Opposite effects of Covid-19 infection on pitchers and batters: a retrospective study on Chinese Professional Baseball League players.

BACKGROUND: The influence of COVID-19 infection on elite athletes remains largely unknown, especially on baseball players. The goal of this study is to examine the actual performance of infected elite baseball players from the Chinese Professional Baseball League (CPBL) from a sabermetric point of view. METHODS: This was a retrospective observational cohort study. CPBL players who were infected with COVID-19 from April 27th to May 31st, 2022, were eligible for this study. The performance of study participants before and after COVID-19 infection was compared, and statistics from the batters and pitchers were analyzed separately. RESULTS: During the study interval, 56 players were infected with COVID-19, including 35 batters and 21 pitchers. After excluding injured players and players with inadequate playing opportunities, 23 batters and 12 pitchers were enrolled. For batters, there were no significant differences before and after COVID-19 infection. However, batters older than 28 years of age showed a decline in slugging percentage (0.372 vs. 0.292, P=0.049). Analysis of pitchers revealed significantly boosted fastball velocity after COVID-19 infection (142.10 km/h vs. 142.82 km/h, P=0.028) and improved strikeouts per nine innings (6.89 vs. 8.56, P=0.021). CONCLUSIONS: COVID-19 might have a potential influence on professional baseball players. For batters, veteran players more than 28 years of age were more likely to be negatively affected by COVID-19, whereas the effect of COVID-19 on pitchers was generally positive, with significantly improved fastball velocity and K/9 numbers.

Transcranial Direct Current Stimulation Decreases the Decline of Speed during Repeated Sprinting in Basketball Athletes.

The purpose of this study was to determine whether transcranial direct current stimulation (tDCS) can improve countermovement jump performance, fatigue index and alleviate the speed decline during repeated shuttle sprints in trained basketball players. Thirteen trained basketball players were divided into the tDCS trial and sham trial by the random crossover design. The tDCS trial was stimulated with 2-mA current in the M1 area in the middle of the top of the head for 20 min. For the sham trial, the current was turned off after 5 s, stopping the electrical stimulation. After warming up, the players underwent countermovement jump test, weighted countermovement jump test and then performed 40 × 15-m sprints with with a 1:4 exercise: rest ratio. The jump height, sprinting time, fatigue index, heart rate and rating of perceived exertion (RPE) were analyzed by paired-sample t-test, when significance was discovered by two-way repeated measures analysis of variance. The study results revealed that the tDCS trial significantly increase the countermovement jump performance (p = 0.04), decrease the sprinting time (p = 0.016), and had improved fatigue index during the sprinting process (p = 0.009). However, the heart rate and RPE during sprinting were nonsignificantly different between the trials. This study has identified that tDCS can decrease the speed decline, fatigue index during sprinting and increase countermovement jump performance without affecting heart rate or the rating of perceived exertion.