Effect of 14-days of Reduced Physical Activity on Muscle Function and Size, Inflammatory Profile, and Exercise-induced Activation of Stress Responses in Skeletal Muscle in Healthy Older Males
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 12
- 试验地点
- 2
- 主要终点
- Lower limb muscle power
研究概览
简要总结
Muscle size declines at around 0.5-1% per year after 50 years of age, with muscle strength declining up to twice as fast as muscle size. This may eventually lead to loss of independence if tasks of daily living become too strenuous to be performed safely. Short periods of bed rest cause very rapid loss of muscle size and strength, and studies using healthy older participants have shown that age increases vulnerability to this muscle loss. However, it is unlikely that healthy individuals would be faced with periods of bed rest unless suffering a severe illness. In light of this, recent evidence has shown that even just reducing walking to less than 1,500 steps per day for two weeks caused 4% loss of leg muscle in over 65 year olds. This amount of activity is roughly the equivalent of being housebound, something that may become more common into older age, for example due to prolonged bad weather, or minor injury or illness.
This study will investigate what causes such stark muscle loss during two weeks of reduced activity, and the impact on skeletal muscle function and size, as well as balance, body composition, and other indicators of general health such as how the body responds to food or exercise. Importantly, exercise strategies that could reduce muscle loss during a period of reduced activity will also be investigated.
In brief, three groups of 10 older men (aged 65-80 years) will undertake two weeks of reduced physical activity by limiting their daily steps to <1,500/day. All groups will then undertake a re-training exercise programme to ensure that any losses in muscle strength or size are regained. One of the groups will be a control, whereby they will undertake the step-reduction intervention and re-training, but no protective exercise before or during the step-reduction intervention. This group will allow us to achieve our primary objective of determining the influence of two weeks of reduced physical activity on muscle strength and size in healthy older males. The two other groups will undertake either four weeks of strength exercise training before the step-reduction intervention, or daily home based exercise 'snacking' during the step-reduction intervention. The potential protective benefits of the exercise interventions in reducing the impact of two weeks of reduced activity on muscle strength and size, and any effect on how muscle is re-gained afterwards, will be compared to the 'control' group.
详细描述
Overall study design:
This study will be structured as a randomised control trial with two exercise treatment groups and one 'control' group. All three groups will undergo 14-days of reduced activity by restricting daily walking to less than 1,500 steps. One group will undertake four weeks of resistance exercise pre-training immediately prior to the 14-day step-reduction (PT group), and another group will undertake short bouts of home-based exercise (exercise snacking) every day during the 14-day step-reduction (ES group). The control group will undertake the 14-day step-reduction with neither exercise strategy. All three groups will then undertake two weeks of laboratory based resistance exercise training immediately after the step-reduction period, and will be offered a further six weeks of gym based personal training, and a six month gym and swimming pool membership at the Team Bath Sports Training Village.
Following advertisement of the study, interested potential participants will be asked to contact the chief investigator for further information via telephone or email correspondence. Further details including inclusion criteria will be provided verbally, and a full participant information sheet will be sent to potential participants that feel that they meet the inclusion criteria. If the potential participant chooses to be considered for inclusion in the trial, they must sign the consent form for initial screening and will be invited to a medical screening meeting with a member of the research team.
Preliminary assessment:
All potential participants will undergo screening to assess eligibility for inclusion before proceeding. This will include an objective assessment of physical function (Short Physical Performance Battery) in which simple tests of walking speed, ability to repeatedly rise from a chair, and simple standing balance are scored based on set criteria. Only participants scoring over 7 out of 12 will be eligible to participate. Participants will wear a step-counter (pedometer), and a physical activity monitor (BodyMedia armband) for one week, and be asked to record all food and drink consumed for three days (including one weekend day) using a provided diet record sheet. Only individuals who average 3,500 steps per day or above will be included in the study. At the end of this monitoring period, eligible participants will be asked to sign a consent form for the main study, and will be randomly assigned to an experimental group by minimisation.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 65 Years 至 80 Years（Older Adult）
- 性别
- Male
- 接受健康志愿者
- 是
入选标准
- •Aged 65 to 80 years
- •Not underweight or obese (body mass index ≥20 and ≤ 30 kg/m2)
- •Non-smoker (for >5 years)
- •Healthy (see exclusion criteria)
排除标准
- •Any chronic illness, cardiac, pulmonary, liver, or kidney abnormalities, uncontrolled hypertension, peripheral arterial disease, insulin- or non-insulin dependent diabetes or other metabolic disorders - all ascertained through medical screening.
- •Individuals who consume on a daily basis any analgesic or anti-inflammatory drug(s), prescription or non-prescription will be excluded.
- •Individuals on any medications known to affect protein metabolism (i.e. corticosteroids, non-steroidal anti-inflammatories, or prescription strength acne medications).
- •Individuals with a history of bone, joint or neuromuscular problems or a current musculoskeletal injury ascertained through medical screening.
- •Individuals with a known bleeding disorder, on the anticoagulant drug Warfarin, or prone to keloid scarring.
- •Individuals with a known negative reaction to lidocaine anaesthetic.
- •Individuals with any joint replacement surgical implants or other artefacts containing metal.
- •Individuals who complete fewer than 3500 steps per day (as assessed by pedometer prior to the study).
- •Individuals who score less than 8 on the short physical performance battery.
研究组 & 干预措施
Control Group
This group will undertake two-weeks of step-reduction to <1,500 steps per day, followed by two-weeks of strength training exercise (6 sessions).
