title: If you don't use it you'll likely lose it.
abstract: This article is a commentary on the recently published manuscript by Drey et al. (2014). The age-related loss of motor units (MU) is an immutable process and understanding the possible role of physical activity in maintaining functional MUs is an important topic. Dysfunctional remodelling of a MU is associated with denervation of the muscle and ultimate death of the spinal motoneurone. Conversely, in cross-sectional studies, high levels of physical activity in humans report a maintenance in the number of functional MUs in older master runners. However, it seems that only those MUs directly associated with the elevated long-term physical activity appear to benefit from any exercise-induced neuroprotective effect.
authors.affiliation: Human Performance Laboratory, University of Calgary, Calgary, AB, Canada. gapower@ucalgary.ca.
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Power
authors.affiliation: Department of Human Physiology, University of Oregon, Eugene, OR, USA.
authors.forename: Brian H
authors.initials: BH
authors.lastname: Dalton
authors.affiliation: Departments of Physical Medicine and Rehabilitation and Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Doherty
authors.affiliation: Faculty of Health Sciences, Canadian Centre for Activity and Aging, School of Kinesiology, The University of Western Ontario, London, ON, Canada.|Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada.
authors.forename: Charles L
authors.initials: CL
authors.lastname: Rice
mesh_terms: D003430:Cross-Sectional Studies; D004576:Electromyography; D015444:Exercise; D006801:Humans; D009046:Motor Neurons; D018482:Muscle, Skeletal
keywords: 
  Electromyography (EMG)
  ; Motor Unit Number Estimate (MUNE); aging; master athlete; motor unit; sarcopenia