeral muscle imbalance by increasing the functional deceleration ratio (FDR) of shoulder muscles in young male volleyball players.

Isokinetic Performance of Shoulder External and Internal Rotators of Professional Volleyball Athletes by Different Positions

This study aimed to exam the isokinetic shoulder rotator strength of professional volleyball athletes, by playing positions. This cross-sectional study included a total of 49 healthy male professional volleyball players. We measured the isokinetic strength of the external rotator (ER) and internal rotator (IR) muscles and compared the dominant and non-dominant shoulders at angular speeds of 60°/s and 180°/s. In ER, all positions of players had similar strength between the dominant shoulder and non-dominant shoulders. Conversely, all playing positions except libero had stronger strength in dominant shoulder than that in the non-dominant shoulder. The ER/IR ratio in the dominant shoulder was significantly lower only for the attacker (outside hitter and opposite) at 60°/s and 180°/s (P < 0.0001; P = 0.0028 respectively) and blocker at 60°/s (P = 0.0273) when compared with non-dominant shoulder. Furthermore, the attacker had a lower ER/IR ratio in the dominant shoulder than setter and libero at 60°/s and 180°/s. For elite volleyball players without injury, the dominant shoulder had a higher strength of internal rotation, causing the relative muscle imbalance than the non-dominant shoulder, especially for the attacker and blocker positions. Training program should be individualized for each playing position to improve the imbalanced shoulder.

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.

Does stroke performance in amateur tennis players depend on functional power generating capacity?

BACKGROUND

Physical preparation is becoming more important in amateur tennis player training programs. Yet, when studying stroke performance in these players, there is a lack of evidence on the role of functional power generating capacity. The aim of the study was therefore to determine whether functional power generating capacity correlates with speed and accuracy of forehand and backhand groundstrokes in amateur players. We also studied the correlation with handgrip strength as a more classical measurement of general muscle strength.

METHODS

A total of 21 male amateur players, aged 33.7±4.6 with 17.1±6.7 years of play, were tested. They performed a medicine ball side throw test, a handgrip dynamometer test, and a stroke performance test.

RESULTS

Distance of the medicine ball throw on the dominant side positively correlated to the speed of the fastest forehand (r=0.52; P=0.017) and backhand accuracy (r=0.49; P=0.024). There was also a correlation between the handgrip strength on the dominant side and the speed of the fastest forehand (r=0.52, P=0.019).

CONCLUSIONS

We concluded that groundstroke performance in amateur tennis players depends on functional power generating capacity, but that it is not the principal contributing factor.

Chronic Adaptations to Eccentric Training: A Systematic Review

BACKGROUND

Resistance training is an integral component of physical preparation for athletes. A growing body of evidence indicates that eccentric strength training methods induce novel stimuli for neuromuscular adaptations.

OBJECTIVE

The purpose of this systematic review was to determine the effects of eccentric training in comparison to concentric-only or traditional (i.e. constrained by concentric strength) resistance training.

METHODS

Searches were performed using the electronic databases MEDLINE via EBSCO, PubMed and SPORTDiscus via EBSCO. Full journal articles investigating the long-term (≥4 weeks) effects of eccentric training in healthy (absence of injury or illness during the 4 weeks preceding the training intervention), adult (17-35 years), human participants were selected for the systematic review. A total of 40 studies conformed to these criteria.

RESULTS

Eccentric training elicits greater improvements in muscle strength, although in a largely mode-specific manner. Superior enhancements in power and stretch-shortening cycle (SSC) function have also been reported. Eccentric training is at least as effective as other modalities in increasing muscle cross-sectional area (CSA), while the pattern of hypertrophy appears nuanced and increased CSA may occur longitudinally within muscle (i.e. the addition of sarcomeres in series). There appears to be a preferential increase in the size of type II muscle fibres and the potential to exert a unique effect upon fibre type transitions. Qualitative and quantitative changes in tendon tissue that may be related to the magnitude of strain imposed have also been reported with eccentric training.

CONCLUSIONS

Eccentric training is a potent stimulus for enhancements in muscle mechanical function, and muscle-tendon unit (MTU) morphological and architectural adaptations. The inclusion of eccentric loads not constrained by concentric strength appears to be superior to traditional resistance training in improving variables associated with strength, power and speed performance.

