Purpose: The purpose of this study was to test the concurrent validity of data from two different global positioning system (GPS) units for obtaining mechanical properties during sprint acceleration using a field method recently validated by Samozino et al. Methods: Thirty-two athletes performed maximal straight-line sprints, and their running speed was simultaneously measured by GPS units (sampling rate: 20 Hz or 5 Hz) and either a radar or laser device (devices taken as references). Lower limb mechanical properties of sprint acceleration (theoretical maximal force, F0; theoretical maximal speed, V0; maximal power, Pmax) were derived from a modeling of the speed-time curves using an exponential function in both measurements. Comparisons of mechanical properties from 20 Hz and 5 Hz GPS units with those from reference devices were performed for 80 and 62 trials, respectively. Results: The percentage bias showed a wide range of over or underestimation for both systems (-7.9-9.7% and -5.1-2.9% for 20 Hz and 5 Hz GPS), while the ranges of its 90% confidence limits for 20 Hz GPS were markedly smaller than those for 5 Hz GPS. These results were supported by the correlation analyses. Conclusions: Overall, the concurrent validity for all variables derived from 20 Hz GPS measurements was better than that obtained from the 5 Hz GPS units. However, in the current state of GPS devices accuracy for speed-time measurements over a maximal sprint acceleration, we recommend that radar, laser devices and timing gates remain the reference methods for implementing Samozino et al.'s computations.

Concurrent validity of GPS for deriving mechanical properties of sprint acceleration

Rejc E.;
2017-01-01

Abstract

Purpose: The purpose of this study was to test the concurrent validity of data from two different global positioning system (GPS) units for obtaining mechanical properties during sprint acceleration using a field method recently validated by Samozino et al. Methods: Thirty-two athletes performed maximal straight-line sprints, and their running speed was simultaneously measured by GPS units (sampling rate: 20 Hz or 5 Hz) and either a radar or laser device (devices taken as references). Lower limb mechanical properties of sprint acceleration (theoretical maximal force, F0; theoretical maximal speed, V0; maximal power, Pmax) were derived from a modeling of the speed-time curves using an exponential function in both measurements. Comparisons of mechanical properties from 20 Hz and 5 Hz GPS units with those from reference devices were performed for 80 and 62 trials, respectively. Results: The percentage bias showed a wide range of over or underestimation for both systems (-7.9-9.7% and -5.1-2.9% for 20 Hz and 5 Hz GPS), while the ranges of its 90% confidence limits for 20 Hz GPS were markedly smaller than those for 5 Hz GPS. These results were supported by the correlation analyses. Conclusions: Overall, the concurrent validity for all variables derived from 20 Hz GPS measurements was better than that obtained from the 5 Hz GPS units. However, in the current state of GPS devices accuracy for speed-time measurements over a maximal sprint acceleration, we recommend that radar, laser devices and timing gates remain the reference methods for implementing Samozino et al.'s computations.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11390/1265966
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