Physical inactivity is the 4th leading cause of death in the world. People with the highest prolonged sedentary time have greater chance of developing health problems such as cardiovascular disease and Type 2 diabetes, and a greater risk of dying younger. High levels of sedentary time are particularly harmful for older adults as they complete less physical activity than other age groups. Up to 20% of individuals aged over 65 are significantly debilitated due to losses in muscle mass and function (sarcopenia). Sarcopenia is associated with increased falling risk and disability.
The mechanisms driving sarcopenia remain poorly understood, however a key risk factor is known to be low physical activity. Among older adults, the reduction in muscle function is much more marked than would be predicted by the loss of muscle mass, suggesting there is likely a neuromuscular component contributing to the loss of strength and power that accompanies ageing and unloading. Preliminary data from our labs has demonstrated significant skeletal muscle dysfunction in young adults, following a step count reduction model. We propose that implementing this model with older adults will be a major step in revealing the mechanistic drivers of sarcopenia, for which novel and effective countermeasures and interventions can then be developed.
The overarching research aim is to determine the key metabolic and neuromuscular response of younger and older adults to reduced physical activity, and to subsequent re-training and recovery.
Key techniques that will be used within this research are: functional assessments, muscle quality assessment, incorporating isometric force measurement and muscle mass determination (B-mode ultrasound and DXA); muscle tone (tensiomyography); voluntary activation and excitation (peripheral nerve stimulation and surface electromyography); motor unit firing rates, number and size (intramuscular electromyography).
The project is self-funded, however the opportunity may occasionally arise for paid tasks relating to teaching and research within the Faculty.
To be eligible for this studentship, you should have a 1st or 2:1 degree in a Health/Sport Science related subject.
McGlory C, Gorissen SHM, Kamal M, Bahniwal R, Hector AJ, Baker SK, Chabowski A and Phillips SM. Omega-3 fatty acid supplementation attenuates skeletal muscle disuse atrophy during two weeks of unilateral leg immobilization in healthy young women. FASEB Journal [Epub ahead of print], 2019.
Brooks NE, Cadena SM, Cloutier G, Vega Lopez S, Roubenoff R, Castaneda Sceppa C Influence of exercise on the metabolic profile caused by 28 days of bed rest with energy deficit and amino acid supplementation in healthy men. Int J Med Sci 11(12):1248-1257, 2014
Brooks NE, Myburgh KH Skeletal muscle wasting with disuse atrophy is multi-dimensional: the response and interaction of myonuclei, satellite cells and signaling pathways. Front Physiol 5:99, 2014
Piasecki M, Ireland A, Piasecki J, Stashuk DW, McPhee JS and Jones DA. The reliability of methods to estimate the number and size of human motor units and their use with large limb muscles. European Journal of Applied Physiology 118: 767–775, 2018.
Macgregor LJ, Hunter AM, Orizio C, Fairweather MM, Ditroilo M. Assessment of skeletal muscle contractile properties by radial displacement: the case for tensiomyography. Sports Medicine. 1-14, 2018
Macgregor LJ and Hunter AM. High-threshold motor unit firing reflects force recovery following a bout of damaging eccentric exercise. PLOS One 3(4), 2018