| Background:Transcranial Direct Current Stimulation(t DCS)is a non-invasive brain stimulation technology that regulates the cortical excitability of the brain area and nearby areas by applying a weak current to a specific brain area.It is now widely used to enhance muscular strength,endurance,skill learning and other abilities in individuals.But the current research is mostly about the immediate effect,and there are few studies on the the cumulative effect of multi-sessions t DCS on physical performance.As a short-term,high-intensity anaerobic test,continuous jump is often used to test the lower limb's antifatigue ability of athletes.Therefore,in order to explore the effect of t DCS on lower limb fatigue,this study compares the changes in the fatigue index and strength output of subjects in 60 s continuous jump before and after 5 consecutive daily sessions of t DCS to explore the cumulative effect on sports performance.Method:Thirty healthy male subjects(age: 21.67±1.83 yrs,height: 174.47±6.58 cm,weight:72.65±11.05 kg)were included.Randomized,double-blinded,and controlled design was used.Subjects were randomly divided into 2 groups: anodal t DCS(a-t DCS)and sham t DCS(shame-t DCS),then received t DCS intervention twice a day for 5consecutive days,which the anodal electrodes over bilateral motor cortices and the cathodal electrodes over the ipsilateral shoulders.The stimulation lasted 20 min and current was set at 2m A.Before,after and one month after the intervention,the Vicon three-dimensional motion capture system and Kistler force plate were used to collect data,including jump height,the flight and ground time,the power output,the joint angle and other indicators of the 60 s continuous jump.Two-way(stimulation × time)repeated ANOVA was performed to compare the differences in the related indicators of the sports performance before and after the two intervention methods.If there was an interaction relationship,the LSD post-test was used for further comparative analysis.Result:(1)Anti-fatigue ability: The Fatigue index of the subjects in the a-t DCS was lower than that in the sham-t DCS group(p<0.05),there was a difference between the groups,while no significant difference between the two groups before and after stimulation;The total jump height of the continuous jump after a-t DCS and one month later was significantly higher than before(p<0.05),and after stimulation a-t DCS was significantly higher than shame-t DCS(p<0.05);(2)Power output: There was no significant difference between the peak power and the average power of the continuous jump.(3)Time characteristics: There was no significant difference in the slope of the flight time of continuous jump before and after stimulation.One month after the intervention,the slope of flight time in a-t DCS was significantly lower than that in the sham-t DCS(p<0.05).In the sham-t DCS,the slope of ground time after stimulation and one month later was significantly higher than before(p<0.05);(4)Joint angle and work:There was no significant difference in the maximum flexion angle of the three joints between and within the group,but after a-t DCS,the decline in the maximum flexion angle of the knee and ankle joints tended to slow down.There was no significant difference between and within groups in the contribution of the three joints during pushoff period.(5)Rating of Perceived Exertion(RPE): Before and after stimulation,there was no significant difference in the changes of the subjects' RPE during and immediately after the test.After a-t DCS,subjects recovered faster after the test.Conclusion:5 consecutive days of 2m A a-t DCS applied on bilateral M1 improved the antifatigue ability and total training load during 60 s continuous jump and reduced the decline of physical performance caused by peripheral fatigue in high-intensity anaerobic exercise,but not enhanced the strength output.The research results could provide theoretical support and method reference for repeated t DCS application in alleviating fatigue caused by short-term,high-intensity exercise or improving the total training load. |
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