Shoulder internal and external rotation strength and prediction of subsequent injury in water-polo players

Validity and Reliability of the Kinvent Handheld Dynamometer in the Athletic Shoulder Test

CONTEXT

Long-lever shoulder strength tests may aid clinical decision-making regarding return to sport after a shoulder injury. The Athletic Shoulder Test (AST) was developed to measure force production in 3 positions of shoulder abduction (90°, 135°, and 180°) using force plates. However, handheld dynamometers (HHDs) are more portable, affordable, and may provide valid and reliable results which would increase the clinical utility of long-lever tests. HHDs vary in shape, design, and their capacity to report parameters such as rate of force production and require further investigation. The aim of this study was to examine the intrarater reliability of the Kinvent HHD and assess its validity against Kinvent force plates in the AST. Peak force (in kilograms), torque (in Newton meters), and normalized torque (in Newton meters per kilogram) were reported.

DESIGN

Validity and reliability study.

METHODS

Twenty-seven participants with no history of upper limb injury performed the test in a randomized order using the Kinvent HHD and force plates. Each condition was assessed 3 times, and peak force was recorded. Arm length was measured to calculate peak torque. Normalized peak torque was calculated by dividing torque by bodyweight (in kilograms).

RESULTS

The Kinvent HHD is reliable when measuring force (intraclass correlation coefficient [ICC] ≥ .80), torque (ICC ≥ .84), and normalized torque (ICC ≥ .64) during the AST. The Kinvent HHD is also valid when compared with the Kinvent force plates for force (ICC ≥ .79; r ≥ .82), torque (ICC ≥ .82; r ≥ .76), and normalized torque (ICC ≥ .71; r ≥ .61). There were no statistically significant differences across the 3 trials on analyses of variance (P > .05).

CONCLUSIONS

The Kinvent HHD is a reliable tool when used to measure force, torque, and normalized torque in the AST. Furthermore, given the lack of significant difference between trials, clinicians can use one test to accurately report relative peak force/torque/normalized torque rather than average 3 separate trials. Finally, the Kinvent HHD is valid when compared with Kinvent force plates.

Genetic Polymorphisms in COL1A2 gene and the Risk of Tendinopathy: Case-Control Study

Objective  To evaluate the influence of polymorphisms on genes encoding type I collagen and the genetic susceptibility of tendinopathy. Methodology  Case-control study involving 242 Brazilian athletes from different sports modalities (55 cases of tendinopathy and 187 controls). The polymorphisms COL1A1 (rs1107946) and COL1A2 (rs412777, rs42524, and rs2621215) were analyzed by the TaqMan system. Odds ratio (OR) with their 95% confidence intervals (CIs) were calculated using a nonconditional logistic regression model. Results  The mean age was 24.0 ± 5.6 years old and 65.3% were men. Of the 55 cases of tendinopathy, 25.4% had > 1 affected tendon, the most frequent being patellar (56.3%), rotator cuff (30.9%) and elbow or hand flexors (30.9%). Age and amount of time of sports practice were associated with a higher chance of presenting tendinopathy (5 and 8 times, respectively). The frequency of variant alleles in control and case patients, respectively, was: COL1A1 rs1107946 24.0 and 29.6%; COL1A2 rs412777 36.1 and 27.8%; rs42524 17.5 and 25.9%; and rs2621215 21.3 and 27.8%. After adjusting for confounding factors (age and years of sports practice), COL1A2 rs42524 and rs2621215 polymorphisms were associated with increased risk of tendinopathy (OR = 5.5; 95%CI = 1.2-24.6 and OR = 3.9; IC95% = 1.1-13.5, respectively). The haplotype COL1A2 CGT was associated with low risk for disease development (OR = 0.5; 95%CI = 0.3-0.9). Conclusion  Age (≥ 25 years old), time of sports practice (≥ 6 years) and polymorphisms in the COL1A2 gene increased the risk of developing tendinopathy.

Intra- and interrater reliability of belt-stabilized hand-held dynamometer in scapular protraction strength tests in individuals with shoulder pain

PURPOSE

Scapular protraction strength can be evaluated using a hand-held dynamometer (HHD). However, it is necessary to measure the reliability of HHD in individuals with shoulder pain and to minimize the limitations related to the evaluator and the low methodological quality cited in previous studies. This study assessed, with methodological enhancement, the intra- and interrater reliability of belt-stabilized HHD in the assessment of scapular protraction strength in individuals with shoulder pain.

