The UNCODE Study: Unravelling the Neural Contributors Of Dynapenia in Elders

The UNCODE Study seeks to better identify the neurological causes of muscle weakness associated with advancing age. The main study consists of 4 laboratory-based testing sessions that involve testing muscle strength and physical and cognitive function as well as a battery of tests to 1) quantify brain excitability (using single and paired pulse transcranial magnetic stimulation of the upper and lower extremity muscles), 2) modulate brain excitability of the upper extremity muscles (using non-invasive transcranial direct current stimulation), 3) spinal motor nerve firing characteristics using decomposition surface electromyography, and 4) brain structure and function characteristics based on magnetic resonance images of the brain. Additionally, three optional sub-studies are also available for enrollment. The first is a genetics sub-study where a cheek swab will be used to examine associations between certain genes (APOE-4 allele) and the physiological and functional measures obtained from the main study. The other two sub-studies are interventions. The first sub-study is a progressive resistance exercise training study where study participants will undergo 12-weeks of exercise training (3x/wk) and at the completion of the exercise training the measures obtained in the main study will be re-assessed. The other sub-study is a mental imagery sub-study where subjects are randomly assigned to perform a mental imagery training program consisting of imaging strong muscle contractions and mobility tasks (5x/wk) or to serve as a control (i.e., to not modify lifestyle) for 6-weeks. At the completion of the respective intervention period the measures obtained in the main study will be re-assessed.