Is cortico-cortical inhibition reduced following short-term strength training?

It has been documented that increases in muscle strength during the early phases of a strength training program (first 2–4 weeks) occur in the absence of measurable muscle hypertrophy. These early strength gains have therefore been attributed to neural adaptations. Although there is little evidence in humans clearly defining the site of such neural changes, adaptations at the level of the primary motor cortex have been suggested to play a role. However, whether similar cortical adaptations are apparent following strength training remains unclear. Overall, relatively few studies have examined adaptations in cortical excitability and inhibition with strength training and there is not a clear consensus on the site of adaptation or the time-course of adaptation. Some investigations show a training-related increase in cortical excitability, but very few have investigated changes in cortico-cortical inhibition. An understanding of the sites of neural adaptation in response to strength training can lead to refinement of strength training and rehabilitation techniques. Therefore, the aim of this study is to examine potential cortico-cortical circuits within the human primary motor cortex following a short-term strength training paradigm.