Anaerobic exercise involves relatively few repetitions at high resistance for ______ periods of time, typically less than how many seconds?

Anaerobic exercise is characterized by short bursts of high-intensity activity, which are performed without the use of oxygen as the primary energy source. This type of exercise relies on energy sources that are stored in the muscles, such as ATP and creatine phosphate. The activity duration is notably brief because it is not sustainable for long periods.

The correct answer indicates that anaerobic exercise typically lasts less than 30 seconds. This aligns with the physiological benefits and characteristics of anaerobic workouts, as they focus on strength, power, and muscle development through high-resistance activities.

Training sessions that exceed 30 seconds often transition into aerobic metabolism, where the body begins to rely more on oxygen to sustain activity, thus not falling under the category of anaerobic exercise. Thus, understanding that anaerobic workouts are effective for short, intense efforts clarifies why 30 seconds is the correct upper limit for this form of exercise.