title: Exercise strategies to protect against the impact of short-term reduced physical activity on muscle function and markers of health in older men: study protocol for a randomised controlled trial.
abstract: Muscles get smaller and weaker as we age and become more vulnerable to atrophy when physical activity is reduced or removed. This research is designed to investigate the potentially protective effects of two separate exercise strategies against loss in skeletal muscle function and size, and other key indices of health, following 14 days of reduced physical activity in older men.
  
  
  
  Three groups of 10 older men (aged 65-80 years) will undertake 2 weeks of reduced activity by decreasing daily steps from more than 3500 to less than 1500 (using pedometers to record step count). Two of the three groups will then undertake additional exercise interventions, either: 4 weeks of progressive resistance training prior to the step-reduction intervention (PT-group), or home-based 'exercise snacking' three times per day during the step-reduction intervention (ES-group). The third group undertaking only the step-reduction intervention (control) will provide a comparison against which to assess the effectiveness of the protective exercise strategies. Pre and post step-reduction assessments of muscle function, standing balance, anthropometry and muscle architecture will be taken. Pre and post step-reduction in postprandial metabolic control, resting systemic inflammation, adipose inflammation, oxidative stress, immune function, sleep quality, dietary habits, and quality of life will be measured. The stress response to exercise, and signalling protein and gene expression for muscle protein synthesis and breakdown following an acute bout of exercise will also be assessed pre and post step-reduction. Rates of muscle protein synthesis and adipose triglyceride turnover during the step-reduction intervention will be measured using stable isotope methodology. All participants will then undertake 2 weeks of supervised resistance training with the aim of regaining any deficit from baseline in muscle function and size.
  
  
  
  This study aims to identify exercise strategies that could be implemented to protect against loss of muscle power during 2 weeks of reduced activity in older men, and to improve understanding of the way in which a short-term reduction in physical activity impacts upon muscle function and health.
  
  
  
  ClinicalTrials.gov: NCT02495727 (Initial registration: 25 June 2015).
authors.affiliation: Department for Health, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
authors.forename: Oliver J
authors.initials: OJ
authors.lastname: Perkin
authors.affiliation: Department for Health, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Travers
authors.affiliation: Department for Health, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
authors.forename: Javier T
authors.initials: JT
authors.lastname: Gonzalez
authors.affiliation: Department for Health, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
authors.forename: James E
authors.initials: JE
authors.lastname: Turner
authors.affiliation: Department for Health, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
authors.forename: Fiona
authors.initials: F
authors.lastname: Gillison
authors.affiliation: Department for Health, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
authors.forename: Cassie
authors.initials: C
authors.lastname: Wilson
authors.affiliation: Department for Health, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
authors.forename: Polly M
authors.initials: PM
authors.lastname: McGuigan
authors.affiliation: Department for Health, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
authors.forename: Dylan
authors.initials: D
authors.lastname: Thompson
authors.affiliation: Department for Health, University of Bath, Claverton Down, Bath, BA2 7AY, UK. K.Stokes@bath.ac.uk.|Arthritis Research UK Centre for Sport, Exercise and Osteoarthritis, Nottingham, UK. K.Stokes@bath.ac.uk.
authors.forename: Keith A
authors.initials: KA
authors.lastname: Stokes
mesh_terms: D015502:Absorptiometry, Photon; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D002985:Clinical Protocols; D004739:England; D015444:Exercise; D006699:Home Care Services; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D009124:Muscle Proteins / Q000096:biosynthesis; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology*; D004856:Postural Balance; D059748:Proteolysis; D020127:Recovery of Function; D012107:Research Design; D055070:Resistance Training / Q000009:adverse effects; D055948:Sarcopenia / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D057185:Sedentary Behavior; D012737:Sex Factors; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014463:Ultrasonography
chemical_list: D009124:Muscle Proteins
keywords: Atrophy; Inactivity; Muscle; Recovery; Reduced activity; Resistance exercise; Step-reduction; Strength