RESUMO
A tiebreak in tennis is one of the critical moments where players are expected to excel under mental pressure and maintain high level of performance. Despite the importance of tiebreak points, research exploring the performance of male and female players during such match phrase remains limited. This study aimed to investigate i) the overall tiebreak performance of male and female players in relation to the outcome, ii) to examine their point-level performance by considering different contextual variables. A total of 535 tiebreaks comprising 6380 points from the 2016-2021 US Open men's and women's singles matches were collected. The difference in match performance between winning and losing players within the entire tiebreak game was explored. A subsequent decision tree analysis was then used to analyse the effect of the contextual and performance variables on tiebreak point-by-point outcome. The results showed that male and female Winning players outperformed the Losing players in 1st Serve, Serve Width and Net approach performance. The analysis of point-level performance showed that Net point, Score scene, and Point server substantially impacted tennis players' tiebreak outcome. These findings provide valuable insight for coaches and players, informing tiebreak tactics tailoring and training in relevance to different match status.
RESUMO
(1) Background: Hydrogen (H2) may be a potential therapeutic agent for managing Long COVID symptoms due to its antioxidant and anti-inflammatory properties. However, more scientific literature is needed to describe the effects of H2 administration on treating symptoms. A study aimed to investigate the impact of hydrogen-rich water (HRW) administration on the fatigue and dyspnea of Long-COVID patients for 14 consecutive days. (2) Methods: In this randomized, single-blind, placebo-controlled study, 55 participants were recruited, and 23 of them were excluded. A total of 32 eligible participants were randomized into a hydrogen-rich water (HRW) group (n = 16) and a placebo water (PW) group (n = 16) in which they were instructed to consume hydrogen-rich water or placebo water for 14 days, respectively. The participants completed the Fatigue Severity Scale (FSS), Six-Minute Walk Test (6MWT), 30 s Chair Stand Test (30s-CST), Modified Medical Research Council Dyspnea Rating Scale (mMRC), Pittsburgh Sleep Quality Index (PSQI), and depression anxiety stress scale (DASS-21) before and after the intervention. A linear mixed-effects model was used to analyze the effects of HRW. Cohen's d values were used to assess the effect size when significance was observed. The mean change with 95% confidence intervals (95% CI) was also reported. (3) Results: The effects of HRW on lowering FSS scores (p = 0.046, [95% CI = -20.607, -0.198, d = 0.696] and improving total distance in the 6WMT (p < 0.001, [95% CI = 41.972, 61.891], d = 1.010), total time for the 30s-CST (p = 0.002, [95% CI = 1.570, 6.314], d = 1.190), and PSQI scores (p = 0.012, [95% CI = -5.169, 0.742], d = 1.274) compared to PW were of a significantly moderate effect size, while there was no significant difference in mMRC score (p = 0.556) or DASS-21 score (p > 0.143). (4) Conclusions: This study demonstrates that HRW might be an effective strategy for alleviating fatigue and improving cardiorespiratory endurance, musculoskeletal function, and sleep quality. Still, it does not ameliorate dyspnea among Long-COVID patients.