Bilateral Deficit and Bilateral Performance: Relationship with Sprinting and Change of Direction in Elite Youth Soccer Players

Abstract

The purpose of the study was to examine the differences in bilateral deficit (BLD) at different loadings during the half-squat jump (SJ) and horizontal countermovement jump (HCMJ) to determine if there is a relationship with linear sprint or change of direction (COD). The second goal was to check if fast players were more powerful in SJ and HCMJ than slow players in bilateral performance (BP). Twenty-seven male youth soccer players participated in the study. Players were divided in two groups, faster and slower, according to their sprint performance (10 and 40 m). BLD average power with body weight (BW) and 25%BW were significantly higher than 50%BW (p < 0.01). BLD during HCMJ was significantly higher than BLD during SJ with BW, 25%BW and 50%BW (p < 0.01). There were no statistical relationships between BLD and sprint or COD performance (p > 0.05). Fast players showed significantly higher SJ power with all the different loads and HCMJ than slow players (p < 0.01), and fast players lost more time executing COD-90° than slow players (p < 0.01). There were no statistical differences between fast and slow players in BLD. BLD seems to be dependent on motor task, contraction type and load and could not be a proper measure to estimate sprint and COD performance. Faster players are confirmed to be more powerful players than slow players, and decrements in COD could be a key benchmark to identify deficit between linear and COD performance.

Bilateral deficit in countermovement jump and its association with change of direction performance in basketball and tennis players

“…The strength of the associations differed between groups, which warrants further investigations in other sports. To the best of our knowledge, only two previous studies have investigated the association between BLD in jumping tasks and CoD performance (Ascenzi et al, 2020;Bishop, Berney et al, 2019). reported moderate associations (r = −0.48 to −0.64) between CoD performance (assessed by 5-0-5 test) and BLD CMJ (JH and concentric FI, but not PP, eccentric FI and peak force).…”

“…However, their study included only 18 non-athlete participants, and authors themselves stressed that larger cohorts of athletes should be investigated (Bishop, Berney et al, 2019). Ascenzi et al, (2020) reported no associations between CoD performance and BLD, which was calculated based on squat jump and horizontal CMJ, in a group of 27 male soccer players. One exception was a moderate (r = −0.45) association between BLD in squat jump with additional weight (+ 25.0% of body mass) and CoD the loss of speed due to CoD manoeuvre (i.e., time to complete straight-line sprint subtracted from total CoD time).…”

“…To this point, very few studies have investigated the association between BLD CMJ and sports performance (Ascenzi et al, 2020;Bishop, Berney et al, 2019;Bračič et al, 2010). Therefore, the present study was conducted to provide more evidence on this topic.…”

“…For instance, if BLD is associated with CoD performance, this could suggest that unilateral training should be prioritised for improvements in CoD performance. Our hypothesis was that BLD CMJ will be inversely associated with CoD performance (time to complete the task) (Bishop, Berney et al, 2019), however, with some available evidence pointing against that (Ascenzi et al, 2020), we expected that these associations will be small or moderate.…”

“…More recently, it has been suggested that larger BLD in CMJ (BLD CMJ ) may be favourable for change of direction (CoD) performance (Bishop, Berney et al, 2019); however, the study was conducted on 18 non-athlete participants. A subsequent study, conducted on 27 young male soccer players showed no relationship between BLD CMJ and sprint performance or CoD performance (Ascenzi et al, 2020). Moreover, inter-limb asymmetries in CMJ were found to be negatively related to CoD performance (Madruga-Parera, Bishop, Read et al, 2020).…”