PMID- 22749379
OWN - NLM
STAT- MEDLINE
DCOM- 20130527
LR  - 20121102
IS  - 1873-5711 (Electronic)
IS  - 1050-6411 (Linking)
VI  - 22
IP  - 6
DP  - 2012 Dec
TI  - Age-related decreases in motor unit discharge rate and force control during 
      isometric plantar flexion.
PG  - 983-9
LID - S1050-6411(12)00109-5 [pii]
LID - 10.1016/j.jelekin.2012.05.009 [doi]
AB  - Aging is related to multiple changes in muscle physiology and function. Previous 
      findings concerning the effects of aging on motor unit discharge rate (DR) and 
      fluctuations in DR and force are somewhat contradictory. Eight YOUNG and nine OLD 
      physically active males performed isometric ramp (RECR) and isotonic (ISO) 
      plantar flexions at 10 and 20% of surface EMG at MVC. Motor unit (MU) action 
      potentials were recorded with intramuscular fine-wire electrodes and decomposed 
      with custom build software "Daisy". DR was lower in OLD in RECR-10% (17.9%, p < 
      0.001), RECR-20% (15.8%, p < 0.05), ISO-10% (17.7%, p < 0.01) and ISO-20% (14%, 
      n.s.). In YOUNG force fluctuations were smaller at ISO-10% (72.1%, p < 0.001) and 
      ISO-20% (55.2%, p < 0.05) which were accompanied with a slight increase in DR 
      variation (n.s.). The observed lower DR in OLD is in line with earlier findings 
      in small distal muscles. Also the larger force fluctuation in OLD was in line 
      with previous studies with smaller hand muscles. These findings suggest that the 
      age-related changes in MU control do exist also in large leg extensors that play 
      an important role in human locomotion and balance control.
CI  - Copyright (c) 2012 Elsevier Ltd. All rights reserved.
FAU - Kallio, J
AU  - Kallio J
AD  - Neuromuscular Research Center, Department of Biology of Physical Activity, 
      University of Jyvaskyla, P.O. Box 35, FIN-40351, Jyvaskyla, Finland. 
      jouni.kallio@jyu.fi
FAU - Sogaard, K
AU  - Sogaard K
FAU - Avela, J
AU  - Avela J
FAU - Komi, P
AU  - Komi P
FAU - Selanne, H
AU  - Selanne H
FAU - Linnamo, V
AU  - Linnamo V
LA  - eng
PT  - Journal Article
DEP - 20120628
PL  - England
TA  - J Electromyogr Kinesiol
JT  - Journal of electromyography and kinesiology : official journal of the 
      International Society of Electrophysiological Kinesiology
JID - 9109125
SB  - IM
MH  - Action Potentials/*physiology
MH  - Adult
MH  - Aged
MH  - Aging/*physiology
MH  - Electromyography
MH  - H-Reflex/physiology
MH  - Humans
MH  - Isometric Contraction/*physiology
MH  - Lower Extremity/physiology
MH  - Male
MH  - Motor Neurons/*physiology
MH  - Muscle, Skeletal/*innervation/physiology
MH  - Range of Motion, Articular/physiology
EDAT- 2012/07/04 06:00
MHDA- 2013/05/29 06:00
CRDT- 2012/07/04 06:00
PHST- 2011/11/01 00:00 [received]
PHST- 2012/05/15 00:00 [revised]
PHST- 2012/05/16 00:00 [accepted]
PHST- 2012/07/04 06:00 [entrez]
PHST- 2012/07/04 06:00 [pubmed]
PHST- 2013/05/29 06:00 [medline]
AID - S1050-6411(12)00109-5 [pii]
AID - 10.1016/j.jelekin.2012.05.009 [doi]
PST - ppublish
SO  - J Electromyogr Kinesiol. 2012 Dec;22(6):983-9. doi: 
      10.1016/j.jelekin.2012.05.009. Epub 2012 Jun 28.