With the integration of neuroscience and sports science, transcranial direct current stimulation (tDCS), due to its simplicity, low cost, and high safety, has become one of the most widely studied methods among non-invasive brain stimulation (NIBS) techniques in high-level athletic training research (Bhattacharya et al., 2022; Chang et al., 2022; Hazime et al., 2017). tDCS involves the application of a low-intensity direct current (typically 1–2 mA) via scalp electrodes to modulate cortical excitability in targeted brain regions, thereby influencing sensorimotor pathways and behavioral outputs (Nitsche and Paulus, 2000). Although the precise neurophysiological mechanisms underlying the effects of tDCS remain incompletely understood, several prevailing hypotheses suggest that alterations in cortical excitability (Notturno et al., 2014), enhancement of synaptic plasticity (Stagg and Nitsche, 2011), modulation of regional cerebral blood flow (Jones et al., 2015; Paquette et al., 2011; Wachter et al., 2011), and reorganization of functional brain network connectivity (Meinzer et al., 2012) are involved.

Rather than relying on a single area, motor activity engages a broad network of brain regions known as the motor neural network. This study focuses on the effects of a-tDCS on four key brain areas: the primary motor cortex (M1), dorsolateral prefrontal cortex (PFC), temporal/temporoparietal cortex (TC), and cerebellum (CB). tDCS can be applied using either anodal (a-tDCS) or cathodal (c-tDCS) stimulation, with the former typically enhancing cortical excitability by depolarizing neurons, and the latter reducing excitability via hyperpolarization (Jamil et al., 2017). However, some studies have reported reversed effects, where a-tDCS decreases excitability and c-tDCS increases it (Batsikadze et al., 2013; Hassanzahraee et al., 2020a; 2020b), suggesting that outcomes depend on electrode placement, individual brain anatomy, and stimulation parameters. Generally, a-tDCS lowers the action potential threshold and increases motor-evoked potentials (MEPs), thus improving motor performance, while c-tDCS can inhibit overly active neural circuits and is sometimes used in treatments such as epilepsy (Sudbrack-Oliveira et al., 2021).

The selection of sport-specific tasks is critical for evaluating the effects of tDCS. In contrast to abstract tasks, such as the sequence reaction-time task (Ehsani et al., 2016) sport-specific tasks offer higher ecological validity, thereby providing a more accurate reflection of actual performance in competitive environments. Sport-specific tasks facilitate the activation of higher potential through the motor transfer effect (Abernethy et al., 2005), capitalizing on the neuromuscular adaptations acquired through an athlete’s long-term training. Based on the theoretical framework of sports science and the neurophysiological mechanisms of tDCS, the study categorized sports performance into four subgroups: endurance, strength, competitive-collaborative skills, and precision skills. Endurance and strength reflect physical demands, involving cardiorespiratory function and explosive power output, respectively, primarily regulated by M1 (motor control) and dlPFC (fatigue tolerance). Competitive-collaborative skills and precision skills involve cognitive and fine motor functions, relying on the autonomic and coordination functions of M1, dlPFC, TC, and CB (Bompa and Buzzichelli, 2019).

Over the past decade, a substantial number of observational studies have emerged globally. However, the findings have been inconsistent. Existing literature reports that tDCS can improve cognitive and motor functions in healthy populations (Angius et al., 2018a; Lu et al., 2021; Teymoori et al., 2023; Zhiqiang et al., 2023) and clinical patients (Bornheim et al., 2022; González-Zamorano et al., 2024; Lee et al., 2019; Wiegand et al., 2019). In athletes, tDCS has shown both positive and negative effects. Several studies have reported that anodal tDCS (a-tDCS) can enhance athletic performance. For instance, Okano et al. (2015) found that M1 stimulation improved peak power output in cyclists, and Pollastri et al. (2021) confirmed that dlPFC stimulation enhanced performance in a 15 km time trial Chen et al., (2021) and Zhang et al. (2024) reported that M1 stimulation improved basketball shooting accuracy and jump height, respectively. However, Lattari et al. (2020) found that M1 stimulation had no significant effect on strength performance, and Mesquita et al. (2020) reported that bilateral M1 stimulation even reduced kicking frequency in taekwondo athletes. These inconsistencies may arise from differences in inter-cortical competitive inhibition, stimulation target areas, stimulation parameters, and task types.

