Optimal stride frequencies in running at different speeds

Area of Science:

• Exercise Physiology
• Biomechanics
• Running Dynamics

Background:

• Optimal stride frequency (SF) minimizes energy expenditure during running.
• The relationship between SF and heart rate (HR) typically follows a u-shaped curve.
• Adjusting SF towards this optimum may enhance running economy and biomechanics.

Purpose of the Study:

• To empirically investigate the effects of running speed on optimal SF.
• To analyze the nature of the SF-HR relationship across different speeds.
• To determine if inexperienced runners need to adapt their SF with varying speeds.

Main Methods:

• Twelve inexperienced runners (4 male, 8 female) completed runs at 90%, 100%, and 110% of their self-selected speed.
• Heart rate (HR) was recorded under various imposed stride frequencies (SF) at each speed.
• Generalized Estimating Equations were used to analyze the SF-HR relationship.

Main Results:

• The SF-HR relationship was consistently parabolic across all tested speeds.
• Running speed did not significantly alter the curvature or the optimal SF.
• Self-selected SF increased with speed, but remained below the identified optimal SF of 83 strides·min-1.

Conclusions:

• Inexperienced runners may not need to adjust their stride frequency (SF) with moderate changes in running speed.
• Increasing self-selected SF towards the optimal value (around 83 strides·min-1) can potentially reduce heart rate (HR).
• Further research could explore long-term adaptations and benefits of optimizing SF in runners.