Isokinetic and isometric torque force relationships.

The torque forces of elbow extensor musculature of 28 men were tested with an isokinetic dynamometer to determine the relationships between maximal isokinetic torque generated at various speeds and maximal isometric forces at specified angles in the arc of elbow extension. The men were tested at constant velocities ranging from 5 to 25 rpm and at angles of elbow extension ranging from 10 degrees to 90 degrees. Product-moment correlation coefficients were calculated between the maximum isometric torque developed at each of the measured angles and the isokinetic torque generated at each of the predetermined speeds. Of the 81 correlation coefficients calculated, 13 differed significantly from zero. There were slight tendencies for the significant correlations to cluster toward the slower speeds and toward the greater angles of elbow flexion. It was suggested that the slight tendency for higher correlations to cluster toward the slower speeds may be due to slower speeds stimulating isometric effort. The slight tendency for the higher correlations to cluster toward the greater angles of elbow flexion may be due to variances in the consistency of muscular strength at different muscle lengths. Since the highest correlation attained yielded a common variability of less than 24% between the two variables tested, it was concluded that measures of isokinetic strength cannot be used to predict isometric strength capabilities.