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Introduction. individual participation in sports with inadequate preparation, especially during competition, results in an increased incidence of injury. Athletes commonly suffer from lower extremity musculoskeletal pain. during growth, several biomechanical factors contribute to muscular imbalance, which results in injury. The aim of the current study was to determine the correlation between lower extremity strength and balance in relation to single leg squat depth. Methods. A total of 100 male football players were included in the study. Lower extremity qualitative and quantitative squat analyses were performed for both legs. isometric strength and balance for the lower extremities were assessed via a dynamometer and the Y balance test, respectively. Results. There is a moderate correlation between the visual squat performance and the strength of the hip extensor in the dominant leg and the hip abductors in the non-dominant leg. A moderate correlation of the maximum squat depth was found with the hip abductors, hip extensor, and knee flexor on the dominant side. The p value was < 0.05 and the r value was between 0.50 and 0.70, which was considered significant. Conclusions. Strength and balance both influence squat performance. Balance has a stronger influence than strength in single leg squat performance. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To determine the effects of kicking leg preference on the bilateral leg strength asymmetries of amateur football players. METHODS: : Thirty-four right-dominant (RD) and twenty-three left-dominant (LD) amateur football players volunteered to participate in the study. Squat and countermovement jump, standing long jump, and isokinetic knee strength (at 60, 180 and 300 ∘ /s) were tested with respect to inter-limb asymmetry index (ASI). RESULTS: There were significant differences in horizontal jump and H/Q ratio at 60 ∘ /s between DL and NDL in all football players. There were also significant differences in standing long jump, hamstring peak torque at 180 ∘ /s and H/Q ratio at 60 ∘ /s in the LD football players ( p < 0.05). Moreover, the LD group had greater percentage of subjects with ASI > 15% for standing long jump, hamstring peak torque at 180 ∘ /s. Furthermore the percentage of subjects with H/Q Ratio < 0.60 for 60 ∘ /s was greater in the LD players' DL. CONCLUSION: Bilateral leg strength asymmetries may be affected by a single leg predominantly in the mobilization workouts. Having higher inter-limb asymmetry index, LD players may be screened and trained to minimize leg strength asymmetries. [ABSTRACT FROM AUTHOR]

This study aimed to clarify the differences in the cross-sectional area (CSA) of the psoas major (PM) muscle and hip flexion force (HFF) of the right (dominant) side between adolescent male soccer players and age-matched non-athletes. PM CSA at L4-L5 and HFF at 1.05 rad/s were determined in 22 early (12.8-13.6 years) and 27 late (16.1-17.9 years) adolescent soccer players and 11 early (12.6-13.5 years) and 20 late (16.0-17.7 years) adolescent non-athletes. Fat-free mass (FFM) was greater in late adolescent soccer players than in late adolescent non-athletes, but was similar between the two early adolescent groups. Without the effect of age, PM CSA and HFF were greater in soccer players than in non-athletes. PM CSA and HFF were significantly correlated to FFM (soccer players, r = 0.860, P < 0.0001; non-athletes, r = 0.709, P < 0.0001) and PM CSA (soccer players, r = 0.760, P < 0.0001; non-athletes, r = 0.777, P < 0.0001), respectively. The difference between soccer players and non-athletes in PM CSA was still significant even when PM CSA was covaried for FFM. On the other hand, HFF covaried for PM CSA was similar between the two groups. The current results indicate that, as compared to age-matched non-athletes: (1) not only late, but also early adolescent soccer players have a greater PM CSA even when the difference in FFM was adjusted, and (2) their superiority in hip flexion force can be attributed to the difference in PM CSA. [ABSTRACT FROM AUTHOR]

The interlimb postural comparison i.e., between the dominant leg and the non-dominant leg has been studied by numerous authors but their results are contradictory and do not lead to a consensus. Some studies showed no difference of postural balance between the dominant and the non-dominant leg whereas other studies concluded that the dominant and non-dominant leg exhibit different postural balance in healthy subjects and athletes. The aim was to analyse all these studies in order to identify the different factors that could facilitate or prevent the appearance of a postural difference between the dominant and non-dominant leg by means of a narrative review. Environmental and experimental conditions (e.g., difficulty and specificity of postural tasks; physiological state, expertise level and moment of season/period over career of subjects/athletes evaluated and nature of sport/physical activity practiced; techniques and methods used for measuring postural balance) in which postural balance is evaluated and intrinsic/individual factors (e.g., morphology, strength/power muscle, proprioception, hemispheric laterality) could influence the results. Thus, the influence of limb dominance on monopedal postural balance would probably be context-dependent. Mechanistic explanations are proposed to explain how each factor could act on the relationship between limb dominance and postural balance. However many mechanisms have not yet been explained and all the factors have not been identified, which suggests that further exploratory research is needed in order to understand this relationship. [ABSTRACT FROM AUTHOR]