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Tracking the corticospinal responses to strength training



The motor cortex (M1) appears to be a primary site of adaptation following both a single session, and repeated strength-training sessions across multiple weeks. Given that a single session of strength-training is sufficient to induce modification at the level of the M1 and corticospinal tract, this study sought to determine how these acute changes in M1 and corticospinal tract might accumulate across the course of a 2-week heavy-load strength-training program.


Transcranial magnetic stimulation (TMS) was used to infer corticospinal excitability (CSE), intracortical facilitation (ICF), short and long-interval intracortical inhibition (SICI and LICI) and silent period duration prior to and following each training session during a 2-week heavy-load strength-training period.


Following 2-weeks of strength-training, increases in strength (15.5%, P = 0.01) were accompanied by an increase in CSE (44%, P = 0.006) and reductions in both silent period duration (14%, P < 0.0001) and SICI (35%, P = 0.0004). Early training sessions acutely increased CSE and ICF, and acutely reduced silent period duration and SICI. However, later training sessions failed to modulate SICI and ICF, with substantial adaptations occurring offline between training sessions. No acute or retained changes in LICI were observed. Co-contraction of antagonists reduced by 36% following 2-weeks of strength-training.


Collectively, these results indicate that corticospinal plasticity occurs within and between training sessions throughout a training period in distinct early and later stages that are modulated by separate mechanisms of plasticity. The development of strength is akin to the previously reported changes that occur following motor skill training.

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One-repetition maximum


Area under the recruitment curve


Active motor threshold


Corticospinal excitability


Confidence interval


Standard deviation


Extensor carpi radialis




Flexor carpi radialis


γ-Aminobutyric acid


Intracortical facilitation


Long-interval cortical inhibition


Motor-evoked potential


Maximal compound wave


Maximal voluntary isometric contraction


Primary motor cortex


Root-mean-square electromyography


Resting motor threshold


Surface electromyography


Short-interval cortical inhibition


Silent period


Transcranial magnetic stimulation


Repetitive transcranial magnetic stimulation


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This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Author information

JM, AF, and DJK conceived and designed the study. JM, AF, GH and DJK conducted experiments, analyzed data, and drafted the first version of the manuscript. AJP, JA critically revised the manuscript. All authors read and approved the manuscript.

Correspondence to Dawson J. Kidgell.

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Mason, J., Frazer, A.K., Avela, J. et al. Tracking the corticospinal responses to strength training. Eur J Appl Physiol (2020).

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  • Corticospinal excitability
  • Cortical plasticity
  • Intracortical facilitation
  • Short-interval cortical inhibition
  • Silent period
  • Strength training