Surface effects on dynamic stability and loading during outdoor running using wireless trunk accelerometry

Area of Science:

• Biomechanics
• Sports Science
• Wearable Technology

Background:

• Wireless accelerometers offer potential for real-world running gait analysis.
• Limited research exists on outdoor surface effects on running biomechanics.
• Understanding surface impacts is crucial for injury prevention and performance optimization.

Purpose of the Study:

• To investigate the effects of different outdoor running surfaces on dynamic stability and loading.
• To assess the utility of tri-axial trunk accelerometry in capturing these surface-induced changes.
• To analyze adaptations in running gait parameters across various surfaces.

Main Methods:

• Twenty-eight runners (highly-trained and recreational) ran on concrete, synthetic track, and woodchip surfaces.
• Tri-axial trunk accelerometry data were collected at 1024Hz.
• Dynamic stability (RMS ratio, regularity, entropy) and loading (peak amplitudes, median frequencies) were analyzed using generalized estimating equations (GEE).

Main Results:

• Woodchip trails significantly altered dynamic stability compared to concrete roads, showing higher anterior-posterior (AP) acceleration RMS ratio and lower medial-lateral (ML) regularity.
• Dynamic loading was affected, with a downward shift in vertical and AP median frequencies on woodchip trails.
• Step frequency was reduced on woodchip trails, with surface effects remaining significant after accounting for running level and speed.

Conclusions:

• Outdoor running surfaces, particularly woodchip trails, demonstrably disrupt dynamic stability and loading.
• A single trunk-mounted accelerometer can effectively detect these biomechanical adaptations in situ.
• Findings provide insights into locomotor adjustments runners make on different surfaces.