Purpose: The aim of this study was to investigate the influence of foot-strike technique on longitudinal arch mechanics and intrinsic foot muscle function during running.
Methods: 13 healthy participants ran barefoot on a force-instrumented treadmill at 2.8ms-1 with a forefoot (FFS) and rear-foot (RFS, habitual) running technique, while kinetic, kinematic and electromyographic (EMG) data from the intrinsic foot muscles were collected simultaneously. The longitudinal arch was modeled as a single "mid-foot" joint representing motion of the rear-foot (calcaneus) relative to the forefoot (metatarsals). An inverse dynamic analysis was performed to estimate joint moments generated about the mid-foot, as well as mechanical work and power.
Results: The mid-foot was more plantar flexed (higher arch) at foot contact when running with a forefoot running technique (RFS 0.2 +/- 1.8o v FFS 6.9 +/- 3.0o, ES = 2.7), however there was no difference in peak mid-foot dorsiflexion in stance (RFS -11.6 +/- 3.0o v FFS -11.4 +/- 3.4o, ES = 0.63). When running with a forefoot technique, participants generated greater moments about the mid-foot (27% increase, ES = 1.1) and performed more negative work (240% increase, ES = 2.2) and positive work (42% increase, ES = 1.1) about the mid-foot. Average stance phase muscle activation was greater for Flexor Digitorum Brevis (20% increase, ES = 0.56) and Abductor Hallucis (17% increase, ES = 0.63) when running with a forefoot technique.
Conclusion: Forefoot running increases loading about the longitudinal arch and also increases the mechanical work performed by the intrinsic foot muscles. These findings have substantial implications in terms of injury prevention and management for runners who transition from a rear-foot to a forefoot running technique.
(C) 2017 American College of Sports Medicine