Research Appraisals
Evidence-based critical appraisals of the latest medical research, systematically evaluated using Oxford CEBM methodology.
Showing 3 appraisals
Behavioural brain research
Effects of anodal transcranial direct current stimulation on athletic performance among elite athletes: A systematic review and meta-analysis
BACKGROUND: Non-invasive brain stimulation techniques, such as transcranial direct current stimulation (tDCS), have been proposed as promising approaches for enhancing motor performance. However, evidence regarding their effects on different domains of athletic performance in elite athletes remains inconclusive. OBJECTIVE: This study aims to quantify the effects of anodal tDCS on athletic performance in elite athletes, compared with a sham condition. METHODS: A comprehensive search of six electronic databases (PubMed, Web of Science, SportDiscus, ECSCO, Embase, and the Cochrane Library) was conducted to identify randomized clinical trials (RCTs). Standardized mean differences (SMDs) based on post-intervention scores were pooled using random-effects models to estimate pooled effect sizes. Subgroup analyses were performed to examine potential moderating variables. Study quality and risk of bias were evaluated using the Cochrane Risk of Bias Tool. RESULTS: A total of 18 studies involving 259 elite athletes were included in the analysis. The results indicated that anodal tDCS had a moderate but significant overall effect on athletic performance in elite athletes (SMD = 0.57, 95% CI [0.39, 0.75], p < 0.01), although moderate heterogeneity was observed ( I²= 51.38%). Subgroup analyses revealed significant domain-specific variability: the effects were strongest in sport-specific performance (SMD = 0.79, 95% CI [0.51, 1.08], p < 0.01) and physical fitness (SMD = 0.58, p < 0.01), whereas the effects on recovery (SMD = 0.17, p = 0.65) and psychological variables (SMD = 0.38, p = 0.09) were negligible and non-significant. Additionally, the M1 area was found to be the most effective cortical target. CONCLUSIONS: Our findings provide evidence that anodal tDCS is a promising tool for enhancing performance in elite athletes, but its effectiveness is highly domain-dependent. It is particularly potent for improving sport-specific skills and physical fitness, while its role in accelerating recovery remains unsupported. Coaches and practitioners should consider these domain-specific variations and the ceiling effect of elite populations when designing tDCS interventions.
7 June 2026
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Oral carbohydrate sensing enhances prefrontal cortex oxygenation, reduces perceived exertion, and improves high-intensity cycling performance: A randomized crossover trial
PURPOSE: Carbohydrate mouth rinsing (CHO-MR) and music listening (MUS) are non-metabolic interventions proposed to attenuate cognitive and perceptual fatigue during exercise. However, their comparative effects on prefrontal cortical oxygenation, executive function, and perceived exertion during high-intensity endurance performance remain unclear. This study examined the effects of CHO-MR and MUS on dorsolateral prefrontal cortex (DLPFC) oxygenation, cognitive performance, perceived exertion, and cycling performance during a 4-km time trial (TT). METHODS: Eleven trained cyclists (7 men, 4 women) completed a randomized, single-blind, crossover trial under three conditions: CHO-MR, MUS (120 beats/min), and placebo mouth rinse (PLA). Bilateral DLPFC oxygenation was assessed using functional near-infrared spectroscopy at rest, during Stroop testing, post-intervention, and post-TT. Stroop performance, rating of perceived exertion (RPE); every 500 m, completion time, power output, heart rate, and blood lactate were measured. Outcomes were analyzed using generalized estimating equations adjusted for period, sequence, and first-order carryover effects with robust standard errors. RESULTS: CHO-MR increased bilateral DLPFC oxygenation compared with MUS and PLA at post-intervention and post-TT time points (p < 0.05), with no differences at rest or baseline. Stroop performance was superior in CHO-MR relative to MUS and PLA following the TT (p < 0.001), without between-condition differences at earlier assessments. RPE was lower in CHO-MR than PLA across all intervals (p ≤ 0.01) and lower than MUS at mid-trial distances (p < 0.05). CHO-MR resulted in faster completion times, greater mean power output, and higher mean speed compared with MUS and/or PLA (p < 0.05), whereas peak power, heart rate, and blood lactate did not differ among conditions. Pooled change-score analyses demonstrated positive associations between bilateral ΔDLPFC oxygenation (p < 0.001) and between ΔDLPFC oxygenation and ΔStroop performance (p < 0.05). CONCLUSION: CHO-MR enhances bilateral DLPFC oxygenation, preserves executive function, and reduces perceived exertion during high-intensity endurance exercise, translating into improved performance without detectable peripheral metabolic alterations. These findings support a central neurocognitive mechanism underlying the ergogenic effects of oral carbohydrate sensing. TRIAL REGISTRATION: ClinicalTrials.gov NCT07099807.
14 May 2026
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Effects of virtual reality training on racket sports performance: A systematic review and meta-analysis of controlled trials
BACKGROUND: Virtual reality (VR) interventions are increasingly used in racket sports, and quantitative evidence is emerging. PURPOSE: To synthesise controlled trials examining the effects of VR-based training on racket sports performance outcomes. METHODS: A systematic search of five databases (PubMed, Web of Science, Scopus, SPORTDiscus, PsycINFO) up to 15 August 2025 was conducted following PRISMA 2020 guidelines. Eligible studies were controlled trials (randomised or non-randomised) comparing VR-based training (immersive or exergaming) with non-VR controls in tennis or table tennis players. Risk of bias was assessed using Cochrane RoB 2 (randomised) and ROBINS-I (non-randomised). Standardised mean differences (Hedges' g) were pooled using a random-effects model with Paule-Mandel τ² and Hartung-Knapp-Sidik-Jonkman (HKSJ) adjustment. The protocol was registered (PROSPERO CRD420251132325). RESULTS: Six controlled trials(total N = 426; analysed N = 401) were included. The pooled meta-analysis indicated a moderate overall effect favouring VR (Hedges' g = 0.78; HKSJ 95% CI [0.41, 1.15]), with moderate heterogeneity (I² = 52%). The 95% prediction interval was [-0.01, 1.57], which spans the null effect, indicating that in some future populations or settings VR training may not yield a meaningful performance advantage. One trial investigated perceptual-cognitive VR training (Anguera et al., 2025), showing a substantial but imprecise effect (g = 0.81, 95% CI [-0.05, 1.67]). As only a single study was available, this evidence is presented descriptively rather than meta-analytically. A subgroup examination of five physically engaging VR interventions found a similarly large effect (*g* = 0.78, 95% CI [0.31, 1.25]) despite considerable heterogeneity (I² = 62%). CONCLUSION: According to six controlled trials, VR training was associated with average performance enhancements in racket sports; however, the 95% prediction interval [-0.01, 1.57] encompasses the null effect, indicating that a future study could plausibly show no benefit. Due to the limited evidence base (k = 6), significant heterogeneity (I² = 52%), and considerable statistical uncertainty, the existing evidence does not allow for definitive conclusions regarding the efficacy of VR. The current findings should be regarded as a preliminary signal rather than confirmation of effectiveness. Larger, more methodologically robust RCTs with standardised outcomes are needed before definitive recommendations can be made.
7 Apr 2026
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