PMID- 18691906
OWN - NLM
STAT- MEDLINE
DCOM- 20091112
LR  - 20090828
IS  - 1873-5711 (Electronic)
IS  - 1050-6411 (Linking)
VI  - 19
IP  - 5
DP  - 2009 Oct
TI  - Motor unit synchronization in FDI and biceps brachii muscles of strength-trained 
      males.
PG  - 800-9
LID - 10.1016/j.jelekin.2008.06.003 [doi]
AB  - Motor unit (MU) synchronization is the simultaneous or near-simultaneous firing 
      of two MUs which occurs more often than would be expected by chance. The present 
      study sought to investigate the effects of exercise training, muscle group, and 
      force level, by comparing the magnitude of synchronization in the biceps brachii 
      (BB) and first dorsal interosseous (FDI) muscles of untrained and 
      strength-trained college-aged males at two force levels, 30% of maximal voluntary 
      contraction (MVC) and 80% MVC. MU action potentials were recorded directly via an 
      intramuscular needle electrode. The magnitude of synchronization was assessed 
      using previously-reported synchronization indices: k', E, and CIS. 
      Synchronization was significantly higher in the FDI than in the BB. Greater 
      synchronization was observed in the strength-trained group with CIS, but not with 
      E or k'. Also, synchronization was significantly greater at 80% MVC than at 30% 
      MVC with E, but only moderately greater with CIS and there was no force 
      difference with k'. Synchronization prevalence was found to be greater in the BB 
      (80.1%) than in the FDI (71.5%). Thus, although the evidence is a bit equivocal, 
      it appears that MU synchronization is greater at higher forces, and greater in 
      strength-trained individuals than in untrained subjects.
FAU - Fling, Brett W
AU  - Fling BW
AD  - Department of Kinesiology, University of Massachusetts-Amherst, 30 Eastman Lane, 
      Amherst, MA 01003, USA.
FAU - Christie, Anita
AU  - Christie A
FAU - Kamen, Gary
AU  - Kamen G
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20080808
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  - Humans
MH  - Male
MH  - Motor Neurons/*physiology
MH  - Muscle Contraction/physiology
MH  - Muscle Strength/*physiology
MH  - Muscle, Skeletal/*physiology
MH  - Physical Endurance/*physiology
MH  - Physical Fitness/*physiology
MH  - Synaptic Transmission/*physiology
MH  - Upper Extremity/physiology
MH  - Weight Lifting/*physiology
MH  - Young Adult
EDAT- 2008/08/12 09:00
MHDA- 2009/11/13 06:00
CRDT- 2008/08/12 09:00
PHST- 2008/02/21 00:00 [received]
PHST- 2008/06/10 00:00 [revised]
PHST- 2008/06/10 00:00 [accepted]
PHST- 2008/08/12 09:00 [pubmed]
PHST- 2009/11/13 06:00 [medline]
PHST- 2008/08/12 09:00 [entrez]
AID - S1050-6411(08)00095-3 [pii]
AID - 10.1016/j.jelekin.2008.06.003 [doi]
PST - ppublish
SO  - J Electromyogr Kinesiol. 2009 Oct;19(5):800-9. doi: 
      10.1016/j.jelekin.2008.06.003. Epub 2008 Aug 8.