The impact of sampling frequency on ground reaction force variables

Area of Science:

• Biomechanics
• Kinetics
• Sports Technology

Background:

• Portable technologies for limb loading assessment offer field utility but often have low sampling frequencies.
• The optimal sampling frequency for accurate impact kinetics measurement remains unestablished.

Purpose of the Study:

• To investigate the impact of varying sampling frequencies on key impact kinetics metrics.
• To establish minimum sampling frequencies for reliable assessment during landing, walking, and running.

Main Methods:

• Retrospective analysis of landing and locomotion data collected at high sampling rates (1920 Hz and 1440 Hz).
• Data were down-sampled to assess the effect on peak impact force, average loading rate (LR), and impulse.
• Minimum sampling frequencies were determined for 90%, 95%, and 99.5% accuracy compared to original data.

Main Results:

• For 90% accuracy of impact force, frequencies of 180 Hz (running), 62 Hz (bilateral landing), and 48 Hz (other tasks) were sufficient.
• Average LR required higher frequencies: 1440 Hz (running), 192 Hz (bilateral landing), 63 Hz (inclined walking), and 48 Hz (other tasks).
• Impulse measurement consistently required only 48 Hz across all tasks.

Conclusions:

• This study provides essential guidance on selecting appropriate sampling frequencies for accurate impact kinetics analysis in diverse activities.
• Findings support the use of lower sampling frequencies in portable biomechanical assessment tools without compromising critical data.