Assessment of the in-season changes in mechanical and neuromuscular characteristics in professional soccer players.

BACKGROUND: The aim of this study was to monitor in-season changes in the mechanical and neuromuscular characteristics of knee extensor and flexor muscles in professional soccer players. METHODS: Twenty-one professional soccer players (soccer group, or SG) and sixteen non-soccer playing males (non-soccer group, or NSG) were assessed by tensiomyography on two occasions: just after the start of the competitive season and 10 weeks later. During this time the soccer players' training sessions were built mainly on speed and strength drills. Mixed-design factorial analysis of variance was conducted and effect sizes were calculated. RESULTS: There was a significant interaction between time (assessment points) x group (SG vs. NSG) x muscle for contraction time (Tc), maximum radial muscle displacement (Dm), and delay time (Td). In the case of the knee extensors, after 10 weeks, there was a 17.7%-22.7% decrease in Tc, an 8.7%-9.9% decrease in Td, and a 12.2%-14.2% decrease in Dm knee extensor in the SG (P<0.01), with a large effect size. In the case of the knee flexors, by contrast, there was an 11.9% increase in Td and a 24.5% increase in Dm (P<0.01), with a moderate to large effect size. The findings confirm that mechanical and neuromuscular characteristics change over time and also vary according to the characteristics of the athlete (SG vs. NSG) and the muscle analyzed. CONCLUSIONS: In conclusion, soccer coaches could use Tc, Td, and Dm data to individualize work load and intensity and control the effects of neuromuscular training throughout the season using a portable, non-invasive technique that, unlike stress tests, does not cause fatigue and therefore does not interfere with training periodization.

Una herramienta para estudiar la dirección de equipos en fútbol / A tool to study the football team management

En este trabajo se presenta un cuestionario destinado a evaluar la dirección de equipos de fútbol denominado ―Inventario de Dirección de Equipos de Fútbol” v.2.0 (IDEF). El cuestionario está basado en diversos estudios que determinan los factores que inciden de forma significativa en la eficacia de un equipo de fútbol. El cuestionario está compuesto de 8 escalas y 84 ítems que explican entre el 42.6% y el 71.1% de la varianza (AU)

In this paper, a questionnaire designed to assess the direction of football teams entitled “Inventory Management Soccer Teams" v.2.0 (IDEF). The questionnaire is based on studies that determine the factors that significantly influence the effectiveness of a football team. The questionnaire consists of 8 scales and 85 items that explain between 42.6% and 71.1% of the variance (AU)