Sport Physiology & Management Investigations

Sport Physiology & Management Investigations

Adaptations of cortical-spinal excitatory and inhibitory pathways in strength changes caused by resistance training in untrained individuals Based on Transcranial Magnetic Stimulation

Document Type : Original Article

Authors
Aref Basereh 1
Hamid Rajabi 2
Shahriar Gharibzadeh 3
Shapour jaberzadeh 4
1 Ph.D. student in Exercise Physiology, Kharazmi University, Tehran, Iran
2 Professor, Department of Exercise Physiology, Kharazmi University, Tehran, Iran (Corresponding Author)
3 Associate Professor, Institute of Cognitive and Brain Sciences, Shahid Beheshti University, Tehran, Iran
4 Associate Professor, Department of Physiotherapy, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
Abstract
Due to the role of neural adaptations in the primary stages of resistance training, this study aimed to determine the adaptations of cortical-spinal excitatory and inhibitory pathways in strength changes in agonist and antagonist muscles after 4 weeks of resistance training using TMS. 10 healthy untrained individuals participated in this study voluntarily. The training protocol included 4-week of seated one-arm dumbbell curl training with 80% of a one-repetition maximum. To assess MEP and CSP, the area under the curve (AURC) was used, which was obtained based on different intensities of the TMS. Repeated-measures ANOVA and Bonferroni were used to analyze the data. The results showed a 21% and 31% increase in agonist muscle strength in weeks 2 and 4 respectively. In contrast, the antagonist muscle just showed a 15% increase in strength in the fourth week. The area under the MEP curve showed a significant increase after 4 weeks of training (p <0.001) in biceps but not in triceps. In addition, CSP showed a significant decrease in biceps and triceps after 4-week (p> 0.05). However, the changes in corticospinal function were not associated with increased muscle strength. The results of this study showed that cortical-spinal responses to resistance training in the upper body are not limited to trained muscles and the nervous system to increase strength by modulating the cortical areas creates different adaptations for both agonist and antagonist muscles.
Keywords
Agonist
Antagonist
coactivation
Neural adaptations
Resistance training
  1. Mason, J., et al., Determining the early corticospinal-motoneuronal responses to strength training: a systematic review and meta-analysis. Reviews in the Neurosciences, 2019. 30(5): p. 463-476.
  2. Kidgell, D.J., et al., Corticospinal responses following strength training: a systematic review and meta‐analysis. European Journal of Neuroscience, 2017. 46(11): p. 2648-2661.
  3. Basereh, A., Rajabi, D. Application of Transcranial Magnetic Stimulation (TMS) in Exercise Respons and Exercise Adaptations. Sport Physiology, 2022; 14(53): 60-17. doi: 10.22089/spj.2021.10502.2135.
  4. Mason, J., et al., Tracking the corticospinal responses to strength training. European Journal of Applied Physiology, 2020: p. 1-16.
  5. Siddique, U., et al., Determining the sites of neural adaptations to resistance training: a systematic review and meta-analysis. Sports Medicine, 2019: p. 1-25.
  6. Mason, J., et al., Adaptations in corticospinal excitability and inhibition are not spatially confined to the agonist muscle following strength training. European Journal of Applied Physiology, 2017. 117(7): p. 1359-1371.
  7. Mason, J., et al., Modulation of intracortical inhibition and excitation in agonist and antagonist muscles following acute strength training. European journal of applied physiology, 2019. 119(10): p. 2185-2199.
  8. Nuzzo, J., et al., Effects of Four Weeks of Strength Training on the Corticomotoneuronal Pathway. Medicine and science in sports and exercise, 2017. 49(11): p. 2286.
  9. Restuccia, J., Effects of hypertrophy training on spinal and corticospinal excitability within the quadriceps muscle group. 2018.
  10. Kamen, G. and C. Knight, Training-related adaptations in motor unit discharge rate in young and older adults. The journals of gerontology. Series A, Biological sciences and medical sciences, 2004. 59(12): p. 1334-1338.
