Peripheral limitations for performance: Muscle capillarization.

Area of Science:

• Exercise physiology and sports science.
• Vascular biology and angiogenesis.
• Skeletal muscle metabolism and function.

Background:

• Muscle performance relies on efficient delivery of oxygen and substrates, and waste removal, primarily via capillaries.
• Muscle capillarization influences diffusion conditions, affecting transit time, surface area, and diffusion distance, potentially limiting performance.
• Exercise training enhances capillary density, with adaptations occurring more rapidly in untrained individuals compared to elite athletes.

Approach:

• This review synthesizes current knowledge on muscle capillarization and its impact on oxygen and glucose uptake.
• It examines the process of capillary growth (angiogenesis) and exercise-induced factors that promote it.
• The review discusses how different training modalities influence muscle capillary development.

Key Points:

• Capillaries are vital for skeletal muscle exchange, and their density impacts performance.
• Exercise training increases capillary numbers, with potential for optimized positioning over time.
• While increased capillarization aids oxygen extraction, direct causal links to performance enhancement require further investigation.

Conclusions:

• Muscle capillarization is a key factor influencing oxygen and glucose uptake during exercise.
• Understanding angiogenesis and training-specific adaptations is crucial for optimizing capillary growth.
• Future research should focus on establishing direct causal relationships between capillarization and exercise performance.