The COVID-19 pandemic has caused huge changes in people’s lifestyle, health, and social relationships. This situation has had an impact on children and adolescents, affecting their health, intellectual, physical, and emotional development. The survey aimed to compare eating behaviors, level of physical activity (PA), hours of sleep, and screen time among Polish children and adolescents aged 6–15 years before and during the COVID-19 pandemic. We obtained self-reported data from 1016 participants at two measurement points before and during the COVID-19 lockdown in Poland to examine the influence of the lockdown and the distance learning on PA, dietary habits, sleep, and media usage of children and adolescents aged 6–15 years. The study identified dietary differences and changes in daily activity patterns (reduced sleep duration with higher sleep quality and reduced physical activity). Additionally, the increase in general media usage was observed during the pandemic alongside a reduction in smartphone usage. Together, the findings indicate increased sleep, physical activity, and reduced media usage and screen time among Polish children and adolescents during the COVID-19 pandemic.

Background: The purpose of this research was to investigate the acute effects of a pre-workout supplement on anaerobic performance in resistance-trained men. Methods: Twenty-three men underwent three randomized, double-blind testing sessions separated by a seven-day break. The participants performed three tests: isokinetic strength, three repetition maximum (3-RM) strength and Wingate. Statistical analysis was conducted in R environment. Linear mixed models were estimated via R package lme4. Results: Mean T@0.2 s was significantly greater in supplemented condition for right and left knee flexors (PL: 103.2 ± 37.6 Nm; supplemented condition: 131.8 ± 29.3 Nm (p = 0.001)), and PL: 103.7 ± 39.3; supplemented condition: 129.4 ± 28.4 (p = 0.001)). T@0.2 s for right and left knee extensors (PL: 202.6 ± 58.6 Nm; supplemented condition: 237.2 ± 54.7 Nm (p = 0.001); PL: 203.3 ± 63.2 Nm, supplemented condition: 229.8 ± 50.8 Nm (p = 0.002)). Significant difference was in mean anaerobic power between supplemented and PL condition for right and left knee flexors (p = 0.002, p = 0.005) and for right and left knee extensors (p = 0.001 and p = 0.002). TTP was significantly shorter in supplemented condition for both sides knee flexors (p = 0.002). There was a significant difference for mean power in the Wingate test (placebo: 8.5 ± 0.6 W/kg; supplemented condition: 8.7 ± 0.5 W/kg (p = 0.038)). Mean 3-RM was significantly greater in supplemented condition (p = 0.001). Conclusions: The supplement significantly improves upper and lower body strength and power output in resistance-trained men.

Background: Velocity-based training (VBT) requires measurement of the velocity at which the barbell is moved in the concentric phase with regard to different resistance exercises, which provides accurate, indirect estimations of 1 RM. However, for assessing punch performance, no study has been carried out to date. The purpose of this study was to analyse the reliability of the GymAware linear transducer for the measurement of barbell velocity during the landmine push throw (LPT) test using four loads. Methods: Twenty-five healthy, physically active male students, aged 24.13 ± 2.82 years, volunteered to take part in this study. The reliability of the LPT test was measured at two separate visits, with a 2-day interval between them. One series of the test protocol included four parts of the LPT test with progressively increasing loads (20, 25, 30, and 35 kg) and 5 min intervals for rests between loads. Results: For all four loads, excellent intra-rater and test–retest reliability was noted for the mean force variable (ICC = 0.97–0.99). Additionally, very strong and significant correlations were established between measurements (r = 0.96–0.99). Poor reliability was observed for barbell height and total work (ICC below 0.5). A trend of decreasing reliability was detected with increasing barbell load. Furthermore, measurements without the barbell throw were more reliable than those with it. Conclusions: These results support the use of the GymAware linear transducer to track barbell velocity during the LPT test. This device may have valuable practical applications for strength and conditioning coaches. Therefore, we suggest that the LPT assessed with the GymAware linear transducer may be a useful method for evaluating upper limb strength and power during boxing punches.