Skeletal muscle adaptation in response to supervised exercise training for intermittent claudication

Area of Science:

• Exercise physiology
• Skeletal muscle adaptation
• Peripheral artery disease research

Background:

• Supervised exercise improves claudication, likely via skeletal muscle adaptation.
• Myosin heavy chain (MHC) protein expression influences muscle fiber type and efficiency.
• Previous methods overlooked hybrid MHC expression in myofibers.

Purpose of the Study:

• To investigate differential MHC protein expression following supervised exercise in claudicants.
• To determine if exercise alters MHC expression profiles in skeletal muscle.

Main Methods:

• 38 claudicants completed a 3-month supervised exercise program.
• Gastrocnemius muscle biopsies were analyzed for MHC protein expression using SDS-PAGE.
• Control group comprised patients awaiting angioplasty.

Main Results:

• Maximum walking distance increased by 94% in the exercise group (p = 0.002).
• MHC I expression increased by 11.1% in the exercise group (p = 0.02), but not in controls.
• Improved MHC I expression correlated positively with increased claudication distance (r = 0.69, p < 0.05).

Conclusions:

• Supervised exercise training increases MHC type I expression in the gastrocnemius muscle of claudicants.
• This adaptation may contribute to the functional improvements observed in supervised exercise programs for claudication.