Energy System: Practice Questions

An elite athlete is competing in a marathon and maintains a steady, moderate pace for over two hours. Which energy system is the primary provider of energy for this activity?

The diagram shows the relative contribution of different energy systems during maximal exercise. Which energy system is represented by the curve that provides the highest percentage of energy during the first 10 seconds?

An athlete is training in their aerobic zone at \( 70\% \) of their maximum heart rate. As the duration of their run exceeds 60 minutes and their internal glycogen stores begin to diminish, which macronutrient becomes the increasingly dominant fuel source for continued energy production?

Which chemical compound is directly broken down to provide the immediate energy required for all muscle contractions?

During a high-intensity 400-meter sprint lasting approximately 50 seconds, which macronutrient is the predominant fuel source used by the anaerobic system?

During a high-intensity weightlifting session, an athlete performs a single repetition of a heavy squat. State the primary energy system used for this short-duration, high-intensity explosive movement and name the molecule, often abbreviated as \( \text{ATP} \), whose breakdown directly releases energy for muscle contraction.

A long-distance runner maintains a steady pace for a \( 10 \) km race. Explain why the aerobic system is the primary provider of energy for this activity compared to the anaerobic systems, and identify one macronutrient that would be the preferred fuel source at this exercise intensity.

An athlete performs a maximal effort run lasting exactly \(2\) minutes. The graph provided illustrates the relative percentage contribution of the three energy systems during this specific exercise duration.

(a) Identify the energy systems represented by Line B and Line C. Compare the relative contributions of these two systems at the \(30\)-second mark versus the \(100\)-second mark to justify your identification. (3 points)

(b) The athlete has a maximum heart rate of \(200\) bpm. To improve her aerobic endurance, her coach suggests training within a zone of \(70\%\) to \(85\%\) of her maximum heart rate. Calculate the heart rate range (in bpm) for this training zone. Show your working. (2 points)

(c) Describe the chemical process by which energy is released from Adenosine Triphosphate (ATP) for muscle contraction, and explain why the body must utilize macronutrients like carbohydrates to resynthesize ATP during this \(2\)-minute run. (2 points)