Limitations to maximum sprinting speed imposed by muscle mechanical properties

Area of Science:

• Biomechanics
• Human Physiology
• Sports Science

Background:

• The force-velocity relationship of skeletal muscle is theorized to limit maximum human sprinting speed.
• Previous research has not directly tested this hypothesis or explored other potential limiting muscle properties.

Purpose of the Study:

• To investigate the role of various skeletal muscle mechanical properties in limiting maximum human sprinting speed.
• To quantify the individual and combined effects of muscle properties on sprint performance using simulations.

Main Methods:

• A 2D musculoskeletal model with Hill muscle models was used to generate forward dynamics simulations of human sprinting.
• Simulations were validated against kinetic, kinematic, and electromyographic data from human sprinters.
• Key muscle mechanical properties (force-velocity, excitation-activation, force-length, series elastic force-extension) were systematically removed to assess their impact.

Main Results:

• Removing the force-velocity, excitation-activation, and force-length relationships increased maximum sprint speed by 15%, 8%, and 4%, respectively.
• Removing the series elastic force-extension relationship decreased maximum sprint speed by 26%.
• Removing all muscular properties increased speed by 22%, more than removing any single property.

Conclusions:

• The force-velocity relationship is the most critical contractile property limiting maximum sprinting speed in humans.
• Other muscle properties, including the series elastic component, also play significant roles.
• Interactions between muscle properties are crucial for understanding the limits of maximal human performance.