Effects of exercise therapy on postural stability, multifidus thickness, and pain intensity in patients with chronic low-back pain

We examined the effects of exercise therapy on postural stability, multifidus thickness, and pain intensity in patients with low-back pain. Subjects were divided into a chronic low-back pain (CLBP; n = 10) group and a healthy control (C; n = 10) group. Group CLBP took part in an 8-week training programme, whereas group C did not. The thickness of the multifidus in both groups was assessed using ultrasonography before and after 8 weeks, in prone and kneeling positions, in relaxed and contracted states. A standing heel-raising test was used to assess postural stability. After the intervention in group CLBP, the thickness of the contracted multifidus increased in the prone position, whereas the thickness of both the contracted and relaxed multifidus decreased in the kneeling position. In group C after 8 weeks, multifidus thickness decreased in both positions, while both relaxed and contracted. Group C performed the standing heel-raising test significantly better than group CLBP before the 8-week period. After the training, group CLBP improved significantly, but no changes were found in group C. Changes in thickness of the multifidus correlate with improved postural stability and decreased pain intensity. Decreasing thickness in healthy individuals may be an early sign of developing CLBP.