The Effects of Spinal Manipulation on Motor Unit Behavior

Lucien Robinault (1) , Aleš Holobar (2) , Sylvain Cremoux (1, 3) , Usman Rashid (4) , Imran Khan Niazi (4, 5) , Kelly Holt , Jimmy Lauber (1) , Heidi Haavik

1 LAMIH - Laboratoire d'Automatique, de Mécanique et d'Informatique industrielles et Humaines - UMR 8201
2 Faculty of Electrical Engineering and Computer Science [Maribor]
3 CERCO UMR5549 - Centre de recherche cerveau et cognition
4 AUT - Auckland University of Technology
5 AAU - Aalborg University [Denmark]

Over recent years, a growing body of research has highlighted the neural plastic effects of spinal manipulation on the central nervous system. Recently, it has been shown that spinal manipulation improved outcomes, such as maximum voluntary force and limb joint position sense, reflecting improved sensorimotor integration and processing. This study aimed to further evaluate how spinal manipulation can alter neuromuscular activity. High density electromyography (HD sEMG) signals from the tibialis anterior were recorded and decomposed in order to study motor unit changes in 14 subjects following spinal manipulation or a passive movement control session in a crossover study design. Participants were asked to produce ankle dorsiflexion at two force levels, 5% and 10% of maximum voluntary contraction (MVC), following two different patterns of force production (“ramp” and “ramp and maintain”). A significant decrease in the conduction velocity (p = 0.01) was observed during the “ramp and maintain” condition at 5% MVC after spinal manipulation. A decrease in conduction velocity suggests that spinal manipulation alters motor unit recruitment patterns with an increased recruitment of lower threshold, lower twitch torque motor units.

Mots clés: high-density surface electromyography; chiropractic; electromyography decomposition; motor unit

Domaines: Automatique / Robotique; Neurosciences [q-bio.NC]; Ingénierie biomédicale

Lucien Robinault, Aleš Holobar, Sylvain Cremoux, Usman Rashid, Imran Khan Niazi, et al.. The Effects of Spinal Manipulation on Motor Unit Behavior. Brain Sciences, 2021, 11 (1), pp.105. ⟨10.3390/brainsci11010105⟩. ⟨hal-03424918⟩