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The Role of Fatigue Associated With Strength Training in Exercise-induced Hypoalgesia

The Role of Fatigue Associated With Different Protocols of Strength Training in Exercise-induced Hypoalgesia: A Randomized Crossover Trial

Status
Not yet recruiting
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07577622
Acronym
FATIGUEIH
Enrollment
27
Registered
2026-05-11
Start date
2026-05-15
Completion date
2027-06-30
Last updated
2026-05-11

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Exercise Induced Hypoalgesia, Healthy Adult Volunteer

Keywords

Fatigue, Exercise, Hypoalgesia, Strength training, Healthy adult, leg extension

Brief summary

Strength exercise is an active and dynamic activity that involves applying force against a resistance. This produces fatigue, seen as a reduced ability to apply force during and after the exercise, and perceived effort, which is a person's subjective feeling of how hard they are working. Strength exercise can also be used for therapy, as it has many benefits for different parts of the body. One of these is changing how the individual feels pain. It has been shown that doing strength exercises can reduce pain perception, a phenomenon called exercise-induced hypoalgesia (EIH), although the exact physical reasons and the amount of exercise needed to cause this effect are not yet known. One of the most studied exercises in this area is the leg extension machine. This is a specific exercise where the legs move freely (open kinetic chain) and the machine guides the movement, which helps keep things stable and limits the effect of other factors. It is usually used to strengthen and grow the muscles in the front of the thigh, especially the quadriceps, but it can also be used to study the effects on EIH. The main goal of this study is to see if fatigue and perceived effort during strength exercise are important for EIH to happen in healthy people. Participants will complete 3 sessions, at least 7 days apart. These will include a control session and 2 sessions designed to show different levels of fatigue. Before, during, and after the sessions, the investigators will measure pain sensitivity, isometric strength, and perceived effort. Also, there will be a test to find the maximum weight for 10 repetitions and several questionnaires to collect basic info (sex, age, height...), weekly physical activity, experience with strength training, and other factors like sleep quality, stress, and mood. All this information will be completely anonymous when the study results are shared.

Interventions

BEHAVIORALSeated leg extension machine: low fatigue

Seated leg extension machine using 10RM external load for 6 sets of 5 repetitions with180 seconds rest between sets and a cadence of 1:2 second concentric:eccentric

BEHAVIORALSeated leg extension machine: high fatigue

Seated leg extension machine using 10RM external load for 3 sets of 10 repetitions with 180 seconds rest between sets and a cadence of 1:2 second concentric:eccentric

BEHAVIORALSeated leg extension: control

Seated leg extension machine using no external load for 6 sets of 5 repetitions with 180 seconds rest between sets and a cadence of 1:2 second concentric:eccentric

Sponsors

Universidad Miguel Hernandez de Elche
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Outcomes Assessor)

Masking description

The Statistician will also be masked

Intervention model description

Double-blind randomized crossover controlled trial

Eligibility

Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes

Inclusion criteria

* Healthy, asymptomatic subjects * Being physically active

Exclusion criteria

* Experiencing episodes of acute pain in any part of the body. * Having chronic pain or a recent history of chronic pain conditions considered resolved within the last 6 months. * Having a serious illness or inability to perform moderate or intense physical activity. * Having taken pain relievers, fever reducers, anti-inflammatory drugs (NSAIDs), steroids, opioids, or similar medications in the 24 hours before a session. * Having consumed alcohol or other psychoactive substances, caffeine, or other stimulants in the 24 hours before a session. * Having performed tiring physical activity or strength exercise in the 24 hours before a session.

Design outcomes

Primary

MeasureTime frameDescription
Pain pressure thresholdBaseline, immediately post-exercise, 30 minutes after exercisePain pressure threshold measured with an analogic algometer (Baseline Dolorimeter, MVS In Motion SL, Belgium), in kilograms. These measurements will be taken at a local level (on one of the thighs, over the rectus femoris of the quadriceps, at the midpoint between the pelvic surface and the patella) and at a distance (on the neck over the belly of one of the upper trapezius muscles, at the midpoint between the surface of C7 and the acromion). The pressure will be applied at a rate of 1kg/s and the patient will be instructed to notify the first instance of pain.
Pressure-evoked painBaseline, immediately post-exercise, 30 minutes after exercisePain evoked by a 6kg pressure exerted with an analogic algometer (Baseline Dolorimeter, MVS In Motion SL, Belgium), at a rate of 1kg/s, measured with a numeric rating scale where zero is equivalent to no pain and 10 indicates the worst possible pain. These measurements will be taken at a local level (on one of the thighs, over the rectus femoris of the quadriceps, at the midpoint between the pelvic surface and the patella) and at a distance (on the neck over the belly of one of the upper trapezius muscles, at the midpoint between the surface of C7 and the acromion).
RPE (Rating of Perceived Exertion)Immediately after each set of the training sessionPerceived exertion was measured on OMNI-Resistance exercise Scale where 0 is equivalent to no effort and 10 indicates maximal exertion.
sRPE (Session rating of perceived exertion)Monitoring will take place 30 minutes after the final set, ensuring that the exertion from the last set does not interfere with the overall session RPE.Session Perceived Exertion was measured on a scale where 0 is equivalent to no effort and 10 indicates maximal exertion.
Repetitions in Reserve (RIR)Immediately after each set of the training session.Using the ERF (Estimated Repetitions to Failure) scale where 0 is equivalent to maximal effort or muscular failure, and higher numbers indicate lower effort. For this purpose, subjects will be asked how many more repetitions they believe they could have performed after each set.
Muscle fatigueBaseline, immediately post-exercise, 30 minutes after exerciseThis will be monitored taking into account objective variables (not dependent on the patient's subjective report), through isometric knee extension action tests measured by dynamometry using a portable load cell (Model 620 Tedea-Huntleigh, Vishay Precision Group Inc., Holon, Israel) and Chronojump software (Chronojump Bosco System, Barcelona, Spain). The variables used are the maximal voluntary isometric contraction (MVIC) measured in Newtons (N) and the Rate of Force Development (RFD) which calculates the slope of the force-time curve.

Secondary

MeasureTime frameDescription
Kinematic measuresDuring each set of the exercise intervention in all 3 sessions (3 or 6 sets depending on each arm). Total measurement time approximately 3 minutes during a single experimental session (as the device will stop recording during rest periods between sets).Angular position (º), velocity(º/s) and acceleration(º/s\^2) of the machine's pad during the exercise will be recorded using an accelerometer (BWT901CL, WitMotion Shenzhen Co., Ltd).
WellnessPrior to each exercise session.Data regarding fatigue, sleep quality, DOMS, stress levels and mood will be tracked every session using a Wellness questionnaire where 5 is the best outcome and 1 is the worst for each individual item.
Fitness levelBaseline (Day 1)The subject's level of physical activity will be collected via the IPAQ (International Physical Activity Questionnaire), which accounts for every physical activity performed throughout the week prior to taking the questionnare and converts them to METs (Metabolic Equivalent of a Task). Higher values indicate higher degree of fitness, and 0 being the floor (zero physical activity).

Countries

Spain

Contacts

CONTACTMiguel Delicado Miralles, Physiotherapy
mdelicado@umh.es+34 679788377

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: May 12, 2026