Abstract
Single outcomes of standard isokinetic dynamometry tests do not discern between various
muscle mechanical capacities. In this study, we aimed to (1) evaluate the shape and
strength of the force-velocity relationship of knee extensors, as observed in isokinetic
tests conducted at a wide range of angular velocities, and (2) explore the concurrent
validity of a simple 2-velocity method. Thirteen physically active females were tested
for both the peak and averaged knee extensor concentric force exerted at the angular
velocities of 30°–240°/s recorded in the 90°–170° range of knee extension. The results
revealed strong (0.960<R<0.998) linear force-velocity relationships that depict the
maximum muscle force (i.e. the force-intercept), velocity (velocity-intercept), and
power (their product). Moreover, the line drawn through only the 60° and 180°/s data
(the ‘2-velocity method’) revealed a high level of agreement with the force-velocity
relationship obtained (0.76<R<0.97; all power<0.001); while the force-intercept highly
correlated (0.68<R<0.84; all power≤0.01) with the directly measured isometric force.
The 2-velocity method could therefore be developed into a standard method for isokinetic
testing of mechanical capacities of knee extensors and, if supported by further research,
other muscles. This brief and fatigue-free testing procedure could discern between
muscle force, velocity, and power-producing capacities.
Key words
muscle - force - velocity - power - quadriceps - linear regression