METHOD

Fifty individuals with unilateral symptoms of subacromial pain syndrome (20 men, aged 40.5 ± 15.3 years) were evaluated in two sessions using the belt-stabilized HHD for maximum isometric strength of scapular protraction with the individual in the sitting and supine positions. Reliability values were obtained using the intraclass correlation coefficient with the standard error of measurement (SEM and %SEM) and the minimal detectable change (MDC).

RESULTS

The intra- and interrater HHD reliability were excellent for all measurements ranging from 0.88 to 0.96 (SEM = 2.0-4.0 kg; %SEM 12 to 17; MDC = 6-11 kg).

CONCLUSION

Belt-stabilized HHD is reliable for the assessment of scapular protraction strength in individuals with subacromial pain syndrome in both the sitting and supine positions.

Exploration of the Shoulder Internal Rotation's Influence on Throwing Velocity in Handball Players: A Pilot Study

The main objective of this study was to test the relationship between shoulder internal rotation strength and standing throwing velocity. A repeated measures cross-sectional study was conducted with 20 professional handball players (mean ± SD; age: 19.28 ± 2.55 years, weight: 81.52 ± 9.66 kg, height: 185 ± 6 cm, BMI: 23.74 ± 1.69). The participants were instructed to perform eight standing throws from the 7 m line of the handball court at maximum velocity to calculate the mean and maximum throwing velocity. An incremental test was performed to calculate the repetition maximum (1-RM) of internal rotation shoulder strength. A Pearson's correlation analysis with a 95% confidence interval (95% CI) was performed to determine whether correlations existed between dominant arm internal rotation strength characteristics and maximum and mean ball-throwing velocity. There is no correlation between the internal rotation strength of the throwing shoulder and the velocity of the ball in the standing handball throw.

The Correlation Between the Strength of the Shoulder and Trunk Muscular Systems in Elite Adolescent Water Polo Athletes

Introduction

Water polo is a competitive team sport played in the water between two teams of seven players each. Water polo players must have swimming speed, strong abdominal and back muscles, and strong shoulder muscles to cope with this sport's special conditions. In this study, we investigate the possible association of shoulder and trunk muscle systems in adolescent water polo athletes of high demands.

Materials and methods

The research included 42 water polo players aged 14-16, who train regularly for at least five years, six times a week, and participate in national championships and national teams. The athletes were evaluated on the strength and torque of these muscular systems using the isokinetic dynamometer Biodex System 4 Pro (Biodex Medical Systems, Inc, Shirley, NY). The correlation of the results was done using the statistical package SPSS 21.

Results

The correlations revealed statistically significant differences in trunk extension in combination with the shoulder external/internal rotation ratio. Also, most of the correlations occurred between the trunk and non-dominant limb of the athletes and, more often, in the female athletes. Furthermore, for the hand grip, the male athletes showed a greater difference in strength between the dominant and the non-dominant member than female athletes. Finally, the evaluation of the trunk extension/flexion ratio and external/internal rotation ratio for the shoulder joint showed that many athletes are outside the normal range and need targeted strengthening.

Conclusion

The negative correlation coefficient between trunk extension/flexion and shoulder external/internal rotation indicates that the trunk extension mechanism helps for better internal rotation of the shoulder. Therefore, water polo players should focus on the training of the stretching mechanism of the trunk and also give weight to achieving a balance between the competing muscular systems of the trunk and the shoulder. Thus, athletes can maximize their skills and, at the same time, protect themselves from injuries.

Shoulder impingement syndrome in water polo players: muscle shortening manoeuvre controls pain intensity, recovers function and normalizes sonographic parameters

PURPOSE

To evaluate the effects of muscle shortening manoeuvre (MSM) by sonography (US) in professional water polo players with shoulder impingement syndrome (SIS).

METHODS

Twenty-four professional water polo players (mean age: 22.13 ± 3.34) with SIS were assigned to one of 2 different treatment interventions: Group (1) MSM: a series of fast accelerations in the upward direction was applied to the upper limb that's connected to a spring through a metal plate with a ring. The ring was linked to a pulley system that was submitted to forces acting in the opposite direction (added mass). Group (2) Simple traction: the series of fast accelerations were performed without the springs. Pain intensity, Yocum and Hawkins tests for SIS, Neer's impingement sign, range of motion, muscle strength and shoulder US were assessed. The examination was performed before, immediately after and 30 days after each treatment to study the US width of subacromial-subdeltoid bursa (SSB), thickness of supraspinatus (ST), long biceps tendons (LBT); hypoechoic halo of surrounding the long biceps (LBH) and subscapular tendons (STH); width of acromio-clavicular joint capsule (ACJ) and the distance between bone heads (ACD). Impingement sign (IS) was evaluated by dynamic examination.

