Metabolic Cost of Running Barefoot versus Shod: Is Lighter Better?

FRANZ, J. R., C. M. WIERZBINSKI, and R. KRAM. Metabolic Cost of Running Barefoot versus Shod: Is Lighter Better? Med. Sci. Sports Exerc., Vol. 44, No. 8, pp. 1519-1525, 2012. Purpose: Based on mass alone, one might intuit that running barefoot would exact a lower metabolic cost than running in shoes. Numerous studies have shown that adding mass to shoes increases submaximal oxygen uptake (VO2) by approximately 1% per 100 g per shoe. However, only two of the seven studies on the topic have found a statistically significant difference in VO2 between barefoot and shod running. The lack of difference found in these studies suggests that factors other than shoe mass (e.g., barefoot running experience, foot strike pattern, shoe construction) may play important roles in determining the metabolic cost of barefoot versus shod running. Our goal was to quantify the metabolic effects of adding mass to the feet and compare oxygen uptake and metabolic power during barefoot versus shod running while controlling for barefoot running experience, foot strike pattern, and footwear. Methods: Twelve males with substantial barefoot running experience ran at 3.35 m.s(-1) with a midfoot strike pattern on a motorized treadmill, both barefoot and in lightweight cushioned shoes (similar to 150 g per shoe). In additional trials, we attached small lead strips to each foot/shoe (similar to 150, similar to 300, and similar to 450 g). For each condition, we measured the subjects' rates of oxygen consumption and carbon dioxide production and calculated metabolic power. Results: VO2 increased by approximately 1% for each 100 g added per foot, whether barefoot or shod (P < 0.001). However, barefoot and shod running did not significantly differ in VO2 or metabolic power. A consequence of these two findings was that for footwear conditions of equal mass, shod running had similar to 3%-4% lower VO2 and metabolic power demand than barefoot running (P < 0.05). Conclusions: Running barefoot offers no metabolic advantage over running in lightweight, cushioned shoes.