Fast Running Does Not Contribute More to Cumulative Load than Slow Running

Area of Science:

• Biomechanics
• Sports Medicine
• Running Science

Background:

• Running speed influences biomechanical loads related to tibial stress fracture risk.
• Runners often use varied speeds, but the impact on cumulative load is not well understood.

Purpose of the Study:

• To investigate how different proportions of running speeds affect cumulative tibial loading.
• To compare loads from running at a normal self-selected speed versus a combination of slow and fast speeds at the same average pace.

Main Methods:

• Forty-three recreational runners completed running trials at slow, normal, and fast speeds.
• Cumulative loads per kilometer, including vertical average loading rate, peak tibial free moment, and peak axial tibial load, were calculated.

Main Results:

• The cumulative vertical average loading rate was higher when running at a combination of slow and fast speeds compared to a normal speed.
• The contribution of fast running to cumulative tibial load was less than that of slow running.

Conclusions:

• Running at a mix of slow and fast speeds increases the cumulative vertical average loading rate, but not overall tibial load or free moment.
• Training programs can incorporate fast running without necessarily increasing cumulative load; distance and average speed alone may not predict cumulative load.