Undergraduate Honors Theses

Thesis Defended

Spring 2011

Document Type

Thesis

Department

Integrative Physiology

First Advisor

Prof. Rodger Kram

Abstract

One might intuit that running barefoot would exact a lower energetic cost than running in shoes since shoes add mass to the foot. Although this is true for typical weight running shoes, lightweight cushioned shoes and barefoot have been shown to have similar costs. Other studies have indicated that there is an energetic cost of cushioning in running. Thus, the cost of barefoot running may reflect the combined effects of a decrease due to lower mass and an increase due to greater muscle actions for cushioning. We hypothesized that running barefoot on a cushioned surface would minimize both the mass cost and the cushioning cost. PURPOSE: To quantify the separate effects of shoe mass and cushioning on the energetic cost of running. METHODS: 12 male experienced barefoot runners ran at 3.35 m/s with a mid-foot strike pattern. Subjects ran both barefoot and in ultra-light cushioned racing shoes (~150 g /shoe) on a treadmill with a rigid deck and barefoot on the same treadmill equipped with a cushioned belt made with foam slats. In additional trials, small lead weights were added to the feet/shoes (~150, ~300, ~450 g). We measured the subjects‟ rates of oxygen consumption and carbon dioxide production to quantify energetic cost. RESULTS: The mass effect was similar for all footwear conditions: approximately 1% increase in oxygen consumption per 100 g of mass added to each foot. The energetic costs of running barefoot with and without the treadmill surface cushioning were not different (p=0.52). Contrary to our hypothesis, running in ultra-light cushioned racing shoes had the lowest energetic cost: 3.4% less than the weight-matched barefoot condition (p=.02). There was no significant difference between the energetic cost of running barefoot with no added mass and shod with the ~150 g running shoe. CONCLUSIONS: Our findings suggest that when mass is controlled for, cushioned shoes provide an energetic advantage over running barefoot.

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