Energy Systems
What is ATP and why is it important?
Energy source for muscle contraction
How much ATP is produced during aerobic respiration?
36 ATP
Which fibre type is slow-twitch?
Type I
What is the pathway of blood from body → heart → lungs?
Vena cava → right atrium → right ventricle → pulmonary artery → lungs
What is the pathway of air to the lungs?
Nose → trachea → bronchi → bronchioles → alveoli
Which energy system is anaerobic and does NOT produce lactic acid?
ATP-PC (alactic)
Why are fats used more during low-intensity exercise?
Require oxygen and produce lots of energy slowly
Which fibre type is fast-twitch glycolytic?
Type IIB
What is the function of capillaries?
Exchange of gases/nutrients
What is the difference between conducting and respiratory zones?
Conducting = air movement, Respiratory = gas exchange
Which system produces lactic acid as a by-product?
Glycolysis (anaerobic lactic)
When might protein be used as an energy source?
extreme endurance exercise or starvation
Which fibre type is a hybrid (both aerobic & anaerobic)?
Type IIA
What is cardiac output?
Amount of blood pumped per minute
Name one factor that increases diffusion rate
Large surface area / thin membrane / high gradient
Which system is used during long-duration, low-intensity exercise?
Aerobic (cellular respiration)
During a long-distance run, your body begins to rely more on fats than carbohydrates. Why does this shift happen?
Fats provide more energy but require oxygen, so they are used during longer, lower-intensity exercise when oxygen is available
Which fibre type resists fatigue the best?
→ Type I
What is the formula for cardiac output?
Q = SV × HR
What is VO₂ max?
Maximum oxygen use by the body
Rank the 3 energy systems from fastest to slowest ATP production
→ ATP-PC → Glycolysis → Aerobic
An athlete suddenly increases intensity from a jog to a sprint. How does their energy source change and why?
The body shifts from aerobic metabolism (fats/carbs) to anaerobic glycolysis (carbohydrates) because it can produce ATP faster without oxygen
Why are fast-twitch fibres important for power athletes?
Produce high force quickly but fatigue fast
Name one adaptation from cardiovascular training
Lower resting HR / increased stroke volume / stronger heart
What happens at the ventilatory or lactate threshold?
Rapid increase in breathing + lactic acid buildup