  11. Narici, M.V., et al., Changes in force, cross-sectional area and neural activation during strength training and detraining of the human quadriceps. European journal of applied physiology and occupational physiology, 1989. 59(4): p. 310-319.
  12. Carroll, T.J., S. Riek, and R.G. Carson, The sites of neural adaptation induced by resistance training in humans. The Journal of physiology, 2002. 544(2): p. 641-652.
  13. Duchateau, J., J. Semmler, and R. Enoka, Training adaptations in the behavior of human motor units. Journal of applied physiology (Bethesda, Md.: 1985), 2006. 101(6): p. 1766.
  14. Del Balso, C. and E. Cafarelli, Adaptations in the activation of human skeletal muscle induced by short-term isometric resistance training. Journal of Applied Physiology, 2007. 103(1): p. 402-411.
  15. Jenkins, N.D., et al., Greater neural adaptations following high-vs. low-load resistance training. Frontiers in physiology, 2017. 8: p. 331.
  16. Farina, D., R. Merletti, and R.M. Enoka, The extraction of neural strategies from the surface EMG: an update. Journal of Applied Physiology, 2014. 117(11): p. 1215-1230.
  17. Carroll, T., et al., Neural adaptations to strength training: moving beyond transcranial magnetic stimulation and reflex studies. Acta physiologica, 2011. 202(2): p. 119-140.
  18. Fimland, M.S., et al., Neural adaptations underlying cross-education after unilateral strength training. European journal of applied physiology, 2009. 107(6): p. 723.
  19. Aagaard, P., et al., Neural adaptation to resistance training: changes in evoked V-wave and H-reflex responses. Journal of applied physiology, 2002.
  20. Lagerquist, O., E.P. Zehr, and D. Docherty, Increased spinal reflex excitability is not associated with neural plasticity underlying the cross-education effect. Journal of Applied Physiology, 2006. 100(1): p. 83-90.
  21. Duclay, J., et al., Spinal reflex plasticity during maximal dynamic contractions after eccentric training. Medicine & Science in Sports & Exercise, 2008. 40(4): p. 722-734.
  22. Fimland, M.S., et al., Functional maximal strength training induces neural transfer to single-joint tasks. European journal of applied physiology, 2009. 107(1): p. 21-29.
  23. Del Vecchio, A., et al., The increase in muscle force after 4 weeks of strength training is mediated by adaptations in motor unit recruitment and rate coding. The Journal of physiology, 2019. 597(7): p. 1873-1887.
  24. Aleman, A., Use of repetitive transcranial magnetic stimulation for treatment in psychiatry. Clinical Psychopharmacology and Neuroscience, 2013. 11(2): p. 53.
  25. Weier, A.T., A.J. Pearce, and D.J. Kidgell, Strength training reduces intracortical inhibition. Acta physiologica, 2012. 206(2): p. 109-119.
  26. Vangsgaard, S., et al., Changes in H reflex and neuromechanical properties of the trapezius muscle after 5 weeks of eccentric training: a randomized controlled trial. Journal of Applied Physiology, 2014. 116(12): p. 1623-1631.
  27. Pearce, A., et al., Corticospinal adaptations and strength maintenance in the immobilized arm following 3 weeks unilateral strength training. Scandinavian journal of medicine & science in sports, 2013. 23(6): p. 740-748.
  28. Lahouti, B., et al., Short-interval intracortical inhibition of the biceps brachii in chronic-resistance versus non-resistance-trained individuals. Experimental brain research, 2019. 237(11): p. 3023-3032.
  29. Tallent, J., et al., Enhanced corticospinal excitability and volitional drive in response to shortening and lengthening strength training and changes following detraining. Frontiers in physiology, 2017. 8: p. 57.
  30. Griffin, L. and E. Cafarelli, Transcranial magnetic stimulation during resistance training of the tibialis anterior muscle. Journal of Electromyography and Kinesiology, 2007. 17(4): p. 446-452.
