The present study examined the effect of 4-week isokinetic trunk training for patients with chronic low back pain (CLBP). 12 CLBP patients and 12 normal controls were trained for the trunk flexor and extensor strengthening for 4 weeks and evaluated the pre and post training for maximal trunk flexion/extension power at 3 specific speeds (30 ˚/sec, 60 ˚/sec, and 120 ˚/sec) with isokinetic dynamometer.

The strength of trunk flexor and extensor of CLBP patients was significantly weaker than that of normal controls. The strength of trunk flexor and extensor were increased after 4-week isokinetic training in both groups. However, post training increments of trunk flexor and extensor were larger in CLBP patients with a greater increment in extensor mucle especially at higher angular velocity. The flexion-extension ratio was also more decreased after 4-week isokinetic training in CLBP patients. The visual analogue scale (VAS) was decreased from 8.55 to 3.82 after training in CLBP patients. Thus, isokinetic back training could be used in CLBP with weak trunk extensors.