Clinical trial NCT05299268: Influence of Pain on Exercise-induced Hypoalgesia
Official title: The Influence of Pain on Exercise-Induced Hypoalgesia in Healthy Women
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Pain
Healthy
Lead sponsor: Aalborg University
Sponsor class: OTHER
Collaborators: name: University of Southern Denmark
First posted: 2022-03-28
Enrollment: 34
Sex: FEMALE
Minimum age (years): 18
Maximum age (years): 50
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: This study is a 2-arm randomized controlled cross-over trial with 1-7 days between arms
Primary purpose: BASIC_SCIENCE

Brief summary: The purpose of this study is to investigate how acute pain induced by hypertonic saline prior to exercise influence the magnitude of exercise-induced hypoalgesia after 1x3 min seated isometric knee extension exercise in healthy women. The study is a blinded randomized cross-over trial The results from the study may be of great importance to the understanding of exercise-induced hypoalgesia, and whether the presence of pain affects the effects of exercise.

Detailed description: Exercise is recommended to promote and maintain health and as treatment for more than 25 chronic diseases and pain conditions.

The mechanisms underlying pain relief of exercise are largely unknown but may be related to the modulation of central descending pain inhibitory pathways after acute exercise bouts. Exercise-induced hypoalgesia (EIH) is typically assessed as the temporary change in pressure pain thresholds (PPT) after a short acute exercise bout and EIH is seen as a proxy of descending pain inhibitory control. In general, EIH seems hypoalgesic (functional) in asymptomatic subjects. A hyperalgesic (impaired) EIH response has been reported in different chronic pain populations, although a functional EIH response also has been reported in subgroups of knee osteoarthritis patients. This implies differences in the acute response to exercise between healthy (pain-free) subjects and chronic pain patients, but it is still unknown whether the presence of pain itself affects the pain alleviating response (i.e. the EIH response) to acute exercise.

It is hypothesized that acute pain will decrease the EIH response magnitude following hypertonic saline injection compared with the control injection. This study will increase the insight into the EIH mechanisms in healthy subjects in general, and how the presence of pain affects the body's own ability to modulate pain during exercise.

Eligibility criteria: Inclusion Criteria:

* Pain-free
* Understands and writes Danish

Exclusion Criteria:

* Pregnancy
* Previous addictive behaviour defined as abuse of hash, opioids or other euphoric substances.
* Previous painful or mental illnesses, neurological or circulatory diseases in the form of heart or lung disease.
* Surgery in the lower extremities within the last 12 months
* Chronic or actual pain on the days of testing
* Under the influence on the days of testing
* Inability to cooperate

Primary outcomes:
measure: Change in pressure pain threshold will be assessed over the dominant quadriceps muscle
timeFrame: Baseline, Day 2 (within 1 week of baseline), Day 3 (within 1 week of Day 2)
Secondary outcomes:
measure: Pressure pain threshold at the non-dominant quadriceps muscle and non-dominant trapezius muscle
timeFrame: Baseline, Day 2 (within 1 week of baseline), Day 3 (within 1 week of Day 2)
measure: Pain Intensity in dominant thigh
timeFrame: Assessed before and immediately after hypertonic and isotonic saline injection as well as 1, 2 and 3 minutes into the Seated Isometric Knee Extension, and immediately after the end of the seated isometric knee extension
Other outcomes:
measure: Pressure pain threshold at the dominant and non-dominant thigh as well as non-dominant trapezius muscle
timeFrame: Before and after determining maximal voluntary contraction on the fist test day and prior to saline injections
measure: Rating of perceived exertion (RPE)
timeFrame: Assessed 1, 2 and 3 minutes into the Seated Isometric Knee Extension
measure: Quantifying the individual´s pain experience
timeFrame: Baseline
measure: Pain experience
timeFrame: Day 3 (within 2-3 weeks of the initial session)
Locations:
city: Aalborg
country: Denmark
facility: Dept. Of Health Science and Technology, Aalborg University
Study officials:
affiliation: Aalborg University
name: Steffan WM Christensen, PhD
role: PRINCIPAL_INVESTIGATOR
References: