Which of the following statements is true regarding anaerobic activities?

Anaerobic activities are characterized by high-intensity efforts that can be sustained for short durations, typically lasting from a few seconds up to around two minutes. These activities, such as sprinting, heavy weight lifting, or high-intensity interval training (HIIT), rely on energy sources stored in the muscles rather than oxygen. The energy is produced through anaerobic metabolism, which does not require oxygen and can quickly provide energy for intense bursts of activity.

The other statements are not accurate in the context of anaerobic activities. Extended performance duration aligns more with aerobic activities, which rely on oxygen and can sustain effort over longer periods. The statement regarding oxygen is also incorrect for anaerobic activities, as they do not primarily rely on oxygen for energy. Muscle recovery is more relevant to the context of rest and nutrition following workouts rather than a characteristic of anaerobic activities themselves. Therefore, the option stating that anaerobic activities require a high-intensity effort is the most accurate depiction of their nature.