Muscle AtrophyPIENCT04900701
The Impact of Energy Intake and Short-term Disuse on Muscle Protein Synthesis Rates and Skeletal Muscle Mass in Middle-aged Adults.
A study testing Energy status in people with Muscle Atrophy and Aging, run by University of Exeter at 2 sites in United Kingdom.
Trial summary
In healthy middle-aged men and women, what is the effect of dietary energy restriction and energy surplus on daily muscle protein synthesis rates and muscle morphology, compared to energy balance, during free-living and immobilisation? Read more about this study
- Who is it for?
- Ages 35 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Muscle Atrophy, Aging, Energy Malnutrition Protein
- What is being tested?
- Energy status
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 23 participants
- Where
- 2 sitesUnited Kingdom
- Study dates
- 1 Nov 2021to 3 Jun 2024
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 35 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Age 35-65 Healthy Non-smoker Recreationally active
Who cannot join
- Any diagnosed metabolic impairment (e.g. type 1 or 2 Diabetes) Any diagnosed cardiovascular disease or hypertension Elevated blood pressure at the time of screening. (An average systolic blood pressure reading of ≥150mmHg over two or more measurements and an average diastolic blood pressure of ≥90mmHg over two or more measurements.) Chronic use of diabetic medication. A personal or family history of epilepsy, seizures or schizophrenia. Allergic to mycoprotein / Quorn, penicillin, or cow's milk. Any musculoskeletal injury that may impair their use of crutches. Any diagnosed severe digestive illness. Any diagnosed severe autoimmune disease. Any diagnosed cancer. Any metal fragments in the eyes, a pacemaker, or metal implants in the body that preclude MRI scanning.
Trial locations and contacts
2 sites in 1 country.
United Kingdom2 sites
Sport & Health Sciences University of Exeter
Exeter, Devon, EX1 2LU
University of Exeter, Sports & Health Sciences, College of Life & Environmental Sciences
Exeter, Devon, EX1 2LU
About this study
In healthy middle-aged men and women, what is the effect of dietary energy restriction and energy surplus on daily muscle protein synthesis rates and muscle morphology, compared to energy balance, during free-living and immobilisation?
Read the detailed description
Background Age related muscle tissue loss, which is associated with a number of negative health outcomes is partially caused by blunted muscle protein synthesis rates (MPS) in response to food ingestion, which is exacerbated by muscle disuse. Concomitantly, consuming an energy balanced diet appears to become more challenging with advancing age, due to a reduction in appetite. Of concern is that the impact of energy intake on muscle protein metabolism during ageing is poorly characterised.
Objective To determine daily MPS and muscle morphology in response to differing energy intakes, in free-living conditions and during immobilisation.
Methods Healthy middle-aged volunteers will consume a hypocaloric, energy-balanced, or hypercaloric diet (providing 1.4 g.kg.day protein) over a three-day free-living period, and a three day period of single leg immobilisation. Deuterium oxide and MRI scans will be used to measure daily MPS and muscle size, respectively.
Value The study will determine the effect of energy intake per se on daily muscle protein synthesis rates and muscle size, in free-living and immobilised conditions. This will inform how energy provision modulates tissue loss with ageing, and how this interacts with the catabolic stress of muscle disuse.
- Conditions
- Muscle Atrophy, Aging, Energy Malnutrition Protein
- Being tested
- Energy status
- Keywords
- Muscle protein synthesis, Ageing, Dietary protein, Disuse
- Medical subject headings
- Muscular Atrophy, Protein-Energy Malnutrition
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Energy statusOther
Varying conditions of energy intake, thereby manipulating whether participants are in a state of energy restriction, balance, or surplus.
| Study group | Role | What they receive |
|---|---|---|
| Hypocaloric | Experimental | Participants placed in energy restriction. Receives: Other: Energy status |
| Energy Balance | Experimental | Participants placed in energy balance. Receives: Other: Energy status |
| Hypercaloric | Experimental | Participants placed in energy surplus. Receives: Other: Energy status |
What is being measured
The primary outcome is the main question the study is designed to answer.
Muscle protein synthesis (MPS)
Daily muscle protein synthesis rates, expressed as fractional synthetic rate (FSR) (%/day)
Measured: 6 days (3 days free-living, 3 days immobilised)
Secondary outcomes (1)
Muscle morphology.
Changes in muscle size, measured via MRI scanning, during immobilisation.
