<clinical_study>
  <!-- This xml conforms to an XML Schema at:
    https://clinicaltrials.gov/ct2/html/images/info/public.xsd -->
  <required_header>
    <download_date>ClinicalTrials.gov processed this data on September 20, 2023</download_date>
    <link_text>Link to the current ClinicalTrials.gov record.</link_text>
    <url>https://clinicaltrials.gov/ct2/show/NCT04422665</url>
  </required_header>
  <id_info>
    <org_study_id>RG_16-100</org_study_id>
    <nct_id>NCT04422665</nct_id>
  </id_info>
  <brief_title>Preventing Bed-rest Induced Muscle Loss in the Elderly</brief_title>
  <official_title>Exercise 'Prehabilitation': A Novel Intervention to Protect Against Disuse-induced Muscle Atrophy and Sarcopenia in the Old</official_title>
  <sponsors>
    <lead_sponsor>
      <agency>University of Birmingham</agency>
      <agency_class>Other</agency_class>
    </lead_sponsor>
    <collaborator>
      <agency>Biotechnology and Biological Sciences Research Council</agency>
      <agency_class>Other</agency_class>
    </collaborator>
    <collaborator>
      <agency>University of Nottingham</agency>
      <agency_class>Other</agency_class>
    </collaborator>
  </sponsors>
  <source>University of Birmingham</source>
  <oversight_info>
    <has_dmc>No</has_dmc>
    <is_fda_regulated_drug>No</is_fda_regulated_drug>
    <is_fda_regulated_device>No</is_fda_regulated_device>
  </oversight_info>
  <brief_summary>
    <textblock>
      Episodes of inactivity due to hospitalisation, as short as 5 days, are associated with rapid&#xD;
      muscle and strength loss in the elderly. The observed muscle loss with inactivity is likely&#xD;
      due to muscle anabolic resistance and increased breakdown rates of muscle tissue. This is of&#xD;
      great concern as the average hospital stay in the elderly is 5-6 days. Moreover, minor&#xD;
      illnesses not requiring hospitalisation generally require short-term periods of inactive&#xD;
      home-based recovery. The accumulation of repeated disuse events in older individuals&#xD;
      manifests in a chronic muscle anabolic resistance (i.e. the inability of muscle to respond to&#xD;
      anabolic stimuli such as exercise and nutrition) that may underpin the slow but devastating&#xD;
      process of age-related muscle loss.&#xD;
&#xD;
      It is our belief that strategies to promote muscle health in ageing and reduce healthcare&#xD;
      expenditure, should focus on alleviating muscle deterioration and anabolic resistance during&#xD;
      short-term disuse.&#xD;
&#xD;
      In this regard, we propose that resistance exercise (i.e. weight lifting) performed prior to&#xD;
      a disuse event (termed 'prehabilitation') may be sufficient to offset muscle loss in older&#xD;
      individuals. Thus, we suggest the potent effect of resistance exercise in older muscles may&#xD;
      prevent muscle loss during short-term disuse.&#xD;
    </textblock>
  </brief_summary>
  <detailed_description>
    <textblock>
      Participants will be assigned to either single-bout (SINGLE; n=10) or multiple-bouts (MULTI;&#xD;
      n=10) of resistance exercise prehabilitation prior to 5 consecutive days of bed rest. Groups&#xD;
      will be matched for age, anthropometric characteristics and activity levels. Only males will&#xD;
      be studied due to potential gender differences in muscle protein turnover. A single-leg&#xD;
      resistance exercise prehabilitation model will allow for a direct within-subject comparison&#xD;
      against the non-exercised control leg.&#xD;
&#xD;
      Preliminary Assessments&#xD;
&#xD;
      Following an induction meeting and obtainment of informed consent, participants will report&#xD;
      to The National Institute of Health/Wellcome Trust Clinical Research Facility (CRF) at&#xD;
      University Hospital Birmingham (UHB) at 0800h having fasted from 2100h the previous night.&#xD;
      After measuring height and weight, the following parameters will be determined in the order&#xD;
      outlined:&#xD;
&#xD;
        1. Muscle biopsy, blood and saliva sampling: a muscle biopsy sample will be obtained from a&#xD;
           specific thigh muscle under local anaesthetic. A blood sample will then be obtained from&#xD;
           a forearm vein. Participants will also provide a saliva sample. This will be obtained&#xD;
           prior to the following measurements.&#xD;
&#xD;
        2. Lower-limb function: The short physical performance battery (SPPB) test will be used.&#xD;
&#xD;
        3. Body composition: bioelectrical impedance analysis will be used to determine&#xD;