Previous meta-analyses on tDCS primarily focused on the general population (Machado et al., 2019a); Winker et al., 2024) or single outcome measures (Lattari et al., 2018; Shyamali Kaushalya et al., 2022). This study systematically analyzes the acute effects of a-tDCS on athletes’ sport-specific performance by integrating Chinese and English literature, conducting subgroup analyses of brain regions, performance domains, and stimulation parameters, aiming to identify optimal protocols and provide a scientific basis for optimizing athletic training.

This meta-analysis aims to systematically evaluate the acute effects of a-tDCS on athletes’ motor performance. The results show that a-tDCS significantly improves motor performance, based on 31 randomized controlled trials, with particularly notable effects in endurance and competitive-collaborative skill tasks. Subgroup analysis confirms M1 as the most effective target area, followed by PFC, with a current intensity of 1.6–2.0 mA and a stimulation duration of 16–20 min as the optimal parameters. Next, we attempt to elucidate the underlying mechanisms of these effects.

The study found that a-tDCS significantly enhances performance in endurance and competitive-collaborative skill tasks, likely due to the synergistic effects of M1 and PFC stimulation. As a key hub for motor output, M1 optimizes motor unit recruitment by reducing action potential thresholds and enhancing corticospinal excitability, thereby extending time to exhaustion in endurance tasks (e.g., cycle ergometer tests) (Etemadi et al., 2023; Bhattacharjee et al., 2021). Additionally, M1 stimulation promotes motor memory formation through long-term potentiation (LTP)-like mechanisms, facilitating learning and retention in repetitive skill tasks (Nitsche and Paulus, 2000; Suppa et al., 2016). Research indicates that pain tolerance induced by exercise affects endurance performance (Astokorki and Mauger, 2017), and M1 stimulation may improve performance by alleviating exercise-induced pain (Gandevia, 2001; Taylor et al., 2016). Furthermore, PFC (particularly dlPFC) stimulation likely enhances cognitive control (Friedman and Robbins, 2022) and suppresses fatigue perception (Rupp and Perrey, 2008), improving athletes’ persistence under high-intensity or mental fatigue conditions (Angius et al., 2019). For competitive-collaborative skill tasks, a-tDCS may enhance neural plasticity in the M1-PFC network, improving perceptual-motor integration and movement execution accuracy. These mechanisms suggest that a-tDCS not only boosts physiological performance but also optimizes cognitive and psychological factors, particularly in competitive settings requiring sustained effort or complex coordination. The TC, a critical region for integrating auditory, language, and motor planning, plays a key role in advanced regulation of cardiac autonomic function (Dono et al., 2020; Reisert et al., 2021; Jackson et al., 2018). However, its deeper cortical location and the distance from scalp to cortex, coupled with tissue impedance, may limit tDCS current penetration, resulting in insufficient stimulation intensity to induce significant neural excitability changes. Similarly, the CB is central to coordination, motor prediction, sensory feedback integration, and balance maintenance, closely linked to various motor skills, postural control, and movement precision (Buckner, 2013; Sokolov et al., 2017). Notably, tDCS efficacy is constrained by the cerebellum’s anatomical structure and current conduction pathways, making it challenging for stimulation currents to penetrate the cerebellar cortex (Koziol et al., 2014; Verduzco-Flores and O'Reilly, 2015). Additionally, athletes’ baseline cortical excitability or training levels may influence CB responses to tDCS, potentially explaining the non-significant effects of TC and CB stimulation in subgroup analyses.

In terms of task types, the meta-analysis indicates that a-tDCS significantly enhances performance in endurance and competitive-collaborative skill tasks, while its effects on strength and precision skill tasks are not significant. The improvement in endurance tasks likely stems from M1 and PFC stimulation, which delays fatigue perception and enhances central drive (Machado et al., 2019b). These tasks involve prolonged low-intensity exercise, where neural factors such as pain tolerance and movement economy significantly influence performance. Competitive-collaborative skill tasks (e.g., basketball shooting, volleyball spiking) rely on fine motor control and perceptual-motor integration, with M1 stimulation significantly improving execution precision by enhancing neural plasticity and the efficiency of motor program retrieval. However, the effects of tDCS on athletic performance are not always positive. For instance, strength performance primarily depends on instantaneous muscle force generation, and while a-tDCS can enhance M1 cortical excitability, its direct impact on peripheral muscle fibers is limited, particularly in elite athletes where short-term stimulation struggles to overcome performance bottlenecks (da Silva Machado et al., 2021). The non-significant effect on precision skill tasks may be attributed to the complexity and diverse neural demands of these tasks. For example, tasks like shooting and golf require greater cognitive control and sensory integration than pure motor output, and single-target stimulation may be insufficient to comprehensively optimize performance.

