Objective: Identify characteristics of patients with myofascial pain syndrome (MPS) of the low back. Methods: Twenty-five subjects with myofascial trigger point(s) [MTrP(s)] on the low back participated in this cross-sectional study. The location, number and type (active or latent) of MTrPs were verified by ultrasound; additionally, data on pain pressure threshold, physical function, quality of life, disability, pain catastrophizing, pain self-efficacy, kinesiophobia, emotional health, exercise motivation and pain were collected. Descriptive statistics, Chi-square, one-way ANOVAs and factorial ANCOVA were used to achieve study objectives. Results: No statistically significant differences in variables were found between types of MTrPs: Group 1 (Active, n=13), 2 (Latent, n=5) 3 (Atypical, no twitching but with spontaneous pain, n=2) and 4 (Atypical, no twitching and no spontaneous pain, n=5) except the number of MTrPs, current pain, and worst pain (p=.01-.001). There were interaction effects between spontaneous pain and twitching response on reports of physical function, current pain level, and worst pain level (p=.04-.002). Participants in Group 3 reported lower levels of physical function, higher levels of current pain, and higher levels of worst pain compared to those in Group 4. Participants in Group 1 and 2 had similar levels of physical function, current pain and worst pain. Discussion: Number of MTrPs is most closely associated with the level of pain. Spontaneous pain report seems to be a decisive factor associated with poor physical function; however, twitching response is not.

The authors have declared no competing interest.

This study was funded by the Research Eureka Accelerator Program (REAP), the Edward Via College of Osteopathic Medicine.

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Auburn University and Edward Via College of Osteopathic Medicine IRB gave ethical approval for this work.

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