Are Previous Joint Injuries Associated with Muscle Performance in Volleyball Athletes?^*

Abstract

Objective

The aim of the present study is to determine whether previous shoulder and knee injuries were associated with isokinetic fatigue index and agonist/antagonist ratio of shoulder internal/external rotators and knee flexors/extensors in male volleyball athletes.

Methods

The current study is a cross-sectional investigation of 49 male elite volleyball players competing at a high level in Brazil. Isokinetic fatigue index and agonist/antagonist profiles were assessed during the preseason. Additionally, in order to record previous injuries, the athletes answered a standardized questionnaire. We conducted a receiver operating characteristic (ROC) curve analysis to determine the association strength and the clinically relevant cut-off point for variables presenting statistical significance for the area under the curve (AUC) (α = 0.05). An independent t-test was used to compare isokinetic variables between athletes with and without previous injury (α = 0.05).

Results

The results of the ROC curve analysis indicated that hamstring fatigue index values at 300^o/s were associated with the presence of previous knee injury (area under the curve [AUC] = 73%, p= 0.004), and shoulder external rotators fatigue index values at 360°/s were not associated with the presence of previous shoulder injury (AUC = 68%, p= 0.053).

Conclusions

Elite volleyball athletes who reported previous knee injuries were prone to a higher fatigue index than those reporting no injuries. Knee flexor resistance training might be useful for those athletes who reported knee injuries in the previous season.

Keywords
knee injuries; muscle strength; shoulder injuries; volleyball