An interventional study of Knee immobilization brace (0°) for 5 days and Knee immobilization brace (60°) for 5 days in Muscle Atrophy, Disuse Atrophy and Immobilization, sponsored by Wageningen University. Not yet recruiting. Open to participants aged 18 Years to 40 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-08.
Sponsored by Wageningen University · Not applicable, Interventional, and Basic science
This study looks at what happens to leg muscles when the knee is kept straight or bent during five days of wearing a brace. We want to find out if keeping the knee bent (so the thigh muscle is stretched) helps prevent muscle loss compared to keeping the knee straight. Thirty healthy adults will take part. They will wear a knee brace for five days and have several tests before and after, including scans, blood samples, and small muscle samples. The results may help doctors find better ways to protect muscles when people cannot move, for example after surgery or illness.
Short periods of physical inactivity, as occur during illness, surgery, or injury, lead to rapid and substantial losses of muscle mass, strength, and metabolic health, often with incomplete recovery in vulnerable individuals. In older adults, repeated bouts of disuse are thought to contribute significantly to age-related sarcopenia. Despite decades of research, the underlying mechanisms remain incompletely elucidated, and effective therapeutic interventions are lacking.
Mechanistically, any muscle atrophy must occur due to a negative muscle protein net balance (MPNB), which can be caused by a decline in muscle protein synthesis (MPS), an increase in muscle protein breakdown (MPB), or a combination of both. Normally, exercise and dietary protein stimulate MPS and maintain muscle mass. During disuse, however, exercise is often impossible, and inactive muscle shows a blunted response to dietary protein. Consequently, these potent strategies become ineffective or even harmful in inactive individuals, highlighting the need for alternative approaches.
Animal studies indicate that immobilizing a muscle in a lengthened (stretched) position can attenuate disuse-induced muscle atrophy and functional decline compared to a shortened position. Whether this phenomenon also occurs in humans, and whether passive muscle length and tension influence muscle metabolism during disuse, remain unexplored.
The objective of this study is to assess whether immobilizing the quadriceps in a lengthened versus neutral position during disuse attenuates losses of muscle mass, function, and metabolic health.
In this randomized, controlled human intervention study with 2 parallel groups 30 healthy, normal weight males and females (18-40 years old, BMI between 18 and 30 kg·m-2) will undergo 5 days of unilateral leg immobilization using a knee brace that prevents voluntary quadriceps contraction. In the neutral group, the leg is fixed in full extension (0° flexion), while in the lengthened group it is fixed at 60° flexion, stretching the quadriceps.
The effects on muscle protein net balance (MPNB), quadriceps muscle volume , muscle quality, muscle strength, fatigue resistance, and muscle mitochondrial bioenergetics will be assessed.
412 studies on the registry are indexed under Muscular Atrophy; 77 are open to participants now.
This study's planned enrollment of 30 is below the median of 40 across 326 interventional studies indexed under Muscular Atrophy.
Browse Muscular Atrophy studies →Wageningen University is the lead sponsor of 153 studies on the registry; 15 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants in this group wear a knee brace in full extension (0°) for five consecutive days.
Device: Knee immobilization brace (0°) for 5 days
Participants in this group wear a knee brace in flexion (60°) for five consecutive days.
Device: Knee immobilization brace (60°) for 5 days
Unilateral knee immobilization at 0° flexion for 5 days using a brace; post-immobilization metabolic testing with tracer infusions and biopsies
Unilateral knee immobilization at 60° flexion for 5 days using a brace; post-immobilization metabolic testing with tracer infusions and biopsies
Muscle protein net balance (MPNB)
Muscle protein net balance expressed as %/h and calculated as the difference between muscle protein synthesis (MPS; fractional synthesis rate, FSR) and muscle protein breakdown (MPB; fractional breakdown rate, FBR), measured in skeletal muscle following 5 days of unilateral knee immobilization
Time frame: Baseline to 3 hours after tracer infusion
Thigh muscle volume
Thigh muscle volume, including muscle length and cross-sectional area, measured via Magnetic Resonance Imaging (MRI)
Time frame: Baseline and after 5 days of immobilization
Muscle strength
Maximal voluntary muscle strength measured as peak torque using isokinetic dynamometry
Time frame: Baseline and after 5 days of immobilization
Muscle fatigue
Muscle fatigue assessed as decline in force during repeated contractions measured using isokinetic dynamometry
Time frame: Baseline and after 5 days of immobilization
Intramuscular fat content
Intramuscular lipid content measured using 1H-magnetic resonance spectroscopy (1H-MRS)
Time frame: Baseline and after 5 days of immobilization
Muscle metabolite concentrations
Carnosine and acetylcarnitine concentrations in skeletal muscle measured using 1H-magnetic resonance spectroscopy (1H-MRS)
Time frame: Baseline and after 5 days of immobilization
Mitochondrial respiration
Mitochondrial respiration measured as oxygen consumption in permeabilized muscle fibres using high-resolution respirometry
Time frame: Baseline and after 5 days of immobilization
Mitochondrial reactive oxygen species production
Mitochondrial reactive oxygen species (ROS) production measured using fluorescence-based detection in permeabilized muscle fibres
Time frame: Baseline and after 5 days of immobilization
Mitochondrial calcium retention capacity
Calcium retention capacity measured in permeabilized muscle fibres using fluorescence-based assays
Time frame: Baseline and after 5 days of immobilization
Muscle gene expression related to atrophy
Expression of genes involved in muscle atrophy measured in skeletal muscle biopsy samples using molecular analysis techniques (e.g. qPCR or RNA sequencing)
Time frame: Baseline and after 5 days of immobilization
Muscle protein markers of atrophy
Protein expression of markers related to muscle protein synthesis and breakdown measured in skeletal muscle biopsy samples
Time frame: Baseline and after 5 days of immobilization
Plasma amino acid concentration
Plasma concentration of amino acids measured in venous blood samples
Time frame: Baseline to 3 hours after tracer infusion
Serum insulin concentration
Serum insulin concentration measured in venous blood samples
Time frame: Baseline and up to 3 hours after tracer infusion
Body weight
Body weight measured in kilograms
Time frame: Baseline (pre-intervention)
Height
Height measured in meters
Time frame: Baseline (pre-intervention)
Body mass index (BMI)
Body mass index calculated as kg/m²
Time frame: Baseline (pre-intervention)
Body composition
Fat mass and lean mass measured using DXA
Time frame: Baseline (pre-intervention)
No study locations are listed for this record.
Start is estimated for Aug 2026; primary completion for Mar 2028, 19 months later.
Of 168 non-industry interventional studies with no phase under Muscular Atrophy, half reached primary completion within 22 months of starting (the median), counting those still running; a quarter within 9 and three quarters within 41. This study's planned 19 months is below that.
Counting every sponsor, half of 174 studies reached it within 22 months; a quarter within 9 and three quarters within 37.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
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