title: Estimation of the neuromuscular fatigue threshold from an incremental cycling test using 1-minute exercise periods.
abstract: BACKGROUND
  The objectives of this study were: 1) to evaluate the method used for estimating the neuromuscular fatigue threshold from surface electromyographic amplitude (the PWCFT test) during a single incremental cycling workout using 1-minute exercise periods, and 2) to investigate the possible associations between PWCFT and metabolic (onset of blood lactate accumulation [OBLA]) and ventilatory (ventilatory threshold [VT] and respiratory compensation point [RCP]) variables.
  
  
  METHODS
  Sixteen cyclists performed incremental cycle ergometer rides to exhaustion with bipolar surface sEMG signals recorded from the vastus lateralis. Subsequently, participants performed one constant-workload exercise test at 100% of their PWCFT.
  
  
  RESULTS
  During the incremental test, the power output at PWCFT was not correlated with that of OBLA (P>0.05), but it was positively correlated with those of VT and RCP (P<0.05). During the constant-workload test, heart rate and blood lactate increased progressively and significantly (P<0.05), whereas sEMG amplitude remained unchanged (P>0.05). The average duration of the constant-workload exercise was 8-9 minutes.
  
  
  CONCLUSIONS
  The application of the PWCFT method using 1-min exercise periods could lead to overestimation of the neuromuscular fatigue threshold most likely because this stage duration allows insufficient time for the sEMG response to manifest.
authors.affiliation: Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain.
authors.forename: Iban
authors.initials: I
authors.lastname: Latasa
authors.affiliation: Department of Physiology and Biochemistry, University of Valladolid, Soria, Spain.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Cordova
authors.affiliation: Department of Physical Education, University of Leon, Leon, Spain.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Villa
authors.affiliation: Department of Engineering and Computer Science, University Jaume I, Castellón, Spain.
authors.forename: Gregorio
authors.initials: G
authors.lastname: Quintana
authors.affiliation: Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain - javier.rodriguez.falces@gmail.com.
authors.forename: Javier
authors.initials: J
authors.lastname: Rodriguez-Falces
mesh_terms: D000293:Adolescent; D000328:Adult; D004576:Electromyography; D016552:Ergometry / Q000379:methods*; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D055815:Young Adult
chemical_list: D019344:Lactic Acid