Abstract
Background:
Youth soccer is the foundation for detecting talent and producing professional players. Soccer academies submit players to high level training and competition. Physical maturity plays a major role in the development of athletes. It is of utmost importance that players are measured and compete against similar age groups during their development to prevent injuries.
Objectives:
Isokinetic strength measurements are higher in older age groups.
Methods:
41 youth professional male soccer players of a Mexican League Under 17 (U-17) team were evaluated. The age groups were 15 years (15Y) (N=5), 16 years (16Y) (N=26), and 17 years (17Y) (N=10). Strength testing was performed in right and left lower limbs using Biodex-4 Isokinetic Dynamometer with the following protocol: 5 repetitions at 60°/s of concentric knee extension and flexion, and 15 repetitions at 180°/s.
Results:
Mean peak torque at 60°/s for knee extension/flexion was 197.3 ± 38.7 Nm/101.56 ± 23.32 Nm in right leg (RL) and 199.2 Nm ± 29.75 Nm/105.56 ± 17.42 Nm in left leg (LL) in 15Y group; 211.95 ± 34.01 Nm/116.5 ± 22.71 Nm (RL) and 212.85 ± 40.1 Nm/112.88 ± 19.97 Nm (LL) in 16Y group; 235.65 ± 35.34 Nm/129.79 ± 19.27 Nm in (RL) and 226.71 ± 38.91 Nm/118.12 ± 19.97 Nm (LL) in 17Y group.
Mean peak torque at 180°/s for knee extension/flexion was 138.72 ± 12.07 Nm/84.58 ± 14.44 Nm (RL) and 131.95 Nm ± 15.65 Nm/ 78 ± 5.03 Nm (LL) in 15Y group; 141.10 ± 20.86 Nm/ 89.32 ± 18.66 Nm (RL) and 144.96 ± 23.34 Nm/ 87.83 ± 14.21 Nm (LL) in 16Y group; 162.66 ± 22.54 Nm/102.04 ± 14.11 Nm (RL) and 156.22 ± 27 Nm/ 99.7 ± 16.69 Nm (LL) in 17Y group.
Hamstrings to quadriceps (H:Q) ratio at 60°/s was 51.37% (RL) and 53.35% (LL) in 15Y; 55.20% (RL) and 53.62% (LL) in 16Y; 55.21% (RL) and 52.38% (LL) in 17Y. H:Q ratios at 180°/s increased to 60.91% (LL) and 59.94% (LL) in 15Y; 63.49% (RL) and 61.26% (LL) in 16Y; 62.91% (RL) and 64.07% (LL) in 17Y. This indicates a greater hamstring contribution with increasing age and angular velocity.
Conclusion:
Quadriceps and hamstring strength was considerably greater in 17Y group compared to 15Y. Although it may be tempting to include younger players in older categories because of their talent level, their physical maturity is lower. More studies in youth professional soccer players are needed to provide training recommendations in these age groups.