Proprioception in classical ballet dancers. A prospective study of the influence of an ankle sprain on proprioception in the ankle joint.

We studied prospectively the influence of ankle sprains on proprioception as measured by recording the postural sway of classical ballet dancers. Excellent balance and coordination are important for classical ballet dancers, and postural stability requires adequate proprioception from the ankle joint. Fifty-three professional dancers from the Royal Swedish Ballet, Stockholm, and 23 nonathletes, the control group, participated in the investigation. Postural sway was recorded and analyzed with a stabilimeter using a specially designed, portable, computer-assisted force plate. Six dancers sustained ankle sprains during followup. The recordings were obtained of these dancers before and after the injuries. The stabilometry results differed among the male and female dancers and the control group as follows: 1) the male dancers demonstrated a smaller total area of sway, and 2) both the male and female dancers had a smaller mean sway on the left foot than on the right (no mean difference in sway was found between the left and right foot in the control group). In comparison with the condition before injury and with the uninjured foot, the postural stability of the dancer was impaired for several weeks after the ankle sprain. Postural stability gradually improved during rehabilitation and improvement still occurred several weeks after professional dancing had resumed.