  31. Kesar, T.M., et al., Agonist-Antagonist Coactivation Enhances Corticomotor Excitability of Ankle Muscles. Neural Plasticity, 2019. 2019.
  32. Latella, C., D.J. Kidgell, and A.J. Pearce, Reduction in corticospinal inhibition in the trained and untrained limb following unilateral leg strength training. European journal of applied physiology, 2012. 112(8): p. 3097-3107.
  33. Roman-Liu, D. and P. Bartuzi, Influence of type of MVC test on electromyography measures of biceps brachii and triceps brachii. International journal of occupational safety and ergonomics, 2018. 24(2): p. 200-206.
  34. Brzycki, M., A practical approach to strength training. 1989: Masters Press Grand Rapids, MI.
  35. Jeyakumar, A., P. Ghugre, and S. Gadhave, Mid-upper-arm circumference (MUAC) as a simple measure to assess the nutritional status of adolescent girls as compared with BMI. ICAN: Infant, Child, & Adolescent Nutrition, 2013. 5(1): p. 22-25.
  36. Christie, A. and G. Kamen, Cortical inhibition is reduced following short-term training in young and older adults. Age, 2014. 36(2): p. 749-758.
  37. Carolan, B. and E. Cafarelli, Adaptations in coactivation after isometric resistance training. Journal of applied physiology, 1992. 73(3): p. 911-917.
  38. Ahtiainen, J.P., et al., Muscle hypertrophy, hormonal adaptations and strength development during strength training in strength-trained and untrained men. European journal of applied physiology, 2003. 89(6): p. 555-563.
  39. Goodwill, A.M., A.J. Pearce, and D.J. Kidgell, Corticomotor plasticity following unilateral strength training. Muscle & nerve, 2012. 46(3): p. 384-393.
  40. Kidgell, D.J. and A.J. Pearce, Corticospinal properties following short-term strength training of an intrinsic hand muscle. Human movement science, 2010. 29(5): p. 631-641.
  41. Coombs, T.A., et al., Cross-education of wrist extensor strength is not influenced by non-dominant training in right-handers. European journal of applied physiology, 2016. 116(9): p. 1757-1769.
  42. Leung, M., et al., The corticospinal responses of metronome-paced, but not self-paced strength training are similar to motor skill training. European journal of applied physiology, 2017. 117(12): p. 2479-2492.
  43. Capaday, C., C. Ethier, and C. Van Vreeswijk, On the functional organization and operational principles of the motor cortex. Frontiers in neural circuits, 2013. 7: p. 66.
  44. Kojima, S., et al., Modulation of the cortical silent period elicited by single-and paired-pulse transcranial magnetic stimulation. BMC neuroscience, 2013. 14(1): p. 1-10.
  45. Lévénez, M., et al., Cortical and spinal modulation of antagonist coactivation during a submaximal fatiguing contraction in humans. Journal of neurophysiology, 2008. 99(2): p. 554-563.
  46. Fisher, B.E., et al., Evidence of altered corticomotor excitability following targeted activation of gluteus maximus training in healthy individuals. Neuroreport, 2016. 27(6): p. 415-421.
  47. Latash, M.L., Muscle coactivation: definitions, mechanisms, and functions. Journal of neurophysiology, 2018. 120(1): p. 88-104.
  48. Clark, B.C., et al., The power of the mind: the cortex as a critical determinant of muscle strength/weakness. Journal of neurophysiology, 2014. 112(12): p. 3219-3226.
  49. Mason, J., et al., Determining the corticospinal responses to single bouts of skill and strength training. The Journal of Strength & Conditioning Research, 2019. 33(9): p. 2299-2307.
  50. Inghilleri, M., et al., Silent period evoked by transcranial stimulation of the human cortex and cervicomedullary junction. The Journal of physiology, 1993. 466(1): p. 521-534.