Which statement describes anaerobic activity?

Which statement describes anaerobic activity?

• A. Energy is produced without oxygen, but only at low intensity.
• B. It lasts for long periods with adequate oxygen supply.
• C. Oxygen debt does not occur.
• D. High intensity, short bursts where oxygen supply is insufficient.

Answer: (D)

Anaerobic activity happens when the muscles contract at high intensity and need energy faster than the body can deliver oxygen. In these moments the body relies on quick, oxygen-free energy sources (like the phosphagen system and anaerobic glycolysis) to produce ATP. This lets you work hard for a short time, but it can’t be sustained because these pathways are limited and lactate builds up. Because the effort is so intense, oxygen supply is insufficient from the start, creating an oxygen deficit that must be paid back after you stop—the oxygen debt. That’s why the description of anaerobic activity as high intensity, short bursts where oxygen supply is insufficient is the best fit. The other ideas don’t match: energy produced without oxygen isn’t limited to low intensity, long efforts with oxygen describe aerobic activity, and oxygen debt does occur after anaerobic work.

Anaerobic activity happens when the muscles contract at high intensity and need energy faster than the body can deliver oxygen. In these moments the body relies on quick, oxygen-free energy sources (like the phosphagen system and anaerobic glycolysis) to produce ATP. This lets you work hard for a short time, but it can’t be sustained because these pathways are limited and lactate builds up.

Because the effort is so intense, oxygen supply is insufficient from the start, creating an oxygen deficit that must be paid back after you stop—the oxygen debt. That’s why the description of anaerobic activity as high intensity, short bursts where oxygen supply is insufficient is the best fit. The other ideas don’t match: energy produced without oxygen isn’t limited to low intensity, long efforts with oxygen describe aerobic activity, and oxygen debt does occur after anaerobic work.