Inspiratory muscle training improves aerobic capacity and pulmonary function in patients with ankylosing spondylitis: a randomized controlled study.

OBJECTIVE

To evaluate the impact of inspiratory muscle training on aerobic capacity and pulmonary function in patients with ankylosing spondylitis.

DESIGN

Randomized controlled study.

SETTING

Rheumatic Rehabilitation Centre.

SUBJECTS: A total of 54 ankylosing spondylitis patients, all males, were randomized to a conventional exercise training associated with an inspiratory muscle training group, or to a conventional exercise training group.

INTERVENTIONS: Group 1 (27 patients) performed eight weeks of conventional exercise training (supervised weekly group sessions followed by a home-based exercise programme) associated with inspiratory muscle training sessions. Group 2 (27 patients) received eight weeks of conventional exercise training only.

MAIN MEASURES: Resting pulmonary function (forced vital capacity - FVC, forced expiratory volume in one second - FEV1); effort ventilatory efficiency (lowest ventilatory equivalent ratio for oxygen and carbon dioxide - VE/VO2 and VE/VCO2) and aerobic capacity (peak oxygen uptake - VO2peak) were assessed at baseline and after eight weeks of exercise-based intervention.

RESULTS

After eight weeks follow-up, patients in Group 1 had a significant increased chest expansion and VO2peak compared with Group 2 (3.6 ±0.8 cm vs. 3.2 ±0.5 cm, P = 0.032; 2.0 ±0.5 l/min vs. 1.8 ±0.3 l/min, P = 0.033). There were no significant differences of spirometric measurements, except FVC which significantly improved in patients who performed inspiratory muscle training (82.7 ±5.1% vs. 79.5 ±3.5%, P = 0.014). VE/VCO2 also improved significantly in Group 1 (26.6 ±3.6 vs. 29.2 ±4.7, P = 0.040).

CONCLUSIONS

Ankylosing spondylitis patients who performed eight weeks of inspiratory muscle training associated to conventional exercise training had an increased chest expansion, a better aerobic capacity, resting pulmonary function and ventilatory efficiency than those who performed conventional exercise training only.