ORIGINAL ARTICLE  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2021 March;61(3):380-5

DOI: 10.23736/S0022-4707.20.11244-1

Copyright © 2020 EDIZIONI MINERVA MEDICA

lingua: Inglese

Validation of the alpine skiing 90 seconds box jump field test and prediction of power output

Pierre-Marc FERLAND ✉, Vincent D. CAREY, Alain S. COMTOIS

Department of Exercise Science, University of Quebec in Montreal, Montreal, QC, Canada

BACKGROUND: The purpose of this study was to validate the alpine ski racing 90 s box jump field-test (BJ90) with the 90 s Wingate test (W90).
METHODS: Fifteen elite alpine ski racers were tested on the BJ90 (0.45 m × 0.75 m × 0.9 m) and the W90 (Ergomedic 894 E Monark; Monark AB, Varberg, Sweden) test in a random order. The number of hits on the BJ90 was written down every 15 s and for the W90 the load (7.5% of body weight) was manually dropped once the subjects reached maximum RPM without resistance. Correlations and partial correlations were calculated with a 2-tailed Pearson correlation analysis. A stepwise forward regression analysis was also performed.
RESULTS: Results present significant (P<0.05) correlations and partial correlations adjusted for body weight between the total number of hits on the BJ90 and W90 peak W, peak W/kg, mean W and mean W/kg as well as with the number of hits and W90 Mean W and mean W/kg between each 15 s time slot. A linear regression predictive equation for mean relative power (W/kg) generated from the BJ90 was established: mean relative power (W/kg)=0.055*total hits+1.080 (r=0.79, P<0.001; total hits with mean W/kg). A stepwise forward regression equation for mean absolute power (W) generated from the BJ90 was also established: mean absolute power (W)=2.305*number of hits+5.081*body weight in kg^-1 -169.8 (R=0.964, P<0.001, SEE=23.56).
CONCLUSIONS: Practitioners could use the BJ90 to assess alpine skiers lower body power as previous research showed that both are correlated with performance and are able to discriminate skier level.

KEY WORDS: Skiing; Leg; Anaerobic threshold; Lactic acid; Glycolysis