actors affecting performance l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
actors Affecting Performance PowerPoint Presentation
Download Presentation
actors Affecting Performance

Loading in 2 Seconds...

play fullscreen
1 / 19

actors Affecting Performance - PowerPoint PPT Presentation


  • 94 Views
  • Uploaded on

actors Affecting Performance. F. Chapter 19. How hard can it be? If world records were easy to set, then everybody would be doing it. Asafa Powell (100 m – 9.77s) ~48 kcal/min Michael Johnson (200 m – 19.32s) ~42 kcal/min Hicham El Guerrouj (1 mile – 3:43.13) ~34 kcal/min

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'actors Affecting Performance' - leoma


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide3

How hard can it be?If world records were easy to set, then everybody would be doing it.

  • Asafa Powell (100 m – 9.77s) ~48 kcal/min
  • Michael Johnson (200 m – 19.32s) ~42 kcal/min
  • Hicham El Guerrouj (1 mile – 3:43.13) ~34 kcal/min
  • Kenenisa Bekele (5K – 12:37.35) ~31 kcal/min
  • Paul Tergat (marathon – 2:04:55) ~28 kcal/min
  • Running at 10 mph (6 min/mile) ~19.6 kcal/min
  • Jumping rope ~10.2 kcal/min
  • Mowing the grass ~9.0 kcal/min
  • Walking at 4 mph (15 min/mile) ~6.9 kcal/min
  • Car washing ~5.7 kcal/min
atigue

F

atigue

Inability to maintain a power output or force during repeated muscle contractions

slide7

F

atigue – confounding variables

  • Fiber type and training state of subject
  • Voluntary or electrical stimulation
  • Intensity/duration of training, continuous/discontinuous activity
entral fatigue

C

entral Fatigue
  • Merton’s (1954) classical experiments
    • muscle fatigued with voluntary contractions, EMS could not restore tension
  • Ikai and Steinhaus (1961)
    • “Psyche” on strength
    • (1969) showed EMS  tension
  • Asmussen and Mazin (1978)
    • physical/mental diversion (i.e., contraction of non-fatigued muscle/math/opening eyes) improved strength (CNS arousal)
entral fatigue9

C

entral Fatigue
  • Mechanisms  exercise induced alterations in CNS neurotransmitters
    • Serotonin (5-hydroxytryptamine)
    • Dopamine
    • ACh

along with the neuromodulators

eripheral fatigue

P

eripheral Fatigue
  • Neural Factors
    • Neuromuscular Junction (Ø or ?)
    • Sarcolemma and T-Tubules
      • inability of NA++/K+ pump to maintain pace might lower action potential amplitude and the frequency
      • amplitude changes as observed do not appear to have an effect; shift in optimal frequency to preserve force
      • could be a blockage of the action potential in the t-tubule thus reducing Ca++ release
eripheral fatigue11

P

eripheral Fatigue
  • Mechanical Factors
    • functional arrangement of actin & myosin
    • Ca++ availability
    • ATP
  • disruption of sarcomere (eccentric)
  • H+ (reduce force, reduce force at [Ca++], inhibit SR Ca++ release)
eripheral fatigue12

P

eripheral Fatigue
  • Energetics of Contraction
    • high Pi levels reduce the cross-bridge binding to actin
    • inability to deliver oxygen (Type I & IIa)
    • inability to produce ATP (aerobic vs anaerobic)
    • production of lactate (recruitment of fibers)
slide19
2:15 time equates to 60 mL/kg/min submaximal VO2

VO2max

LT80% = 75 mL/kg/min

LT70% = 85 mL/kg/min

LT60% = 100 mL/kg/min

3:00 time equates to 46 mL/kg/min submaximal VO2

VO2max

LT80% = 58 mL/kg/min

LT70% = 66 mL/kg/min

LT60% = 77 mL/kg/min

C

omparative analysis (Marathon)

  • 4:00 time equates to 35 mL/kg/min submaximal VO2

VO2max

  • LT80% = 44 mL/kg/min
  • LT70% = 50 mL/kg/min
  • LT60% = 58 mL/kg/min