PMID- 22913025
OWN - NLM
STAT- MEDLINE
DCOM- 20120920
LR  - 20120823
IS  - 0031-5125 (Print)
IS  - 0031-5125 (Linking)
VI  - 114
IP  - 3
DP  - 2012 Jun
TI  - Contraction intensity and velocity on vastus lateralis SEMG power spectrum and 
      amplitude.
PG  - 847-56
AB  - Effect of contraction intensity [100%, 75%, 50%, and 25% maximum voluntary 
      contraction (MVC)] and movement velocity [0 degrees (isometric)], 50 degrees, 100 
      degrees, 200 degrees, and 400 degrees/sec. [isovelocities]) on root mean square 
      amplitude (SEMG-RMS) and median frequency power spectrum (SEMG-MNF) of vastus 
      lateralis (VL) surface electromyography was investigated with ten healthy female 
      university students. Peak torque (PT), mean torque (MT), SEMG-MNF, and SEMG-RMS, 
      analyzed using separate repeated-measures analyses of variance (p < or = .05), 
      indicated: (1) an inverse relation between PT and MT and movement velocity, (2) 
      greater SEMG-MNF values during all isovelocity conditions compared with isometric 
      conditions, with highest values occurring at 50 degrees /sec. and at 100% and 75% 
      MVC, and (3) at all contraction intensities SEMG-RMS values were higher during 
      dynamic movements than isometric movements and highest at 200 degrees /sec. 
      Isovelocity contractions were inferred to facilitate a greater recruitment of 
      fast-twitch fibers (via increased SEMG-MNF), which was intensified at 50 degrees 
      /sec., whereas greater overall muscle activation was found at 200 degrees /sec.
FAU - Miller, John
AU  - Miller J
AD  - Department of Kinesiology, University of New Hampshire, Durham 03824, USA. 
      jm@unh.edu
FAU - Croce, Ronald
AU  - Croce R
FAU - Horvat, Michael
AU  - Horvat M
FAU - Smith, Wayne
AU  - Smith W
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Percept Mot Skills
JT  - Perceptual and motor skills
JID - 0401131
SB  - IM
MH  - Adult
MH  - Electromyography
MH  - Female
MH  - Humans
MH  - Isometric Contraction/physiology
MH  - Knee Joint/physiology
MH  - Movement/*physiology
MH  - Muscle Contraction/*physiology
MH  - Muscle Fibers, Fast-Twitch/physiology
MH  - Quadriceps Muscle/*physiology
MH  - Recruitment, Neurophysiological
MH  - Torque
EDAT- 2012/08/24 06:00
MHDA- 2012/09/21 06:00
CRDT- 2012/08/24 06:00
PHST- 2012/08/24 06:00 [entrez]
PHST- 2012/08/24 06:00 [pubmed]
PHST- 2012/09/21 06:00 [medline]
AID - 10.2466/25.26.27.PMS.114.3.847-856 [doi]
PST - ppublish
SO  - Percept Mot Skills. 2012 Jun;114(3):847-56. doi: 
      10.2466/25.26.27.PMS.114.3.847-856.