title: Effect of four different step detection thresholds on nonmotorized treadmill sprint measurement.
abstract: The purpose of this study was to investigate the effect of 4 different step detection thresholds (10, 15, 20, and 30% body mass [BM]) on the kinetics and kinematics of a youth population sprinting on a Woodway nonmotorized treadmill (NMT). A total of 16 male youth athletes sprinted 30 m from a split start position. Of the 15 variables measured, significant differences (p ≤ 0.05) were found in the measurement of 5 kinematic (step length, vertical displacement, contact time, eccentric, and concentric time) and 2 kinetic (vertical and leg stiffness) variables between the 10 vs. 20 and 30% BM step detection thresholds. Contact time was also significantly different (12%) between 15 vs. 30% BM step detection thresholds. In terms of reliability, the 15 and 30% BM step detection thresholds were found the most stable across all variables (average coefficient of variation ∼6.0%). Given this information, a step detection threshold of 15% BM is recommended for quantifying kinematic and kinetic variables on a NMT, as this threshold seems to account for signal variability appropriately without compromising reliability.
authors.affiliation: 1AUT University, Sport Performance Research Institute New Zealand; 2School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Perth, Australia; and 3National Sports Medicine Programme, Excellence in Football Project, Aspetar, Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.
authors.forename: John B
authors.initials: JB
authors.lastname: Cronin
authors.forename: Michael C
authors.initials: MC
authors.lastname: Rumpf
mesh_terms: D001696:Biomechanical Phenomena; D002648:Child; D005080:Exercise Test / Q000295:instrumentation / Q000379:methods*; D005684:Gait; D006801:Humans; D007700:Kinetics; D008297:Male; D015203:Reproducibility of Results; D012420:Running / Q000502:physiology*