Do footfall patterns in forefoot runners change over an exhaustive run?

Area of Science:

• Biomechanics
• Exercise Physiology
• Sports Science

Background:

• Forefoot running is a common gait pattern.
• Prolonged running can lead to fatigue.
• The effects of fatigue on forefoot running mechanics are not fully understood.

Purpose of the Study:

• To investigate changes in footfall patterns in habitual forefoot runners during prolonged, exhaustive running.
• To identify kinematic and kinetic alterations associated with fatigue in forefoot runners.
• To explore the role of ankle plantar flexor muscle fatigue in these changes.

Main Methods:

• 14 habitual forefoot runners completed a prolonged run to exhaustion.
• Vertical ground reaction forces (VGRFs) and kinematics were measured at the start and end of the run.
• Ankle plantar flexor torque and triceps surae electromyographic activity (iEMG) were assessed pre- and post-run.

Main Results:

• Increased VGRF loading rate and impact peak magnitude were observed by the end of the run.
• Greater dorsiflexion at foot contact and increased knee flexion during stance were noted.
• Significant decreases in ankle plantar flexor torque and gastrocnemius iEMG indicated muscle fatigue.

Conclusions:

• Forefoot runners exhibited altered landing mechanics, transitioning towards a midfoot strike pattern during exhaustive runs.
• Ankle plantar flexor muscle fatigue may contribute to altered mechanics and increased eccentric loading.
• Forefoot running patterns may be unsustainable in long endurance events, necessitating training modifications to enhance performance and reduce injury risk.