Measured: 3 day immobilisation phase.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 May 2021
- Study start1 Nov 2021
- Primary completion3 Jun 2024
- Study completion3 Jun 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Muscle AtrophyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 23 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Exeter
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04900701
- Sponsor's protocol ID
- 201209-B-01
- Acronym
- PIE
- Status last verified
- May 2026
- First submitted
- 20 May 2021
- Last updated
- 8 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 8 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Impact of Energy Intake and Short-term Disuse on Muscle Protein Synthesis Rates and Skeletal Muscle Mass in Middle-aged Adults.
- ClinicalTrials.gov ID
- NCT04900701
- Acronym / sponsor ID
- PIE / 201209-B-01
- Conditions
- Muscle Atrophy, Aging, Energy Malnutrition Protein
- Keywords
- Muscle protein synthesis, Ageing, Dietary protein, Disuse
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 23 participants (actual)
- Lead sponsor
- University of ExeterUniversity, hospital or other
- Study start
- 1 Nov 2021 (actual)
- Primary completion
- 3 Jun 2024 (actual)
- Study completion
- 3 Jun 2024 (actual)
- First posted
- 25 May 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
In healthy middle-aged men and women, what is the effect of dietary energy restriction and energy surplus on daily muscle protein synthesis rates and muscle morphology, compared to energy balance, during free-living and immobilisation?
Detailed description
Background Age related muscle tissue loss, which is associated with a number of negative health outcomes is partially caused by blunted muscle protein synthesis rates (MPS) in response to food ingestion, which is exacerbated by muscle disuse. Concomitantly, consuming an energy balanced diet appears to become more challenging with advancing age, due to a reduction in appetite. Of concern is that the impact of energy intake on muscle protein metabolism during ageing is poorly characterised.
Objective To determine daily MPS and muscle morphology in response to differing energy intakes, in free-living conditions and during immobilisation.
Methods Healthy middle-aged volunteers will consume a hypocaloric, energy-balanced, or hypercaloric diet (providing 1.4 g.kg.day protein) over a three-day free-living period, and a three day period of single leg immobilisation. Deuterium oxide and MRI scans will be used to measure daily MPS and muscle size, respectively.
Value The study will determine the effect of energy intake per se on daily muscle protein synthesis rates and muscle size, in free-living and immobilised conditions. This will inform how energy provision modulates tissue loss with ageing, and how this interacts with the catabolic stress of muscle disuse.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Hypocaloric | Experimental | Other: Energy statusParticipants placed in energy restriction. |
| Energy Balance | Experimental | Other: Energy statusParticipants placed in energy balance. |
| Hypercaloric | Experimental | Other: Energy statusParticipants placed in energy surplus. |
Who may qualify
- Ages
- 35 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Age 35-65 Healthy Non-smoker Recreationally active
Key exclusion criteria (1 listed)
- Any diagnosed metabolic impairment (e.g. type 1 or 2 Diabetes) Any diagnosed cardiovascular disease or hypertension Elevated blood pressure at the time of screening. (An average systolic blood pressure reading of ≥150mmHg over two or more measurements and an average diastolic blood pressure of ≥90mmHg over two or more measurements.) Chronic use of diabetic medication. A personal or family history of epilepsy, seizures or schizophrenia. Allergic to mycoprotein / Quorn, penicillin, or cow's milk. Any musculoskeletal injury that may impair their use of crutches. Any diagnosed severe digestive illness. Any diagnosed severe autoimmune disease. Any diagnosed cancer. Any metal fragments in the eyes, a pacemaker, or metal implants in the body that preclude MRI scanning.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Energy statusVarying conditions of energy intake, thereby manipulating whether participants are in a state of energy restriction, balance, or surplus. | Other | Energy Balance, Hypercaloric, Hypocaloric |
Primary outcome
Muscle protein synthesis (MPS)
Time frame: 6 days (3 days free-living, 3 days immobilised)
Daily muscle protein synthesis rates, expressed as fractional synthetic rate (FSR) (%/day)
1 secondary outcome
Muscle morphology.
Time frame: 3 day immobilisation phase.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 May 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Energy status in people with Muscle Atrophy and Aging, run by University of Exeter at 2 sites in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 8 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Muscle protein synthesis (MPS) (time frame: 6 days (3 days free-living, 3 days immobilised)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 May 2026; AzTrials last refreshed its copy on 8 Nov 2026.