To evaluate the effect of dorsiflexion shoes on the energy cost of running (Cr), with or without noticeable acute neuromuscular fatigue. Methods On four separate occasions, thirteen trained subjects (23.1 ± 4.2 y), wearing standard (twice) or dorsiflexion (twice) shoes, performed two successive 5-min submaximal running exercise bouts (Sub1 and Sub2, 45% of the speed reached at the end of the 30-15 Intermittent Fitness Test), interspersed by a repeated sprint exercise aimed at inducing acute neuromuscular fatigue. Oxygen uptake (VO2), heart rate (HR), blood lactate (Delta[La]b) and rating of perceived exertion (RPE) were computed for all tests. Cr was calculated using the mean measured over the last three minutes of Sub1 and Sub2, and expressed in ml kg-1 m-1. Results HR, Delta[La]b and RPE were significantly higher for Sub2 (P < 0.01). Delta[La]b were lower for dorsiflexion compared with standard shoes (P = 0.03), without a `shoe x repetition` interaction for any parameter (P > 0.46). Nevertheless, for Sub2, qualitative analyses suggested that HR, VO2 and Cr tended to be higher, and Delta[La]b tended to be lower wearing dorsiflexion (i.e., `very likely` (99%) substantial effect on Cr). Conclusions Present results suggest that wearing dorsiflexion shoes may reduce blood lactate levels but increase Cr under conditions of acute neuromuscular fatigue.
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