This study aimed to investigate the effects of contextual match factors (quality of opposition, match outcome, change of head coach or playing style) on internal and external load in elite Brazilian professional soccer players, considering the total and effective playing time. Twenty-two professional male outfield soccer players participated in this study (age 28.4 ± 4.9 years; height 1.78 ± 0.1 cm; body mass 72.9 ± 7.1 kg). The internal (rating of perceived exertion-based load [sRPE]) and external load (distance and accelerometry-based measures) were recorded during 38 matches, over the 2021 season of the Brazilian National 1st Division League using a global position system (10 Hz) integrated with an accelerometer (200 Hz). The main results were: (i) matches played against weak opponents presented greater values of sprinting distances compared to matches against intermediate and strong opponents; (ii) players covered greater high-intensity running distances when drawing than winning the matches; (iii) matches with assistant coaches presented higher mean speed relative to effective playing time (MSEPT) compared to coach 1 and coach 2 conditions. In addition, players covered greater MSEPT and high-acceleration in matches with coach 2 vs. coach 3; (iv) finally, small positive correlations were observed between positional attack sequences and MSTPT, total distance covered, and acceleration. Coaches and practitioners should consider these results when interpreting external load variables during elite Brazilian soccer matches.

Ergogenic strategies have been studied to alleviate muscle fatigue and improve sports performance. Sodium bicarbonate (NaHCO3) has improved repeated sprint performance in adult team-sports players, but the effect for adolescents is unknown. The aim of the present study was to evaluate the effect of NaHCO3 supplementation on repeated sprint performance in semiprofessional adolescent soccer players. In a double-blind, placebo-controlled, crossover trial, 15 male semiprofessional adolescent soccer players (15 ± 1 years; body fat 10.7 ± 1.3%) ingested NaHCO3 or a placebo (sodium chloride) 90 min before performing the running anaerobic sprint test (RAST). A countermovement jump was performed before and after the RAST, and ratings of perceived exertion, blood parameters (potential hydrogen and bicarbonate concentration), and fatigue index were also evaluated. Supplementation with NaHCO3 promoted alkalosis, as demonstrated by the increase from the baseline to preexercise, compared with the placebo (potential hydrogen: +0.07 ± 0.01 vs. −0.00 ± 0.01, p < .001 and bicarbonate: +3.44 ± 0.38 vs. −1.45 ± 0.31 mmol/L, p < .001); however, this change did not translate into an improvement in RAST total time (32.12 ± 0.30 vs. 33.31 ± 0.41 s, p = .553); fatigue index (5.44 ± 0.64 vs. 6.28 ± 0.64 W/s, p = .263); ratings of perceived exertion (7.60 ± 0.33 vs. 7.80 ± 0.10 units, p = .525); countermovement jump pre-RAST (32.21 ± 3.35 vs. 32.05 ± 3.51 cm, p = .383); or countermovement jump post-RAST (31.70 ± 0.78 vs. 32.74 ± 1.11 cm, p = .696). Acute NaHCO3 supplementation did not reduce muscle fatigue or improve RAST performance in semiprofessional adolescent soccer players. More work assessing supplementation in this age group is required to increase understanding in the area.

Big Data has real value when the veracity of the collected data has been previously identified. However, data veracity for load monitoring in professional soccer players has not been analyzed yet. This systematic review aims to evaluate the current evidence from the scientific literature related to data veracity for load monitoring in professional soccer. Systematic searches through the PubMed, Scopus, and Web of Science databases were conducted for reports onthe data veracity of diverse load monitoring tools and the associated parameters used in professional soccer. Ninety-four studies were finally included in the review, with 39 different tools used and 578 associated parameters identified. The pooled sample consisted of 2066 footballers (95% male: 24 ± 3 years and 5% female: 24 ± 1 years). Seventy-three percent of these studies did not report veracity metrics for anyof the parameters from these tools. Thus, data veracity was found for 54% of tools and 23% of parameters. The current information will assist in the selection of the most appropriate tools and parameters to be used for load monitoring with traditional and Big Data approaches while identifying those still requiring the analysis of their veracity metrics or their improvement to acceptable veracity levels.

Purpose This study aimed to look into the effects of competitive standards based on contextual match factors on external and internal load in elite Brazilian professional soccer players. Forty-six professional male soccer players participated in this descriptive study. Methods The physical demands were monitored by distance-based measures and rating perceived exertion-based training load during 76 matches at 2 competitive standards: 1st and 2nd Brazilian leagues. Results Home and away matches played in the 2nd Brazilian national league presented greater values of the total distance (TD) and moderate-intensity running (MSR) [p < 0;05, effect size (ES) = small-moderate] than the 1st Brazilian national league. When losing and winning matches in the top national, players covered shorter TD, MSR, and high-speed running distances (p < 0;05, ES = small-moderate). The matches against intermediate and weak opposition required high values of TD and MSR (p < 0;05, ES = small-moderate) in the lower national league. Conclusions In a Brazilian league, our results highlight the differences in the external load of top and lower national leagues according to contextual match factors. The evidence emphasizes the importance of developing appropriate attributes to prepare professional soccer players for various competitive standards.