Increasing Step Rate Reduces Peak and Cumulative Insole Force in Collegiate Runners

Area of Science:

• Biomechanics
• Sports Medicine
• Running Science

Background:

• Running involves repetitive impact forces that can lead to injuries.
• Step rate is a key parameter in running mechanics that can influence these forces.
• Understanding the relationship between step rate and impact forces is crucial for injury prevention.

Purpose of the Study:

• To investigate how increasing step rate affects peak insole force and cumulative weighted peak force (CWPF)/km in collegiate runners.
• To determine if sacral acceleration correlates with insole force during changes in step rate.

Main Methods:

• Twelve collegiate runners completed a 1000m run at preferred and 10% increased step rates.
• Insole forces and sacral acceleration were measured during the runs.
• CWPF/km was calculated using cumulative damage models; statistical analyses compared forces at different step rates and correlated acceleration with force.

Main Results:

• Peak insole force and CWPF/km significantly decreased with an increased step rate (P < 0.001).
• Peak axial sacral acceleration did not correlate with peak insole force at the cohort level (r = 0.35, P = 0.109).
• However, a correlation was observed between sacral acceleration and insole force within individual runners (mean r = 0.69-0.78, P < 0.05).

Conclusions:

• Increasing step rate appears to reduce both peak and cumulative loading in collegiate runners.
• Clinicians may consider step rate modification as an intervention strategy to mitigate running-related injuries.
• Individualized calibration of wearable accelerometers may be necessary for accurate assessment of impact force changes with altered step rates.