The gearing function of running shoe longitudinal bending stiffness
Steffen Willwacher1, Manuel König1, Björn Braunstein1
1Institute of Biomechanics and Orthopaedics, German Sport University, Cologne, Germany.
Gait & Posture
|June 3, 2014
Summary
Altering running shoe midsole longitudinal bending stiffness (LBS) shifts lower extremity joint lever arms anteriorly. Individual runners adapt differently to these changes, influencing ankle joint moments and push-off times.
Area of Science:
- Biomechanics
- Sports Engineering
- Human Movement Science
Background:
- Running shoe midsole longitudinal bending stiffness (LBS) is a key design parameter.
- Understanding how LBS affects lower extremity biomechanics is crucial for injury prevention and performance optimization.
- Previous research has not fully elucidated the direct impact of LBS on ground reaction force (GRF) lever arms.
Purpose of the Study:
- To investigate the systematic changes in lower extremity joint lever arms due to manipulated midsole LBS during running.
- To determine the relationship between altered LBS and ground reaction force (GRF) lever arms in the sagittal plane.
- To identify individual running strategies in response to modified LBS.
Main Methods:
- Nineteen male subjects ran at 3.5 m/s.
- Inverse dynamics procedures were used to calculate joint moments and GRF lever arms.
- Midsole LBS was manipulated using carbon fiber insoles of 1.9 mm and 3.2 mm thickness.
Main Results:
- Increased LBS significantly shifted joint lever arms to a more anterior position, particularly at distal joints.
- Ankle joint moments did not significantly increase on average, despite altered lever arms.
- Two distinct individual strategies were observed: increasing or decreasing ankle joint moments with corresponding changes in push-off times.
Conclusions:
- Longitudinal bending stiffness (LBS) systematically influences GRF lever arms of lower extremity joints during the running push-off phase.
- Individual responses to altered LBS suggest personalized approaches to shoe design may be beneficial.
- Further research could explore optimal LBS values tailored to individual biomechanical characteristics.
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