A hypothesis for the function of braking forces during running turns

Area of Science:

• Biomechanics
• Human locomotion
• Sports science

Background:

• Turning maneuvers in running involve complex interactions of forces.
• The role of braking forces in controlling body orientation during turns is not fully understood.
• Maintaining body alignment with the direction of movement is crucial for efficient locomotion.

Purpose of the Study:

• To investigate the functional role of braking forces in human running turns.
• To determine if braking forces prevent excessive body rotation during directional changes.
• To model the relationship between braking forces and body rotation during running maneuvers.

Main Methods:

• Analysis of kinematic data from sidestep and crossover running cuts.
• Measurements taken at an average initial running velocity of 3 m/s.
• Development of a simple model to explain braking forces based on body rotation.

Main Results:

• Braking forces contribute to changing the center of mass (COM) direction and maintaining velocity.
• Without braking, lateral forces would cause body rotations 1.4-3 times the COM movement change.
• A model where body rotation matches COM deflection explained 70% of the variance in braking forces.

Conclusions:

• Braking forces play a critical role in preventing over-rotation of the body during running turns.
• These forces are essential for aligning body orientation with the direction of movement.
• The findings support a model linking braking forces to the control of body rotation in agile maneuvers.