Glycogen utilization in wheelchair-dependent athletes

Area of Science:

• Sports Medicine
• Exercise Physiology
• Rehabilitation Science

Background:

• Wheelchair-dependent athletes engage in prolonged upper body exercise.
• Understanding their physiological responses is crucial for training and performance optimization.

Purpose of the Study:

• To determine aerobic capacity, plasma substrate concentration, and muscle glycogen utilization in wheelchair athletes during prolonged exercise.
• To compare these physiological responses to those of able-bodied athletes.

Main Methods:

• Maximal and submaximal (SM) testing on a wheelchair ergometer.
• Muscle biopsy samples from the M. deltoideus before and after a 1-h SM endurance ride.
• Analysis of plasma substrates (glycerol, glucose, free fatty acids) and muscle glycogen.

Main Results:

• Plasma volume and substrate level changes were similar to those observed in able-bodied athletes.
• Type I muscle fibers showed significant glycogen depletion post-exercise.
• Muscle glycogen utilization varied among subjects, ranging from 17.4 to 46.6 mmol X kg-1.

Conclusions:

• Physiological response patterns in wheelchair athletes' upper arm muscles mirror those of able-bodied athletes' leg muscles during acute endurance exercise.
• This suggests similar metabolic and aerobic adaptations occur regardless of the mode of exercise or limb involvement.