Segmental and plurisegmental modulation of pressure pain thresholds during static muscle contractions in healthy individuals

Abstract

The purpose of this study was to assess possible segmental (uni- and/or bilateral) and plurisegmental changes in pressure pain thresholds (PPTs) during static muscle contractions. Twenty-four healthy subjects (12 female, 12 male) performed a standardised isometric contraction with the dominant m. quadriceps femoris (MQF) and m. infraspinatus (MI), respectively. PPTs were assessed using pressure algometry at the contracting muscle, at the contralateral (resting) muscle and at a distant resting muscle (MI during contraction of MQF and vice versa). The PPT assessments were performed before, during and 30min. following each contraction. The contractions were held until exhaustion or for a maximum of 10 PPT assessments/muscle. During contraction of MQF PPTs increased compared to baseline at the middle ( p<0.001) and the end (p<0.001) of the contraction period at all assessed sites alike. During contraction of MI PPTs increased compared to baseline at the middle (p<0.001) and the end (p<0.007) of the contraction period at all sites. The increase was more pronounced at the contracting muscle compared to the contralateral (p<0.002; p<0.01) and the distant (p<0.002; p<0.002) site. No statistically significant difference was seen in PPTs between the latter two. Following the contractions PPTs returned to baseline. Submaximal isometric contraction of MQF and MI gave rise to a statistically significant increase in PPTs at the contracting muscle, the resting homologous contralateral muscle and at the distant resting muscle indicating that generalised pain inhibitory mechanisms were activated. Contraction of MI, but not of MQF, gave rise to an additional activation of unilateral segmental antinociceptive effects.

Sex-Specific Links in Motor and Sensory Adaptations to Repetitive Motion–Induced Fatigue

“…Despite previous research demonstrating that sensory supplementation has a beneficial effect on sensory function (Freyer, Reinacher, Nolte, Dinse, & Ritter, 2012;Kalisch, Tegenthoff, & Dinse, 2008), our data suggest that stimulation may add the effects of fatigue on the sensory system and lead to a larger decrease in sensory detection capability. Results from other experimental fatigue protocols have found significant increases in sensory thresholds of both fatigued and nonfatigued muscles (Han et al, 2015;Kosek & Lundberg, 2003;Moufflet & Côté, 2015). In our study, significant effects of fatigue were only observed in the SP condition and at a single muscle.…”

Conditioned Pain Modulation Predicts Exercise-Induced Hypoalgesia in Healthy Adults

“…9,16,17,21 Attenuation of pain outside of the exercising muscles suggests that central or systemic mechanisms are involved in EIH. Both opioid and nonopioid mechanisms have been implicated 3,8,13 and include the following: increase in beta endorphins, altered psychological states, interaction between the cardiovascular and pain processing systems, recruitment of high threshold motor units, and activation of the primary motor cortex.…”

Exercise-induced Hypoalgesia Profiles for Pain Prediction in the Trigeminal System

“…This suggests a generalized modulation effect of the pain mechanisms. 12 Studies have shown that swimming can significantly reduce NP 13,14 and reduce mechanical allodynia and thermal hyperalgesia induced by chronic constriction nerve injury (CCI) in rat model of nerve injury. 15 Also, high-intensity swimming exercise can reduce NP in an animal model of complex regional pain syndrome type I.…”