Pain Modulatory Profiles in Massage for Healthy Participants

One in ten adults experience widespread pain. Neck pain, for example, is a prevalent condition with a high rate of recurrence that affects between 10.4% and 21.3% of the population annually. Massage is a common manual therapy intervention for individuals with musculoskeletal pain. However, the mechanisms of massage are not well established. Also, the conditioned pain modulation (CPM) paradigm is a dynamic quantitative sensory testing measure of a pain inhibitory process in which pain sensitivity is lessened in response to a remotely applied painful stimulus. This study will evaluate the association between pain inducing massage and the conditioned pain modulation paradigm.

Conditioned pain modulation (CPM) is the physical manifestation of the diffuse noxious inhibitory control (DNIC), an endogenous pain inhibitory pathway in which pain inhibits pain. Conditioned pain modulation is less efficient in individuals with chronic pain conditions and it is a predictor for the development of chronic pain. Massage is a common manual therapy intervention for individuals with musculoskeletal pain. Greater changes in pain sensitivity occur following pain inducing massage suggesting a mechanism dependent upon the efficiency of the conditioned pain modulation response. The study team will evaluate the association between pain inducing massage and the conditioned pain modulation paradigm. Healthy participants will be randomly assigned to receive a pain inducing massage, a pain free massage, or participate in a coldpressor task. Pre-and post intervention pain sensitivity including conditioned pain modulation will be assessed. The study team will determine if analgesia induced by massage is similar to the conditioned pain modulation paradigm and compare changes in pain sensitivity between groups. Previous research has indicated pain inducing massage is more effective than pain free massage suggesting a mechanism dependent upon conditioned pain modulation. However, this study will be the first to systematically investigate if analgesia induced by pain inducing massage is similar to the conditioned pain modulation paradigm. Furthermore, this study will be the first to determine the association between baseline conditioned pain modulation and massage related hypoalgesia.

Participants will place hand into water cooled to 6 degrees Celsius (males) or 8 degrees Celsius (females).

Participants will receive 60 seconds of manual pressure applied to one myofascial trigger point so the participant rates the pain = 5/10 on a scale from 0 to 10. This will be followed by 30 seconds of complete pressure release. This will occur 4 times.

Participants will receive 60 seconds of light touch applied to one myofascial trigger point so the participant rates the pain = 0/10 on a scale from 0 to 10. This will be followed by 30 seconds of complete pressure release. This will occur 4 times.

Participants will place their non-dominant hand into water cooled by a refrigeration unit temperature of 6 degrees Celsius (males) or 8 degrees Celsius (females). The participant will place his or her hand in the cooled water for 60 seconds followed by a 30 second break in which the participant will remove his or her hand from the water. This will occur 4 times.

Temperature at which ascending thermal stimulus first changes from warm to painful and maximum temperature tolerated

Participants will rate their pain using a 101 point mechanical visual analog scale to thermal stimuli of 45, 47, 49, and 50 degree Celsius each of 5 seconds duration will be applied to the forearm and to the muscle on the side of the neck

Participants will rate their pain using a 0 to 10 numeric rating scale to a train of 10 50 degree Celsius heat pulses will be applied to the skin in the plantar surface of the hand.

Pressure in kilograms at which ascending pressure stimulus applied to the foot first changes from pressure to painful both prior to and immediately following immersion of the opposite hand in a cold water bath

Inclusion Criteria: pain free blood pressure under 140/90 mmHg ability of therapist to locate necessary trigger points on participant Exclusion Criteria: blood pressure over 140/90 mmHg inability of therapist to locate necessary trigger points on participant 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 any contraindication to application of ice or cold pack, such as: uncontrolled hypertension, cold urticaria, cryoglobulinemia, paroxysmal cold hemoglobinuria, and circulatory compromise non-English speaking