           fat/fat-free mass on a whole-body and anatomical regional basis (CRF nurse).&#xD;
&#xD;
        4. Muscle size/architecture: The thickness of the thigh muscles will be determined via&#xD;
           non-invasive ultrasound imaging.&#xD;
&#xD;
        5. Leg strength and muscle activation: Estimated maximal leg strength will be measured&#xD;
           firstly on a standard knee extension exercise machine.&#xD;
&#xD;
        6. Stable isotope procedure: Immediately following muscle biopsy, blood and saliva&#xD;
           sampling, participants will orally consume a small bolus of 'heavy water' tracer to&#xD;
           label the body water pool with a small amount of this isotope. Participants will provide&#xD;
           a daily saliva sample to monitor body water tracer enrichment. This technique will allow&#xD;
           us to quantify muscle protein synthesis over the course of prehabilitation and bed-rest.&#xD;
&#xD;
        7. Participants will be fitted with an accelerometer and pedometer to asses daily activity&#xD;
           levels.&#xD;
&#xD;
        8. Participants are given a food diary to record daily nutritional intake over a 3-day&#xD;
           period.&#xD;
&#xD;
      Exercise Prehabilitation (Days 0-7) Participants will be randomly assigned to undergo 4&#xD;
      resistance exercise bouts the week before (Day 1, 2, 5 and 7), or 1 resistance exercise bout&#xD;
      on the evening prior to bed rest (i.e. Day 7). Exercise bouts will consist of 8 sets of&#xD;
      single-leg knee extension exercise and 8 sets of single-leg leg curls. The non-exercised&#xD;
      control leg will remain passive throughout training. Resistance exercise will be performed at&#xD;
      70% of previously determined maximal strength (10-15 repetitions).&#xD;
&#xD;
      Intervention - 5-days of bed-rest (Days 8-13) Participants will report to the CRF at 0700h&#xD;
      the morning immediately after exercise prehabilitation phase. At 0800h, muscle biopsies will&#xD;
      be obtained from both legs to assess changes in muscle metabolism over the 7 days of&#xD;
      prehabilitation. Participants will then be transported for dual energy x-ray absorptiometry&#xD;
      (DXA), Magnetic Resonance Imaging (MRI) and ultrasound assessment of body/muscle composition,&#xD;
      after which the 5 consecutive days of strict bed rest will begin. The bed rest model will&#xD;
      mimic a traditional inpatient hospital stay and reflect the level of muscle unloading that&#xD;
      occurs in older individuals following acute illness. Participants will spend the majority of&#xD;
      time in bed and will be allowed to adjust the hospital bed head height for reading, eating&#xD;
      and watching television, but will otherwise be instructed to lie flat in bed. Bathing/hygiene&#xD;
      will be performed in a wheelchair at a sink. The bathroom accessed using a wheelchair.&#xD;
      Adherence to bed rest will be monitored by nursing staff and through daily analysis of&#xD;
      accelerometry data.&#xD;
&#xD;
      Post Intervention Assessments (Day 13) On the morning after completion of the 5-day bed rest&#xD;
      phase (i.e. Day 13) participants will awake at 0700h in the CRF and remain in bed for&#xD;
      assessment of muscle protein synthesis in trained and untrained control legs. A cannula will&#xD;
      be inserted into a vein of both forearms for frequent blood sampling and a stable isotope&#xD;
      tracer infusion. During the tracer infusion, muscle biopsies will be obtained from both&#xD;
      trained and untrained legs before and after consumption of a milk protein drink, to assess&#xD;
      muscle metabolism. Participants will then be transported by wheelchair for repeat&#xD;
      bioelectrical impedance analysis, MRI and ultrasound scans to assess body/muscle composition.&#xD;
      Leg strength will be reassessed in trained and untrained legs. A physiotherapist will perform&#xD;
      a functional assessment of participants before they are discharged.&#xD;
&#xD;
      Rehabilitation Training Participants will be given the opportunity to complete a 6-week&#xD;
      rehabilitation programme, consisting of a progressive 3 x weekly leg resistance training with&#xD;
      protein supplementation, designed to fully restore any loss in muscle mass and strength from&#xD;
      short-term bed rest. Resistance training rehabilitation will not form a specific study&#xD;
      objective, but muscle size and strength will be assessed to ensure restoration of any muscle&#xD;
      decline from bed rest.&#xD;
