Unilateral and ipsilateral strength asymmetries in elite youth soccer players with respect to muscle group and limb dominance
Abstract
The purpose was to compare knee extensors and flexors' strength in sedentary children and detect its differences with respect to gender and lower limb dominancy. The group of untrained children (boys: n = 20, age = 14.5 +- 0.2 years, height = 171.1 +- 5.3cm, weight = 60.4 +- 20.3 cm, girls: n = 18, age = 11.6 +- 0.4 years, height = 163.5 +- 5.0 cm, weight = 55.2 +- 8.9 cm) was tested on the Cybex isokinetic dynamometer at 60 o.s-1 for the dominant (DL) and non-dominant leg (NL) in concentric contraction.
Univariate ANOVA (2x2) with two between subject effects (gender (G), laterality (L)) was used for evaluation of peak torque (PT) differences between the factors for extensors or flexors. Strength of knee extensors (PTE) and flexors (PTF) was significantly different depending on gender (PTE: F1,76 = 23.92, p .05, ηp2 = .01) and PTF (F1,76 = 0.48, p > .05, ηp2 = .01).
The interaction effect between velocity and gender was insignificant (p > .05). Bilateral strength deficit between the limbs (Q:Q) was 7.27 % in boys and 1.78 % in girls.
Concerning knee flexors, the bilateral deficit in boys was 5.39 % while in girls it was 3.41 %. The unilateral ratio (H:Q) in boys was 50.28 % (DL) and 51.31 % (NL).
The girls achieved a lower unilateral ratio in comparison to the boys (49.74 % - DL and 48.92 % - NL). Early identification of muscle imbalances and their compensation using verified intervention procedures should be a part of movement intervention at schools, sports clubs and free time activities in youth age with the aim of early elimination of the detected maladaptive effects.