Abstract
Muscle balance is vital in preventing injuries and may assist in the development of maximum speed and improved muscular performance. If not addressed, muscle imbalances can slow down and possibly cause injuries. There is a link between lower-limb asymmetry, functional performance, and sports injury. The stronger limb may obtain unnecessary stress because of the high dependence and heavier load being placed on it. It has been proposed that stronger athletes demonstrate superior Rate of Force Development (RFD), power, jump higher, run faster, perform change of direction (COD) tasks faster, and are less likely to get injured. There is still ongoing uncertainty in research regarding whether asymmetries truly impact athletes across varying performance levels. Therefore, the purpose and primary aim of the study is to investigate the effects of lower limb asymmetries on sprint and change of direction ability performance. The cross-sectional study consisted of 42 male university athletes. The mean age of the athletes was 20.71±2.16 years, the recorded mean height was 1.77±08.89 m, and the recorded mean weight was 66.40±9.66 kg. Before any testing, athletes completed a physical activity readiness questionnaire (PAR-Q) and underwent a standard anthropometric assessment. The athletes performed three 30m repeated sprints and a two 45-degree cutting task change of direction test for each foot. Additionally, the participants performed three countermovement vertical jumps (CMJ’s) on a force platform in a randomized manner. Effectively, T-tests were used to compare/identify asymmetries in continuous force and power metrics for the right and left limbs. Additionally, continuous correlations were run between asymmetry data and sprint and COD tests. This information could assist coaches and trainers to make better training programs to reduce asymmetries in multidirectional movement sport athletes and ultimately improve their performance. The CMJ jump metrics showed that there was no major difference between concentric peak and concentric mean forces (p>0.05). The only statistical difference was between the right (358.79 ± 68.43N) and left (347.5 ± 55.57N) eccentric mean forces. There is a statistically significant difference between right and left eccentric mean (p=0,017). Correlational analysis in the present study indicated that sprint metrics and measures of asymmetries showed a significant moderate relationship between sprint time and concentric max RFD (r= 0.355; p=0.039). Significant moderate relationship between COD deficit left (L) and Concentric Mean Force (r= 0.306; p=0.049). In addition, a
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negative moderate relationship was also found between COD deficit R and Concentric Max RFD (r= -0.482; p=0.004). The CMJ jump metrics and measures of asymmetries found moderate relationships between Sprint times, COD L, and CMJ metrics (r= -0.477 to r= -0.330; p=0.001 to p=0.024). Furthermore, moderate to large relationships were found between COD deficit tasks and CMJ. (r= 0.372 to r= 0.493; p= 0.001 to p=0.015). Additionally, a large relationship was evident between COD deficit R and Vertical Velocity at Take-off (r= 0.519; p=0.000). Furthermore, moderate relationships were noted between COD deficit L and CMJ metrics (r= 0.307 to r= 0.348), (p=0.024 to p=0.048). Muscle imbalances can hinder performance and increase the risk of injury, making muscle balance a vital aspect of athletic training. This research sought to explore the influence of lower limb asymmetry on sprint performance and COD ability by utilizing various testing methods. The research uncovered that the athletes who had received comprehensive training exhibited no asymmetries. They engaged in bilateral training both in the gym and on the field. Nevertheless, the study was unable to definitively establish whether there was no detrimental effect, as the entire sample was able to carry out their tasks without any issues.