Shoulder injury in water polo: A systematic review of incidence and intrinsic risk factors

OBJECTIVES

Water polo is a popular water-based contact sport that involves swimming, throwing and defending. Cumulatively, these repetitive overhead activities are thought to increase the risk of shoulder injury and, subsequently to affect players' physical conditioning as well as team performance. The purpose of this review was to examine available evidence relating to shoulder injury rates and risk factors for shoulder injury in water polo.

DESIGN

Systematic review METHODS: CINAHL, AUSPORT, Pubmed, Pedro and SPORTDiscus databases were searched for original research papers using the predefined terms ("water polo") AND (shoulder OR glenohumeral* OR arm OR "upper limb").

RESULTS

Twenty papers were identified as suitable for inclusion. Reported shoulder injury rates varied from 24% - 51%. Shoulder injuries were more likely to become chronic compared to all other reported injuries. Injury data during the last three World Championships indicates an increasing rate of shoulder injuries-per-year with participation in aquatic sports. Risk for shoulder injury in water polo is multi-factorial. Volume of shooting, range of motion, scapular dyskinesis, strength imbalance, proprioceptive deficit and altered throwing kinematics have been proposed to be associated with an increased risk of injury.

CONCLUSIONS

Although this review showed water polo to have a high propensity for shoulder injury, the descriptive nature of the included papers limited the inferences that could be drawn from the pooled literature. Future directions for research include collecting normative data for shoulder range of motion, strength ratio and proprioception with prospective analysis of these attributes in relation to injury rates and time lost.

Evaluation of the relative contribution of peripheral and focal vision to proprioceptive differentiation of underfoot inversion angles in young elite athletes

Different visual conditions during proprioceptive testing have the potential to mask clinically meaningful differences in proprioceptive acuity, and must be understood in order to improve testing accuracy. This study compared the proprioceptive acuity achieved in estimating underfoot surface angles when looking ahead vs looking down during an active stepping task. 40 athletes from national development squads (23 male, 17 female, M age = 16 yr.) judged the inversion angle of a footplate when stepping onto and across it. 19 participants were permitted to briefly look down and see the footplate before stepping onto it, while 21 looked ahead and saw the footplate only in peripheral vision as they walked across. Looking down before stepping contributed to higher proprioceptive acuity scores. These results indicate that during a stepping task, a short opportunity to assess ground angle with focal vision supports the peripheral sensory receptors in proprioceptive acuity to a greater extent than peripheral vision alone.

Risk factors associated with medial tibial stress syndrome in runners: a systematic review and meta-analysis

Background

Medial tibial stress syndrome (MTSS) affects 5%–35% of runners. Research over the last 40 years investigating a range of interventions has not established any clearly effective management for MTSS that is better than prolonged rest. At the present time, understanding of the risk factors and potential causative factors for MTSS is inconclusive. The purpose of this review is to evaluate studies that have investigated various risk factors and their association with the development of MTSS in runners.

Methods

Medical research databases were searched for relevant literature, using the terms “MTSS AND prevention OR risk OR prediction OR incidence”.

Results

A systematic review of the literature identified ten papers suitable for inclusion in a meta-analysis. Measures with sufficient data for meta-analysis included dichotomous and continuous variables of body mass index (BMI), ankle dorsiflexion range of motion, navicular drop, orthotic use, foot type, previous history of MTSS, female gender, hip range of motion, and years of running experience. The following factors were found to have a statistically significant association with MTSS: increased hip external rotation in males (standard mean difference [SMD] 0.67, 95% confidence interval [CI] 0.29–1.04, P<0.001); prior use of orthotics (risk ratio [RR] 2.31, 95% CI 1.56–3.43, P<0.001); fewer years of running experience (SMD −0.74, 95% CI −1.26 to −0.23, P=0.005); female gender (RR 1.71, 95% CI 1.15–2.54, P=0.008); previous history of MTSS (RR 3.74, 95% CI 1.17–11.91, P=0.03); increased body mass index (SMD 0.24, 95% CI 0.08–0.41, P=0.003); navicular drop (SMD 0.26, 95% CI 0.02–0.50, P=0.03); and navicular drop >10 mm (RR 1.99, 95% CI 1.00–3.96, P=0.05).

