Does inspiration efficiency influence the stability limits of the trunk in patients with chronic low back pain?

To determine the effects of diaphragm-strengthening training on the stability limits of the trunk and inspiratory function in patients with low back pain.

A randomized comparative trial including a diaphragm training group that took part in conventional training together with diaphragm strengthening, and a control group that took part in conventional training only. Both groups participated in an 8-week training, 2 times/week. All subjects underwent the same measurement protocol before and after the intervention.

The study included 52 subjects with chronic low back pain.

The inspiratory functions (chest excursion, maximal inspiratory pressure, peak inspiratory flow, and volume of inspired air) and stability limits of the trunk with the subject in the sitting position (modified functional and lateral reach test) were assessed.

Maximal inspiratory pressure and stability limit tests showed a statistically significant improvement only in the diaphragm training group. Statistically significant improvements in chest excursion and peak expiratory flow tests were found in both groups; however, the improvement was more greater in the diaphragm training group.

Conventional exercises together with diaphragm training result in a greater improvement than conventional exercises alone in patients with chronic low back pain.