An interventional study of Accelerated anodal tDCS and Single-session anodal tDCS in Muscle Strength and Sedentary Behaviors, sponsored by Beijing Sport University. Completed at 1 site in China. Open to participants aged 18 Years to 25 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-04.
Sponsored by Beijing Sport University · Not applicable, Interventional, and Basic science
The goal of this clinical trial is to learn whether accelerated transcranial direct current stimulation (tDCS), in which two sessions of stimulation are delivered within a single day, can immediately improve leg muscle strength in physically inactive college students. tDCS is a non-invasive technique that applies a weak, constant electrical current through electrodes on the scalp to change the excitability of the brain area under the electrode. In this study, stimulation targets the leg area of the primary motor cortex.
The main questions it aims to answer are:
Researchers will compare five groups: two accelerated tDCS groups (two 10-minute sessions separated by 3 or 20 minutes), two single-session tDCS groups (one 10-minute or one 20-minute session) and a sham stimulation group.
Participants will:
Background: Muscle strength comprises maximal strength, explosive strength and muscular endurance. Anodal tDCS over the primary motor cortex (M1) can increase motor cortical excitability, and several studies have reported improvements in muscle strength after single sessions. Neurophysiological studies show that a second session of anodal tDCS delivered within the after-effect period of the first (for example after 3 or 20 minutes) prolongs the increase in cortical excitability, whereas longer intervals do not. Protocols that deliver two or more sessions within one day are termed accelerated tDCS. Accelerated protocols have been applied in cognitive and clinical research, but their effects on muscle strength have not been examined.
Objective: To compare the acute effects of accelerated and single-session anodal tDCS over M1 on maximal strength, explosive strength and muscular endurance of the lower limbs in physically inactive college students.
Design: Single-center, randomized, single-blind, sham-controlled, five-arm parallel-group trial conducted at Beijing Sport University, Beijing, China. The protocol was approved by the Sports Science Experiment Ethics Committee of Beijing Sport University (No. 2025391H), and all participants provide written informed consent.
Participants: Seventy-five physically inactive college students aged 18 to 25 years (15 per group). Physical inactivity is defined as fewer than three sessions per week of moderate-intensity exercise lasting at least 30 minutes during the previous 3 months.
Randomization and blinding: Randomization is stratified by sex. A researcher not involved in testing or stimulation generates separate random number sequences for men and women in SPSS 27.0 and allocates participants of each sex to the five groups. Participants are blinded to the stimulation condition, and the researchers who collect and analyze the data are not involved in group allocation.
Interventions: tDCS is delivered with a dual-channel stimulator (TCS-E2, Shenzhen Yingchi Technology Co., Ltd., Shenzhen, China) through saline-soaked sponge electrodes (35 cm2, 5 x 7 cm). The anode is placed over Cz (leg area of M1), located according to the international 10-20 system and confirmed with a positioning cap, and the cathode over Fpz. Active stimulation is delivered at 1 mA. The five groups are: (1) two 10-minute sessions separated by 3 minutes; (2) two 10-minute sessions separated by 20 minutes; (3) one 10-minute session; (4) one 20-minute session; (5) sham stimulation, in which current is ramped up over 15 seconds and down over 15 seconds and the electrodes remain in place for 10 minutes (n = 8) or 20 minutes (n = 7). Participants remain seated at rest during stimulation.
Procedures: At a single laboratory visit, participants complete a 3-minute warm-up on the isokinetic dynamometer and the baseline test (T0). After a 10-minute rest, the assigned stimulation protocol is administered, and the same tests are repeated immediately after stimulation (T1), followed by a cool-down. Tests are performed on a Biodex System 4 Pro dynamometer in reciprocal concentric mode for the knee flexors and extensors of both legs, with the right leg tested first, in the order maximal strength, explosive strength and muscular endurance. Participants are asked to avoid strenuous exercise, sleep deprivation, alcohol, caffeine and related medications for 24 hours before testing. Sensations and adverse effects are recorded after the intervention with a transcranial electrical stimulation sensation questionnaire.
Outcomes: Peak torque at 60 degrees per second (maximal strength), average power at 180 degrees per second (explosive strength) and work fatigue during 20 repetitions at 180 degrees per second (muscular endurance) of the right and left knee flexors and extensors.
Sample size: An a priori calculation in G*Power 3.1 for a repeated-measures analysis of variance (effect size f = 0.35, alpha = 0.05, power = 0.80) indicated a minimum of 66 participants. Seventy-five participants (15 per group) are recruited to allow for dropout.
Statistical analysis: Change scores (T1 minus T0) are compared among the five groups with one-way analysis of variance, followed by least significant difference post hoc tests when the omnibus test is significant. Partial eta-squared and Cohen's d are reported as effect sizes. Welch's analysis of variance is used when variances are unequal, and a sensitivity analysis excluding extreme values (beyond three times the interquartile range) is performed. All randomized participants are included in the analysis, and the significance level is set at 0.05.
1,273 studies on the registry are indexed under Sedentary Behavior; 300 are open to participants now.
This study's enrollment of 75 is above the median of 60 across 1,076 interventional studies indexed under Sedentary Behavior.
