Which activity is a clearly aerobic form of exercise?

• A. Sprinting 100 meters
• B. Powerlifting attempt
• C. Distance running (e.g., 5k)
• D. High-intensity interval sprints

Answer: (C)

Distance running engages the body's aerobic energy system, meaning it relies on oxygen to fuel activity that can be sustained for a longer duration. A 5k is typically performed at a steady, moderate pace that keeps you in an aerobic state, supporting continuous leg muscle work over several minutes and improving cardiovascular endurance. The other options are short, high-intensity efforts that depend mainly on anaerobic energy systems (phosphagen and glycolysis) and are not primarily oxygen-driven. Sprinting short distances uses stored energy for a brief burst, powerlifting is all-out effort with little time for oxygen delivery, and high-intensity interval sprints mix bursts of anaerobic work with recovery rather than staying in the aerobic zone. So, distance running is the clearly aerobic form.