Kr. Kaufman et al., A COMPARISON OF INTERSEGMENTAL JOINT DYNAMICS TO ISOKINETIC DYNAMOMETER MEASUREMENTS, Journal of biomechanics, 28(10), 1995, pp. 1243
This study quantified the errors associated with measurements obtained
using an isokinetic dynamometer for knee evaluation at 60 degrees and
180 degrees s(-1). Five normal subjects were tested. A triaxial elect
rogoniometer was used to measure the kinematics. A custom-designed loa
d cell was used to measure the three orthogonal components of the reac
tion force applied by the isokinetic dynamometer to the leg. The inver
se dynamics problem was solved to obtain the intersegmental dynamics a
t the knee joint. These data were compared to those obtained from the
isokinetic dynamometer. The results indicate that the knee motion reco
rded by the isokinetic dynamometer was in error by 7-9 degrees during
flexion and 10-13 degrees during extension. The isokinetic dynamometer
recorded knee flexions which were less than actual during the flexion
portion of the exercise and greater than actual during extension. The
duration of constant velocity was limited based on the speed selected
. The knee moment was in error by 5 Nm during flexion and 25-29 Nm dur
ing extension. The use of a gravity correction factor reduced the knee
moment error during extension, but increased it during flexion.