Browse Sedentary Behavior studies →Beijing Sport University is the lead sponsor of 54 studies on the registry; 9 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Two 10-minute sessions of anodal tDCS at 1 mA over the leg area of the primary motor cortex (anode over Cz, cathode over Fpz), separated by a 3-minute interval and delivered once at a single laboratory visit (n = 15).
Device: Accelerated anodal tDCS
Two 10-minute sessions of anodal tDCS at 1 mA over the leg area of the primary motor cortex (anode over Cz, cathode over Fpz), separated by a 20-minute interval and delivered once at a single laboratory visit (n = 15).
Device: Accelerated anodal tDCS
One continuous 10-minute session of anodal tDCS at 1 mA over the leg area of the primary motor cortex (anode over Cz, cathode over Fpz), delivered once at a single laboratory visit (n = 15).
Device: Single-session anodal tDCS
One continuous 20-minute session of anodal tDCS at 1 mA over the leg area of the primary motor cortex (anode over Cz, cathode over Fpz), delivered once at a single laboratory visit (n = 15).
Device: Single-session anodal tDCS
Same electrode montage as the active groups. Current is ramped up over 15 seconds and down over 15 seconds (30 seconds in total), and the electrodes remain in place for 10 minutes (n = 8) or 20 minutes (n = 7) to match the duration of the single-session protocols (n = 15).
Device: Sham tDCS
Anodal transcranial direct current stimulation delivered as two 10-minute sessions at 1 mA within one visit, with an inter-session interval of 3 or 20 minutes according to the assigned arm. Stimulation is delivered with a dual-channel stimulator (TCS-E2, Shenzhen Yingchi Technology Co., Ltd., China) through saline-soaked sponge electrodes (35 cm2), with the anode over Cz and the cathode over Fpz.
Also known as: Accelerated transcranial direct current stimulation; TCS-E2 stimulator
Anodal transcranial direct current stimulation at 1 mA delivered as one continuous session lasting 10 or 20 minutes according to the assigned arm, using the same stimulator, electrodes and montage as the accelerated protocols.
Also known as: Transcranial direct current stimulation; TCS-E2 stimulator
Sham transcranial direct current stimulation using the same stimulator, electrodes and montage. The current is delivered for 30 seconds (15-second ramp-up and 15-second ramp-down) and then switched off while the electrodes remain in place.
Also known as: Sham transcranial direct current stimulation
Change in Peak Torque of the Knee Flexors and Extensors at 60 Degrees per Second
Maximal strength is assessed as peak torque (newton-meters) during five consecutive maximal concentric knee flexion-extension cycles at an angular velocity of 60 degrees per second on an isokinetic dynamometer (Biodex System 4 Pro). The right and left knee flexors and extensors are assessed separately, with the right leg tested first. Change is calculated as the post-stimulation value minus the baseline value.
Time frame: Baseline (before stimulation) and immediately after the end of stimulation, on the single study day (Day 1)
Change in Average Power of the Knee Flexors and Extensors at 180 Degrees per Second
Explosive strength is assessed as average power (watts) during five consecutive knee flexion-extension cycles performed with maximal speed and effort at an angular velocity of 180 degrees per second on an isokinetic dynamometer (Biodex System 4 Pro). The right and left knee flexors and extensors are assessed separately. Change is calculated as the post-stimulation value minus the baseline value.
Time frame: Baseline (before stimulation) and immediately after the end of stimulation, on the single study day (Day 1)
Change in Work Fatigue of the Knee Flexors and Extensors at 180 Degrees per Second
Muscular endurance is assessed as work fatigue (percentage) during 20 consecutive knee flexion-extension cycles performed with maximal speed and effort at 180 degrees per second. Work fatigue = (1 - work in the last third of the repetitions / work in the first third) x 100. Higher values indicate greater fatigue. The right and left knee flexors and extensors are assessed separately. Change is calculated as the post-stimulation value minus the baseline value.
Time frame: Baseline (before stimulation) and immediately after the end of stimulation, on the single study day (Day 1)
Number of Participants With Stimulation-Related Adverse Effects
Sensations and adverse effects related to stimulation (for example tingling, itching, burning sensation, headache and fatigue) are recorded with a transcranial electrical stimulation sensation questionnaire after the intervention. The number of participants reporting each adverse effect is summarized by group.
Time frame: Immediately after the end of stimulation, on the single study day (Day 1)
Plan to share: Yes — De-identified individual participant data underlying the results reported in the publication, including demographic characteristics and isokinetic strength outcomes, will be shared.
Supporting information: Study protocol, Statistical analysis plan
Time frame: Beginning after publication of the main results.
Access criteria: Data will be available from the corresponding author (Fengxue Qi, fengxue.qi@hotmail.com) upon reasonable request for non-commercial research purposes, subject to approval of the request and a data use agreement.
No publications or documents are linked to this record.
Ran from Oct 2025 to primary completion in Dec 2025, 2 months.
Of 733 non-industry interventional studies with no phase under Sedentary Behavior, half reached primary completion within 14 months of starting (the median), counting those still running; a quarter within 6 and three quarters within 31. This study's 2 months is below that.
Counting every sponsor, half of 741 studies reached it within 14 months; a quarter within 6 and three quarters within 31.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is completed, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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Beijing Sport University