Objective: The purpose of this study was to investigate if spinal manipulative therapy (SMT) can evoke immediate regional antinociceptive effects in myofascial tissues by increasing pressure pain thresholds (PPTs) over myofascial trigger points in healthy young adults.
Methods: A total of 36 participants (19 men, 17 women; age, 28.0 [5.3] years; body mass index, 26.5 [5.7] kg/m(2)) with clinically identifiable myofascial trigger points in the infraspinatus and gluteus medius muscles were recruited from the University of Guelph, Ontario, Canada. Participants were randomly allocated to 2 groups. Participants in the test group received chiropractic SMT targeted to the C5-C6 spinal segment. Participants in the control group received sham SMT. The PPT was recorded from the right infraspinatus and gluteus medius muscles at baseline (preintervention) and 1, 5, 10, and 15 minutes postintervention.
Results: Three participants were disqualified, resulting in a total of 33 participants analyzed. Significant increases in the PPT (decreased pain sensitivity) were observed in the test infraspinatus group when compared with test gluteus medius, control infraspinatus, and control gluteus medius groups (P < .05). No significant differences in PPT were observed at any time point when comparing test gluteus medius, control infraspinatus, and control gluteus medius groups (P > .05).
Conclusions: This study showed that SMT evokes short-term regional increases in PPT within myofascial tissues in healthy young adults.
Keywords: Chiropractic; Manipulation; Myofascial Pain Syndrome; Myofascial Trigger Point; Pain Threshold.
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