Integrative neuromuscolar and balance training to decrease inter-limb asymmetry values in young soccer players

Purpose: The lower limbs functional asymmetries are determined by strength deficits between the two limbs(Read et al., 2021). This asymmetry seems to significantly affect performance but above all it seems to represent an injury risk factor (Filter et al., 2021; Helme et al., 2021). The purpose of the study is to analyse and understand the lower limb asymmetry values in the young soccer players. The study also verify whether neuromuscular training on unstable and small surfaces provides an effective plan able to reduce functional asymmetries and allows the strength performance increase. Methods: 32 young male soccer players (14.22 ± 0.61 years, 47.66 ± 4.89 kg; 162.3 ± 7.7 cm, age training: 8,3 ± 1,1 years) have been randomly divided into Experimental Group, EG (n = 15) and Control Group, CG (n = 17). The EG completed a total of 16 training sessions directed at balance and neuromuscular training on unstable or small surfaces: two 30-min sessions/week over a 8-week period. The CG followed an identical training schedule, but training sessions consisted of soccer- specific drills only. The performances were assessed in the One-Leg Hop test and Side-Hop test, to quantify percent asymmetries in lower-limb strength before (T0) and following (T1) training. Results: The data analysis returns the highlights significant intergroup results (T0vsT1): the One-Leg Hop test left limb (p = 0.05, d = -2,67), the One-Leg Hop asimmetry score (%, p = 0.0005, d = 10.77), the Side-Hop asymmetry score (%, p = 0.0005, d = 4.25). Conclusions: The neuromuscular and balance training on small and unstable surfaces seem to respond effectively to two needs of the young soccer player: the injury prevention, by reducing the strength asymmetry values, and increasing the lower limb explosive strength values.