The Influence of Midsole Thickness on Running, Does Size Matter?

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In 2020, World Athletics amended their footwear regulations to include a maximum midsole thickness of 40-mm to “protect the integrity of sport”. However, there was no evidence to support the restriction therefore, the purposes of this dissertation were to determine; i) the influence of midsole thickness on the energetic cost of running, ii) the influence of midsole thickness on frontal plane ankle angle and performance when running curves, and iii) the influence of midsole thickness on muscle damage associated with a training-style run. Twenty-one runners participated in the first study, performing five-minute treadmill running trials in four footwear conditions. The footwear conditions were nearly identical except for their midsole which ranged from 35- to 50-mm in increments of 5-mm. Midsole thickness did not influence the energetic cost of running however, it did increase ankle eversion. In conclusion, running on a midsole thicker than 35-mm is inadvisable given that it will not provide a performance advantage but will impact frontal plane ankle angle. Thirteen recreational athletes participated in the second study testing the impact of two footwear conditions on curved running. Participants performed ten running trials around each of three curves of radii. Midsole thickness did not impact frontal plane ankle angle of the outside leg or performance across any of the three curves. Sixteen recreational runners with personal best 5-, or 10-km race times shorter than 24-, and 50-minutes, respectively, were recruited to participate in the third study. Participants performed a 60-minute training-style run in two nearly identical footwear conditions that differed only in midsole thickness, before and after which blood draws were performed for markers of muscle damage. Pre-to-post, there was not a statistically significant difference in magnitude of change in concentration of markers of muscle damage between shoes, although the concentration of lactate dehydrogenase did increase more so when running in the 35-mm footwear condition. In conclusion, midsole thickness did not impact the change in concentration of markers of muscle damage during a simulated training-style run. The results of this dissertation would suggest the World Athletic restriction on midsole thickness is not required and should be reconsidered.
Footwear, Gender, Performance
Barrons, Z. (2023). The influence of midsole thickness on running, does size matter? (Unpublished doctoral thesis). University of Calgary, Calgary, AB.