Influence of Reduced Daily Step Count and Anabolic Interventions on Muscle Protein Metabolism in Older Persons

January 21, 2015 updated by: McMaster University

Efficacy of Isolated Whey and Micellar Whey Protein (+/-Citrulline) to Stimulate Protein Synthesis in 'Healthy' and 'Anabolically Resistant' Elderly Muscle

As the loss of muscle mass with aging is associated with a dysregulation of muscle protein synthesis (MPS) that is generally characterized by an 'anabolic resistance' to nutrients, the primary outcome of the trial is to investigate the effect of a mixed macronutrient beverage on post-prandial myofibrillar MPS. However, the 'anabolic resistance' of aging may be predominantly influenced by the contractile activity of skeletal muscle; for example, the investigators have demonstrated that 2 weeks of reduced habitual activity (i.e. daily step count) induces anabolic resistance in otherwise healthy older adults. In contrast, resistance exercise is well-known to enhance muscle mass and can increase the sensitivity of skeletal muscle to dietary amino acids. Therefore, all participants will undergo a 2-week reduced step count intervention combined with a unilateral leg resistance exercise protocol to induce an 'unhealthy' or 'anabolically resistant' leg and a relatively 'healthy' or 'anabolically sensitive' leg, respectively; this within subject model will be utilized to investigate the effect of the mixed macronutrient beverage in both relatively 'healthy' and 'unhealthy' older muscle. The investigators will also measure changes in muscle mass, muscle function, and cardiovascular health of both legs before and after the 2-week intervention to determine the effect of reduced activity and the protective effect of minimal, low-intensity exercise on these outcomes.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

30

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Hamilton, Ontario, Canada, L8S 4K1
        • Exercise Metabolism Research Laboratory, McMaster Univeristy

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

65 years to 80 years (Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Male

Description

Inclusion Criteria:

  • Non-smoker

Exclusion Criteria:

  • Health problems such as: heart disease, rheumatoid arthritis, diabetes, poor lung function, uncontrolled hypertension, or any health conditions that might put the participant at risk for this study
  • Failed clearance for exercise participation by the participants family physician/medical doctor
  • Failed an exercise strength test.
  • Regular consumption of any analgesic or anti-inflammatory drug(s), prescription or non-prescription, chronically will be excluded.
  • Taking any medications known to affect protein metabolism (i.e. corticosteroids, non-steroidal anti-inflammatories, or prescription strength acne medications).
  • Factors that may exclude a participant from an MRI scan (i.e. various implants, metal in the eyes etc)
  • Participants who complete fewer than 5000 steps per day (as assessed by pedometer prior to the study).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Isolated Whey Protein
20 g isolated whey protein + 15 g non-essential amino acids
Other: step-reduction
reduce daily physical activity to less than 1500 steps per day
Other: step-reduction plus resistance exercise
reduce physical activity to less than 1500 steps per day with thrice weekly low-load, high effort resistance exercise
Experimental: Micellar Whey Protein
20 g micellar whey protein + 15 g non-essential amino acids
Other: step-reduction
reduce daily physical activity to less than 1500 steps per day
Other: step-reduction plus resistance exercise
reduce physical activity to less than 1500 steps per day with thrice weekly low-load, high effort resistance exercise
Experimental: Micellar Whey Protein + Citrulline
20 g micellar whey protein + 5 g citrulline
Other: step-reduction
reduce daily physical activity to less than 1500 steps per day
Other: step-reduction plus resistance exercise
reduce physical activity to less than 1500 steps per day with thrice weekly low-load, high effort resistance exercise

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Myofibrillar fractional synthetic rate will be measured using 13C6 ring phenylalanine
Time Frame: 7 hours
analysis
7 hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
body composition (lean body mass, fat mass, leg lean mass, leg fat mass) will be measured using dual energy xray absorptiometry
Time Frame: 14 days
analysis
14 days
leg muscle strength (leg press and leg extension 1 repetition maximum [1-RM], peak knee extensor torque) will be measured using a dynamometer
Time Frame: 14 days
analysis
14 days
vascular function (femoral blood flow, femoral artery diameter, leg pulse) will be measured using doppler ultrasound
Time Frame: 14 days
analysis
14 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

McMaster University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

July 1, 2012

Primary Completion (Actual)

May 1, 2013

Study Completion (Actual)

May 1, 2013

Study Registration Dates

First Submitted

January 6, 2015

First Submitted That Met QC Criteria

January 21, 2015

First Posted (Estimate)

January 27, 2015

Study Record Updates

Last Update Posted (Estimate)

January 27, 2015

Last Update Submitted That Met QC Criteria

January 21, 2015

Last Verified

January 1, 2015

More Information

Terms related to this study

Other Study ID Numbers

  • 11-267

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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