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AIS Chapter 6 Blood lactate thresholds

AIS Chapter 6 Blood lactate thresholds. Production of Lactic Acid (lactate). Normally, O 2 is available in the mitochondria to accept H + (and electrons) from NADH produced in glycolysis In anaerobic pathways, O 2 is not available

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AIS Chapter 6 Blood lactate thresholds

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  1. AIS Chapter 6Blood lactate thresholds

  2. Production of Lactic Acid (lactate) • Normally, O2 is available in the mitochondria to accept H+ (and electrons) from NADH produced in glycolysis • In anaerobic pathways, O2 is not available • H+ and electrons from NADH are accepted by pyruvic acid (pyruvate) to form lactic acid

  3. Conversion of Pyruvic Acid to Lactic Acid • Recycling of NAD (NADH  NAD) • So that glycolysis can continue • LDH: lactate dehydrogenase 乳酸去氫脢

  4. Blood lactate testing rationale • Indicators of training adaptation • Adapts to a greater degree than VO2max • Especially true in highly trained athletes • Correlate with endurance performance • Better indicator than VO2max • Optimal training stimuli

  5. Lactate response after training adaptation

  6. Lactate response after training adaptation

  7. Definitions of lactate threshold • Various terminology • Anaerobic threshold, aerobic-anaerobic threshold, onset of blood lactate accumulation (OBLA) • Lactate threshold 1 (LT1) • First exercise intensity at which there is a sustained increase in lactate above resting level • Usually < 2.0 mM • Lactate threshold 1 (LT2) • First exercise intensity at which there is a very rapid increase in lactate • Shift from oxidative to partly anaerobic energy • 2.5-5.5 mM

  8. LT1 and LT2

  9. Fixed lactate concentration2.0, 2.2, 2.5, 3.0, 4.0 mM

  10. Individualized lactate threshold Lactate E for ADAPT: http://www.nuigalway.ie/maths/jn/LACTATE/html/lactate-e.html

  11. Test protocols • Incremental duration: 5-8 min • < 5 min may overestimate LT2 • Especially the purpose is to prescribe exercise intensity for endurance training • Rest interval duration: 0-60 s • For blood collection and/or modify equipment • Number of increments: 5-7 • Relatively small increments in intensity: 1-2 km/hrper stage (~1 km/hrperferred)

  12. Lactate concentrations in difference durations of stages

  13. LT2 occurs at different lactate concentrations for difference exercise modes

  14. Lactate concentration in muscle and blood • Strong correlation between muscle and blood lactate concentration • Blood lactate NOT wholly reflective of muscle lactate • High muscle lactate requires significant time lag before lactate equilibrates with blood • Require longer (> 5 min) stage duration

  15. Practical applications • Use individually measured LT1 and LT2 • Prescribe endurance training intensities • T1: light aerobic • T2: moderate aerobic • T3: heavy aerobic • T4: anaerobic threshold • T5: maximal aerobic • Evaluate training adaptations • Graphical overlays for subjective assessment • ↑intensity at LT1: ↑ base aerobic condition • ↑intensity at LT2: ↑high-level aerobic endurance

  16. Endurance training zones

  17. Training adaptations in lactate concentration

  18. Homework • Design protocols for running MAOD (p67-68) • Design protocols for running lactate threshold (p84-89) • Design protocols for running VO2max (p113-114) • Chapter 26 Runners and walkers (p401-408)

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