Effect of slope and footwear on running economy and kinematics

Lower energy cost of running ( C r) has been reported when wearing minimal ( MS ) vs traditional shoes ( TS ) on level terrain, but the effect of slope on this difference is unknown. The aim of this study was to compare C r, physiological, and kinematic variables from running in MS and TS on different slope conditions. Fourteen men (23.4 ± 4.4 years; 177.5 ± 5.2 cm; 69.5 ± 5.3 kg) ran 14 5‐min trials in a randomized sequence at 10 km/h on a treadmill. Subjects ran once wearing MS and once wearing TS on seven slopes, from −8% to +8%. We found that C r increased with slope gradient ( P < 0.01) and was on average 1.3% lower in MS than TS ( P < 0.01). However, slope did not influence the C r difference between MS and TS . In MS , contact times were lower ( P < 0.01), flight times ( P = 0.01) and step frequencies ( P = 0.02) were greater at most slope gradients, and plantar‐foot angles – and often ankle plantar‐flexion ( P = 0.01) – were greater ( P < 0.01). The 1.3% difference between footwear identified here most likely stemmed from the difference in shoe mass considering that the C r difference was independent of slope gradient and that the between‐footwear kinematic alterations with slope provided limited explanations.