Effects of Additional Load on the Occurrence of Bilateral Deficit in Counter-Movement and Squat Jumps

The effects of sex and load on quantifying the bilateral force deficit during an upper body Wingate test

Introduction

The bilateral deficit (BLD) is a reduction in the amount of force during a bilateral task vs. the total force from the unilateral limbs performing the same task. We quantified the BLD during an upper body Wingate Anaerobic Test (WAnT) and evaluated the influence of sex and load on the BLD in force.

Methods

Eighteen participants performed maximum handgrip strength, voluntary isometric contractions (MVIC), and three 30s WAnTs. In each session they completed the tasks with the dominant-arm, non-dominant arm and with both arms, randomly. WAnT intensities were 3, 4, and 5% body weight (BW). Instantaneous force data was used to calculate the BLD.

Results

Males showed greater (p < .001) BLD of force at 3, 4, and 5% BW than females by -17, -27.6 and -36%, respectively and had a greater (p < .001) BLD of force than females throughout time points 1-10 s, 11-20 s, and 21-30 s by -16, -29 and -35%, respectively. Females showed a difference (p < .001) in BLD of force between loads (-19% at 3%, -10% at 4% and +7% at 5%). Males had an increase (p < .001) in BLD of force from the beginning to the end of the WAnT starting with -18% (1-10 s), -38% (11-20 s) and -40% (21-30 s). WAnT had the highest BLD, followed by MVIC and grip strength.

Discussion

BLD in force is present during WAnTs and the sex-load interaction is important for determining this BLD during this maximal cycling test. Thus, when developing training or rehabilitation programs related to BLD in force, sex, load and exercise type should be taken into consideration.

The Association between Bilateral Deficit and Athletic Performance: A Brief Review

An abundance of information can be found in the scientific literature regarding the bilateral deficit (BLD) in different contraction types, including its possible underlying mechanisms. On the other hand, studies on the relationship between BLD and athletic performance have only begun to emerge in recent years. The purpose of this review article is to assemble and analyze the literature on the topic of the relationship between BLD and athletic performance. After a detailed review of the scientific databases, we analyzed 10 relevant scientific articles. BLD calculated from outcomes of vertical jumps was positively related to the ability to change direction quickly in volleyball, basketball, tennis and student population, but not in soccer. Sprint running performance does not seem to be associated with BLD, while one study suggested that a smaller BLD is associated with a more efficient start in a sprint. Apart from the associations with change in direction performance, there is little evidence to support the association between BLD and athletic performance; thus, further research is required in other sports, incorporating sport-specific performance outcomes and multiple tasks to calculate the BLD.

Center of pressure-based postural sway differences on parallel and single leg stance in Olympic deaf basketball and volleyball players

In sports such as basketball and volleyball, loss of balance due to the inability to maintain body stability and lack of postural control adversely affect athletic performance. Deaf athletes appear to struggle with balance and postural stability problems. The purpose of this study was to examine postural sway values in parallel and single leg stance of Olympic deaf basketball and volleyball players and reveal differences between the branches. Twenty-three male athletes from the Turkish national deaf basketball (n=11) and volleyball (n=12) teams participated in the study. After anthropometric measurements, the subjects completed postural sway (PS) tests in parallel/single leg stances with open eyes and closed eyes on a force plate. PS parameters (sway path, velocity, and area) obtained from the device software were used for the statistical analysis. The Mann-Whitney U-test was used to compare differences in PS parameters between basketball and volleyball players, and the alpha value was accepted as 0.05. Volleyball players had significantly better results in parallel stance and dominant leg PS values than basketball players (P<0.05). There was no significant difference between the groups in nondominant leg PS values (P>0.05). We think that proprioceptive and vestibular system enhancing training practices to be performed with stability exercises will be beneficial in terms of both promoting functional stability and interlimb coordination. Trainers and strength coaches should be aware of differences in the postural control mechanism of deaf athletes.

Bilateral counter movement jump, squat, and drop jump performances in deaf and normal-hearing volleyball players: a comparative study

Since deaf athletes do not have any physical deficiencies, it is known that they can easily participate in sports competitions if their communication problems are resolved. This study aimed to compare the performances of olympic deaf and elite normal-hearing volleyball players in different jumping test protocols. A total of 26 male volleyball players participated in the study, comprised of 12 olympic level deaf and 14 elite level normal-hearing. Following anthropometric measurements, athletes performed bilateral counter movement, squat and drop jump tests on a force plate. Each test was performed 3 times with maximal effort separated by 45 seconds of passive recovery and the mean of the three trials was selected for analysis. Independent Samples t-test was used to compare the differences in mean values of jumping test parameters between the groups. Normal-hearing athletes are observed to have significantly better scores than deaf athletes in all test protocols. Considering that the number of studies on athletic performance in deaf athletes is limited, it can be said that our study will contribute to researchers and coaches in respect of detecting a key ability in volleyball, such as jumping, in different jump protocols.

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

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.