Effects of long-term detraining on muscle performance in young soccer players.

Background: Long-term detraining consists of a physiological partial or total reduction of the adaptations induced by training caused by a suspension period of the training itself longer than 4 weeks. The aim of this study was to analyze a group of young soccer players by assessing the effects of long-term detraining on neuromuscular performance.
Methods: A study sample of 35 young soccer players of subelite level (age: 14.5±0.5 years) was recruited. The subjects were tested 7 days before the interruption of training for the summer break (T0), and at the end of the 7-week detraining period (T1).
Results: No statistically significant differences were found for BMI (P=0.283) and percentage of fat mass (P=0.273) between T0 and T1. PUSH UP (P=0.016; ES [effect size]=0.2) and SIT UP (P=0.001; ES=1.2) test values show statistically significant increase, those of CHIN UP (P=0.05; ES=-0.2), instead, a statistically significant worsening. Statistically significant but moderate differences on speed running test 30 meters (P=0.001; ES=0.3) are observed as well as trivial differences on 50 meters (P=0.001; ES=0.2), while differences on 10, 15 and 20 meters are irrelevant. As for the jump tests, values show a slight worsening (P=0.135; ES=0.2) in Squat Jump and Counter Movement Jump (P=0.153; ES=0.2) without statistical significance.
Conclusions: A 7-week-long detraining period does not seem to produce any appreciable changes on neuromuscular performance of the lower limb (trained muscle) in young soccer players. As regards the analyzed age group, coaches should not focus their attention on neuromuscular efficiency maintenance exercises in the off-season period.