Interlimb coordination as a function of isometric force output.

In the 2 experiments reported here, the influence of level of force output on interlimb coordination in an isometric force tusk was examined. Healthy adults (N = 8) were required to match a continuous total level of isometric force produced by the output of the two index fingers over a range of force levels (1 % to 80% ot maximum). The results showed that (a) coordination between fingers increased as force level increased; (b) coordination between fingers was less than that of the force output of each finger to the total force, but that difference in relative coordination decreased as target force levels increased; and (c) the regularity of the force output of each finger considered separately was greater than that of the total force. Overall, force level was found to have a small but reliable effect on interlimb coordination within a compensatory action between fingers that reduces task error.