Multi-Joint Synergy in Foot Height Stabilization Across Different Running Speeds: An Uncontrolled Manifold Analysis
Mateus S Dias1, Sandra M S F Freitas2, Paulo B de Freitas1
1Universidade Cruzeiro do Sul.
Research Quarterly for Exercise and Sport
|April 10, 2025
Summary
Runners use multi-joint coordination to stabilize foot height during running. This running synergy strengthens at faster speeds and the end of the swing phase for safe landings.
Area of Science:
- Biomechanics
- Motor Control
- Human Movement Science
Background:
- Treadmill running involves complex multi-joint coordination.
- Foot height stabilization is crucial for safe and efficient locomotion.
- The uncontrolled manifold (UCM) framework offers insights into motor redundancy and synergy.
Purpose of the Study:
- To investigate multi-joint synergies stabilizing foot height during treadmill running.
- To determine if these synergies are dependent on running speed.
- To analyze the temporal characteristics of foot height stabilization across the swing phase.
Main Methods:
- Employed the uncontrolled manifold (UCM) framework.
- Collected kinematic data from 28 experienced runners at 2.5, 3.5, and 4.5 m/s.
- Calculated variances in joint space (V_u, V_e) and the synergy index (ΔV_z) across the swing phase.
Main Results:
- A significant multi-joint synergy (ΔV_z > 0) was present, stabilizing foot height.
- Synergy strength varied across the swing phase, peaking at 81-100%.
- Slower running speeds resulted in lower synergy in the latter half of the swing phase.
Conclusions:
- The central nervous system actively organizes multi-joint synergies to stabilize foot height.
- Synergy is strongest at the end of the swing phase, ensuring safe foot placement.
- Faster running speeds enhance this stabilizing synergy, improving adaptability.
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