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NCT Number: NCT05299268

Influence of Pain on Exercise-induced Hypoalgesia

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.

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Key information

Conditions

Pain Healthy Neurologic Manifestations Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–50 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Dept. Of Health Science and Technology, Aalborg University

Aalborg, 9220, Denmark

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Pain (hypertonic saline)

Behavioral

A bolus injection (1 ml) of hypertonic saline (5.8%) is injected into the dominant vastus medialis muscle 20 cm proximal from the basis of patella before performance of the 1x3 min Seated Isometric Knee Extension.

No pain (Isotonic saline)

Behavioral

A bolus injection (1 ml) of isotonic saline (0.9%) is injected into the dominant vastus medialis muscle 20 cm proximal from the basis of patella before performance of the 1x3 min Seated Isometric Knee Extension

Primary outcomes

  1. Change in pressure pain threshold will be assessed over the dominant quadriceps muscle

    Time frame: Baseline, Day 2 (within 1 week of baseline), Day 3 (within 1 week of Day 2)

    Between group comparison of the primary outcome, which is change in pressure pain threshold over the dominant quadriceps muscle before and after performing seated isometric knee extension.

    Pressure pain threshold is measured with a handheld pressure algometer.

Secondary outcomes

  1. Pressure pain threshold at the non-dominant quadriceps muscle and non-dominant trapezius muscle

    Time frame: Baseline, Day 2 (within 1 week of baseline), Day 3 (within 1 week of Day 2)

    Between group comparison of the secondary outcome, which is change in pressure pain threshold at the non-dominant quadriceps muscle and non-dominant trapezius muscle from before Seated Isometric Knee Extension to after Seated Isometric Knee Extension.

    Pressure pain threshold is measured with a handheld pressure algometer.

  2. Pain Intensity in dominant thigh

    Time frame: 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

    Pain intensity is assessed with numerical rating scales with 0 = no pain and 10 = maximal pain.

Other outcomes

  1. Pressure pain threshold at the dominant and non-dominant thigh as well as non-dominant trapezius muscle

    Time frame: Before and after determining maximal voluntary contraction on the fist test day and prior to saline injections

    Pressure pain threshold is measured with a handheld pressure algometer.

  2. Rating of perceived exertion (RPE)

    Time frame: Assessed 1, 2 and 3 minutes into the Seated Isometric Knee Extension

    Perceived exertion is assessed with Borg RPE scale with 6 = no exertion and 20 = maximal exertion

  3. Quantifying the individual´s pain experience

    Time frame: Baseline

    Quantifying the individual´s pain experience will be assessed using the Pain Catastrophizing Scale (PCS) at the first session. The pain catastrophizing scale have 13 sentences regarding pain-related thoughts. Participants are asked to indicate how well each sentence applies for them: 0 = not at all, 1 = to a slight degree, 2 = to a moderate degree, 3 = to a great degree and 4 = all the time. A higher score is worse

  4. Pain experience

    Time frame: Day 3 (within 2-3 weeks of the initial session)

    Participants will be interviewed at the end of the study regarding the experience of pain during the study. The interview will be conducted after all other experimental procedures have been completed.

Sponsors and collaborators

Lead sponsor

Aalborg University

Other

Collaborators

  • University of Southern Denmark

Registry information

Official study title

The Influence of Pain on Exercise-Induced Hypoalgesia in Healthy Women

Important dates

Study start
2022
Primary completion
2022
Study completion
2022
First posted
Mar 28, 2022
Registry last updated
Apr 20, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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