Increasing Ball Velocity in the Overhead Athlete: A Meta-analysis of Randomized Controlled Trials

Overhead athletes routinely search for ways to improve sport performance, and one component of performance is ball velocity. The purpose of this meta-analysis was to investigate the effect of different strengthening interventions on ball and serve velocity. A comprehensive literature search with pre-set inclusion and exclusion criteria from 1970 to 2014 was conducted. Eligible studies were randomized control trials including the mean and SDs of both pretest and posttest ball velocities in both the experimental and the control groups. The outcome of interest was ball/serve velocity in baseball, tennis, or softball athletes. Level 2 evidence or higher was investigated to determine the effect different training interventions had on velocity. Pretest and posttest data were extracted to calculate Hedges's g effect sizes with 95% confidence intervals (CIs). Methodological qualities of the final 13 articles within the analysis were assessed using the Physiotherapy Evidence Database scale. The majority of the articles included in this analysis had an effect on velocity with the strongest effect sizes found in periodized training (Hedges's g = 3.445; 95% CI = 1.976-4.914). Six studies had CI that crossed zero, indicating that those specific interventions should be interpreted with caution. Consistent and high-quality evidence exists that specific resistance training interventions have an effect on velocity. These findings suggest that interventions consisting of isokinetic training, multimodal training, and periodization training are clinically beneficial at increasing velocity in the overhead athlete over different windows of time.

Muscular activation during plyometric exercises in 90° of glenohumeral joint abduction

BACKGROUND

Plyometric exercises are frequently used to increase posterior rotator cuff and periscapular muscle strength and simulate demands and positional stresses in overhead athletes. The purpose of this study was to provide descriptive data on posterior rotator cuff and scapular muscle activation during upper extremity plyometric exercises in 90° of glenohumeral joint abduction.

HYPOTHESIS

Levels of muscular activity in the posterior rotator cuff and scapular stabilizers will be high during plyometric shoulder exercises similar to previously reported electromyographic (EMG) levels of shoulder rehabilitation exercises.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Twenty healthy subjects were tested using surface EMG during the performance of 2 plyometric shoulder exercises: prone external rotation (PERP) and reverse catch external rotation (RCP) using a handheld medicine ball. Electrode application included the upper and lower trapezius (UT and LT, respectively), serratus anterior (SA), infraspinatus (IN), and the middle and posterior deltoid (MD and PD, respectively) muscles. A 10-second interval of repetitive plyometric exercise (PERP) and 3 repetitions of RCP were sampled. Peak and average normalized EMG data were generated.

RESULTS

Normalized peak and average IN activity ranged between 73% and 102% and between 28% and 52% during the plyometric exercises, respectively, with peak and average LT activity measured between 79% and 131% and between 31% and 61%. SA activity ranged between 76% and 86% for peak and between 35% and 37% for average activity. Muscular activity levels in the MD and PD ranged between 49% and 72% and between 12% and 33% for peak and average, respectively.

CONCLUSION

Moderate to high levels of muscular activity were measured in the rotator cuff and scapular stabilizers during these plyometric exercises with the glenohumeral joint abducted 90°.

Fitness testing of tennis players: how valuable is it?

In tennis, sport-specific technical skills are predominant factors, although a complex profile of physical performance factors is also required. The fitness test batteries assist in examining tennis players' capabilities for performance at different levels in the laboratory as well as in the field, in the junior or elite level. While laboratory tests can be, and are, used to evaluate basic performance characteristics of athletes in most individual sports, in a more specific approach, field-based methods are better suited to the demands of complex intermittent sports like tennis. A regular test battery performed at different periods of the year allows to obtain an individual's performance profile, as well as the ability to prescribe individual training interventions. Thus, the aim of the present review was to describe and evaluate the different physical tests recommended and used by practitioners, sports scientists and institutions (national tennis federations).

Muscle conduction velocity, strength, neural activity, and morphological changes after eccentric and concentric training

This study compared the effects of concentric and eccentric training on neuromuscular adaptations in young subjects. Twenty-two men and women were assigned to one of two groups: concentric (CON, n = 11) and eccentric (ECC, n = 11) training. Training consisted of 6 weeks of isokinetic exercise, performed twice weekly, starting with two sets of eight repetitions, and progressing to five sets of 10 repetitions. Subjects were tested in strength variables [concentric, eccentric, and isometric peak torque (PT), and rate of force development (RFD)], muscle conduction velocity (CV), neuromuscular activity, vastus lateralis (VL) muscle thickness, and echo intensity as determined by ultrasonography. There were similar increases in the concentric and eccentric PTs in both the CON and ECC groups (P < 0.01), but only the ECC group showed an increase in isometric PT (P < 0.001). Similarly, both groups exhibited increased VL muscle thickness, CV, and RFD, and reduced VL echo intensity (P < 0.05). Significant correlations were observed among the relative changes in the neuromuscular outcomes and training variables (e.g., total work, average PT) (r = 0.68-0.75, P < 0.05). The results showed that both training types similarly improved dynamic PT, CV, RFD, and muscle thickness and quality during the early weeks of training.

