Education Time Influence on Exercise-Induced Hypoalgesia

The use of fliers will be posted on USD campus explaining study and the need for volunteers. Potential volunteers will contact study personal listed on the flier to set up potential time for study enrollment. When the prospective participant arrives, they will be provided a hard copy of informed consent and study personnel will be available to answer questions. If the participant consents and signs, they will then be screened to ensure inclusion/exclusion by answering screening questions.

Once they have consented and met study inclusion/exclusion the participants will then be randomized into 1 of 2 groups by picking a number out of an envelope. Group 1 will receive a more extensive education session (10-15 min) on the benefits of exercise and EIH. Group 2 will receive a brief education session (1 minute) on the benefits of exercise and EIH. Next participants will complete basic demographic information: age, gender, history of injuries, athletic participation history, and Knowledge and Beliefs about Exercise and Pain Questionnaire (questions 1 -4).

Then they will be introduced and tested for pain pressure threshold (PPT). This standard measurement assesses the threshold when a pressure applied to the body passes from pressure to pain. A PPT algometer with a 1 cm tip is used to apply pressure to a body part slowly. When the participant first feels the sensation of pain, the pressure being applied is stopped and the amount of force is recorded as the individual's PPT. The participant will initially be introduced to the testing at the web space of the thumb and index finger on their dominant hand, this is done 3 times with minimum 15 seconds between each measurement and the average of the 3 measurements is used.

Participants then will receive the education about EIH depending on their group allocation last 1 minute or 10-15 minutes. After the education, the participants will be asked question #5 on the Knowledge and Beliefs about exercise and pain questionnaire. Both groups will be shown a picture of the exercise (wall squat) that they will perform and provided instruction on the exercise before they begin. The wall squat exercise will consist of standing upright with their back against the wall with feet 45 cm from the wall, feet parallel and shoulder width apart, and hands at their side. They will slide down the wall bending at the hips and knees, keeping their back against the wall and feet in place until their knee joint angle reaches 100 degrees of flexion measured by the study personnel. All participants are asked to maintain the position for 3 minutes or until fatigued and need to stop.

Prior to beginning the wall squat exercise, participants are asked to rate the intensity of pain in their legs using the Numeric Rating Scale (NRS=0-10, 0=no pain, 10=worst imaginable pain). Pain Pressure Threshold will be measured on the dominant quadriceps muscle and the non-dominate upper trapezius muscle. During the exercise, the NRS and category-ration scale of Rating of Perceived Exertion (CR 10, 0=nothing at all, 10=extremely strong) will be measured while performing the exercise at 1 minute, 2 minutes, and 3 minutes. Immediately post-exercise, Pain Pressure Threshold will be measured again on the dominant quadriceps muscle and the non-dominate upper trapezius muscle. The participants will also be asked to assess exercise expectations on EIH immediately post-exercise.

Inclusion criteria

• Able to read and understand English,
• Refrained from alcohol, pain medication, and vigorous exercise for the past 24 hours,
• No history of chronic pain (pain > 3 months), or current pain/injury that would prevent the ability to do exercise.

Exclusion criteria

• unable to meet screening questions for PAR-Q+ for safe exercise