Reliability of the kinetics of British Army foot drill in untrained personnel

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 three testing sessions across a 1-week period, with each session separated by 24 h. Within each testing session participants (mean ± SD; age 22.4 ± 1.7 years; height 177 ± 5.6cm; weight 83 ± 8.7kg) completed ten 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 and within session reliability was calculated as systematic bias, coefficient of variation calculated from the typical error (CVte%) and intra-class correlation coefficient (ICC). Significant (P≤0.05) between session differences were found for the vGRF SaA, SaE and vertical RFD SaA, 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 testretest 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 eight-trials of vGRF are required to achieve acceptable levels of reliability.