A combined inspiratory and expiratory muscle training program improves respiratory muscle strength and fatigue in multiple sclerosis

Abstract

Objective: To determine the effects of a short-duration, combined (inspiratory and expiratory), progressive resistance respiratory muscle training (RMT) protocol on respiratory muscle strength, fatigue, health-related quality of life, and functional performance in individuals with mild-to-moderate multiple sclerosis (MS).

Design: Quasi-experimental before-after trial.

Setting: University rehabilitation research laboratory.

Participants: Volunteers with MS (N=21) were divided into 2 groups: RMT (n=11; 9 women, 2 men; mean age ± SD, 50.9 ± 5.7y, mean Expanded Disability Status Scale score ± SD, 3.2 ± 1.9) and a control group that did not train (n=10; 7 women, 3 men; mean age ± SD, 56.2 ± 8.8y, mean Expanded Disability Status Scale score ± SD, 4.4 ± 2.1). Expanded Disability Status Scale scores ranged from 1 to ≤6.5. No patients withdrew from the study.

Intervention: Training was a 5-week combined progressive resistance RMT program, 3d/wk, 30 minutes per session.

Main outcome measures: The primary outcome measures were maximal inspiratory pressure and expiratory pressure and the Modified Fatigue Impact Scale. All subjects completed secondary measures of pulmonary function, the six-minute walk test, the timed stair climb, the Multiple Sclerosis Self-Efficacy Scale, the Medical Outcomes Study 36-Item Short-Form Health Survey, and the Physical Activity Disability Scale.

Results: Maximal inspiratory pressure and expiratory pressure (mean ± SD) increased 35% ± 22% (P<.001) and 26% ± 17% (P<.001), respectively, whereas no changes were noted in the control group (12% ± 23% and -4% ± 17%, respectively). RMT improved fatigue (Modified Fatigue Impact Scale, P<.029), with no change or worsening in the control group. No changes were noted in the six-minute walk test, stair climb, Multiple Sclerosis Self-Efficacy Scale, or Physical Activity Disability Scale in the RMT group. The control group had decreases in emotional well-being and general health (Medical Outcomes Study 36-Item Short-Form Health Survey).

Conclusions: A short-duration, combined RMT program improved inspiratory and expiratory muscle strength and reduced fatigue in patients with mild to moderate MS.

Keywords: 6MWT; ATS; American Thoracic Society; Breathing exercises; EDSS; Expanded Disability Status Scale; FEV(1); FVC; Fatigue; HRQOL; MFIS; MS; MSSE; MVV(12); Medical Outcomes Study 36-Item Short-Form Health Survey; Modified Fatigue Impact Scale; Multiple Sclerosis Self-Efficacy Scale; Multiple sclerosis; PFT; Pemax; Pimax; Positive-pressure respiration; RMT; Rehabilitation; SF-36; forced expiratory volume in 1 second; forced vital capacity; health-related quality of life; maximal expiratory pressure; maximal inspiratory pressure; maximal voluntary ventilation in 12 seconds; multiple sclerosis; pulmonary function test; respiratory muscle training; six-minute walk test.