Cross-education of muscular strength is facilitated by homeostatic plasticity
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We examined the effect of priming the ipsilateral motor cortex (M1) using anodal transcranial direct current stimulation (tDCS) prior to a single bout of strength training on the cross-transfer of strength and corticospinal excitability and inhibition of the ipsilateral M1.
In a randomized double-blinded cross-over design, changes in strength and indices of corticospinal plasticity were analysed in 13 adults who were exposed to 20 min of ipsilateral anodal and sham tDCS (applied to the ipsilateral M1 to the training arm) followed by a single strength training session of the right Biceps Brachii only.
The induction of homeostatic plasticity via anodal tDCS priming, significantly increased strength of the untrained left Biceps Brachii (12%) compared to sham tDCS (2%), increased corticospinal excitability (12–33%) and cross-activation (25%) when ipsilateral anodal tDCS was applied to the right M1 prior to a single session of strength training. Interestingly, ipsilateral sham tDCS and strength training resulted in an average increase in MEP amplitude of 2–32%.
The novel findings of this study include: priming the ipsilateral M1 via anodal tDCS prior to a single bout of strength training augments the cross-transfer of strength which is manifested by an increase in corticospinal excitability and cross-activation. These findings provide insight into how priming methods that induce homeostatic plasticity may be used to enhance the cross-education phenomenon.
KeywordsCross-education Homeostatic plasticity Priming Strength training Transcranial direct current stimulation
- Anodal tDCS + ST
Anodal transcranial direct current stimulation and strength training
Maximum compound wave
Maximal voluntary isometric contraction
Primary motor cortex
Non-invasive brain stimulation
Root-mean square electromyography
- Sham tDCS + ST
Sham transcranial direct current stimulation and strength training
Short-interval intracortical inhibition
Transcranial direct current stimulation
Transcranial magnetic stimulation
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Compliance with ethical standards
Conflict of interest
None of the authors have potential conflicts of interest to be disclosed.
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