Electromyography vs. Foot Pedal Force Assessment During High-G Centrifuge Qualification Testing.

INTRODUCTION

Traditional assessment of the anti-G straining maneuver through foot pedal force measurements has limitations in capturing muscle engagement. This study evaluated surface electromyography (EMG) as an alternative tool during routine centrifuge qualification.

METHODS

There were 19 aircrew trainees who underwent centrifuge testing with concurrent EMG monitoring of 4 muscle groups and pedal force measurements during gradual onset runs and rapid onset runs. EMG data from lower limb and abdominal muscles were compared with pedal forces to assess correlation and timing differences across acceleration profiles.

RESULTS

EMG-pedal correlations were limited and profile dependent. Only right pedal force demonstrated consistent correlation with right vastus medialis activity across profiles (gradual onset: r = 0.756; rapid onset +6 Gz: r = 0.620; rapid onset +8 Gz: r = 0.463). No significant correlations were observed between pedal forces and hamstring or abdominal muscle activity. Duration analysis showed systematic differences, with right pedal force duration (46.36 ± 17.92 s) exceeding both rectus abdominis (28.98 ± 17.27 s) and vastus medialis activation (38.35 ± 14.90 s) during gradual onset runs. Rectus abdominis activation remained consistently lower than other muscles during rapid onset high-G exposure, reaching 48.67 ± 20.45% maximum voluntary contraction at +8 Gz compared with 72.28-82.56% in other groups.

DISCUSSION: EMG provides more comprehensive assessment than pedal force alone, delineating muscle activation patterns and timing differences that conventional methods cannot detect. The profile-dependent correlations and duration discrepancies highlight limitations of foot pedal measurements. These findings support incorporating EMG into routine centrifuge qualification to improve assessment accuracy and enable more targeted training interventions. Woo JHA, Pollock RD, See B, Lim SWY. Electromyography vs. foot pedal force assessment during high-G centrifuge qualification testing. Aerosp Med Hum Perform. 2026; 97(3):204-209.