An interventional study of Fatiguing Exercise in Aging, Muscle Atrophy or Weakness and Sarcopenia in Elderly, sponsored by University of Oregon. Recruiting at 1 site in United States. Open to participants aged 18 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-09.
Sponsored by University of Oregon · Not applicable, Interventional, and Basic science
This study is investigating changes to the proteins in skeletal muscle that contribute to reduced muscle size and muscle function that occurs with aging.
Age-related muscle atrophy and contractile dysfunction have been well described at the cellular level, but the molecular mechanisms that contribute to this dysfunction are poorly understood. Improved understanding of these mechanisms is critically important for the improvement of physical rehabilitation in older adults at risk for mobility impairment and physical disability. Our studies will pursue pre-clinical evidence that post translational modification of specific proteins in skeletal muscle lead to an "aging phenotype" in skeletal muscle that may unlock new strategies for improving physical function in older adults with physical frailty.
1,329 studies on the registry are indexed under Sarcopenia; 420 are open to participants now.
This study's planned enrollment of 24 is below the median of 60 across 855 interventional studies indexed under Sarcopenia.
Browse Sarcopenia studies →University of Oregon is the lead sponsor of 75 studies on the registry; 18 are open to participants now.
Compared within Sarcopenia, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Muscular Atrophy. The counts are of registry records indexed under each term, refreshed daily. How we classify →
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.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Volunteers will perform one-legged knee extension exercise until fatigue while seated on an ergometer. Volunteers will then undergo bilateral skeletal muscle biopsies of the vastus lateralis muscle in their thigh.
Behavioral: Fatiguing Exercise
Volunteers will perform knee extension exercise of the dominant limb while seated in a chair designed for exercise of the knee extensor muscle group. The chair will be equipped with a lever arm, aligned with the axis of rotation of the knee and fixed to the distal shank, 2 centimeters proximal to the ankle joint. The lever arm will be instrumented to provide resistance and measure velocity. The volunteers will perform 3-5 maximum voluntary contractions (MVC) to determine peak torque. Once established, volunteers will rest for 5 minutes before initiating the fatigue protocol, whereby they will perform repeated MVC of the dominant limb against resistance equal to or less than 50% of MVC until range of motion cannot be maintained. Because the goal of this exercise is to uniformly fatigue the quadriceps muscle group, this exercise will be performed continuously. It is expected to take between 1 and 3 minutes to achieve the desired level of fatigue.
Phosphorylation of myosin binding protein c (MyBP-C)
Muscle tissue is immediately frozen after biopsy. Liquid chromatography and high resolution mass spectrometry will be used to do a full analysis of the phosphorylation sites on MyBP-C isolated from the biopsied muscle tissue.
Time frame: One week after the participant undergoes the biopsies.
Muscle fiber Force
Ex vivo assessment of Force (mN) will be performed on muscle fibers and bundles isolated from fatigued and non-fatigued muscle biopsies.
Time frame: Within three weeks of the intervention and biopsies.
Muscle fiber Tension
Ex vivo assessment of Tension (kPa) will be performed on muscle fibers and bundles isolated from fatigued and non-fatigued muscle biopsies.
Time frame: Within three weeks of the intervention and biopsies.
Muscle fiber Velocity
Ex vivo assessment of Velocity (Lo/s) will be performed on muscle fibers and bundles isolated from fatigued and non-fatigued muscle biopsies.
Time frame: Within three weeks of the intervention and biopsies.
Muscle fiber Power
Ex vivo assessment of Power (w/L) will be performed on muscle fibers and bundles isolated from fatigued and non-fatigued muscle biopsies.
Time frame: Within three weeks of the intervention and biopsies.
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Started Nov 2017 (actual). Primary completion is estimated for Jan 2027, 110 months after the start.
Of 492 non-industry interventional studies with no phase under Sarcopenia, half reached primary completion within 18 months of starting (the median), counting those still running; a quarter within 8 and three quarters within 34. This study's planned 110 months is above that.
Counting every sponsor, half of 503 studies reached it within 18 months; a quarter within 8 and three quarters within 34.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
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University of Oregon