    </textblock>
  </detailed_description>
  <overall_status>Completed</overall_status>
  <start_date type="Actual">September 1, 2017</start_date>
  <completion_date type="Actual">January 1, 2020</completion_date>
  <primary_completion_date type="Actual">October 1, 2019</primary_completion_date>
  <phase>N/A</phase>
  <study_type>Interventional</study_type>
  <has_expanded_access>No</has_expanded_access>
  <study_design_info>
    <allocation>Randomized</allocation>
    <intervention_model>Parallel Assignment</intervention_model>
    <intervention_model_description>Participants will be randomly allocated to one of two intervention groups. Due to the single-legged typed of resistance exercise, each subject will be its own control.</intervention_model_description>
    <primary_purpose>Basic Science</primary_purpose>
    <masking>None (Open Label)</masking>
  </study_design_info>
  <primary_outcome>
    <measure>Integrated myofibrillar protein synthesis rates</measure>
    <time_frame>2 years</time_frame>
    <description>Myofibrillar protein synthesis rates will be measured during the prehabilitation and bed rest period in both the exercising and resting leg.</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Muscle mass via MRI</measure>
    <time_frame>2 years</time_frame>
    <description>Muscle volume in the quadriceps will be assessed before and after bed rest using magnetic resonance imaging techniques</description>
  </primary_outcome>
  <secondary_outcome>
    <measure>Muscle fibre properties</measure>
    <time_frame>2 years</time_frame>
    <description>Via immunohistochemical staining procedures muscle fibre cross sectional area will be determined</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Physical activity levels</measure>
    <time_frame>2 years</time_frame>
    <description>Daily average time spent in sedentary, light, moderate or vigorous intensity activity using an accelerometer</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Step-count</measure>
    <time_frame>2 years</time_frame>
    <description>activity will be determined using accelerometry. Furthermore, step count will be Daily step-count assessed using a hip-worn pedometer</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Plasma biomarkers of metabolic health</measure>
    <time_frame>2 years</time_frame>
    <description>Blood markers - serum total cholesterol, serum high-density lipoprotein cholesterol, serum non-high-density lipoprotein cholesterol, total cholesterol, serum non-esterified fatty acids, serum triglycerides (units of measure for all - mmol/L)</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Serum insulin</measure>
    <time_frame>2 years</time_frame>
    <description>Via ELISA kits, resting insulin will be assessed using baseline plasma samples from before and after the bed rest period (pmol/l)</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Intramuscular signaling via western blot</measure>
    <time_frame>2 years</time_frame>
    <description>Western blots for phosphorylation of key anabolic and catabolic signaling proteins will be performed.</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Gene expression</measure>
    <time_frame>2 years</time_frame>
    <description>Search Results Web results&#xD;
Reverse transcription polymerase chain reaction (RT-PCR) will be performed to assess gene-expression of muscle anabolic and catabolic genes.</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Dietary intake</measure>
    <time_frame>2 years</time_frame>
    <description>Dietary intake will be assessed using 3-day weighed food diaries.</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Body composition</measure>
    <time_frame>2 years</time_frame>
    <description>Bioelectrical impedance analysis will be used to determine whole body fat and fat-free mass (units are % of total body mass for both fat and fat-free mass).</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Leg strength</measure>
    <time_frame>2 years</time_frame>
    <description>Estimated maximal leg strength will be determined for the leg extension and leg curl before and after the bed rest period</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Height</measure>
    <time_frame>2 years</time_frame>
    <description>measured using a stadiometer (cm)</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Body weight</measure>
    <time_frame>2 years</time_frame>
    <description>Measured using a digital weighing scale (kg)</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Body Mass Index</measure>