RESULTS

Immediately after treatment with MSM, pain was much reduced (p = 0.002); Yocum and Hawkins tests were decreased (p = 0.008, p = 0.031); Neer's impingement sign was negative; range of motion and muscle strength were increased. US showed that the following parameters were significantly reduced: SSB (p = 0.001), LBT (p = 0.014), LBH (p = 0.014), SSH (p = 0.002), ACJ (p = 0.004), ACD (p = 0.001). IS was no more detected. After 30 days, the improvement of clinical and US findings was maintained. In the control group, after simple traction, no clinical amelioration of US parameters was found immediately after the procedure.

CONCLUSION

These data show that MSM could be significantly and rapidly effective against pain and the loss of function due to shoulder impingement in water polo players.

The Effectiveness of Shoulder Mobility and Strength Programs in Competitive Water-Polo Players

Background: Water-polo is the water sport with the highest incidence of injuries, with shoulder pain being the most common one. The understanding of risk factors and guidance on preventive measures is essential in this sport discipline. The aim of this study was to determine the effects of a specific 6-week training plan on range of motion (ROM) and joint strength levels in a group of professional water-polo players. Methods: Quasi-experimental study with a sample of 28 participants (age: 20.1 ± 2.5 years; height: 176.9 ± 6.2 cm; body mass: 74.6 ± 8.1 kg). Three study groups, which consisted of one control group and two experimental groups, were established. Two repeated measurements, pre and post intervention, were performed. During these measurements, ROM of the glenohumeral joint was analyzed both in external (ER) and internal (IR) rotation, as well as the maximal isometric strength. Conclusions: The application of a training program improved glenohumeral joint ROM. ER and IR evolve differently in both shoulders. ER improved only in the throwing arm only in the group undergoing intervention but for the non-dominant side, improvements were observed in both ER and IR, regardless of whether or not they had followed the intervention plan. No improvements were observed in either the isometric strength or contralateral asymmetries.

Upper limb muscle strength and knee frontal plane projection angle asymmetries in female water-polo players

Water-polo players frequently perform overhead throws that could result in shoulder imbalances. For overhead throws, execution of the 'eggbeater kick' (cyclical movement of the legs) is required to lift the body out of the water. Although a symmetrical action, inter-limb differences in task execution could lead to knee frontal plane projection (FPPA) differences. The present study examined imbalances shoulder and knee FPPA in female players. Eighteen competitive female field players (24.1 ± 5.5 years, 1.68 ± 0.06 m, 72.9 ± 13.3 kg) had their shoulder strength assessed in a shot-mimicking position with a portable dynamometer, standing and seated (isolating the shoulder contribution). Anterior: posterior and shooting: non-shooting shoulder comparison were made. Additionally, players performed a drop jump. Knee FPPA was recorded from digitising and comparing the frames just before landing and at stance phase. During standing, players exhibited higher shooting: non-shooting asymmetry (p = 0.032) in the anterior contraction direction, while during seated the shooting shoulder anterior: posterior asymmetry was higher (p = 0.032). Interlimb knee FPPA asymmetry was higher in the stance phase (p = 0.02). Despite the overhead throwing and egg-beater demands impacting differently on each limb, considerable asymmetries do not develop, suggesting the overall training requirements (e.g. swimming, resistance training) were sufficient to maintain the asymmetry within desirable limits.

Risk Factors for Shoulder Injuries in Water Polo: a Cohort Study

BACKGROUND

Very limited investigations have been conducted exploring risk factors for injury in water polo players. A gap remains in the literature regarding identification of variables that should be considered as part of player screening evaluations.

PURPOSE

To estimate whether previous injury, changes in strength, range of motion (ROM) or upward scapular rotation (UR) are related to shoulder injuries in water polo players.

STUDY DESIGN

Descriptive cohort study.

