Muscle fiber size increases following resistance training in multiple sclerosis

Area of Science:

• Neurology
• Exercise Physiology
• Muscle Biology

Background:

• Multiple sclerosis (MS) is a central nervous system disorder impacting mobility and muscle function.
• Muscle atrophy and weakness are common in MS patients, affecting quality of life.
• Understanding the effects of exercise interventions on muscle adaptations in MS is crucial for rehabilitation.

Purpose of the Study:

• To investigate the effects of lower body progressive resistance training (PRT) on muscle fiber cross-sectional area (CSA) and fiber type proportions in patients with multiple sclerosis (MS).
• To assess changes in thigh volume and isokinetic muscle strength following a 12-week PRT program in MS patients.

Main Methods:

• A randomized controlled trial (RCT) involving 38 MS patients (Expanded Disability Status Scale 3-5.5) was conducted.
• Participants were assigned to either a 12-week lower body PRT program or a control group maintaining usual activity.
• Muscle biopsies, thigh volume, and isokinetic strength were measured before and after the intervention.

Main Results:

• The PRT group showed significant increases in the mean CSA of all muscle fibers and type II muscle fibers compared to the control group.
• No significant changes were observed in muscle fiber type proportions or total thigh volume in the PRT group.
• Isokinetic strength of knee extensors and flexors improved significantly in the PRT group.

Conclusions:

• Progressive resistance training (PRT) can induce compensatory increases in muscle fiber size in patients with multiple sclerosis (MS).
• PRT improves muscle strength in MS patients without altering muscle fiber type proportions.
• These findings suggest PRT is a viable intervention for improving muscle adaptations in MS.