Wrapping the transverse foot arch improves running economy

Area of Science:

• Human evolutionary biology
• Biomechanics
• Locomotor energetics

Background:

• Humans possess more curved transverse foot arches than apes.
• Transverse foot arch curvature enhances foot stiffness via cross-axis coupling.

Purpose of the Study:

• To investigate if accentuating evolved human foot arch features by wrapping the transverse arch facilitates bipedal running.
• To understand the biomechanical implications of increased transverse arch curvature on running economy.

Main Methods:

• Participants' transverse foot arches were tightly wrapped to accentuate their evolved curvature.
• Biomechanical and electromyographical data were collected during running with wrapped versus bare arches.
• Ankle gear ratio and leg muscle activation were analyzed.

Main Results:

• Wrapping increased transverse and medial longitudinal arch height and curvature, and longitudinal arch stiffness.
• Running with wrapped arches reduced leg muscle activation and whole-body metabolic power.
• Peak ankle gear ratio increased, enabling power production at slower angular velocities.

Conclusions:

• Wrapping the transverse foot arch improves running economy by allowing leg muscles to operate more efficiently.
• The evolved curvature of human transverse foot arches likely enhances overall foot stiffness, facilitating efficient bipedal running.
• Increased foot stiffness, not medial longitudinal arch stiffening, is key to improved running economy.