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Effects of Body Weight Unloading and Treadmill Belt Surface on Tibial Acceleration-Based Loading Indicators During
Łukasz Oleksy1,2,3, Anna Mika4, Martyna Sopa5
1Department of Orthopedics, Traumatology and Hand Surgery, Faculty of Medicine, Wroclaw Medical University, 50-556 Wroclaw, Poland.
Journal of Clinical Medicine
|May 27, 2026
Summary
Running on a microgravity treadmill with body weight support significantly reduces tibial acceleration, indicating lower impact loading. Moderate unloading (80% body weight support) may best preserve natural running mechanics.
Area of Science:
- Biomechanics
- Sports Science
- Human Physiology
Background:
- Understanding tibial loading during running is crucial for injury prevention and training.
- Microgravity treadmills offer controlled unloading for studying running biomechanics.
- The influence of treadmill surface on tibial acceleration requires further investigation.
Purpose of the Study:
- To compare tibial acceleration under varying body weight support (BWS) levels on a microgravity treadmill.
- To assess the effect of treadmill surface by comparing microgravity and conventional treadmills.
- To examine acceleration-based indicators of tibial loading during unloaded running.
Main Methods:
- Twenty-six healthy adults ran at 8 km/h on a microgravity treadmill with 100%, 80%, 60%, and 40% body weight support.
- Tibial acceleration was measured using inertial measurement units.
- Running on a conventional treadmill served as a comparison for 100% body weight condition.
Main Results:
- Cadence decreased with increasing body weight support.
- Magnitude of axial acceleration (MAA), peak positive (PPAA), and negative (PNAA) axial accelerations significantly reduced with unloading, especially at 60% and 40% BW.
- Time to peak positive axial acceleration increased, indicating delayed peak loading, while positive axial acceleration duration showed a non-linear response.
Conclusions:
- Progressive body weight unloading on a microgravity treadmill significantly reduces impact-related tibial acceleration.
- Running at 100% BW showed biomechanical similarity between microgravity and conventional treadmills, but subtle differences suggest surface influence.
- Moderate unloading (~80% BW) appears optimal for balancing load reduction and maintaining natural running mechanics.
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