On the relationship between peak force and peak force variability in isometric tasks.
An experiment is reported documenting the relationship between peak force and peak force variability with a fixed criterion time to peak force for an isometric task requiring activation of the elbow flexors. The results show that maximum peak force increases with increments in time to peak force and that peak force variability increases with increments of peak force in an exponential type function. Furthermore, despite the presence of peak force and time to peak force feedback, subjects systematically shifted time to peak force as a function of the percentage of peak force being produced. This temporal modulation changes the percentage of peak force represented by any given peak force criterion. When peak force is made proportional to the degree of departure from the criterion time to peak force, a linear relationship is found between peak force and peak force variability. These findings suggest that time to peak force and rate of force production are parameters that influence veridical estimates of the force variability function.
Newell
K M
KM
Institute for Child Behavior and Development, University of Illinois, Champaign, Illinois 61820, USA.
Carlton
L G
LG