External loading of common training drills: Ranking drills to design progressive return-to-run programs

Return-to-run protocols following lower extremity injuries commonly include a gradual training and loading progression to allow positive adaptation of musculoskeletal tissue. Before full return to running, training drills designed to provide a low to high external loading progression (i.e., vertical forces) may therefore minimize the risks of re-injury. However, the magnitude of external loading among various training drills has not yet been quantified. The purpose of this study was to quantify peak vertical forces of multiple common training drills and rank each of them in order from lowest to highest peak vertical force. /Participants: 11 experienced runners completed five trials of 46 training drills while in-shoe vertical reaction force (vRF) was measured with wireless force insoles. Average peak vRF was calculated for each drill across all participants. Drills were also grouped by vRF into four categories intended for use by clinicians as stages of rehabilitation. 46 training drills were ranked in order from least to greatest vRF. The drill with the highest average peak vRF was “Ladder Single Leg Hop Forward”, at 2.80 BW. The drill with the lowest average peak vRF was “Squat Mini Jump”, at 1.02 BW. These data provide valuable information for clinicians, coaches and pelvic floor practitioners when programming rehabilitation and return-to-run training progressions for runners coming back from lower extremity or pelvic injuries.