    <time_frame>2 years</time_frame>
    <description>Weight and height will be combined to report BMI in kg/m^2</description>
  </secondary_outcome>
  <number_of_arms>2</number_of_arms>
  <enrollment type="Actual">20</enrollment>
  <condition>Muscle Loss</condition>
  <condition>Disuse Atrophy</condition>
  <condition>Protein Metabolism</condition>
  <condition>Prehabilitation</condition>
  <condition>Sarcopenia</condition>
  <arm_group>
    <arm_group_label>Single Exercise</arm_group_label>
    <arm_group_type>Experimental</arm_group_type>
    <description>Subjects allocated to this group will perform a single bout of one-legged resistance exercise. This bout will take place 1 day prior to the start of the bed rest. The resistance exercise will consist of 8 sets of leg extensions and 8 sets of leg curls. The non-exercising leg will serve as an internal control. The dominant leg will perform the exercise.</description>
  </arm_group>
  <arm_group>
    <arm_group_label>Multi Exercise</arm_group_label>
    <arm_group_type>Experimental</arm_group_type>
    <description>Subjects allocated to this group will perform 4 bouts of one-legged resistance exercise. These bouts will take place on alternate days the week leading up to the bed rest. Each resistance exercise bout will consist of 8 sets of leg extensions and 8 sets of leg curls. The non-exercising leg will serve as an internal control. The dominant leg will perform the exercise.</description>
  </arm_group>
  <intervention>
    <intervention_type>Other</intervention_type>
    <intervention_name>Resistance exercise</intervention_name>
    <description>Single-legged resistance exercise</description>
    <arm_group_label>Multi Exercise</arm_group_label>
    <arm_group_label>Single Exercise</arm_group_label>
  </intervention>
  <eligibility>
    <criteria>
      <textblock>
        Inclusion Criteria:&#xD;
&#xD;
          -  Males aged between 65-80 years&#xD;
&#xD;
          -  No history of structured resistance training within 10 years prior to study&#xD;
             participation.&#xD;
&#xD;
          -  Generally good health as indicated by a thorough health questionnaire.&#xD;
&#xD;
          -  A score of ≥9 points on the Short Physical Performance Battery to assess lower&#xD;
             extremity function.&#xD;
&#xD;
          -  Body Mass Index &lt;30kg/m2&#xD;
&#xD;
        Exclusion Criteria:&#xD;
&#xD;
          -  Coagulation disorders&#xD;
&#xD;
          -  Myocardial infarction&#xD;
&#xD;
          -  Artery/vein disease&#xD;
&#xD;
          -  Hormone replacement therapy&#xD;
&#xD;
          -  Other chronic/systemic illnesses (i.e. renal failure, chronic obstructive pulmonary&#xD;
             disease, cancer).&#xD;
&#xD;
          -  Undergone 2 or more muscle biopsies from each leg previously.&#xD;
&#xD;
          -  Received a stable isotope infusion in the last 3 years prior to study enrollment.&#xD;
      </textblock>
    </criteria>
    <gender>Male</gender>
    <minimum_age>65 Years</minimum_age>
    <maximum_age>80 Years</maximum_age>
    <healthy_volunteers>Accepts Healthy Volunteers</healthy_volunteers>
  </eligibility>
  <location>
    <facility>
      <name>University of Birmingham, School of Sport, Exercise and Rehabilitation Sciences</name>
      <address>
        <city>Edgbaston</city>
        <state>West Midlands</state>
        <zip>B15 2TT</zip>
        <country>United Kingdom</country>
      </address>
    </facility>
  </location>
  <location_countries>
    <country>United Kingdom</country>
  </location_countries>
  <verification_date>January 2020</verification_date>
  <study_first_submitted>June 1, 2020</study_first_submitted>
  <study_first_submitted_qc>June 4, 2020</study_first_submitted_qc>
  <study_first_posted type="Actual">June 9, 2020</study_first_posted>
  <last_update_submitted>June 4, 2020</last_update_submitted>
  <last_update_submitted_qc>June 4, 2020</last_update_submitted_qc>
  <last_update_posted type="Actual">June 9, 2020</last_update_posted>
  <responsible_party>
    <responsible_party_type>Sponsor</responsible_party_type>
  </responsible_party>
  <condition_browse>
    <!-- CAUTION:  The following MeSH terms are assigned with an imperfect algorithm            -->
    <mesh_term>Muscular Disorders, Atrophic</mesh_term>
    <mesh_term>Sarcopenia</mesh_term>
    <mesh_term>Atrophy</mesh_term>
  </condition_browse>
  <patient_data>
    <sharing_ipd>No</sharing_ipd>
  </patient_data>
  <!-- Results have not yet been posted for this study                                          -->
</clinical_study>


