A randomized, double blind, parallel groups, sham-controlled trial.
The aim of this study was to analyze the acute effects of spinal manipulative therapy (SMT) on performance and autonomic modulation.
The use of SMT is progressively spreading from the clinical to the sporting context owing to its purported ergogenic effects. However, its effects remain unclear.
Thirty-seven male recreational athletes (aged 37 ± 9 years) who had never received SMT were assigned to a sham (n = 19) or actual SMT group (n = 18). Study endpoints included autonomic modulation (heart rate variability), handgrip strength, jumping ability, and cycling performance [8-minute time trial (TT)]. Differences in custom effects between interventions were determined using magnitude-based inferences.
A significant and very likely lower value of a marker of sympathetic modulation, the stress score, was observed in response to actual compared with sham SMT [P = 0.007; effect size (ES) = -0.97]. A trend toward a significant and likely lower sympathetic:parasympathetic ratio (P = 0.055; ES = -0.96) and a likely higher natural logarithm of the root-mean-square differences of successive heartbeat intervals [(LnRMSSD), P = 0.12; ES = 0.36] was also found with actual SMT. Moreover, a significantly lower mean power output was observed during the TT with actual compared with sham SMT (P = 0.035; ES = -0.28). Nonsignificant (P > 0.05) and unclear or likely trivial differences (ES < 0.2) were found for the rest of endpoints, including handgrip strength, heart rate during the TT, and jump loss thereafter.
A single pre-exercise SMT session induced an acute shift toward parasympathetic dominance and slightly impaired performance in recreational healthy athletes.
Level of Evidence: 2
This randomized, double blind, parallel groups, sham-controlled trial analysed the acute effects of spinal manipulative therapy on performance and autonomic modulation in 37 male recreational athletes. Our results show that this strategy induced an acute shift towards parasympathetic dominance and slightly impaired performance in recreational healthy athletes.
∗Physiology Unit, Systems Biology Department, University of Alcalá, Madrid, Spain
†Department of Sport and Health, Spanish Agency for Health Protection in Sport (AEPSAD), Madrid, Spain
‡San Lorenzo de El Escorial – Madrid College of Chiropractic (MCC), Madrid, Spain
§Faculty of Sport Sciences, Universidad Europea de Madrid, Madrid, Spain.
Address correspondence and reprint requests to Pedro L. Valenzuela, MSc, Physiology Unit, Department of Systems Biology, School of Medicine, University of Alcalá, Ctra. Barcelona, Km 33,600, 28871. Alcalá de Henares, Madrid 28871, Spain; E-mail: email@example.com
Received 27 June, 2018
Revised 18 September, 2018
Accepted 28 September, 2018
Pedro L. Valenzuela and Sara Pancorbo contributed equally.
The manuscript submitted does not contain information about medical device(s)/drug(s).
Pedro L. Valenzuela is supported by a contract granted by University of Alcalá (FPI2016).
No relevant financial activities outside the submitted work.