Which of the following activities primarily tests cardiorespiratory endurance?

Cardiorespiratory endurance refers to the ability of the heart, lungs, and circulatory system to supply oxygen to the muscles during sustained physical activity. Activities that promote and test this type of endurance typically involve continuous, rhythmic movements that utilize large muscle groups over an extended period.

Walking or jogging for a long period is a quintessential activity for testing cardiorespiratory endurance because it requires sustained effort and engages both the aerobic energy system and multiple muscle groups, particularly the legs. This type of activity elevates the heart rate and challenges the body's ability to consume and utilize oxygen efficiently over time, making it an excellent indicator of cardiorespiratory fitness.

In contrast, weightlifting predominantly builds muscular strength and endurance rather than focusing on cardiovascular capacity. Stretching exercises improve flexibility and the range of motion but do not significantly engage the cardiovascular system. Isometric exercises, while beneficial for muscle strength, typically involve static holds that do not elevate the heart rate or significantly test cardiorespiratory endurance.

Therefore, the choice of walking or jogging for a long period directly aligns with the criteria for assessing cardiorespiratory endurance.