UNIT 1 (Lacate, the fate of lactate and lactate threshold) Flashcards
what is aerobic threshold?
the point during exercise when your body must switch from anaerobic to aerobic metabolism/energy systems
what is anaerobic threshold?
the point during exercise when your body must switch from aerobic systems to anaerobic systems to meet energy demands
what is lactate threshold?
the point during incremental exercise where the body produces lactate quicker than it can be removed. The lactate turn point is called OBLA
lactate is a good indicator of submaximal fitness. TRUE or FAlSE
TRUE
what benefits does training near the lactate threshold have?
-improve body use of lactate as an energy source(via cori cycle)
-improve the bodys clearance mechanisms (removal of lactate and H+)
-improve buffering capacity which is the ability of the muscles to neutralise the acid that accumulates during exercise)§
what are the immediate physiological effects of OBLA
- increase in H+ ions concentration (Decreases pH)
- muscle fatigue and discomfort
- impaired glycolysis and ATP production
- inhibition of enzyme activity
- oxygen debt
what is the cori cycle also know as
lactic acid cycle
what is the cori cycle
where lactate produced in anaerobic glycolysis is sent to the liver via the blood and converted back to glucose for more energy production. (it must be converted back to pyruvic acid before glucose)
how does the cori cycle benefit performance
-delays fatigue
-enhances recovery
-recycles energy
cori cycle flow chart
glucose –> glucose, 2x pyruvic acid then 2x lactate (2ATP released)–>2x lactate enters cori cycle–> 2xlactate into 2x pyruvic acid then back to glucose. it then goes through anaerobic glycolysis and repeats again
what percent of lactate is converted back to glucose?
10-20%
how much lactate is oxidised into CO2 and H2O to be used in the ETC
50-75% (majority)
what is 5-10% of lactate converted in to?
protein
how much lactate is converted into urine and sweat
5-10%
explain the possible causes of fatigue during anaerobic exercise (3marks)
-build up of lactic acid / OBLA
- Glycogen depletion
-reduced levels of acetylcholine which will slow nerve impulses
how does low levels of acetylcholine increase anaerobic fatigue
-low acetylcholine weakens the ability of the motor neurons to stimulate muscle fibres, resulting in decreased muscle force and contributing to fatigue
-nerver impulses become weaker and less effectively transmitted to muscles, so contractions become weaker and less coordinated leading to early muscle fatigue during anaerobic activities.
