What best defines physical activity?

The definition of physical activity encompasses any movement that engages the body, particularly movements involving large muscle groups. This aligns with the idea that physical activity is not limited to specific body parts, such as just the upper body, but rather includes comprehensive movements that promote overall bodily function and fitness.

Movement that engages large muscles is critical because it generally leads to a greater expenditure of energy, improves cardiovascular health, enhances muscle strength, and supports metabolic processes. This type of activity forms the foundation of many physical fitness programs and health guidelines, which emphasize the importance of engaging major muscle groups through various forms of exercise.

Other options do not accurately represent the broader concept of physical activity. For instance, focusing only on upper body muscles limits the definition and disregards the importance of lower body movement. Static exercises and physical relaxation techniques fall outside the standard definition of physical activity because they do not involve sustained movement that raises heart rate or actively engages muscles in a dynamic way. Thus, the best definition of physical activity is centered around the movement of the body that involves large muscles.