Strength Level of Professional Elite Soccer Players after the COVID-19 Lockdown Period: A Retrospective Double-Arm Cohort Study

Abstract

Background. It is well known that periods of inactivity generate a loss of muscle strength, a fundamental component of sports performance in soccer. However, little information is available on the decrease in strength levels in professional soccer players after the quarantine lockdown that occurred during the COVID-19 pandemic. Aim. To compare the isokinetic peak torque profiles of professional soccer players from different teams before and after the quarantine period generated by COVID-19. Methods. A retrospective observational study was performed using data collected from two different professional elite-level soccer teams just before and immediately after the COVID-19 quarantine period. One team gave individual instructions to its players for conditioning maintenance at home during the quarantine period, while the other team used regular video calls to maintain the player’s conditioning status on home training. The main outcomes were the mean peak torque of knee extensors and flexors, from concentric and eccentric contractions of each playing position. Analysis. A two-way ANOVA analysis was used to compare peak torque before and after the quarantine period and between both teams’ strategies, showing a statistically significant reduction in eccentric knee flexor peak torque from the team that did not have remote monitoring. Conclusions. Remote monitoring programs are recommended so that athletes are less affected by the deleterious effects of confinement.

Impact of the COVID-19 Lockdown on the Body Composition and Physical Performance of Athletes: A Systematic Review with Meta-Analysis and Meta-Regression

“…The 29 studies selected for systematic review [ 8 , 9 , 10 , 13 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ] and the quality of all of the studies analyzed are presented in Table 1 . The details of these studies are presented in Table 2 .…”

“…In summary, the motivation of exclusion was as follows: the number of subjects per group was not clear [ 24 ]; the data of O2peak was reported in other measurement units (meters) [ 31 ]; and no access to data in mean and standard deviation (even after email request) [ 43 , 45 , 46 ]. A total of 24 studies [ 8 , 9 , 10 , 13 , 23 , 25 , 26 , 27 , 28 , 29 , 30 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 44 , 47 ] and 447 athletes were included in this meta-analysis. This study resulted in six forest plots.…”

Effects of COVID-19 Lockdown on Physical Performance, Sleep Quality, and Health-Related Quality of Life in Professional Youth Soccer Players

“…Grazioli et al ( 2020 ) also reported no significant changes in hamstring eccentric strength in male professional soccer players after 63 days of home training compared to tests after the traditional off-season period. Another study found that in professional soccer players, in whom home training was controlled by video training, no changes in isokinetic peak torque were noted in contrast to the group of soccer players who were not controlled (Scoz et al, 2022 ). In contrast, another study showed reduced eccentric hamstring strength in soccer players in a 7-week home training period despite a training program that included strength-based activities (Moreno-Pérez et al, 2020 ).…”

Championship interseason period did not reduce knee peak moment: A 10-years retrospective study of 467 elite soccer players

“…Positional groupings were goalkeepers (G), defenders (D), sidebacks (S), midfielders (M) and forwards (F). Dominant leg was defined as their preferred kicking leg for a penalty kick [4,[32][33][34]]. Anthropometric information was recorded by team's medical staff before players completed a standardized warm-up on the isokinetic machine to minimize error.…”

“…However, some athletes employ personal trainers or follow their team's coach regular training regime. A recent study of our group [34], found that this strategy was used during COVID-19 lockdown regime by some teams with different results.…”