Relationship Between the Patterns of Time-Course Changes in Running Pace and Running Mechanics in a Full Marathon

Area of Science:

• Biomechanics
• Sports Science
• Human Movement

Background:

• The "hitting the wall" phenomenon in marathons is a well-known slowdown after 30 km.
• The precise biomechanical mechanisms driving this fatigue are not fully understood.

Purpose of the Study:

• To investigate pacing patterns and kinematic alterations in marathon runners.
• To identify biomechanical factors associated with marathon-induced slowdowns.

Main Methods:

• Analysis of 58 marathon races involving 297 participants.
• Hierarchical clustering of per-kilometer pace data.
• Tracking biomechanical changes using wearable sensors.

Main Results:

• Three distinct pacing groups were identified, showing varied biomechanical responses.
• Runners experiencing slowdowns exhibited decreased step length, step frequency, and vertical stiffness.
• Increased ground contact time was observed in runners who slowed down, differing from laboratory findings.

Conclusions:

• Marathon slowdowns are associated with specific kinematic changes, including reduced step length and stiffness.
• The interplay between contact time, step length, and vertical stiffness may explain the "hitting the wall" effect.
• The distinct mechanism of sudden late-race slowdown warrants differentiation from earlier fatigue onset.