METHODS

Thirty-nine international-level players participated (19 males). Shoulder internal (IR) and external rotation (ER) peak torque was measured using an isokinetic device (CONtrex MJ). Shoulder ROM was measured passively using standard goniometry. Scapular UR was measured using a laser digital inclinometer. At baseline players were divided into groups: those with and without previous shoulder injuries. Independent t-tests and Mann-Whitney U tests were used to compare the study variables between groups. After nine months, a second analysis compared the same athletes, who were then grouped by those who had or had not sustained new injuries. Effect sizes were calculated with a Hedge's g. Chi squared analysis compared proportion of injured players with and without previous injury.

RESULTS

Eighteen participants (46%) had previous injuries at baseline. Players with a previous injury showed higher peak torques for IR (0.62±0.15 vs 0.54±0.13N/kg, p=0.04, g=0.60); larger loss of IR ROM (9.9±9.1 vs 4.1±7.5°, p=0.04, g=0.68), but no statistical difference in UR (p=0.70). After nine months, there were no statistical strength differences between groups. Loss of IR ROM was significantly higher in the injured group (9.8±9.8 vs 4.0±6.7°, p=0.04, g=0.68), as well as UR (13.0±3.0 vs 10.4±3.3°, p=0.01, g=0.81). History of previous injury was significantly related to developing a new injury (OR 6.5, p=0.02). Logistic regression found previous injury and UR most important contributors to injury risk.

CONCLUSIONS

Previous injury, changes in IR ROM and UR are related to new shoulder injuries in water polo, but further variables such as rest, training load, or psychosocial factors may explain the incidence of new injuries.

LEVEL OF EVIDENCE

Level 3.

Prevalence and mechanisms of injuries in water polo: a systematic review

Objective

To summarise the information available in the literature on the prevalence of injuries in water polo and injury risk factors.

Methods

Protocol was registered on Open Science Framework. MEDLINE, CINAHL, Embase and SPORTDiscus databases were searched for keywords relating to water polo and injuries on 3 February 2021. References were searched for additional studies. Only original research papers in English or French were included, and studies without an injured group were excluded. A data extraction file was made based on the Cochrane Collaboration recommendations. Study quality was evaluated with the Newcastle-Ottawa scales for cohorts and a modified version for cross-sectional studies.

Results

The initial search yielded 581 articles, with 5 more added from reference lists, but only 41 remained after removing duplicates and applying inclusion/exclusion criteria. Thirty-one articles identified the head, fingers and shoulders as the most common sites of injury. Ten articles on mechanism of injury focused mainly on the shoulder, with degenerative changes, posture, scapular alignment, strength, flexibility and overhead shooting kinematics as the main injury risk factors. Publication types included cohort studies, cross-sectional studies, and one case series.

Conclusions

Most traumatic injuries affect the hands and the head from unexpected contact with the ball or opponents. Conversely, training injuries seem to affect mainly the shoulder area. Low level evidence suggests a correlation between shoulder injuries and lack of strength or flexibility as well as large volumes of overhead throwing. Further prospective research is needed to investigate risk factors for other body areas.

Reliability of the ForceFrame With and Without a Fixed Upper-Limb Mold in Shoulder Rotation Strength Assessments Compared With Traditional Hand-Held Dynamometry

CONTEXT

An imbalance between shoulder internal rotation (IR) and external rotation (ER) strength in athletes is proposed to increase the risk of sustaining a shoulder injury. Hand-held (HHD) and externally fixed dynamometry are reliable forms of assessing shoulder IR and ER strength. A new externally fixed device with an attachable fixed upper-limb mold (The ForceFrame) exists; however, its reliability in measuring shoulder strength is yet to be investigated.

OBJECTIVE

To determine the test-retest reliability of the ForceFrame, with and without the fixed upper-limb mold, in the assessment of shoulder IR and ER strength, as compared with HHD.

DESIGN

Test-retest reliability study.

SETTING

Laboratory, clinical.

PARTICIPANTS

Twenty-two healthy and active individuals were recruited from the university community and a private physiotherapy practice.

MAIN OUTCOME MEASURES

Maximal isometric shoulder IR and ER strength was measured using the ForceFrame and traditional HHD in neutral and at 90° shoulder abduction. Mean (SD) strength measures were calculated. Test-retest reliability was analyzed using intraclass correlation coefficients (3, 1). The SEM and minimal detectable change were calculated.

RESULTS

Good to excellent test-retest reliability was found for all shoulder strength tests across HDD and ForceFrame dynamometry (intraclass correlation coefficients [3, 1] = .854-.916). The minimal detectable changes ranged between 25.61 and 41.84 N across tests. Test-retest reliability was not affected by the dynamometer or testing position.

