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.

Accurate Estimation of Running Temporal Parameters Using Foot-Worn Inertial Sensors

“…IC and TC events were detected using a threshold on the filtered vertical GRF signal, setting the first threshold-crossing occurrence as IC and the second as TC for each step. As previous studies ( Weyand et al, 2001 ; Cronin and Rumpf, 2014 ) used different reference thresholds, we have decided to investigate the effect of eight reference thresholds on the validation results. Four thresholds were set to 20, 30, 40, and 50 N, independently of the subjects’ body weight (BW) and four others were set to 3, 5, 7, and 9 %BW.…”

“…Although force plates are accepted as state-of-the-art systems for temporal events detection in running, they suffer from several limitations. In fact, the detection timing of IC and TC on the vertical ground reaction force depends on the filtering method and on the detection threshold used ( Cronin and Rumpf, 2014 ). Moreover, their lack of portability and their setup complexity restrict their use for in-laboratory experiments, which is a major drawback given the in-field nature of the running activity.…”

Validation of a Step Detection Algorithm during Straight Walking and Turning in Patients with Parkinson’s Disease and Older Adults Using an Inertial Measurement Unit at the Lower Back

“…Several methods have been successfully utilized to extract time-related gait parameters, including optical systems ( 13 , 14 ), instrumented walkways ( 12 , 15 ), and treadmills ( 16 ). However, such equipment is expensive, restricted to specialized laboratories, and can thus not be applied in large populations and in home environments.…”

Accuracy of PARTwear Inertial Sensor and Optojump Optical Measurement System for Measuring Ground Contact Time During Running

“…From these previous investigations, video techniques and force plates were recommended as the gold standard to measure GCT or flight time (e.g. to determine vertical jump height; 1,10,22,29,33). Of these two systems, video has the advantage of high spatio-temporal resolution to clearly determine and visualize the phase of contact without the need to pre-process (e.g.…”

“…filter) the data. In contrast, data obtained from force plates rely on filtering methods and step detection thresholds that may significantly affect GCT (10,15). In general, data collection with the aforementioned devices mostly takes place in laboratory settings or at least in confined conditions due to the sensitivity of the devices and/or the need for a standardized infrastructure.…”