download date: ClinicalTrials.gov processed this data on September 20, 2023
link text: Link to the current ClinicalTrials.gov record.
url: https://clinicaltrials.gov/ct2/show/NCT04422665
org study id: RG_16-100
nct id: NCT04422665
lead sponsor: 
collaborator: 
collaborator: 
has dmc: No
is fda regulated drug: No
is fda regulated device: No
Episodes of inactivity due to hospitalisation, as short as 5 days, are associated with rapid
      muscle and strength loss in the elderly. The observed muscle loss with inactivity is likely
      due to muscle anabolic resistance and increased breakdown rates of muscle tissue. This is of
      great concern as the average hospital stay in the elderly is 5-6 days. Moreover, minor
      illnesses not requiring hospitalisation generally require short-term periods of inactive
      home-based recovery. The accumulation of repeated disuse events in older individuals
      manifests in a chronic muscle anabolic resistance (i.e. the inability of muscle to respond to
      anabolic stimuli such as exercise and nutrition) that may underpin the slow but devastating
      process of age-related muscle loss.

      It is our belief that strategies to promote muscle health in ageing and reduce healthcare
      expenditure, should focus on alleviating muscle deterioration and anabolic resistance during
      short-term disuse.

      In this regard, we propose that resistance exercise (i.e. weight lifting) performed prior to
      a disuse event (termed 'prehabilitation') may be sufficient to offset muscle loss in older
      individuals. Thus, we suggest the potent effect of resistance exercise in older muscles may
      prevent muscle loss during short-term disuse.
Participants will be assigned to either single-bout (SINGLE; n=10) or multiple-bouts (MULTI;
      n=10) of resistance exercise prehabilitation prior to 5 consecutive days of bed rest. Groups
      will be matched for age, anthropometric characteristics and activity levels. Only males will
      be studied due to potential gender differences in muscle protein turnover. A single-leg
      resistance exercise prehabilitation model will allow for a direct within-subject comparison
      against the non-exercised control leg.