The disabled throwing shoulder: spectrum of pathology-10-year update

In the 10 years since the current concept series entitled "The Disabled Throwing Shoulder: Spectrum of Pathology" was conceived and written, many studies have been reported that add much more information to the understanding of the disabled throwing shoulder (DTS). The editors of Arthroscopy and the authors of the original series believed that an update to the original series would be beneficial to provide an organized overview of current knowledge that could update the thought process regarding this problem, provide better assessment and treatment guidelines, and guide further research. A dedicated meeting, including current published researchers and experienced clinicians in this subject, was organized by the Shoulder Center of Kentucky. The meeting was organized around 5 areas of the DTS that were highlighted in the original series and appear to be key in creating the DTS spectrum and to understanding and treating the DTS: (1) the role of the kinetic chain; (2) the role and clinical evaluation of the scapula; (3) the role of deficits in glenohumeral rotation, glenohumeral internal rotation deficit, and total range-of-motion deficit in the causation of labral injury and DTS; (4) the role of superior labral (SLAP) injuries and rotator cuff injuries; and (5) the composition and progression of rehabilitation protocols for functional restoration of the DTS. The meeting consisted of presentations within each area, followed by discussions, and resulted in summaries regarding what is known in each area, what is not known but thought to be important, and strategies to implement and enlarge the knowledge base.

Strength Values of Shoulder Internal and External Rotators in Elite Volleyball Players

Objective:

To determine concentric shoulder external-internal rotator strength, dominant and non-dominant shoulder differences and agonist/antagonist ratios.

Design:

A transversal study of isokinetic dynamometry of healthy shoulders, 95% confidence intervals are presented.

Participants:

35 asymptomatic elite, male volleyball players.

Measurements:

Peak torque normalized for body weight was recorded at 60, 180, and 300°/sec. with a Cybex 6000 dynamometer.

Results:

(1) internal rotators were significantly stronger than external rotators of the same shoulder; (2) internal rotators of the dominant arm were significantly stronger than of the non-dominant arm; (3) no difference existed between external rotators of the dominant and the non-dominant arm; (4) external–internal rotator ratios of the dominant arm were significantly lower than of the non-dominant arm; and (5) no differences were found between the ratios of each arm separately.

Conclusions:

Data presented are important for interpreting isokinetic shoulder rotator strength tests in elite volleyball players and could be relevant in rehabilitation and prevention of shoulder injuries.

Descriptive report of shoulder range of motion and rotational strength 6 and 12 weeks following rotator cuff repair using a mini-open deltoid splitting technique

STUDY DESIGN

Retrospective chart review.

OBJECTIVES

To measure short-term postsurgery glenohumeral internal rotation and external rotation strength, shoulder range of motion (ROM), and subjective self-report ratings following mini-open rotator cuff repair of full-thickness rotator cuff tears.

BACKGROUND

Physical therapists provide rehabilitation for patients following mini-open rotator cuff repair. Long-term outcome studies have reported a high percentage of good and excellent results following surgery; however, little has been published regarding the immediate short-term results of this procedure, during which the patient is under the direct care of the physical therapist.

MATERIALS AND METHODS

Charts from 11 female and 26 male patients, with a mean +/- SD age of 57.3 +/- 9.9 years, were reviewed following rotator cuff repair, using an arthroscopically assisted mini-open deltoid-splitting approach. All patients underwent postsurgery rehabilitation by the same therapist using a standard protocol. Retrospective chart review was used to obtain descriptive profiles of shoulder joint ROM at 6 and 12 weeks postsurgery and isokinetically assessed shoulder strength at 12 weeks postsurgery.

RESULTS

For the postsurgical shoulder, ROM deficits ranging between 5 degrees to 7 degrees were measured for shoulder abduction and external rotation and internal rotation at 90 degrees of abduction. The postsurgical extremity had greater flexion ROM (9 degrees ) compared to the contralateral side. Isokinetic external rotation strength deficits of 5% to 7% were present at 12 weeks postsurgery, with 2% to 11% greater internal rotation shoulder strength on the operative extremity, when compared to the other side. Patients completed the self-report section of the modified American Shoulder Elbow Surgeons (ASES) Rating Scale at 12 weeks postsurgery and scored a mean of 38.7/45.0 points.

CONCLUSION

The application of early ROM and progressive strengthening following mini-open rotator cuff repair allows for the successful return of ROM and strength 12 weeks postsurgery. The results of this study provide objective data for both shoulder ROM and strength at time points during which patients are traditionally receiving physical therapy following surgery.

