Causes of Different Force-Velocity Relationships in Sprint Running Depending on Horizontal Loads and Profiling...

Area of Science:

• Biomechanics
• Sports Science
• Human Movement

Background:

• The horizontal force-velocity (Fvh) relationship is a key concept in sprint running biomechanics.
• Understanding Fvh relationships helps optimize training and performance.
• Previous research has shown potential dependencies of Fvh parameters on resistance loading and profiling methods.

Purpose of the Study:

• To investigate how horizontal resistance loads affect the Fvh relationship during over-ground sprint running.
• To compare Fvh profiling using multiple-trial versus single-trial methods.
• To evaluate the fit of linear and curvilinear models to Fvh data.

Main Methods:

• Twelve male participants performed unresisted and resisted sprint running with a motorized loading device.
• Ground reaction forces were measured using a force plate system.
• Step-averaged Fvh relationships were determined using single- and multiple-trial methods with linear and curvilinear regression models.

Main Results:

• Fvh plots largely overlapped during acceleration but diverged around maximal velocity.
• Linear Fvh parameters derived from the single-trial method exhibited load dependency.
• Curvilinear models provided a better fit to the pooled data across all loading conditions compared to linear models.

Conclusions:

• Load dependency in Fvh parameters is primarily influenced by high horizontal forces at low velocities in resisted sprinting.
• Profiling method dependency arises from force attenuation near maximal velocity.
• Further research is needed on factors causing deviations from linearity and the utility of nonlinear models.