CONCLUSIONS

The results from this study indicate that both the ForceFrame and HHD are suitable for measuring shoulder strength in clinical practice. The use of the fixed upper-limb mold with the ForceFrame does not improve reliability.

Hand-Held Shoulder Strength Measures Correlate With Isokinetic Dynamometry in Elite Water Polo Players

CONTEXT

Previous authors suggest that lack of strength is an important risk factor for injuries in water polo. Hand-held dynamometers have potential as a clinical tool to measure strength, but they have not been validated in water polo players.

OBJECTIVE

The purpose of this study was to estimate intertrial variability and concurrent validity of hand-held dynamometer shoulder strength measurements in elite water polo players.

METHODS

A total of 19 male and 20 female elite water polo players performed isometric external (ER) and internal (IR) rotation strength tests against a hand-held dynamometer bilaterally in supine position with the shoulder in a 90-90 position. In addition, concentric IR and ER was captured at 90 deg/s with an isokinetic dynamometer, and torque values were determined near the 90-90 position.

MAIN OUTCOME MEASURES

Spearman correlation coefficients were calculated for ER torque, IR torque, and ER/IR ratios between the devices. Two-way mixed-model intraclass correlations were used to assess intertrial variability.

RESULTS

Correlations between the devices were strong to very strong (ρ = .65-.82, P < .01) for absolute IR and ER but low for ER/IR ratios (ρ = .29, P = .07). There was less agreement at higher torque values. Intertrial variability was low with intraclass correlation values .88 to .93, P < .05.

CONCLUSIONS

These results show that hand-held dynamometers are adequate clinical alternatives to measure absolute shoulder strength in water polo players. Stronger players may require stronger evaluators to resist the player's push and obtain reliable results.

External rotator strength deficits in non-athletic people with rotator cuff related shoulder pain are not associated with pain intensity or disability levels

BACKGROUND

Strength deficits are often reported in people with rotator cuff related shoulder pain. However, these have mainly been tested in athletic populations and pain interference with testing has not been considered.

OBJECTIVES

To examine strength without pain interference in non-athletic people with rotator cuff related shoulder pain and its association with pain intensity and disability.

DESIGN

Cross-sectional study.

METHODS

Sixty-seven participants with rotator cuff related shoulder pain were assessed for isometric strength of shoulder external rotator and internal rotator muscles without pain interference with a hand-held dynamometer. Strength was normalized (%body weight). Differences in external and internal rotation strength and external:internal rotator strength ratio between symptomatic and asymptomatic sides were examined (Independent t-tests, Wilcoxon rank sum tests). Spearman's rank correlation coefficients were used to examine associations between strength and pain and disability levels.

RESULTS

There was no significant difference in internal rotator strength normalized to body weight between symptomatic and asymptomatic sides. There was a significant difference in external rotator strength normalized to body weight (p < .001) and external:internal ratio (p < .001) between sides. No significant correlations were found between strength and pain or disability levels.

CONCLUSION

Non-athletic people with rotator cuff related shoulder pain had external rotator strength deficits without pain interference during strength testing, which were not associated with pain and disability levels.

Technology Used in the Prevention and Treatment of Shoulder and Elbow Injuries in the Overhead Athlete

PURPOSE OF REVIEW

To review the current technology available for the prevention and treatment of shoulder and elbow injuries in the overhead athlete.

RECENT FINDINGS

Shoulder and elbow injuries are common in recreational and high-level overhead athletes. Injury prevention in these athletes include identifying modifiable risk factors, offering effective preventative training programs, and establishing safe return-to-sport criteria. The advent and use of technologies and wearable devices with concomitant development of software and data analytic programs has significantly changed the role of sports technology in injury identification and prevention. Over the last few decades, leveraging new technologies to better understand and treat patients has become an increasing focus of healthcare. Technologies currently being applied to the treatment of the overhead athlete include kinesiotaping, heart rate monitors, accelerometers/gyroscopes, dynamometers/force plates, camera-based monitoring systems (optical motion analysis), and inertial sensor monitoring units. Advances in technology have made it possible to acquire large amounts of data on athletes that may be used to guide treatment and injury prevention programs; however, literature validating the clinical efficacy of many of these technologies is limited. Further research is needed to continue to allow team physicians to provide better, cost-efficient, and individualized care to the overhead athlete using technology.