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.
Age range
18 Years – 45 Years
Sex
ALL
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AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
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Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
Pain pressure threshold
Timeframe: Baseline, immediately post-exercise, 30 minutes after exercise
Pressure-evoked pain
Timeframe: Baseline, immediately post-exercise, 30 minutes after exercise
RPE (Rating of Perceived Exertion)
Timeframe: Immediately after each set of the training session
sRPE (Session rating of perceived exertion)
Timeframe: 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.
Repetitions in Reserve (RIR)
Timeframe: Immediately after each set of the training session.
Muscle fatigue
Timeframe: Baseline, immediately post-exercise, 30 minutes after exercise