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Approaches to the study of artificial sports surfaces
Published in Youlian Hong, Roger Bartlett, Routledge Handbook of Biomechanics and Human Movement Science, 2008
To overcome the limitation of tests that do not include shoe characteristics, efforts have been made to develop mechanical tests to include the shoe. For example, for frictional characteristics, a weighted shoe may be dragged across a playing surface. The vertical and horizontal force components can be measured using a force platform (Schlaepfer, Unold and Nigg, 1983) or a strain gauge system (Wojcieszak, Jiang and Frederick, 1997), allowing the calculation of friction values for different shoe-surface combinations.
Effects of stretch-shortening cycle fatigue protocol on lower limb asymmetry and muscle soreness in judo athletes
Published in Sports Biomechanics, 2023
Rafael Lima Kons, Lucas Bet da Rosa Orssatto, Raphael Luiz Sakugawa, Jorge Nelson da Silva Junior, Fernando Diefenthaeler, Daniele Detanico
Neuromuscular status, assessed through unilateral CMJ, has been used as a reliable and non-invasive method to assess the effects of fatigue and muscle damage (Claudino et al., 2016; Wiewelhove et al., 2015). CMJ was assessed by a strain gauge force platform (AMTI model OR6-6, Watertown, MA, U.S.A), which measures ground reaction force sampling at 1000 Hz. Before each assessment, the participants performed a warm-up, which consisted of 5-min on a cycle ergometer at 50–70 W, followed by 10 hops, and five submaximal bilateral and three submaximal unilateral (each leg) CMJs (30 s rest between jumps) in baseline, 24, and 48h. Two minutes after the warm-up, five consecutive maximal CMJs were performed 30s before the unilateral CMJs to ensure potentiated performance. To avoid exacerbating recovery, only one unilateral CMJ for each leg was recorded 30s after the 5th and 10th sets of the SSC protocol for fatigue monitoring. The CMJs always began with the preferred limb reported by participants.
Optimisation of applied loads when using the two-point method for assessing the force-velocity relationship during vertical jumps
Published in Sports Biomechanics, 2021
Amador García-Ramos, Alejandro Pérez-Castilla, Slobodan Jaric
Vertical jumps were performed on a force platform (Dinascan/IBV, Biomechanics Institute of Valencia, Spain) that sampled the vertical ground reaction force (GRF) data at a frequency of 1,000 Hz. Prior to each jump, the participants were weighed over 4 s with the external load laid on their shoulders to determine the total system weight (sum of body weight and external weight). The start of the jump was defined as the first time point when vertical GRF was 10 N above (SJ) or below (CMJ) the total system weight (McLellan, Lovell, & Gass, 2011; Moir et al., 2004). For each jump, the system’s centre-of-mass velocity was calculated through the trapezoidal rule (Linthorne, 2001). Specifically, the net GRF was calculated as the amount of force exceeded the system weight and then divided by the system mass to determine acceleration. Acceleration was numerically integrated to provide instantaneous centre-of-mass velocity. Maximum values of force and velocity at each loading condition as well as the jump height reached during unloaded jumps were the dependent variables analysed. Jump height was calculated following the take-off velocity procedure (Linthorne, 2001).
Effects of running with minimal and conventional footwear in habitual and non-habitual users: a musculoskeletal simulation and statistical parametric mapping based approach
Published in Footwear Science, 2020
Jonathan Sinclair, Paul John Taylor, Naomi Bernadette Liles
Participants ran at 4.0 m/s (±5%), striking an embedded piezoelectric force platform (Kistler Instruments Ltd., Winterthur, Switzerland) with their right (dominant) foot. Running velocity was monitored using infra-red timing gates (Newtest, Oy Koulukatu, Finland). The stance phase was delineated as the duration over which 20 N or greater of vertical ground reaction force (GRF) was applied to the force platform. Runners completed five successful trials in each footwear condition. The order that participants ran in each footwear condition was counterbalanced. Kinematic and GRF data were synchronously collected. Kinematic data were captured at 250 Hz via an eight-camera motion analysis system (Qualisys Medical AB, Goteburg, Sweden). Dynamic calibration of the motion capture system was performed before each data collection session.