PMID- 28515833
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20191120
IS  - 1939-795X (Print)
IS  - 1939-795X (Electronic)
IS  - 1939-795X (Linking)
VI  - 10
IP  - 3
DP  - 2017
TI  - Time Course of Changes in Neuromuscular Responses at 30% versus 70% 1 Repetition 
      Maximum during Dynamic Constant External Resistance Leg Extensions to Failure.
PG  - 365-378
AB  - The purpose of the current study was to examine the time course of changes in 
      neuromuscular responses from the vastus medialis (VM) during low versus high 
      intensity dynamic constant external resistance (DCER) leg extension muscle 
      actions to failure. Thirteen men performed DCER leg extensions to failure at 30% 
      and 70% 1-repetition maximum (1-RM) as well as 1-RM measurements pretest and 
      posttest. Electromyogaphy and mechanomyographic signals were measured from the 
      VM. There were no differences in neuromuscular responses pretest versus posttest 
      1-RM. There were time-dependent differences between the 30% and 70% 1-RM 
      protocols. The initial phase of the 30% 1-RM protocol exhibited increases in 
      electromyographic-amplitude and mechanomyographic amplitude, but no changes at 
      70% 1-RM. The middle phases indicated decreases in mechanomyographic amplitude at 
      30% 1-RM, but increases in mechanomyographic amplitude at 70% 1-RM. The 70% 1-RM 
      protocol had earlier decrease in mechanomyographic frequency than 30% 1-RM. Both 
      protocols in the final phases exhibited increases in electromyographic amplitude 
      and mechanomyogrpahic-amplitude, but decreases in electromyographic frequency and 
      mechanomyographic frequency. Low and high intensity DCER leg extensions to 
      failure have time-dependent differences in neuromuscular responses during the 
      process of fatigue which suggested that motor unit activation strategies may by 
      influenced by the intensity of a fatiguing workbout. Thus, examining the time 
      course of changes in neuromuscular responses during a fatiguing workbout allowed 
      for the identification of the time-points associated with the onset of fatigue.
FAU - Smith, Cory M
AU  - Smith CM
AD  - Department of Nutrition and Health Sciences, Human Performance Laboratory 
      University of Nebraska-Lincoln, Lincoln, NE, USA.
FAU - Housh, Terry J
AU  - Housh TJ
AD  - Department of Nutrition and Health Sciences, Human Performance Laboratory 
      University of Nebraska-Lincoln, Lincoln, NE, USA.
FAU - Hill, Ethan C
AU  - Hill EC
AD  - Department of Nutrition and Health Sciences, Human Performance Laboratory 
      University of Nebraska-Lincoln, Lincoln, NE, USA.
FAU - Schmidt, Richard J
AU  - Schmidt RJ
AD  - Department of Nutrition and Health Sciences, Human Performance Laboratory 
      University of Nebraska-Lincoln, Lincoln, NE, USA.
FAU - Johnson, Glen O
AU  - Johnson GO
AD  - Department of Nutrition and Health Sciences, Human Performance Laboratory 
      University of Nebraska-Lincoln, Lincoln, NE, USA.
LA  - eng
PT  - Journal Article
DEP - 20170501
PL  - United States
TA  - Int J Exerc Sci
JT  - International journal of exercise science
JID - 101513127
PMC - PMC5422004
OTO - NOTNLM
OT  - EMG
OT  - MMG
OT  - fatigue
OT  - resistance training
EDAT- 2017/05/19 06:00
MHDA- 2017/05/19 06:01
PMCR- 2017/05/01
CRDT- 2017/05/19 06:00
PHST- 2017/05/19 06:00 [entrez]
PHST- 2017/05/19 06:00 [pubmed]
PHST- 2017/05/19 06:01 [medline]
PHST- 2017/05/01 00:00 [pmc-release]
AID - ijes.10.03.365 [pii]
PST - epublish
SO  - Int J Exerc Sci. 2017 May 1;10(3):365-378. eCollection 2017.