['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).', 'Quasi-experimental before-after trial.', 'University rehabilitation research laboratory.', '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.', 'Training was a 5-week combined progressive resistance RMT program, 3d/wk, 30 minutes per session.', '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.', '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).'] Does a combined inspiratory and expiratory muscle training program improve respiratory muscle strength and fatigue in multiple sclerosis?