Glycolytic system Flashcards
The glycolytic system
> Takes over from ATP-PC system when PC stores are exhausted
Used for 3 minutes, until aerobic system takes over due to lactic acid build up
Produces 2ATP
Stores are replenished 20-60 minutes after rest
Step 1
Glycogen phosphorylase (GPP) catalyses the breakdown of glycogen (stored in the muscles and liver) into glucose
Step 2
When ADP and P levels rise, this triggers the release of phosphofructokinase (PFK)
Step 3
PFK catalyses the breakdown of glucose, which releases energy for ATP resynthesis
(this process is anaerobic glycolysis)
Step 4
Anaerobic glycolysis results in the production of pyruvic acid and energy for 2ATP
Step 5
Fermentation:
Lactate dehydrogenase (LDH) converts pyretic acid into lactic acid
Step 6
Lactic acid accumulates - reducing pH levels, enzyme activity, causing muscle fatigue and slower ATP resynthesis
Step 7
OBLA:
(Onset of blood lactate accumulation)
Blood lactate levels rise significantly
Step 8
EPOC:
(Excess post-exercise oxygenated blood consumption) - oxygen debt
Exercise stops, extra O2 is taken up to remove lactic acid by converting it back into pyruvic acid
Glycolytic system: Sporting examples
> 200m, 400m
100m freestyle
Counter attack - football
Distancing from the pack - marathon
Training the glycolytic system
> build tolerance to lactic acid
delaying muscle fatigue
high intensity anaerobic and aerobic training closer t anaerobic threshold
E.g.
3 sets of 10 reps of slow resistance training
gym circuit class
Sprint repetitions
Glycolytic system: +
> High intensity activity
Large fuel stores
No delay for O2 delivery
Relatively Fast Fuel breakdown for ATP resynthesis
Lactic acid can be recycled into fuel
Glycolytic system: -
> Short duration
Low ATP yield
Fatiguing by-product (lactic acid)
Lengthy recovery
