The Role of Postural Support in Young Adults' Control of Stationary Kicking

The requirement for postural stability during the performance of motor skills has been clearly demonstrated in infants, but the necessity for such a postural substrate is not well documented in adults. The present study investigated the role of postural stability during a ballistic ball-kicking task in adults by providing varying degrees of external postural support.

In the 1st experiment, 30 participants performed 20 maximal-velocity kicks under each of 3 conditions: grasping a rigid stable handle, light fingertip touch, and grasping a suspended elastic tube. A 2nd experiment with 16 participants varied the position of the stable handle to examine if the handle position in Experiment 1 might simply act as a fulcrum to enhance torque generation.

In Experiment 1, ball velocity was significantly higher in the stable-grasp condition in both men and women with the men showing greater improvement relative to the other conditions. Experiment 2 showed that the position of the stable handle did not significantly affect kicking velocity, indicating that the handle was not simply acting as a fulcrum during the kick.

Together, the findings suggest that postural stability may be a rate limiter in the performance of dynamic motor tasks in adults.