• myGriffith
    • Staff portal
    • Contact Us⌄
      • Future student enquiries 1800 677 728
      • Current student enquiries 1800 154 055
      • International enquiries +61 7 3735 6425
      • General enquiries 07 3735 7111
      • Online enquiries
      • Staff phonebook
    View Item 
    •   Home
    • Griffith Theses
    • Theses - Higher Degree by Research
    • View Item
    • Home
    • Griffith Theses
    • Theses - Higher Degree by Research
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

  • All of Griffith Research Online
    • Communities & Collections
    • Authors
    • By Issue Date
    • Titles
  • This Collection
    • Authors
    • By Issue Date
    • Titles
  • Statistics

  • Most Popular Items
  • Statistics by Country
  • Most Popular Authors
  • Support

  • Contact us
  • FAQs
  • Admin login

  • Login
  • The Slow Component of O2 Uptake Kinetics : the Relationship Between Blood Lactate, pH and Motor Unit Recruitment.

    Thumbnail
    View/Open
    OsborneM_2009_02Thesis.pdf (849.5Kb)
    Author(s)
    Osborne, Mark
    Primary Supervisor
    Schneider, Donald
    Other Supervisors
    Gass, Greg
    Year published
    2009
    Metadata
    Show full item record
    Abstract
    The primary aim of this thesis was to develop a better understanding of the physiological mechanisms that cause the slow rise in O2 uptake ([V.O2]) that occurs during heavy- and severe-intensity exercise. The slow rise in [V.O2] during heavy-intensity exercise is known as the slow component of O2 uptake kinetics. This thesis includes a series of three studies investigating the mechanisms underlying the elevated O2 cost observed during heavy-intensity constant-load cycling exercise. Eight recreational cyclists ([V.O2]peak: [55.6 plus or minus 1.3 ml per kg per minute]) participated in each of the three studies. Each study was ...
    View more >
    The primary aim of this thesis was to develop a better understanding of the physiological mechanisms that cause the slow rise in O2 uptake ([V.O2]) that occurs during heavy- and severe-intensity exercise. The slow rise in [V.O2] during heavy-intensity exercise is known as the slow component of O2 uptake kinetics. This thesis includes a series of three studies investigating the mechanisms underlying the elevated O2 cost observed during heavy-intensity constant-load cycling exercise. Eight recreational cyclists ([V.O2]peak: [55.6 plus or minus 1.3 ml per kg per minute]) participated in each of the three studies. Each study was designed to manipulate blood lactate concentration ([La-]) and/or blood pH, or type II motor unit recruitment to determine if a corresponding change would occur in the amplitude of the [V.O2] slow component. All studies used a similar research design with each trial involving 3 minutes of baseline cycling (25 W) prior to 8 minutes of heavy-intensity constant-load cycling at a power output equal to 50% of the difference between the power output achieved at the ventilatory threshold and peak aerobic power ([change of] 50% work rate). Surface electromyographic (EMG) activity from the vastus medialis and vastus lateralis was measured throughout each constant-load cycling trial. Integrated EMG activity was used as an index of total neural activity, while the mean power frequency of the EMG signal was used as an indication of motor unit recruitment pattern. Blood lactate, pH and bicarbonate concentrations were determined under resting conditions prior to the start of exercise, at the end of 3 minutes at 25 W, and after 1.5, 3, 4.5, 6 and 8 minutes of heavy-intensity constant-load exercise. O2 uptake, CO2 production ([V.CO2]), and minute ventilation ([V.E]) were measured breath-by-breath while heart rate was measured continually throughout each constant-load trial. [V.O2] kinetics were determined using a double-exponential model with independent time delays beyond the phase I component.
    View less >
    Thesis Type
    Thesis (PhD Doctorate)
    Degree Program
    Doctor of Philosophy (PhD)
    School
    School of Physiotherapy and Exercise Science.
    DOI
    https://doi.org/10.25904/1912/1668
    Copyright Statement
    The author owns the copyright in this thesis, unless stated otherwise.
    Item Access Status
    Public
    Subject
    Blood lactate.
    Exercise
    Motor unit recruitment
    Physiological mechanisms.
    Publication URI
    http://hdl.handle.net/10072/365879
    Collection
    • Theses - Higher Degree by Research

    Footer

    Disclaimer

    • Privacy policy
    • Copyright matters
    • CRICOS Provider - 00233E
    • TEQSA: PRV12076

    Tagline

    • Gold Coast
    • Logan
    • Brisbane - Queensland, Australia
    First Peoples of Australia
    • Aboriginal
    • Torres Strait Islander