This study involved a comparison of 5 kinematic-based algorithms to detect heel strike (HS) and toe-off (TO) events during human locomotion at different speeds. The objective was to assess how different running and walking speeds affect contact event determination during treadmill locomotion. Thirty male runners performed walking at 5 km/h and running at 9, 11, and 13 km/h on a treadmill. A kinematic system was used to capture the trajectories of 2 retro-reflective markers placed at the subject’s right heel and second metatarsal. A footswitch device was used to determine the “true” times of HS and TO compared with 5 kinematic-based algorithms. The results of the current study illustrated that speed influences the HS error in the vertical position and horizontal velocity algorithms, and the TO error in the vertical position and horizontal velocity algorithms. This difference was found in the transition from walking to running; however, higher running speeds did not affect the error estimation. Higher accuracy was found with combined algorithms, namely, one using vertical acceleration and position and another using horizontal and vertical position with no influence from different locomotion speeds. Therefore, these algorithms are recommended in studies where speed is self-selected because they work well for a broad range of locomotion velocities.
Felipe Alvim, Lucenildo Cerqueira, and Aluízio D’Affonsêca Netto are with the Biomedical Engineering Program, PEB/COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. Guilherme Leite is with the Military Institute of Engineering, IME, Rio de Janeiro, Brazil. Adriane Muniz is with the Department of Post-graduation, Physical Education College of Brazilian Army, EsEFEx, Rio de Janeiro, Brazil.