Neuromuscular performance development in highly trained youth soccer players over time: a longitudinal observational study

Attributes required for soccer performance may be developed through involvement in pitch-based training and its interaction with growth and maturation processes even in the absence of specific strength, speed, and power training. This study was designed to investigate the effects of training stimuli and its interaction with growth and maturation on changes in physical performance over a 7−8-month period. Highly-trained youth soccer players affiliated to a professional soccer club (PSA; age: 13.8 ± 0.53, stature: 162.8 ± 8.3 cm, body mass: 52.2 ± 7.1 kg) exposed to both pitch-based training and strength, speed, and power training, were compared to amateur (ASA; age: 14.3 ± 0.53, stature: 166.8 ± 8.9 cm, body mass: 55.4 ± 7.7 kg) players that undertook pitch-based training alone. Two age groups from each club completed an isometric squat test (ISqT), countermovement jump (CMJ), 10 m, 20 m, and 30 m sprint tests. PSA players improved (p = < 0.001 and 0.023, respectively) CMJ and ISqT relative peak force (rPF) scores by 3.53 cm and 6.75 N/kg respectively, compared to the ASA players. Maturation improved (p < 0.05) performance in all physical tests and metrics apart from ISqT rPF. The results suggest that maturation combined with pitch- and specific training results in greater improvements in muscle force production and CMJ height compared to maturation pitch-based training alone. Although maturation processes likely contributed towards a significant proportion of the improvements in aforementioned characteristics, practitioners should consider programming additional tailored training strategies to optimise these effects.