Peak Loads Associated With High-Impact Physical Activities in Children.

Abstract

Examine the magnitude of peak ground reaction forces (pGRF) across different jumping activities in children. Eight children between 8 and 12 years (9.63 [1.49]y; 1.42 [0.08]m; 33.69 [4.81]kg), performed 5 trials of a broad jump, countermovement jump, jumping jack, leap jump, and drop jump on a force plate. The pGRF were determined during the landing phase of each activity and expressed in units of body weight (BW). A repeated-measures analysis of variance was employed to assess differences in pGRF across activities. Drop jump exhibited the greatest pGRF (3.09 [0.46]BW) in comparison with the vertical jumping jack (2.56 [0.21]BW; P < .001) and countermovement jump (2.45 [0.22]BW; P = .001), as well as the horizontal broad jump (2.25 [0.2]BW; P = .003), and leap jump (2.01 [0.1]BW; P = .002). Peak loads between 2 and 3.1BW were exhibited across each jump activity, which is moderate compared with magnitudes in most jump interventions seeking to improve bone health. All conditions except drop jump exhibited loading <3BW, suggesting these activities may not produce sufficient loads to improve bone outcomes.