Discrimination of active plantarflexion and inversion movements after ankle injury.

To assess active ankle function in normal weightbearing after injuries, with a task that required discrete movements, 40 ankles were tested from subjects who had previously injured both ankles, injured one ankle only, or had never injured an ankle. Tests to assess discrimination between the extents of movements, in a range around 12 degrees off horizontal, were made in standing and carried out on both ankles, in plantarflexion and inversion directions. Subjects were found to have a greater ability to discriminate between movements in plantarflexion (a just noticeable difference of 7.5 per cent) than in inversion (10.4 per cent). Never injured subjects had better overall discrimination (7.3 per cent) than previously injured subjects (9.7 per cent) and there was no significant difference between the average discrimination score for both ankles from subjects with previous bilateral or unilateral injuries. This result is consistent with earlier findings on the bilateral associations of unilateral lower limb injuries.