Physical Capacity After SARS-CoV-2 Infection in Adolescent Male Soccer Players: A Three-Month Follow-Up Study.

Background and aim Although many adolescent athletes experience mild or no symptoms following SARS-CoV-2 infection, the potential mid-term effects on physical performance have not been fully characterized. COVID-19 has been associated with alterations in physiological systems related to strength, speed, and aerobic capacity, which may persist after return to sports activity. Furthermore, limited information is available on postinfection recovery trajectories in adolescent athletes, and return-to-play recommendations for this population often rely on data derived from adults. The aim of this study was to evaluate the impact of SARS-CoV-2 infection on physical performance and the recovery trajectory over three months in adolescent male soccer players in Romania. Methods A retrospective analysis was conducted on 120 male soccer players aged 12-16 years, equally divided into COVID-19 and non-COVID-19 groups. The COVID-19 group included athletes with confirmed SARS-CoV-2 infection by RT-PCR or rapid antigen testing, while the non-COVID-19 group consisted of athletes with no history of infection, confirmed by negative IgM/IgG serology. Participants underwent weekly fitness tests, including handgrip strength, 10 m and 30 m sprints, bench press, and beep test. For the COVID-19 group, results were analyzed at three time points: one month before infection, one month after infection, and three months postinfection. The Friedman test with Bonferroni correction was applied to assess intragroup changes over time, and differences between the two groups were analyzed using the Mann-Whitney U test. Effect sizes were calculated using Cliff's delta (δ) for nonparametric comparisons. Results All performance metrics showed significant deterioration one month postinfection (p < 0.001). Partial or full recovery was observed at three months. While bench press and 10 m sprint performance returned to baseline levels, handgrip strength, 30 m sprint, and beep test scores remained significantly lower than pre-COVID values. In contrast, the non-COVID-19 group showed stable performance and better results across all time points. Conclusions SARS-CoV-2 infection was associated with significant, but predominantly transient, impairments in strength, speed, and aerobic capacity in adolescent soccer players. Although most performance parameters showed partial or complete recovery at three months postinfection, persistent deficits were observed in grip strength and cardiovascular endurance. These results suggest that the neuromuscular and aerobic systems may require longer recovery periods in adolescents compared with other components of performance. Structured functional monitoring and individualized return-to-play protocols are essential to ensure a safe and effective return to sport activity after COVID-19.