Secondary axes activity of normal subjects and low back pain patients.

The purpose of this study was to compare the secondary axes activity of normal subjects and low back pain patients. Each subject performed maximum isometric trials in all six primary directions. This was followed by five dynamic repetitions in each of the cardinal planes against relative resistances set at 50% of the recorded maximum isometric torques for each axis. The results showed that for all movement axes the secondary axes torques were significantly less (p = 0.01-0.001) for low back pain patients compared to normal subjects. The secondary axes torques were generally weakly related to an individual's ability to both generate maximum isometric torques about the same axis and the primary axes maximum velocities.