Anaerobic Systems

Question 1

Be able to discuss which energy systems are activated (dominating) during various types of exercise (e.g., Wingate vs. marathon).

Answer 1

-Not one energy system contributed to ATP production

• Wingate: anaerobic glycolysis- PCr, anaerobic glycolysis but not as much, then a little aerobic glycolysis

-Marathon: aerobic glycolysis (slow glycolysis) and aerobic lipolysis

• Different systems dominating different exercises

-Glycolytic System: short, high-intensity energy source- anaerobic breakdown of carbohydrates (glucose and glycogen)

-Oxidative System: long-term aerobic energy production (carbohydrate and fat metabolism)

Question 2

Be able to describe the ATP-PCr system. What happens to muscle PCr and ATP concentrations during high intensity exercise? What is their relationship to each other?

Answer 2

Quick explosive energy source

In cytosol in the cell

Provides ATP for a couple seconds at high intensity (3-15 sec)

PCr decreases during high intensity to regenerate ATP

Prevents energy depletion by forming more ATP

Instantaneous process but the substrate quickly depleted

-Exergonic: PCr -> Pi + Creatine
-Endergonic: ADP + Pi -> ATP

Question 3

Glycolysis

Answer 3

Breakdown of glucose; may be anaerobic or aerobic

Question 4

Glycogenesis

Answer 4

Process by which glycogen is synthesized from glucose to be stored in the liver/muscle

Question 5

Glycogenolysis

Answer 5

The process by which glycogen is broken down into glucose-1- phosphate to be used by muscles

Question 6

Where does glycolysis take place in the cell?

Answer 6

Within the cytosol of the muscle cell

important for glycolysis is 2NAD

Question 7

Which enzyme is responsible for breaking down muscle glycogen? Why does glucose derived from muscle glycogen yield more ATP when compared to circulating glucose?

Answer 7

Glycogen Phosphorylase

Since it is already in the cell it does not lose the ATP required to enter the cell

Question 8

What is the fate of pyruvate in the absence of oxygen?

Answer 8

Turns into lactic acid

Question 9

Why is increased lactic acid a potential problem?

Answer 9

• Muscle Fatigue: Causes burning sensation, reducing performance.
• pH Balance: Lowers pH, disrupting muscle function and contractions.
• Oxygen Debt: Increases reliance on less efficient anaerobic metabolism.
• Delayed Recovery: Prolongs recovery time as the body clears lactate.
• Reduced Performance: Limits ability to sustain high-intensity efforts.

Factors affecting lactate concentration:

• Oxygen availability, enzyme activity, muscle fiber type, muscle lactate transporters

Decrease muscle pH

• Metabolic inhibition (decrease enzyme activity), contractile inhibition (decrease X-bridge cycling)

Question 10

What is the lactate threshold (aka, onset of blood lactate accumulation [OBLA])? Why does it matter for exercise performance? Does training alter OBLA?

Answer 10

Definition: Intensity at which lactate accumulates in the blood faster than it can be cleared.

Importance:
* Indicator of endurance performance.
* Aids in effective pacing strategies.
* Enhances training efficiency.
*
Training Effects:

• Endurance training raises LT.
• Improves lactate utilization and clearance.
  *

Question 11

What test measures the capacity of short-term energy system? What variables are generally measured during this test? Why is this information important?

Answer 11

Wingate Cycle Test
-200-400M running
–Peak Power (PP)
–Mean Power (MP)
–Percent Fatigue (%F)

Lactic Acid
–glucose from muscle glycogen or blood glucose goes through fast glycolysis giving 2 ATP turning into Lactic Acid
–High rate of ATP and can get it anaerobically
–Produces Lactate and H+
—Lower cell pH, causes fatigue, doesn’t completely oxidize glucose