Joel Mason1, Ashlyn Frazer1, Deanna M Horvath2, Alan J Pearce1, Janne Avela3, Glyn Howatson4,5, Dawson Kidgell6. 1. Discipline of Exercise Science, School of Allied Health, La Trobe University, Melbourne, Australia. 2. Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Australia. 3. Department of Biology and Physical Activity, University of Jyväskylä, Jyväskylä, Finland. 4. Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle, UK. 5. Water Research Group, School of Environmental Sciences and Development, Northwest University, Potchefstroom, South Africa. 6. Discipline of Exercise Science, School of Allied Health, La Trobe University, Melbourne, Australia. D.Kidgell@latrobe.edu.au.
Abstract
PURPOSE: We used transcranial magnetic stimulation (TMS) to determine the corticospinal responses from an agonist and synergist muscle following strength training of the right elbow flexors. METHODS: Motor-evoked potentials were recorded from the biceps brachii and flexor carpi radialis during a submaximal contraction from 20 individuals (10 women, 10 men, aged 18-35 years; training group; n = 10 and control group; n = 10) before and after 3 weeks of strength training at 80% of 1-repetition maximum (1-RM). To characterise the input-output properties of the corticospinal tract, stimulus-response curves for corticospinal excitability and inhibition of the right biceps brachii and flexor carpi radialis were constructed and assessed by examining the area under the recruitment curve (AURC). RESULTS:Strength training resulted in a 29% (P < 0.001) increase in 1-RM biceps brachii strength and this was accompanied by a 19% increase in isometric strength of the wrist flexors (P = 0.001). TMS revealed an increase in corticospinal excitability AURC and a decrease in silent period duration AURC for the biceps brachii and flexor carpi radialis following strength training (all P < 0.05). However, the changes in corticospinal function were not associated with increased muscle strength. CONCLUSION: These findings show that the corticospinal responses to strength training of a proximal upper limb muscle are not spatially restricted, but rather, results in a change in connectivity, among an agonist and a synergistic muscle relevant to force production.
RCT Entities:
PURPOSE: We used transcranial magnetic stimulation (TMS) to determine the corticospinal responses from an agonist and synergist muscle following strength training of the right elbow flexors. METHODS: Motor-evoked potentials were recorded from the biceps brachii and flexor carpi radialis during a submaximal contraction from 20 individuals (10 women, 10 men, aged 18-35 years; training group; n = 10 and control group; n = 10) before and after 3 weeks of strength training at 80% of 1-repetition maximum (1-RM). To characterise the input-output properties of the corticospinal tract, stimulus-response curves for corticospinal excitability and inhibition of the right biceps brachii and flexor carpi radialis were constructed and assessed by examining the area under the recruitment curve (AURC). RESULTS: Strength training resulted in a 29% (P < 0.001) increase in 1-RM biceps brachii strength and this was accompanied by a 19% increase in isometric strength of the wrist flexors (P = 0.001). TMS revealed an increase in corticospinal excitability AURC and a decrease in silent period duration AURC for the biceps brachii and flexor carpi radialis following strength training (all P < 0.05). However, the changes in corticospinal function were not associated with increased muscle strength. CONCLUSION: These findings show that the corticospinal responses to strength training of a proximal upper limb muscle are not spatially restricted, but rather, results in a change in connectivity, among an agonist and a synergistic muscle relevant to force production.
Authors: Richard G Carson; Barry D Nelson; Alison R Buick; Timothy J Carroll; Niamh C Kennedy; Rachel Mac Cann Journal: Brain Stimul Date: 2013-02-24 Impact factor: 8.955
Authors: Scott R Brown; Edward P Washabaugh; Aviroop Dutt-Mazumder; Edward M Wojtys; Riann M Palmieri-Smith; Chandramouli Krishnan Journal: Sports Health Date: 2020-12-18 Impact factor: 3.843