Neuromuscular changes and the rapid adaptation following a bout of damaging eccentric exercise

Goodall, S.; Thomas, K.; Barwood, M.; Keane, K.; Gonzalez, J. T.; St Clair Gibson, A.; Howatson, G.

Abstract

Introduction
An initial bout of eccentric exercise is known to protect against muscle damage following a repeated bout of the same exercise; however, the neuromuscular adaptations owing to this phenomenon are unknown.

Aim
To determine whether neuromuscular disturbances are modulated following a repeated bout of eccentric exercise.

Methods
Following eccentric exercise performed with the elbow flexors, we measured maximal voluntary force, resting twitch force, muscle soreness, creatine kinase (CK) and voluntary activation (VA) using motor point and motor cortex stimulation at baseline, immediately post‐exercise and at 1, 2, 3, 4 and 7 days post‐exercise on two occasions, separated by 3 weeks.

Results
Significant muscle damage and fatigue were evident following the first exercise bout; maximal voluntary contraction (MVC) was reduced immediately by 35% and remained depressed at 7 days post‐exercise. Soreness and CK release peaked at 3 and 4 days post‐exercise respectively. Resting twitch force remained significantly reduced at 7 days (−48%), whilst VA measured with motor point and motor cortex stimulation was reduced until 2 and 3 days respectively. A repeated bout effect (RBE) was observed with attenuated soreness and CK release and a quicker recovery of MVC and resting twitch force. A similar decrement in VA was observed following both bouts; however, following the repeated bout there was a significantly smaller reduction in, and a faster recovery of, VA measured using motor cortical stimulation.

Conclusion
Our data suggest that the RBE may be explained, partly, by a modification in motor corticospinal drive.

Citation

Goodall, S., Thomas, K., Barwood, M., Keane, K., Gonzalez, J. T., St Clair Gibson, A., & Howatson, G. (2017). Neuromuscular changes and the rapid adaptation following a bout of damaging eccentric exercise. Acta Physiologica, 220(4), 486-500. https://doi.org/10.1111/apha.12844

• Journal Article Type: Article
• Acceptance Date: Dec 7, 2016
• Online Publication Date: Dec 16, 2016
• Publication Date: 2017-08
• Deposit Date: Jan 27, 2021
• Journal: Acta Physiologica
• Print ISSN: 1748-1708
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 220
• Issue: 4
• Pages: 486-500
• DOI: https://doi.org/10.1111/apha.12844
• Keywords: Fatigue; Lengthening contractions; Motor cortex; Recovery; Repeated bout; Stimulation
• Public URL: https://hull-repository.worktribe.com/output/3703070
• Publisher URL: https://onlinelibrary.wiley.com/doi/abs/10.1111/apha.12844
• Related Public URLs: http://nrl.northumbria.ac.uk/id/eprint/28835/