      Preliminary Assessments

      Following an induction meeting and obtainment of informed consent, participants will report
      to The National Institute of Health/Wellcome Trust Clinical Research Facility (CRF) at
      University Hospital Birmingham (UHB) at 0800h having fasted from 2100h the previous night.
      After measuring height and weight, the following parameters will be determined in the order
      outlined:

        1. Muscle biopsy, blood and saliva sampling: a muscle biopsy sample will be obtained from a
           specific thigh muscle under local anaesthetic. A blood sample will then be obtained from
           a forearm vein. Participants will also provide a saliva sample. This will be obtained
           prior to the following measurements.

        2. Lower-limb function: The short physical performance battery (SPPB) test will be used.

        3. Body composition: bioelectrical impedance analysis will be used to determine
           fat/fat-free mass on a whole-body and anatomical regional basis (CRF nurse).

        4. Muscle size/architecture: The thickness of the thigh muscles will be determined via
           non-invasive ultrasound imaging.

        5. Leg strength and muscle activation: Estimated maximal leg strength will be measured
           firstly on a standard knee extension exercise machine.

        6. Stable isotope procedure: Immediately following muscle biopsy, blood and saliva
           sampling, participants will orally consume a small bolus of 'heavy water' tracer to
           label the body water pool with a small amount of this isotope. Participants will provide
           a daily saliva sample to monitor body water tracer enrichment. This technique will allow
           us to quantify muscle protein synthesis over the course of prehabilitation and bed-rest.

        7. Participants will be fitted with an accelerometer and pedometer to asses daily activity
           levels.

        8. Participants are given a food diary to record daily nutritional intake over a 3-day
           period.

      Exercise Prehabilitation (Days 0-7) Participants will be randomly assigned to undergo 4
      resistance exercise bouts the week before (Day 1, 2, 5 and 7), or 1 resistance exercise bout
      on the evening prior to bed rest (i.e. Day 7). Exercise bouts will consist of 8 sets of
      single-leg knee extension exercise and 8 sets of single-leg leg curls. The non-exercised
      control leg will remain passive throughout training. Resistance exercise will be performed at
      70% of previously determined maximal strength (10-15 repetitions).

      Intervention - 5-days of bed-rest (Days 8-13) Participants will report to the CRF at 0700h
      the morning immediately after exercise prehabilitation phase. At 0800h, muscle biopsies will
      be obtained from both legs to assess changes in muscle metabolism over the 7 days of
      prehabilitation. Participants will then be transported for dual energy x-ray absorptiometry
      (DXA), Magnetic Resonance Imaging (MRI) and ultrasound assessment of body/muscle composition,
      after which the 5 consecutive days of strict bed rest will begin. The bed rest model will
      mimic a traditional inpatient hospital stay and reflect the level of muscle unloading that
      occurs in older individuals following acute illness. Participants will spend the majority of
      time in bed and will be allowed to adjust the hospital bed head height for reading, eating
      and watching television, but will otherwise be instructed to lie flat in bed. Bathing/hygiene
      will be performed in a wheelchair at a sink. The bathroom accessed using a wheelchair.
      Adherence to bed rest will be monitored by nursing staff and through daily analysis of
      accelerometry data.

      Post Intervention Assessments (Day 13) On the morning after completion of the 5-day bed rest
      phase (i.e. Day 13) participants will awake at 0700h in the CRF and remain in bed for
      assessment of muscle protein synthesis in trained and untrained control legs. A cannula will
      be inserted into a vein of both forearms for frequent blood sampling and a stable isotope
      tracer infusion. During the tracer infusion, muscle biopsies will be obtained from both
      trained and untrained legs before and after consumption of a milk protein drink, to assess
      muscle metabolism. Participants will then be transported by wheelchair for repeat
      bioelectrical impedance analysis, MRI and ultrasound scans to assess body/muscle composition.
      Leg strength will be reassessed in trained and untrained legs. A physiotherapist will perform
      a functional assessment of participants before they are discharged.

