经颅直流电刺激对人体单腿落地稳定性的影响

Effect of transcranial direct current stimulation on human single-leg landing stability

背景:经颅直流电刺激作为一种非侵入脑刺激技术可即时提高人体肌肉力量,或可即时提升人体单腿落地稳定性,但尚未有相关研究进行论证。目的:验证经颅直流电刺激对人体单腿落地稳定性的影响。方法:选择武汉体育学院男性大学生为受试者,按随机数字表法分为A组(n=6)和B组(n=5),A组受试者先接受假刺激,随后经过3 d的清洗期,再接受经颅直流电刺激;B组受试者先接受经颅直流电刺激,随后经过3 d的清洗期,再接受假刺激,刺激后即刻进行单腿落地测试,采集并分析受试者单腿落地时的生物力学参数。将经颅直流电刺激干预的数据汇总为试验组数据,假刺激干预的数据汇总为对照组数据。结果与结论:①核心稳定性:经颅直流电刺激干预与落地高度对躯干最大屈曲角具有交互效应(P<0.05),在30 cm落地高度条件下,相较于假刺激,经颅直流电刺激后受试者躯干最大屈曲角显著降低;经颅直流电刺激干预对躯干最大侧屈角、躯干侧屈角速度具有主效应(P<0.05),相较于假刺激,经颅直流电刺激后受试者躯干最大侧屈角、躯干侧屈角速度显著降低;②下肢关节稳定性:经颅直流电刺激干预对踝关节最大外翻角具有主效应(P<0.05),相较于假刺激,经颅直流电刺激后受试者踝关节最大外翻角显著降低;经颅直流电刺激干预对腓肠肌外侧头的峰值激活水平具有主效应(P<0.05),相较于假刺激,真刺激后腓肠肌外侧头的峰值激活水平显著提升;经颅直流电刺激干预与落地高度对胫骨前肌的峰值激活水平具有交互效应(P<0.05),在60 cm落地高度条件下,相较于假刺激,经颅直流电刺激后受试者胫骨前肌峰值激活水平显著升高;③压力中心稳定性:经颅直流电刺激干预与落地高度对压力中心横向平均位移距离、压力中心横向平均位移速度、压力中心纵向平均位移距离、压力中心纵向平均位移速度等指标均无交互作用(P>0.05),经颅直流电刺激干预对各压力中心指标均无主效应(P>0.05);④结果表明:经颅直流电刺激可即刻改善人体单腿落地时的核心稳定性与下肢关节稳定性,可将其作为运动前的重要热身手段,提高人体单腿落地稳定性、降低下肢损伤风险。

BACKGROUND:Transcranial direct current stimulation(tDCS),as a non-invasive brain stimulation technique,can enhance human muscle strength or improve single-leg landing stability instantly,but no relevant research has demonstrated this yet.OBJECTIVE:To investigate the effect of tDCS on the stability of single-leg landings in human subjects.METHODS:Male undergraduate students from Wuhan Sports University were recruited as study participants.They were divided into two groups,A(n=6)and B(n=5),using a random number table.Group A underwent a sham stimulation session followed by a 3-day washout period,after which they received tDCS.Conversely,Group B received tDCS initially,followed by a 3-day washout period,and subsequently underwent the sham stimulation session.Following the respective stimulation sessions,an immediate single-leg landing test was administered to assess and collect biomechanical parameters.Data resulting from the tDCS intervention were aggregated and analyzed as the experimental group dataset,whereas data stemming from the sham stimulation were consolidated as the control group dataset.RESULTS AND CONCLUSION:Regarding core stability,the tDCS intervention showed a significant interaction with landing height on the maximal trunk flexion angle(P<0.05).A paired comparison of the data showed a significant decrease in the maximum trunk flexion angle following true stimulation compared to sham stimulation at a 30-cm landing height.Additionally,the tDCS intervention had a significant main effect on the maximum trunk lateral bending angle and the mean trunk lateral bending angular velocity(P<0.05).Following true stimulation,there was a significant decrease in the maximum trunk lateral bending angle and the mean trunk lateral bending angular velocity compared to sham stimulation.In terms of lower limb joint stability,the tDCS intervention had a significant main effect on the maximum dynamic ankle valgus angle(P<0.05).This resulted in a significant decrease in the angle following true stimulation compared to sham stimulation.In addition,the tDCS intervention had a significant main effect on the peak muscle activation of the lateral head of the gastrocnemius lateralis(P<0.05).This showed a significant increase after true stimulation compared to sham stimulation.An interaction between the tDCS intervention and landing height was observed for the peak muscle activation of the tibialis anterior(P<0.05).Paired comparison analyses revealed a significant increase in muscle activation after true stimulation specifically at a 60-cm landing height.Regarding center of pressure stability,there were no significant interactions or main effects of the tDCS intervention on the mean lateral displacement,mean lateral displacement velocity,mean anterior-posterior displacement,or mean anterior-posterior displacement velocity at the center of pressure(P>0.05).Furthermore,the tDCS intervention had no significant main effects on any of the center of pressure indicators(P>0.05).In conclusion,tDCS can immediately improve core stability and lower limb joint stability during single-leg landing,making it an effective warm-up technique for improving single-leg landing stability and reducing the risk of lower limb injuries.