The aim of this study was to investigate motor control in subjects with functional
instability of the ankle joint. This was achieved by analysing patterns of lower extremity
motion prior to and immediately following landing during single leg jumping in subjects
with functional instability of the ankle. Fourteen subjects with unilateral functional
instability and 10 healthy control subjects performed single leg jumps from a 40 cm
height whilst angular displacement of their ankle and knee joints were recorded. Subjects
with functional instability demonstrated significantly greater ankle dorsiflexion
over the period encompassing 10 ms pre landing to 20 ms post landing (p < 0.05). They
also exhibited a significantly greater level of knee flexion than controls over the
period from 20 ms pre landing to 60 ms post landing (p < 0.05). The timing of these
significant differences leads us to conclude that they do not arise as a result of
reflexively mediated peripheral events following landing.
Lateral ligament sprain · motor programme·reflex control·central control