The analysis of stimulation parameters indicates that a moderate current intensity of 1.6–2.0 mA and a moderate stimulation duration of 16–20 min represent the optimal protocol for enhancing motor performance. Low-intensity and short-duration stimulation yield weak effects, likely due to insufficient current to induce adequate cortical excitability or insufficient time to establish stable neural plasticity (Jamil et al., 2017). While high-intensity and long-duration stimulation perform better than low-intensity/short-duration protocols, they are less effective than moderate parameters, possibly due to excessive intensity causing cortical competition or prolonged stimulation leading to reduced neural adaptability. These findings suggest that moderate current intensity and duration effectively balance the induction of neural excitability and plasticity.

Compared with previous meta-analyses, this study establishes a more comprehensive evidence base by incorporating both Chinese and English literature (6 Chinese, 25 English studies), expanding to 31 studies (n = 473), and integrating the latest evidence up to March 2025. Angius Luca (Angius et al., 2018b) conducted a narrative review exploring the effects of tDCS on motor performance in healthy individuals but did not focus on athletes. Holgado (Holgado et al., 2019) analyzed the impact of tDCS on objective and subjective motor performance indicators but was limited by a smaller sample size and high heterogeneity. Holgado (Holgado et al., 2024) provided a broader umbrella review but lacked detailed subgroup analyses. (Maudrich et al., 2022) et al. emphasized the enhancement of sport-specific performance through single-session a-tDCS but did not include Chinese literature or thoroughly explore parameter optimization. The novelty of this study lies in: 1) being the first to integrate Chinese and English literature, reducing cultural and publication biases; 2) conducting refined subgroup analyses by brain region and dosage, confirming the optimal efficacy of M1 stimulation (1.6–2.0 mA, 16–20 min) for endurance and competitive-collaborative skill tasks; and 3) incorporating new studies to address gaps in prior research. Furthermore, the GRADE assessment (Figure 4) confirms high-certainty evidence for M1 and PFC stimulation, providing robust support for the practical application of tDCS.

Although this study provides high-certainty evidence for the impact of a-tDCS on athletic performance, several limitations remain. First, including only Chinese and English literature may overlook studies in other languages, limiting global representativeness. Second, small sample sizes in individual studies may reduce statistical power, particularly in TC and CB subgroup analyses, affecting result robustness. Third, heterogeneity in tDCS protocols (e.g., electrode placement, stimulation timing, athlete training levels) may influence effect consistency. Fourth, the focus on acute a-tDCS effects restricts inferences about long-term or repeated stimulation. Finally, athletes’ baseline cortical excitability or training levels (e.g., elite vs. amateur) may affect tDCS responsiveness, but data limitations prevented deeper exploration. These limitations suggest cautious interpretation of a-tDCS’s broad applicability. Future research should: 1) include multilingual literature to enhance global representativeness; 2) conduct large-scale, multi-center trials to improve statistical power; 3) standardize tDCS protocols (e.g., electrode placement, timing) to reduce variability; 4) explore cumulative effects of long-term tDCS; 5) develop personalized protocols to address individual athlete differences and validate a-tDCS’s practical value in real competition settings. These directions will further advance the optimized application of a-tDCS in athletic training.

Coaches may use a-tDCS (1.6–2.0 mA, 16–20 min, targeting M1 or dlPFC) as a pre-competition intervention to enhance endurance performance (e.g., prolonging time to exhaustion) or competitive-collaborative skills. However, the moderate certainty for strength and precision skill tasks suggests cautious application, recommending multi-target stimulation or higher-intensity protocols to further validate efficacy. The moderate effect size and acute nature indicate that coaches should temper expectations, integrating a-tDCS with conventional training to maximize benefits rather than relying solely on it.

The meta-analysis results show that the acute effects of a-tDCS significantly improve athletes’ endurance and competitive-collaborative skill performance by enhancing cortical excitability and neuroplasticity in M1 and PFC, with optimal stimulation parameters of 1.6–2.0 mA for 16–20 min. The effects on strength and precision skill tasks are limited. Future research should optimize stimulation strategies and incorporate neuroimaging techniques to enhance the application value of a-tDCS in competitive training.