      Rehabilitation Training Participants will be given the opportunity to complete a 6-week
      rehabilitation programme, consisting of a progressive 3 x weekly leg resistance training with
      protein supplementation, designed to fully restore any loss in muscle mass and strength from
      short-term bed rest. Resistance training rehabilitation will not form a specific study
      objective, but muscle size and strength will be assessed to ensure restoration of any muscle
      decline from bed rest.
allocation: Randomized
intervention model: Parallel Assignment
intervention model description: Participants will be randomly allocated to one of two intervention groups. Due to the single-legged typed of resistance exercise, each subject will be its own control.
primary purpose: Basic Science
masking: None (Open Label)
measure: Integrated myofibrillar protein synthesis rates
time frame: 2 years
description: Myofibrillar protein synthesis rates will be measured during the prehabilitation and bed rest period in both the exercising and resting leg.
measure: Muscle mass via MRI
time frame: 2 years
description: Muscle volume in the quadriceps will be assessed before and after bed rest using magnetic resonance imaging techniques
measure: Muscle fibre properties
time frame: 2 years
description: Via immunohistochemical staining procedures muscle fibre cross sectional area will be determined
measure: Physical activity levels
time frame: 2 years
description: Daily average time spent in sedentary, light, moderate or vigorous intensity activity using an accelerometer
measure: Step-count
time frame: 2 years
description: activity will be determined using accelerometry. Furthermore, step count will be Daily step-count assessed using a hip-worn pedometer
measure: Plasma biomarkers of metabolic health
time frame: 2 years
description: Blood markers - serum total cholesterol, serum high-density lipoprotein cholesterol, serum non-high-density lipoprotein cholesterol, total cholesterol, serum non-esterified fatty acids, serum triglycerides (units of measure for all - mmol/L)
measure: Serum insulin
time frame: 2 years
description: Via ELISA kits, resting insulin will be assessed using baseline plasma samples from before and after the bed rest period (pmol/l)
measure: Intramuscular signaling via western blot
time frame: 2 years
description: Western blots for phosphorylation of key anabolic and catabolic signaling proteins will be performed.
measure: Gene expression
time frame: 2 years
description: Search Results Web results
Reverse transcription polymerase chain reaction (RT-PCR) will be performed to assess gene-expression of muscle anabolic and catabolic genes.
measure: Dietary intake
time frame: 2 years
description: Dietary intake will be assessed using 3-day weighed food diaries.
measure: Body composition
time frame: 2 years
description: Bioelectrical impedance analysis will be used to determine whole body fat and fat-free mass (units are % of total body mass for both fat and fat-free mass).
measure: Leg strength
time frame: 2 years
description: Estimated maximal leg strength will be determined for the leg extension and leg curl before and after the bed rest period
measure: Height
time frame: 2 years
description: measured using a stadiometer (cm)
measure: Body weight
time frame: 2 years
description: Measured using a digital weighing scale (kg)
measure: Body Mass Index
time frame: 2 years
description: Weight and height will be combined to report BMI in kg/m^2
arm group label: Single Exercise
arm group type: Experimental
description: Subjects allocated to this group will perform a single bout of one-legged resistance exercise. This bout will take place 1 day prior to the start of the bed rest. The resistance exercise will consist of 8 sets of leg extensions and 8 sets of leg curls. The non-exercising leg will serve as an internal control. The dominant leg will perform the exercise.
arm group label: Multi Exercise
arm group type: Experimental
description: Subjects allocated to this group will perform 4 bouts of one-legged resistance exercise. These bouts will take place on alternate days the week leading up to the bed rest. Each resistance exercise bout will consist of 8 sets of leg extensions and 8 sets of leg curls. The non-exercising leg will serve as an internal control. The dominant leg will perform the exercise.
intervention type: Other
intervention name: Resistance exercise
description: Single-legged resistance exercise
arm group label: Multi Exercise
arm group label: Single Exercise
criteria: 
gender: Male
minimum age: 65 Years
maximum age: 80 Years
healthy volunteers: Accepts Healthy Volunteers
facility: 
country: United Kingdom
responsible party type: Sponsor
mesh term: Muscular Disorders, Atrophic
mesh term: Sarcopenia
mesh term: Atrophy
sharing ipd: No