Adaptive locomotion: Foot strike pattern and limb mechanical stiffness while running over an obstacle
Roxanne J Larsen1, Robin M Queen2, Daniel Schmitt3
1Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA.
Journal of Biomechanics
|September 16, 2022
Summary
Runners adapt their foot strike and leg stiffness when encountering a surface height drop. Variable foot strike patterns help stabilize limb mechanics on uneven terrain, suggesting adaptability in running biomechanics.
Area of Science:
- Biomechanics
- Running Mechanics
- Human Movement Analysis
Background:
- Previous research indicates runners adjust foot strike to manage leg stiffness during level running.
- Understanding how runners adapt to sudden changes in surface height is crucial for injury prevention and performance optimization.
Purpose of the Study:
- To investigate how runners modify mechanical stiffness and foot strike patterns before, during, and after a drop in surface height.
- To compare the biomechanical responses of runners with consistent versus variable foot strike patterns when navigating an unexpected surface change.
Main Methods:
- Ten healthy runners were video recorded while running over a 12.5 cm drop in surface height.
- Key biomechanical parameters including foot strike, flight time, contact time, ground reaction forces, hip displacement, leg compression, and stiffness were calculated.
Main Results:
- After the drop, runners exhibited increased flight time, ground reaction force, and leg stiffness, with decreased contact time, hip displacement, and leg compression.
- Runners with consistent foot strike patterns showed more pronounced shifts (e.g., rear-foot to fore-foot) compared to those with variable patterns.
- Significant differences in most mechanical parameters were observed based on foot strike pattern and in response to the surface drop.
Conclusions:
- Runners dynamically adjust their biomechanics, including foot strike and leg stiffness, to accommodate changes in running surface height.
- Variable foot strike patterns appear to confer a stabilizing effect on limb mechanics during abrupt surface transitions, potentially reducing injury risk.