干预措施: Step-reduction (Behavioral)
Pre-Training Group
This group will undertake four weeks of strength training exercise (10 sessions) before two-weeks of step-reduction to <1,500 steps per day, followed by two-weeks of strength training exercise (6 sessions).
干预措施: Step-reduction (Behavioral)
Pre-Training Group
This group will undertake four weeks of strength training exercise (10 sessions) before two-weeks of step-reduction to <1,500 steps per day, followed by two-weeks of strength training exercise (6 sessions).
干预措施: Pre-training (Behavioral)
Exercise Snacking Group
This group will undertake home-based 'exercise snacks' of simple lower limb movement (5 minutes, 3 times a day) whilst undertaking two-weeks of step-reduction to <1,500 steps per day, followed by two-weeks of strength training exercise (6 sessions).
干预措施: Step-reduction (Behavioral)
Exercise Snacking Group
This group will undertake home-based 'exercise snacks' of simple lower limb movement (5 minutes, 3 times a day) whilst undertaking two-weeks of step-reduction to <1,500 steps per day, followed by two-weeks of strength training exercise (6 sessions).
干预措施: Exercise snacking (Behavioral)
结局指标
主要结局
Lower limb muscle power
时间窗: Two weeks- Change from baseline to post-step-reduction intervention
Measured during leg pressing
次要结局
- Lower limb muscle power(Four weeks- Change from pre-pre-training intervention to 'baseline' pre-step-reduction intervention)
- Postprandial blood insulin concentration(Two weeks- Change from baseline to post-step-reduction intervention)
- Postprandial blood glucose concentration(Two weeks- Change from baseline to post-step-reduction intervention)
- Postural sway during standing balance with eyes open and closed(Four weeks- Change from pre-pre-training intervention to 'baseline' pre-step-reduction intervention)
- Inflammation and oxidative stress response transcription factor activation in response to strenuous exercise(Two weeks- Change from baseline to post-step-reduction intervention)
- Subcutaneous adipose tissue cytokine secretion at rest(Two weeks- Change from baseline to post-step-reduction intervention)
- Postprandial blood triglyceride concentration(Two weeks- Change from baseline to post-step-reduction intervention)
- Single leg balance(Four weeks- Change from pre-pre-training intervention to 'baseline' pre-step-reduction intervention)
- Body composition(Four weeks- Change from pre-pre-training intervention to 'baseline' pre-step-reduction intervention)
- Free-living adipose triglyceride incorporation assessed by D2O incorporation(Two weeks- Change from baseline to post-step-reduction intervention)
- Total and phosphorylated muscle protein synthesis and breakdown signalling proteins after exercise(Two weeks- Change from baseline to post-step-reduction intervention)
- Heat Shock Protein 27 muscle content in response to strenuous exercise(Two weeks- Change from baseline to post-step-reduction intervention)
- Lower limb muscle force(Four weeks- Change from pre-pre-training intervention to 'baseline' pre-step-reduction intervention)
- Lower limb muscle velocity(Four weeks- Change from pre-pre-training intervention to 'baseline' pre-step-reduction intervention)
- Lower limb muscle cross-sectional area and tissue density(Four weeks- Change from pre-pre-training intervention to 'baseline' pre-step-reduction intervention)
- Gastrocnemius and quadriceps muscle fibre pennation angle(Four weeks- Change from pre-pre-training intervention to 'baseline' pre-step-reduction intervention)
- Rates of free-living muscle protein synthesis assessed by stable isotope tracer deuterium oxide (D2O) incorporation rate(3, 8, 15, and 18 days- Change in rate of incorporation from baseline to 3 days post-step-reduction intervention)
- Messenger Ribonucleic acid (mRMA) expression of muscle protein synthesis and breakdown signalling proteins(Two weeks- Change from baseline to post-step-reduction intervention)
- nicotinamide adenine dinucleotide phosphate-oxidase (NAD(P)H oxidase) production in response to strenuous exercise(Two weeks- Change from baseline to post-step-reduction intervention)
- Aconitase activity in response to strenuous exercise(Two weeks- Change from baseline to post-step-reduction intervention)
- Systemic cytokines at rest(Two weeks- Change from baseline to post-step-reduction intervention)
- Cytotoxic "killer" T lymphocyte interferon-gamma production in response to proteins from common viruses(Two weeks- Change from baseline to post-step-reduction intervention)
- Postprandial blood high-density lipoprotein concentration(Two weeks- Change from baseline to post-step-reduction intervention)
- Postprandial blood low-density lipoprotein concentration(Two weeks- Change from baseline to post-step-reduction intervention)
- Postprandial blood non-esterified fatty acid concentration(Two weeks- Change from baseline to post-step-reduction intervention)
- Lower limb movement variability(Four weeks- Change from pre-pre-training intervention to 'baseline' pre-step-reduction intervention)
- Hydrogen peroxide production in response to strenuous exercise(Two weeks- Change from baseline to post-step-reduction intervention)
- Sleep quality(Two weeks- Change from baseline to post-step-reduction intervention)
- Qualitative feedback of participant experience of the interventions(Less than 6 weeks post-re-training intervention)
- Dietary intake(Approximately 4 or 8 weeks- Change from preliminary screening period to during step-reduction intervention)
- Quality of life(Two weeks- Change from baseline to post-step-reduction intervention)
研究者
Mr Oliver Perkin
Mr Oliver Perkin
University of Bath