Effects of additional load on the occurrence of bilateral deficit in counter-movement and squat jumps

Stelios Psycharakis, Shawn Eagle, Gavin Moir, Alex Rawcliffe, Clive Mckenzie, Scott M Graham, Hugh Lamont, Chris Connaboy

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Purpose: A vertical jump (VJ) is a common task performed in several sports, with the height achieved correlated to skilled performance. Loaded VJs are often used in the training of recreational and professional athletes. The bilateral deficit (BLD), which refers to the difference between the heights achieved by a bilateral jump and the sum of two unilateral jumps, has not been reported for loaded jumps and the findings for unloaded jumps are inconclusive. The purpose of this study was threefold: (a) to quantify and compare BLD in countermovement (CMJ) and squat jumps (SJ), (b) to explore the effects of an additional 10% of body weight (BW) load on the BLD in both CMJ and SJ, and (c) examine the relationship between magnitude of BLD and jump performance in both jumps and conditions. Methods: Forty participants (20 for CMJ and 20 for SJ) performed a bilateral jump and unilateral jumps on each leg with and without an added load equivalent to 10% of each participant’s bodyweight. Results: BLD was evident in all conditions, with CMJ BLD values nearly double those for the SJ. The extra load did not affect the magnitude of BLD. BLD had a significant correlation with unilateral jump height, expect for the 110%BW SJ. Conclusions: BLD is present in SJs and CMJs at both loaded and unloaded conditions. The SJs have about half of the BLD observed in CMJs regardless of additional load. Participants who had higher single leg jumps seemed to also have higher BLDs, but there was no evidence of association between the bilateral jump height and BLD.
Original languageEnglish
Pages (from-to)461-469
Number of pages9
JournalResearch Quarterly for Exercise and Sport
Issue number4
Early online date11 Jun 2019
Publication statusPublished - Nov 2019

Keywords / Materials (for Non-textual outputs)

  • performance
  • weighted-vest
  • asymmetry
  • biomechanics


Dive into the research topics of 'Effects of additional load on the occurrence of bilateral deficit in counter-movement and squat jumps'. Together they form a unique fingerprint.

Cite this