An investigation of the effects of acupuncture upon experimentally-induced myogenic pain

Abstract

Acupuncture has been promoted as a potent analgesic modality in the treatment of musculoskeletal pain. Despite such claims, the quality and standard of the supporting literature has been criticised. The aim of the current thesis was to investigate the analgesic efficacy of acupuncture upon experimentally induced myogenic pain utilising standardised pain induction techniques [namely those of experimentally-induced ischaemic pain and delayed onset muscle soreness (DOMS)], and to compare the putative analgesic effect of this modality with commonly available oral analgesics (codeine, aspirin and paracetamol) and ascorbic acid. Additionally, in an effort to elucidate possible neurophysiological mechanisms involved in exercise-induced muscle pain and soreness, an investigation of the effects of an ischaemic block upon DOMS-induced mechanical allodynia was carried out. Results from the investigations on the analgesic efficacy of acupuncture revealed no hypoalgesic effect of this modality upon DOMS and a slight hypoalgesic effect upon experimentally induced ischaemic pain; this latter effect was observed for both acupuncture and placebo acupuncture stimulation. Comparable results were obtained in the investigation of the effect of common oral analgesics and ascorbic acid upon DOMS; again, no hypoalgesic/analgesic effect of these agents upon exercise induced muscle pain was demonstrated. In the study examining the effect of an ischaemic block upon DOMS-induced mechanical allodynia interesting results were found. It was shown that mechanical pain threshold reached normal values in subjects experiencing DOMS-induced mechanical allodynia when an ischaemic block was applied. These results suggest that this type of allodynia is mediated, at least in part, by large diameter myelinated afferent fibres. Thus, based on the results of these investigations, it may be suggested that acupuncture has demonstrated no hypoalgesic effect upon experimentally induced muscle pain. Additionally, the current thesis highlights the difficulty in conducting placebo-controlled acupuncture studies, as well as the complex pathophysiology of delayed-onset muscle soreness and exercise-induced muscle damage.

Date of Award	Apr 1997
Original language	English