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.
© Georg Thieme Verlag KG Stuttgart · New York.