Analysis of the Sustainability of Long-Term Detraining Caused by COVID-19 Lockdown: Impact on the Maximal Aerobic Speed of Under-16 Soccer Players

This retrospective cohort study aimed to analyze the effect of a 9-week detraining caused by COVID-19 lock-down on the maximal aerobic speed (MAS) of youth soccer players. The study included twenty-two under-16 male players competing at the national league level (15.4 +/- 0.7 years old) who were analyzed pre and post the detraining period. The MAS was estimated using the Bronco's test. Moreover, the self-regulated physical exercise performed by the players during the lockdown was monitored using a questionnaire. Considering the training volume per week, the players were grouped into those working more (>180 min/week) and those working less (<180 min/week) during the lockdown. Within-group changes revealed no significant differences (p = 0.122; d = 0.381) in the group that self-trained less than 180 min/week started (pre-lockdown) at 3.97 +/- 0.29 m/s and ended (post-lockdown) at 3.85 +/- 0.34 m/s, corresponding to a decrease of 3.02%. For those who self-trained more than 180 min/week during the lockdown, they started with 4.33 +/- 0.28 m/s and decreased by 1.62% for 4.26 +/- 0.28 m/s (p = 0.319; d = 0.250). The team as a whole (pooled data, all players included) decreased 2.27% from 4.15 +/- 0.34 to 4.06 +/- 0.37 m/s (p = 0.077; d = 0.321). Between group analysis revealed that the group of players that trained more than 180 min/weeks were significantly better than players working below 180 min/week in both pre-lockdown moment (+9.01%; p = 0.007; d = 1.263) and post-lockdown moment (10.6%; p = 0.006; d = 1.323). Home-based training can be a good strategy to mitigate the detraining effects caused by a lockdown.