Posture and isokinetic shoulder strength in female water polo players

Abstract

Background: Being overhead athletes, water polo players can present with muscular imbalances of the shoulder, between the internal rotators (IR) and external rotators (ER), leading to changes in posture and an increased risk of injury.

Objectives: To assess posture and isokinetic shoulder strength of female club-level water polo players.

Methods: A descriptive study assessing posture and isokinetic strength of the IR and ER shoulder muscles in 15 female club-level South African water polo players (age: 21.3 ± 1.5 years) was conducted. Posture was assessed using a posture grid. Isokinetic shoulder rotator muscle strength was tested over five repetitions concentrically and eccentrically at 60°/sec using a Biodex system 3 isokinetic dynamometer. The bilateral, reciprocal and functional dynamic control ratios (DCR) were calculated.

Results: Typical postures noted were a forward head, rounded shoulders, increased thoracic spine kyphosis, elevated non-dominant shoulder and mild scapula winging. The mean concentric reciprocal ratios for the dominant (52.2 ± 7%) and non-dominant (51.9 ± 6.4%) sides indicated ER muscle weakness. DCR values were within normal limits for the group. (D: 0.75 ± 0.2 and ND: 0.75 ± 0.1).

Conclusion: There is a trend for these female water polo players to have rounded shoulders and forward head postures, as well as ER muscle strength weakness, the combination of which could predispose the athletes to shoulder injury.

Keywords: dynamic control ratio, shoulder injury, rounded shoulders, reciprocal ratio