Thigh Peak Torques and Lower-Body Injuries in Dancers

The purpose of this study was to identify possible relationships between the sum of knee flexion and extension peak torques and the severity of lower-body injuries in professional dancers. Twenty male [age 26.6 (± 6.0) years] and 22 female [age 27.1 (± 5.4) years] ballet and contemporary dancers reported one or more low-back, pelvis, leg, knee and foot injuries. The severity of injuries was established by recording the days off dance activities. Subjects were then monitored on a Cybex II or a KIN-CON isokinetic dynamometer. Knee flexion and extension peak torques were obtained bilaterally during three maximal contractions at the velocities of 1.04 and 4.19 rad/sec. No musculoskeletal injuries were reported at the time of data collection. At 1.04 rad/sec, results revealed significant correlation coefficients between relative thigh peak torques — expressed in Nm/kg fat free mass (FFM) — and prevalence of low extremity injuries. These findings suggest that the lower the thigh-power output, the greater the degree of injury. Female dancers demonstrated higher correlation coefficients (r -0.70; p < 0.005) than their male counterparts (r = -0.61; p < 0.01). However, no such correlations were found at the angular velocity of 4.19 rad/sec (p > 0.05), nor when low-back injuries and thigh-power outputs were considered at both velocities (p > 0.05). The main conclusions are: a) low thigh power outputs are likely to be associated with the severity of low extremity injuries, but not with low-back injuries, and b) such relationships are better identified at lower compared to higher isokinetic velocities.