Conclusion

Female gender, previous history of MTSS, fewer years of running experience, orthotic use, increased body mass index, increased navicular drop, and increased external rotation hip range of motion in males are all significantly associated with an increased risk of developing MTSS. Future studies should analyze males and females separately because risk factors vary by gender. A continuum model of the development of MTSS that links the identified risk factors and known processes is proposed. These data can inform both screening and countermeasures for the prevention of MTSS in runners.

Ankle instability effects on joint position sense when stepping across the active movement extent discrimination apparatus

CONTEXT

Individuals with and without functional ankle instability have been tested for deficits in lower limb proprioception with varied results.

OBJECTIVE

To determine whether a new protocol for testing participants' joint position sense during stepping is reliable and can detect differences between participants with unstable and stable ankles.

DESIGN

Descriptive laboratory study.

SETTING

University clinical laboratory.

PATIENTS OR OTHER PARTICIPANTS

Sample of convenience involving 21 young adult university students and staff. Ankle stability was categorized by score on the Cumberland Ankle Instability Tool; 13 had functional ankle instability, 8 had healthy ankles.

INTERVENTION(S)

Test-retest of ankle joint position sense when stepping onto and across the Active Movement Extent Discrimination Apparatus twice, separated by an interim test, standing still on the apparatus and moving only 1 ankle into inversion.

MAIN OUTCOME MEASURE(S)

Difference in scores between groups with stable and unstable ankles and between test repeats.

RESULTS

Participants with unstable ankles were worse at differentiating between inversion angles underfoot in both testing protocols. On repeated testing with the stepping protocol, performance of the group with unstable ankles was improved (Cohen d = 1.06, P = .006), whereas scores in the stable ankle group did not change in the second test (Cohen d = 0.04, P = .899). Despite this improvement, the unstable group remained worse at differentiating inversion angles on the stepping retest (Cohen d = 0.99, P = .020).

CONCLUSIONS

The deficits on proprioceptive tests shown by individuals with functional ankle instability improved with repeated exposure to the test situation. The learning effect may be the result of systematic exposure to ankle-angle variation that led to movement-specific learning or increased confidence when stepping across the apparatus.

Intrinsic functional deficits associated with increased risk of ankle injuries: a systematic review with meta-analysis

BACKGROUND

A history of ankle injury is known to be associated with an increased risk of future injuries. Prevention of a first-time injury to an ankle will also prevent subsequent re-injury; yet these participants are often overlooked in reports of preventive testing. Determining the functional deficits which promote injury risk in all ankles, through studies inclusive of previously injured and never injured ankles, will enable training to be directed at improving known deficits in all sports participants.

OBJECTIVE

To review studies investigating the measurement of intrinsic functions in healthy ankles and assess their predictive value for injury.

METHOD

Systematic review and meta-analysis of journal articles from selected electronic databases. Using all papers that included sufficient data for extraction in any paradigm, the authors pooled results for measures of strength, postural control, proprioception, muscle reaction time in response to perturbation, range of movement and ligament stability.

RESULTS

Thirteen papers were found with adequate data reporting to allow calculation of pooled standardised mean difference (SMD) or pooled RR. The following are all associated with an increased risk of ankle injury: higher postural sway (SMD=0.693, 95% CI=0.151 to 1.235, p=0.012), being in the lower postural stability group (RR=2.06, 95% CI=1.364 to 3.111, p=0.001), lower inversion proprioception (0.573, 0.244 to 0.902, <0.001), higher concentric plantar flexion strength at faster speeds (0.372, 0.092 to 0.652, 0.009) and lower eccentric eversion strength at slower speeds (0.337, 0.117 to 0.557, 0.003).

CONCLUSION

There is a set of intrinsic functional and structural ankle deficits associated with significantly increased risk of ankle injury. These findings will enable clinicians and sports trainers to measure and train specific deficits in sports people for the prevention of ankle injury.