A novel approach to enhancing muscular strength and function: A pilot study using transcranial direct current stimulation

Ashlee M. Hendy, Dawson Kidgell

Research output: Contribution to journalMeeting AbstractOtherpeer-review

Abstract

Introduction: Transcranial direct current stimulation (tDCS) is a neuromodulation technique that provides benefits for motor function. When low level electrical current is applied to the scalp, the resting membrane potential of the underlying cortical neurons is altered, influencing depolarisation and synaptic efficacy. Acute application of tDCS can produce immediate increases in skill performance, muscular strength, and endurance. While some studies have noted a cumulative effect following acute session delivered across several days, the application of tDCS during strength training programs has not been investigated. Therefore, the aim of this study was to assess changes in muscular strength and neurological function following three weeks of training the wrist extensors with simultaneous application of tDCS. Methods: 12 volunteers were randomly allocated to a control group (CONT), a sham tDCS training group (SHAM) or a tDCS training group (tDCS). Outcome measures included dynamic strength (1RM wrist extension), muscle thickness (measured with ultrasound), corticospinal excitability and cortical inhibition (measured with transcranial magnetic stimulation). The SHAM and tDCS groups underwent training of the wrist extensors (4 sets of 6–8 repetitions 3 x per week) at 80% 1RM intensity for 3 weeks. The CONT group did not train. Anodal tDCS (2mA) was applied to the motor cortex for 20 minutes (tDCS group only). Results: Dynamic strength increased significantly (p < 0.05) for both the tDCS (18.2%) andSHAM(10.4%) groups following the intervention, but not the CONT group. The amplitude of motor evoked potentials (MEPs) obtained at motor threshold increased for the tDCS group (30.8%) but not the SHAM (-15.2%) or CONT (0.2%) group. Maximal MEP amplitude increased for the tDCS (14.0%) and SHAM (3.4%) groups but not the CONT (-2.1%) group. These findings did not produce statistical significance, but the tDCS group displayed effect sizes of 0.74 and 0.45 respectively. No significant changes in muscle thickness were detected. Discussion: Results from this pilot data suggest a potential for utilizing tDCS with training programs to further enhance strength gains and neurological adaptation. Testing continues and power analyses have indicated that significant findings will emerge with increased sample size. This indicates that the use of tDCS in conjunction with training sessions may be of benefit to athletes, during rehabilitation or in any situation where maximal strength and performance gains are desired. Future research must assess the performance benefits of tDCS when utilized in trained athletes, among different muscle groups, and when delivered during rehabilitation programs.
Original languageEnglish
Pages (from-to)S119-S120
Number of pages2
JournalJournal of Science and Medicine in Sport
Volume15
Issue numberS1
DOIs
Publication statusPublished - Dec 2012
Externally publishedYes
EventInternational Congress on Physical Activity and Public Health 2012 - Sydney Convention and Exhibition Centre, Sydney, Australia
Duration: 31 Oct 20123 Nov 2012
Conference number: 4th

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