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Does Footfall Pattern in Forefoot Runners Change over a Prolonged Run?
Document Type Open Access
There has been much debate on the benefits of a forefoot versus rearfoot strike pattern in distance running for performance and injury prevalence. Recent studies indicate that a forefoot strike pattern may not be maintainable over endurance efforts. This study tested the hypothesis that habitual forefoot runners cannot maintain their strike pattern throughout a prolonged, intensive run.
Fourteen forefoot runners ran to exhaustion on an instrumented force treadmill. Kinematic and kinetic data were sampled each minute. Ankle plantar-flexor torque was measured pre- and post-run, along with electromyographic activity (EMG) of the triceps surae.
Loading rate, impact peak, peak knee flexion, and sagittal ankle angle at touchdown increased significantly throughout the run. Ankle torque decreased significantly from pre- to post-run, along with a decrease in medial and lateral gastrocnemius integrated EMG (iEMG).
There were significant changes in landing mechanics with increased levels of exertion, as the runners shifted towards rearfoot strike patterns by run’s end. These changes support metabolic findings of other studies. Increased eccentric loading of the ankle plantar-flexor muscles at touchdown in forefoot runners may contribute to a decreased torque output by the end of the run. The decline in iEMG may indicate altered central drive of the system and a decline in the impact attenuation ability of the triceps surae, leading to the changes exhibited up the kinematic chain. These findings suggest that while forefoot strike patterns are good for speed, the onset of fatigue may affect the ability to maintain this pattern during a prolonged, intensive effort.