Tennis injuries: occurrence, aetiology, and prevention

A systematic search of published reports was carried out in three electronic databases from 1966 on to identify relevant articles relating to tennis injuries. There were 39 case reports, 49 laboratory studies, 28 descriptive epidemiological studies, and three analytical epidemiological studies. The principal findings of the review were: first, there is a great variation in the reported incidence of tennis injuries; second, most injuries occur in the lower extremities, followed by the upper extremities and then the trunk; third, there have been very few longitudinal cohort studies that investigated the association between risk factors and the occurrence of tennis injuries (odds ratios, risk ratios, hazard ratios); and fourth, there were no randomised controlled trials investigating injury prevention measures in tennis. More methodologically sound studies are needed for a better understanding of risk factors, in order to design useful strategies to prevent tennis injuries.

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.

Postrehabilitation Outcomes of Muscle Power (Torque-Acceleration Energy) in Patients with Selected Shoulder Dysfunctions

Context:

Most patients on an index concentric isokinetic test of the shoulder internal and external rotators have significant torque-acceleration-energy (TAE) deficits.

Objective:

To assess the effectiveness of rehabilitation on muscle power in patients with shoulder dysfunctions.

Design:

Prospective, pretest–posttest.

Setting:

Physical therapy clinic.

Participants:

67, mean age 28.7 ± 12.89 years.

Main Outcome Measures:

Concentric shoulder internal and external rotators measured with arm at 90° of abduction, 90° of elbow flexion. Isokinetic velocities tested: 60°, 180°, and 300°/s.

Results:

A pairedttest (P< .05) compared the differences from index to discharge test for involved and uninvolved internal and external shoulder rotators. Percentages of TAE deficits involved vs uninvolved on discharge and change in TAE from index to discharge were also analyzed. Significant improvement of the involved shoulder for all velocities for both internal and external rotators was seen. The uninvolved extremity saw statistically significant improvements at all velocities for external rotators yet only at 300°/s for internal rotators. Involved-extremity TAE deficits returned to within 10% on discharge.

Conclusions:

The study demonstrated improved muscle power as measured by TAE in shoulder internal and external rotators in a sample of patients treated in an outpatient clinic.

Results of arthroscopic treatment of posterosuperior glenoid impingement in tennis players

Twenty-eight tennis players with symptomatic posterosuperior glenoid impingement limiting their participation underwent arthroscopic debridement of the supraspinatus tendon and glenoid lesions associated with this diagnosis after nonoperative treatment had failed. The dominant extremity was affected in all patients; the patients' average age was 26.9 years. Eighteen patients participated at the highest level of competition for their age, and the remaining patients participated at the intermediate level. Patients were evaluated at an average of 45.7 months after surgery by physical examination, an activities questionnaire, a subjective result questionnaire, and a questionnaire regarding their return to activity. Postoperatively, the patients averaged 26.9 of 30 possible points on the activities questionnaire. Twenty-three of the patients were subjectively satisfied with the surgical result. Twenty-two patients had returned to tennis. Despite their return, 20 of the 22 patients reported some persistent pain with participation. To our knowledge, this is the first report detailing the results of operative treatment for posterosuperior glenoid impingement in a population limited to tennis players. Even though the results are encouraging in terms of the high number of patients returning to tennis, the effects of this persistent pain with activity, although diminished in severity, on long-term participation is unknown.

Overuse injuries of the upper extremity in tennis players

Several overuse injuries can affect the upper extremity of tennis players. A thorough understanding of anatomy and knowledge of these common conditions and their treatment facilitates the management of these athletes.

The Effects of Training the Humeral Rotators on Arm Elevation in the Scapular Plane

Context:

It has been hypothesized that the fibers of the infraspinatus and subscapularis superior to the glenohumeral axis of rotation contribute directly to arm elevation.

Objective:

To test this hypothesis by assessing the impact of 5 weeks of concentric isokinetic humeral-rotator training in a modified neutral position on scapular-plane arm-elevation peak torque.

Design:

Prospective, pretest/posttest with control group.

Participants:

24 female and 6 male noninjured college students (N = 30).

Main Outcome Measures:

Scapular-plane-elevation peak torque at 60, 180, and 300°/s.

Results:

Repeated-measures ANOVA indicated no difference in peak torque between groups at any of the angular velocities tested (P< .05)

Conclusions:

5 weeks of concentric isokinetic humeral-rotator training did not significantly increase scapular-plane-elevation peak torque.

Isokinetic performance and shoulder mobility in elite volleyball athletes from the United Kingdom

OBJECTIVES

To evaluate the differences in strength and mobility of shoulder rotator muscles in the dominant and non-dominant shoulders of elite volleyball players.

