Massage and the Gate Control Model

Abstract

Purpose: Musculoskeletal pain is a significant problem in the United States, and medical interventions are not always effective in alleviating pain. Complementary therapies such as massage have been shown to have potent effects in reducing pain, stress and fatigue, as well as improving immune function and restoring function to damaged musculoskeletal tissue. However, rigorous evaluation of the mechanisms of massage is still in its infancy. The goal of the present study was to examine potential mechanisms of massage using the theoretical framework of the gate control model, which provides a framework for examining both sensory and cognitive/emotional mechanisms of massage. Methods: The current study examined the experience of experimentally-induced pain across four study groups in a repeated measures design. Female undergraduate participants and female community participants were randomly assigned to either a no-treatment control group, guided imagery alone group, massage alone group, or massage plus guided imagery group. Pain and affect were assessed after each of three stimulation periods and two rest periods to determine if group assignment has a differential effect on the experience of pain and affect. Relaxation was assessed after the intervention period to determine if group assignment had a differential effect on self-report relaxation level. Heart-rate, respiration, and blood pressure were recorded continuously throughout the experimental period to determine if group assignment had a differential effect on sympathetic or parasympathetic outcomes. Results: Contrary to study hypotheses there were no group differences in pain threshold, pain tolerance, pain intensity, worst pain intensity or least pain intensity. Pain unpleasantness and residual pain intensity, on-the-other hand, did show group differences. Specifically, pain unpleasantness, increased for the control group, while remaining at baseline stimulation levels for the guided imagery alone, massage alone, and massage plus guided imagery groups. Residual pain intensity remained at baseline stimulation levels for the control and guided imagery alone groups, while decreasing for the massage alone and massage plus guided imagery groups during intervention. Regarding primary affect outcomes, all three intervention groups reported a decrease in unpleasant affect during intervention and recovery, while the control group maintained baseline levels of unpleasant affect throughout the study. Pleasant affect decreased for the control and guided imagery alone groups during intervention and recovery, while the two massage groups were able to maintain baseline levels of pleasant affect throughout the study. In addition, the two massage groups reported significantly greater levels of self-report relaxation during intervention compared to the control group and guided imagery alone group. Preliminary group differences in sympathetic MHR and MIBI activity were found to be mediated by individual affect and self-report relaxation levels. Conclusions: These findings support past research that recommends massage as an intervention for pain, and suggests that massage produces influences on ascending pain, as well as unique effects on affect and relaxation compared to guided imagery. Results provided some support for the commonly cited hypothesis that massage decreases ascending pain signals, but suggest that massage may alter affective and secondary qualities of pain versus physically interrupting pain signals via the GCM ascending pain pathway. Overall, these results provide evidence for the value of massage in mental and physical health outcomes.