PMID- 26190479
OWN - NLM
STAT- MEDLINE
DCOM- 20160712
LR  - 20151010
IS  - 1873-6815 (Electronic)
IS  - 0531-5565 (Linking)
VI  - 70
DP  - 2015 Oct
TI  - Motor unit loss is accompanied by decreased peak muscle power in the lower limb 
      of older adults.
PG  - 111-8
LID - S0531-5565(15)30015-2 [pii]
LID - 10.1016/j.exger.2015.07.007 [doi]
AB  - This study investigated the relationship between motor unit (MU) properties and 
      the isometric strength and power of two lower limb muscles in healthy young and 
      older adults. Twelve older adults (6 men, mean age, 77 +/- 5 years) and twelve 
      young adults (6 men, mean age, 24 +/- 3 years) were studied. MU properties of the 
      tibialis anterior (TA) and vastus medialis (VM) muscles were determined 
      electrophysiologically using decomposition-enhanced spike-triggered averaging 
      (DE-STA). Motor unit number estimates (MUNEs) of the TA were significantly 
      reduced (p<0.05) in older adults (102 +/- 76) compared to young adults (234 +/- 109), 
      primarily as a result of significantly larger surface-detected motor unit 
      potentials (S-MUPs) in older adults (63 +/- 29 muV) compared to young adults (27 +/- 
      14 muV). Although VM S-MUP values were larger in older adults (60 +/- 31 muV) 
      compared to young (48 +/- 42 muV), the difference was not significant. Maximal 
      isometric strength was significantly larger in both the TA and knee extensors of 
      young adults (TA: 0.56 Nm/kg, KE: 2.2 Nm/kg) compared to old (TA: 0.4 Nm/kg, KE: 
      1.3 Nm/kg). Similar reductions in peak muscle power were observed between young 
      (TA: 33 W, KE: 35 7 W) and old adults (TA: 26 W, KE: 224 W). The greatest deficit 
      between young and old subjects in peak power output occurred at 20% MVC for the 
      TA and 40% MVC for the knee extensors. Results from this study indicate that 
      there are changes in MU properties with age, and that this effect may be greater 
      in the more distal TA muscle. Further, this study demonstrates that muscle power 
      may be a sensitive marker of changes in neuromuscular function with aging.
CI  - Copyright (c) 2015 Elsevier Inc. All rights reserved.
FAU - McKinnon, Neal B
AU  - McKinnon NB
AD  - School of Health and Rehabilitation Sciences, Faculty of Health Sciences, Western 
      University, London, Ontario, Canada.
FAU - Montero-Odasso, Manuel
AU  - Montero-Odasso M
AD  - Gait and Brain Lab, Parkwood Hospital, Lawson Health Research Institute, Canada; 
      Division of Geriatric Medicine, Schulich School of Medicine and Dentistry, 
      Western University, London, Ontario, Canada.
FAU - Doherty, Timothy J
AU  - Doherty TJ
AD  - School of Health and Rehabilitation Sciences, Faculty of Health Sciences, Western 
      University, London, Ontario, Canada; Department of Physical Medicine and 
      Rehabilitation, Schulich School of Medicine and Dentistry, Western University, 
      London, Ontario, Canada; Department of Clinical Neurological Sciences, Schulich 
      School of Medicine and Dentistry, Western University, London, Ontario, Canada. 
      Electronic address: tim.doherty@lhsc.on.ca.
LA  - eng
GR  - Canadian Institutes of Health Research/Canada
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20150717
PL  - England
TA  - Exp Gerontol
JT  - Experimental gerontology
JID - 0047061
SB  - IM
MH  - Adult
MH  - Aged
MH  - Aged, 80 and over
MH  - Aging/*pathology/physiology
MH  - Electromyography/methods
MH  - Female
MH  - Humans
MH  - Knee Joint/physiopathology
MH  - Lower Extremity/physiopathology
MH  - Male
MH  - Motor Neurons/*pathology/physiology
MH  - Muscle Fibers, Skeletal/*pathology/physiology
MH  - Muscle Strength/*physiology
MH  - Muscle, Skeletal/physiopathology
MH  - Sarcopenia/*pathology/physiopathology
MH  - Young Adult
OTO - NOTNLM
OT  - Aging
OT  - Electromyography (EMG)
OT  - Motor unit
OT  - Motor unit number estimation (MUNE)
OT  - Power
OT  - Sarcopenia
EDAT- 2015/07/21 06:00
MHDA- 2016/07/13 06:00
CRDT- 2015/07/21 06:00
PHST- 2015/03/10 00:00 [received]
PHST- 2015/07/08 00:00 [revised]
PHST- 2015/07/09 00:00 [accepted]
PHST- 2015/07/21 06:00 [entrez]
PHST- 2015/07/21 06:00 [pubmed]
PHST- 2016/07/13 06:00 [medline]
AID - S0531-5565(15)30015-2 [pii]
AID - 10.1016/j.exger.2015.07.007 [doi]
PST - ppublish
SO  - Exp Gerontol. 2015 Oct;70:111-8. doi: 10.1016/j.exger.2015.07.007. Epub 2015 Jul 
      17.