Abstract des Autors

Context: Minimalist shoes have been suggested as a way to alter running biomechanics to improve running performance and reduce injuries. However, to date, researchers have only considered the effect of minimalist shoes at slow running speeds. Objective: To determine if runners change foot-strike pattern and alter the distribution of mechanical work at the knee and ankle joints when running at a fast speed in minimalist shoes compared with conventional running shoes. Design: Crossover study. Setting: Research laboratory. Patients or Other Participants: Twenty-six trained runners (age¼30.0 6 7.9 years [age range, 18_40 years], height¼1.79 6 0.06 m, mass ¼ 75.3 6 8.2 kg, weekly training distance ¼ 27 6 15 km) who ran with a habitual rearfoot foot-strike pattern and had no experience running in minimalist shoes. Intervention(s): Participants completed overground running trials at 18 km/h in minimalist and conventional shoes. Main Outcome Measure(s): Sagittal-plane kinematics and joint work at the knee and ankle joints were computed using 3- dimensional kinematic and ground reaction force data. Footstrike pattern was classified as rearfoot, midfoot, or forefoot strike based on strike index and ankle angle at initial contact. Results: We observed no difference in foot-strike classification between shoes (v2 1¼2.29, P¼.13). Ankle angle at initial contact was less (2.468 versus 7.438; t25 ¼ 3.34, P ¼ .003) and strike index was greater (35.97% versus 29.04%; t25¼2.38, P¼ .03) when running in minimalist shoes compared with conventional shoes. We observed greater negative (52.87 J versus 42.46 J; t24 ¼ 2.29, P ¼ .03) and positive work (68.91 J versus 59.08 J; t24¼2.65, P¼.01) at the ankle but less negative (59.01 J versus 67.02 J; t24¼ 2.25, P¼ .03) and positive work (40.37 J versus 47.09 J; t24 ¼ 2.11, P ¼ .046) at the knee with minimalist shoes compared with conventional shoes. Conclusions: Running in minimalist shoes at a fast speed caused a redistribution of work from the knee to the ankle joint. This finding suggests that runners changing from conventional to minimalist shoes for short-distance races could be at an increased risk of ankle and calf injuries but a reduced risk of knee injuries.