Mechanisms of Massage

Study Overview
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Brief Summary
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The investigators have previously found moderately painful massage produces comparable changes in pain sensitivity as a conditioned pain modulation paradigm in healthy participants suggesting shared underlying mechanisms. The researchers aim to extend these findings by understanding the influence of expectation on these findings.

Detailed Description
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Massage is a muscle biased intervention individuals seek for pain alleviation; however, the mechanisms of massage are not well established. In this study, the investigators aim to determine the effect of expectations on massage related hypoalgesia. Individuals meeting eligibility criteria and agreeing to participate will attend one session that lasts approximately one hour. A myofascial trigger point (taut band of muscle tissue) will be assessed on the neck of the participant. Next, a baseline assessment of pressure pain threshold will be performed followed by random assignment to one of four study arms.

Official Title
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Mechanisms of Massage

Conditions
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Healthy, Pain

Intervention / Treatment
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* Other: Pain Inducing Massage
* Other: Pain Free Massage
* Other: Positive Expectation Instructional Set
* Other: Negative Expectation Instructional Set


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Pain Free Exclusion Criteria: non-English speaking systemic medical condition known to affect sensation (i.e. diabetes) regular use of prescription pain medication to manage pain current or history of chronic pain condition currently using blood thinning medication any blood clotting disorder such as hemophilia

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Pain Inducing Massage and Positive Expectation Instructions<br>A myofascial trigger point will be assessed in the trapezius muscle and massage applied to this area of the neck. Participants in this arm will receive a positive expectation instructional set followed by a moderately painful massage (pain = 50/100). Massage will be applied for one minute, four times with assessment of pressure pain threshold at the foot between each interval. | Other: Pain Inducing Massage<br>* A pain inducing massage (pain intensity = 50/100) will be applied for 60 seconds, 4 times.<br>Other: Positive Expectation Instructional Set<br>* Participants will be instructed that the massage is effective for some people with neck pain.<br>|
| Active Comparator: Pain Inducing Massage and Negative Expectation Instructions<br>A myofascial trigger point will be assessed in the trapezius muscle and massage applied to this area of the neck. Participants in this arm will receive a negative expectation instructional set followed by a moderately painful massage (pain = 50/100). Massage will be applied for one minute, four times with assessment of pressure pain threshold at the foot between each interval. | Other: Pain Inducing Massage<br>* A pain inducing massage (pain intensity = 50/100) will be applied for 60 seconds, 4 times.<br>Other: Negative Expectation Instructional Set<br>* Participants will be instructed that the massage is ineffective for some people with neck pain.<br>|
| Active Comparator: Pain Free Massage and Positive Expectation Instructions<br>A myofascial trigger point will be assessed in the trapezius muscle and massage applied to this area of the neck. Participants in this arm will receive a positive expectation instructional set followed by a pain free massage (pain = 0/100). Massage will be applied for one minute, four times with assessment of pressure pain threshold at the foot between each interval. | Other: Pain Free Massage<br>* A pain free massage (pain intensity = 0/100) will be applied for 60 seconds, 4 times.<br>Other: Positive Expectation Instructional Set<br>* Participants will be instructed that the massage is effective for some people with neck pain.<br>|
| Active Comparator: Pain Free Massage and Negative Expectation Instructions<br>A myofascial trigger point will be assessed in the trapezius muscle and massage applied to this area of the neck. Participants in this arm will receive a negative expectation instructional set followed by a pain free massage (pain = 0/100). Massage will be applied for one minute, four times with assessment of pressure pain threshold at the foot between each interval. | Other: Pain Free Massage<br>* A pain free massage (pain intensity = 0/100) will be applied for 60 seconds, 4 times.<br>Other: Negative Expectation Instructional Set<br>* Participants will be instructed that the massage is ineffective for some people with neck pain.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pressure Pain Threshold | A computerized pressure algometer with a 1cm diameter rubber tip will be applied to the web space of the non-dominant foot. Participants are instructed to say stop so the stimulus can be terminated when the sensation first transitions from pressure to pain (threshold). | 1 hour |