Graduate Program in Physical Education, State University of Londrina, Londrina, PR, Brazil.
Department of Biomedical Engineering, The City College of New York of CUNY, New York, NY, USA.
Brain Stimul. 2019 May-Jun;12(3):593-605. doi: 10.1016/j.brs.2018.12.227. Epub 2018 Dec 24.
Transcranial direct current stimulation (tDCS) has been used to improve exercise performance, though the protocols used, and results found are mixed.
We aimed to analyze the effect of tDCS on improving exercise performance.
A systematic search was performed on the following databases, until December 2017: PubMed/MEDLINE, Embase, Web of Science, SCOPUS, and SportDiscus. Full-text articles that used tDCS for exercise performance improvement in adults were included. We compared the effect of anodal (anode near nominal target) and cathodal (cathode near nominal target) tDCS to a sham/control condition on the outcome measure (performance in isometric, isokinetic or dynamic strength exercise and whole-body exercise).
22 studies (393 participants) were included in the qualitative synthesis and 11 studies (236 participants) in the meta-analysis. The primary motor cortex (M1) was the main nominal tDCS target (n = 16; 72.5%). A significant effect favoring anodal tDCS (a-tDCS) applied before exercise over M1 was found on cycling time to exhaustion (mean difference = 93.41 s; 95%CI = 27.39 s-159.43 s) but this result was strongly influenced by one study (weight = 84%), no effect was found for cathodal tDCS (c-tDCS). No significant effect was found for a-tDCS applied on M1 before or during exercise on isometric muscle strength of the upper or lower limbs. Studies regarding a-tDCS over M1 on isokinetic muscle strength presented mixed results. Individual results of studies using a-tDCS applied over the prefrontal and motor cortices either before or during dynamic muscle strength testing showed positive results, but performing meta-analysis was not possible.
For the protocols tested, a-tDCS but not c-tDCS vs. sham over M1 improved exercise performance in cycling only. However, this result was driven by a single study, which when removed was no longer significant. Further well-controlled studies with larger sample sizes and broader exploration of the tDCS montages and doses are warranted.
经颅直流电刺激（tDCS）已被用于提高运动表现，但使用的方案和得出的结果参差不齐。
我们旨在分析 tDCS 对提高运动表现的效果。
我们对以下数据库进行了系统搜索，截至 2017 年 12 月：PubMed/MEDLINE、Embase、Web of Science、SCOPUS 和 SportDiscus。纳入使用 tDCS 提高成年人运动表现的全文文章。我们比较了阳极（阳极接近目标）和阴极（阴极接近目标）tDCS 与假刺激/对照条件对结果测量（等长、等速或动力力量运动和全身运动的表现）的效果。
22 项研究（393 名参与者）纳入定性综合分析，11 项研究（236 名参与者）纳入荟萃分析。初级运动皮层（M1）是主要的名义 tDCS 目标（n=16；72.5%）。发现运动前应用于 M1 的阳极 tDCS（a-tDCS）显著有利于提高自行车耐力测试的时间（平均差异=93.41 秒；95%CI=27.39 秒-159.43 秒），但这一结果受到一项研究的强烈影响（权重=84%），阴极 tDCS（c-tDCS）没有效果。在运动前或运动期间应用于 M1 的 a-tDCS 对上下肢的等长肌肉力量没有显著影响。关于运动前或运动期间应用于 M1 的 a-tDCS 对等速肌肉力量的研究结果喜忧参半。个别研究应用于前额叶和运动皮层的 a-tDCS 在动态肌肉力量测试前或期间显示出积极的结果，但无法进行荟萃分析。
对于测试的方案，与 sham 相比，M1 上的 a-tDCS 但不是 c-tDCS 改善了仅在自行车上的运动表现。然而，这一结果受到一项研究的驱动，当去除这项研究时，结果就不再显著。需要进一步进行具有更大样本量和更广泛探索 tDCS 模式和剂量的对照良好的研究。
