A LARGE-SCALE NUMERICAL ANALYSIS OF UNIMODAL AND BIMODAL FEATURES IN FORCE PLATE DATA MEASURED DURING VERTICAL COUNTERMOVEMENT JUMPING

Authors

John Cockcroft, Stellenbosch UniversityFollow
Aneurin Robyn, Stellenbosch UniversityFollow
Quinette Louw, Stellenbosch UniversityFollow
Helen Bayne, Department of Physiology, Faculty of Health Sciences, University of PretoriaFollow

Category

Methods

Document Type

Paper

Abstract

This study presents a novel algorithm for automatically analyzing modality patterns in countermovement jump (CMJ) force-time curves. Bimodal peaks (F_z1, F_z3) are identified using a minimum threshold (T_{trough_drop}) for their relative drop to the intermediate trough value (F_z2). In a large sample of athletes (n = 214), 75% of jumps were technically bimodal (T_{trough_drop} > 0%) but this decreased to 17% (T_{trough_drop} > 5%) and 0% (T_{trough_drop} > 20%) using alternative definitions. This suggests that conflicting findings in other studies may be explained by a lack of standardized criteria for classifying modality. The drop from F_z1 to F_z2 in bimodal jumps was also largely correlated (r = 0.75) to the force at zero velocity and braking acceleration (r = 0.63). These findings highlight the potential value of extracting new quantitative features related to curve modality for CMJ research and interpretation.

Recommended Citation

Cockcroft, John; Robyn, Aneurin; Louw, Quinette; and Bayne, Helen (2019) "A LARGE-SCALE NUMERICAL ANALYSIS OF UNIMODAL AND BIMODAL FEATURES IN FORCE PLATE DATA MEASURED DURING VERTICAL COUNTERMOVEMENT JUMPING," ISBS Proceedings Archive: Vol. 37: Iss. 1, Article 102.
Available at: https://commons.nmu.edu/isbs/vol37/iss1/102