METHODS

Isokinetic muscle strength tests were performed at speeds of 60 and 120 degrees/s, and shoulder mobility was examined in ten players from the England national men's volleyball squad. The subjects also completed a questionnaire that included a visual prompt and analogue pain scale.

RESULTS

The range of motion of internal rotation on the dominant side was less than that on the non-dominant side (p < 0.01). The average peak strength at 60 degrees/s external eccentric contraction was lower than that of internal concentric contraction in the dominant arm, but was higher in the non-dominant arm. Six of the ten subjects reported a shoulder problem, described as a diffuse pain located laterally on the dominant shoulder.

CONCLUSIONS

These elite volleyball players had a lower range of motion (internal rotation) and relative muscle imbalance in the dominant compared with the non-dominant shoulder.

Effects of Theraband and lightweight dumbbell training on shoulder rotation torque and serve performance in college tennis players

The purpose of this study was to determine whether a 4-week isotonic resistance training program using Theraband elastic tubing and lightweight dumbbells would significantly increase concentric shoulder rotator strength or velocity of serve or both in a group of elite-level tennis players. Twenty-two male and female varsity college tennis players were randomly assigned to control or 4-week training groups. Subjects were pre- and posttested in concentric internal and external rotation torque using an isokinetic dynamometer. Functional performance was assessed before and after training by recording the peak and average velocities of eight maximal serves. The experimental group exhibited significant gains in internal rotation torque at both slow (120 deg/sec) and fast speeds (300 deg/sec) for total work and in peak torque to body weight ratio and torque acceleration energy at the fast speed. This group also exhibited significant gains in external rotation torque for the same parameters at fast speed. Regarding speed to serve, the experimental group exhibited significantly greater increase in peak speed (+6.0% compared with -1.8%) and average speed (+7.9% compared with -2.3%) compared with the control group. Men exhibited greater internal and external rotation torque on all parameters and in peak and mean speed of serve on both evaluations. Men also exhibited greater imbalance in external to internal rotation torque ratios. In conclusion, resistance training using Theraband tubing and lightweight dumbbells may have beneficial effects on strength and functional performance in college-level tennis players.

Electromyographic activity and applied load during shoulder rehabilitation exercises using elastic resistance

Muscle activity (measured by electromyography) and applied load were measured during seven shoulder rehabilitation exercises done with an elastic resistance device. Nineteen men with no shoulder abnormalities performed seven exercises: external and internal rotation, forward punch, shoulder shrug, and seated rowing with a narrow, middle, and wide grip. Qualitative video (60 Hz) was synchronized with the electromyography data from eight muscles (2000 Hz). Fine-wire intramuscular electrodes were inserted into the supraspinatus and subscapularis muscles, and surface electrodes were placed over the anterior deltoid, infraspinatus, pectoralis major, latissimus dorsi, serratus anterior, and trapezius muscles. Ten trials per subject were analyzed for average and peak amplitude, and the results were expressed as a percentage of maximum voluntary contractions. The peak loads for all exercises ranged from 21 to 54 N. The muscle activity patterns suggest that these shoulder rehabilitation exercises incorporating elastic resistance, controlled movements, and low initial loading effectively target the rotator cuff and supporting musculature and are appropriate for postinjury and postoperative patients.

Shoulder strength and range of motion in symptomatic and pain-free elite swimmers

To evaluate differences in shoulder strength and range of motion between painful and pain-free shoulders we examined two matched groups of athletes. Fifteen competitive swimmers were allocated to two groups. Group 1 consisted of seven swimmers with unilateral shoulder pain related to swimming (Neer and Welsh phase I to II). The control group (Group 2) consisted of eight swimmers with no present or previous history of shoulder pain. Concentric and eccentric internal rotational torques were reduced in painful shoulders in between-group comparisons as well as in side-to-side comparisons. The decrease in internal rotational torque resulted in significantly greater concentric and eccentric external-to-internal rotational strength ratios of the painful shoulder in Group 1 swimmers compared with the controls. Furthermore, the functional ratio (eccentric external rotation:concentric internal rotation) was significantly greater in the painful shoulder in both between-group and side-to-side comparisons. Both groups of swimmers exhibited increased external range of motion and reduced internal range of motion compared with normalized data, but no between-group or side-to-side differences were detected. Our findings suggest that prevention or rehabilitation of swimmer's shoulder might not solely involve strengthening of the external rotators of the shoulder joint. Attention might also be drawn toward correction of a possible deficit in internal rotational strength. Changes in shoulder range of motion seem unrelated to the occurrence of shoulder pain.