Background Functional asymmetry (FA) is often analyzed to reduce the young soccer players injury risk. Strength asymmetry values greater than or equal to 15% indicate a potential injury risk (Noyes et al., 1991).

Objective Describe lower limb FA values.

Design Descriptive study.

Setting Youth soccer.

Participants 112 young soccer players (n=47 under 13 male, 12.4±0.6 yrs, 44.2±7.8 kg, 152.8±11.1 cm, BMI:17.7±0.8; n=26 under 14 male, 13.9±0.4 yrs, 56.4±8.2 kg, 168.8±8.6 cm, BMI:18.6±0.2; n=25 Under 15 female, 13.6±1.9 yrs, 49.8±6.4 kg, 159.3±6.5 cm, BMI:18.2±1.2). Inclusion criteria: no lower limb injury in the last 1 yr; soccer training age at least 3 yrs (n=15 were excluded).

Interventions (or Assessment of Risk Factors) Single leg jumps, performed as Hop Test (HT), Side Hop (SH) and Triple Hop(TH) tests were used a validated marker of lower limb FA.

Main Outcome Measurements Young soccer players were assessed by HT, SH, TH to evaluate strength. FA was calculated between the two limbs as follows: (jump dominant limb–jump non-dominant limb)/jump dominant-limb*100 (Yamamoto, 1993)

Results FA values are shown in the table below. *indicates p<0.05.⇓

Conclusions Monitoring of functional strength asymmetry values in the young player may help staff in reducing injury risk in youth soccer. The SH reveals s asymmetry values greater than the other two tests. The large standard deviations observed suggest that individualized preventive strategies should be adopted.