Edinburgh Napier University

  The purpose of this study was to quantify the reliability of kinetic variables of British Army foot drill performance within untrained civilians and report the magnitude of vertical ground reaction force (vGRF) and vertical rate of force development (RFD) of foot drills. Fifteen recreational active males performed 3 testing sessions across a 1-week period, with each session separated by 24 hours. Within each testing session participants (mean ± SD; age 22.4 ± 1.7 years; height 177 ± 5.6 cm; weight 83 ± 8.7 kg) completed 10 trials of stand-at-attention (SaA), stand-at-ease (SaE), Halt, quick-march (QM) and a normal walking gait, with vGRF and vertical RFD measured on a force plate. Between-session and within-session reliability was calculated as systematic bias, coefficient of variation calculated from the typical error (CVte%), and intraclass correlation coefficient (ICC). Significant (p ≤ 0.05) between-session differences were found for the vGRF SaA and SaE, and vertical RFD SaA and SaE conditions. Significant (p ≤ 0.05) within-session differences were found for the vGRF SaA and SaE conditions. A mean vGRF CVte% ≤10% was observed across all foot drills. However, the mean vertical RFD CVte% observed was ≥10% (excluding SaE) across all foot drills. The ICC analyses indicated that the vGRF Halt, QM, SaA, and Walk condition achieved moderate to large levels of test-retest reliability, with only SaE failing to achieve an ICC value ≥0.75. The vertical RFD QM, SaE, and Walk condition achieved moderate levels of test-retest reliability, with Halt and SaA failing to achieve an ICC value ≥0.75. It was determined that a single familiarization session and using the mean of 8 trials of vGRF are required to achieve acceptable levels of reliability.