The influence of athletic status on maximal and rapid isometric torque characteristics and postural balance performance in Division I female soccer athletes and non-athlete controls

The purpose of this study was to examine the effectiveness of maximal and rapid isometric torque characteristics of the hip extensor muscles and postural balance performance to discriminate between female collegiate soccer athletes and non-athlete controls. Ten athletes (mean +/- SE: age=1920 +/- 036year; mass= 6223 +/- 312kg; height=16243 +/- 170cm) and 10 non-athletes (age= 2030 +/- 040year; mass=6964 +/- 320kg; height= 16322 +/- 210cm) performed two isometric maximal voluntary contractions (MVCs) of the hip extensor muscles. Peak torque (PT) and absolute and relative rate of torque development (RTD) at early (0-50ms) and late (100-200ms) phases of muscle contraction were examined during each MVC. Postural balance was assessed using a commercially designed balance testing device, which provides a measurement of static stability based on sway index (SI). Results indicated that absolute and relative RTD at 0-50ms (RTD50 and RTD50norm) were greater (P=0007 and 0026), and postural SI was lower (P=0022) in the athletes compared with the non-athletes. However, no differences (P=0375-0709) were observed for PT nor absolute and relative RTD at 100-200ms (RTD100-200 and RTD100-200norm). Significant relationships were also observed between RTD50 and RTD50norm and SI (r=-0559 and -0521; P=0010 and 0019). These findings suggest that early rapid torque characteristics of the hip extensor muscles and postural balance performance may be sensitive and effective measures for discriminating between college-aged athletes and non-athletes. Coaches and practitioners may use these findings as performance evaluation tools to help in identifying athletes with both superior early rapid torque and balance performance abilities, which may possibly be an indicator of overall athletic potential.