Reliability of Performance Measurements Derived From Ground Reaction Force Data During Countermovement Jump and the Influence of Sampling Frequency

Naruhiro Hori, Robert U Newton, Naoki Kawamori, Michael R McGuigan, William J Kraemer, Kazunori Nosaka
2009 Journal of Strength and Conditioning Research  
Hori, N, Newton, RU, Kawamori, N, McGuigan, MR, Kraemer, WJ, and Nosaka, K. Reliability of performance measurements derived from ground reaction force data during countermovement jump and the influence of sampling frequency. J Strength Cond Res 23(3): 874-882, 2009-Force platforms are used extensively to measure force and power output during countermovement jump (CMJ). The purpose of this study was to examine measurement reliability and validity of commonly used performance measurements derived
more » ... from ground reaction force (GRF)-time data during CMJ and the influence of sampling at different frequencies. Twenty-four men performed 2 trials of CMJ on a force platform, and GRF-time data were sampled at a rate of 500 Hz. Data obtained at 500 Hz were considered as the reference, and then data were resampled at 400, 250, 200, 100, 50, and 25 Hz, using interpolation. Commonly used power, force, and velocity performance measures were obtained from GRF-time data. Reliability was assessed by intraclass correlation coefficient (ICC) and coefficient of variation (CV) between the 2 trials within the session. Peak power, peak force, and peak velocity were highly reliable across all sampling frequencies (ICC = 0.92-0.98, CV = 1.3-4.1). Percentage differences from 500-Hz reference values ranged from 20.85 to 0.20% at 400 Hz, 21.88 to 0.89% at 250 Hz, 21.80 to 1.31% at 200 Hz, 23.63 to 3.34% at 100 Hz, 211.37 to 6.51% at 50 Hz, and 213.17 to 9.03% at 25 Hz. In conclusion, peak power, force, and velocity measurements derived from GRF to assess leg extensor capabilities are reliable within a test session except for peak rate of force development and time to peak power. With regard to sampling frequency, scientists and practitioners may consider sampling as low as 200 Hz, depending on the purpose of measurement, because the percentage difference is not markedly enlarged until the frequency is 100 Hz or lower. ICC = intraclass correlation coefficient; CV = coefficient of variation; RFD = rate of force development; RPD = rate of power development.
doi:10.1519/jsc.0b013e3181a00ca2 pmid:19387390 fatcat:jabbcr6vbjbspoq2hnarywsol4