Shoes alter the spring-like function of the human foot during running.
The capacity to store and return energy in legs and feet that behave like springs is crucial to human running economy. Recent comparisons of shod and barefoot running have led to suggestions that modern running shoes may actually impede leg and foot-spring function by reducing the contributions from the leg and foot musculature. Here we examined the effect of running shoes on foot longitudinal arch (LA) motion and activation of the intrinsic foot muscles. Participants ran on a force-instrumented treadmill with and without running shoes. We recorded foot kinematics and muscle activation of the intrinsic foot muscles using intramuscular electromyography. In contrast to previous assertions, we observed an increase in both the peak (flexor digitorum brevis +60%) and total stance muscle activation (flexor digitorum brevis +70% and abductor hallucis +53%) of the intrinsic foot muscles when running with shoes. Increased intrinsic muscle activation corresponded with a reduction in LA compression (-25%). We confirm that running shoes do indeed influence the mechanical function of the foot. However, our findings suggest that these mechanical adjustments are likely to have occurred as a result of increased neuromuscular output, rather than impaired control as previously speculated. We propose a theoretical model for foot-shoe interaction to explain these novel findings.
Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, The University of Queensland, 26B Blair Drive, St Lucia, Queensland 4072, Australia l.kelly3@uq.edu.au.
Luke A
LA
Kelly
Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, The University of Queensland, 26B Blair Drive, St Lucia, Queensland 4072, Australia.
Glen A
GA
Lichtwark
Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, The University of Queensland, 26B Blair Drive, St Lucia, Queensland 4072, Australia.
Dominic J
DJ
Farris
Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, The University of Queensland, 26B Blair Drive, St Lucia, Queensland 4072, Australia.
Andrew
A
Cresswell
D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D005528:Foot / Q000502:physiology*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D012420:Running / Q000502:physiology*; D012775:Shoes
barefoot running; intrinsic foot muscles; leg-spring mechanics; longitudinal arch