Which statement best defines physical activity?

The definition of physical activity encompasses any movement that is produced by the contraction of skeletal muscles and results in energy expenditure. This includes a broad range of movements, from structured exercise routines to everyday activities. Occasional walking or stair climbing reflects this wide-ranging nature of physical activity, as it serves as an example of movement that can contribute positively to overall health without needing to be part of a formal exercise regimen.

Walking or stair climbing, while more informal, plays an important role in encouraging individuals to integrate physical movement into their daily lives. It emphasizes that engaging in any form of movement, even if it is not a part of a structured or intense workout session, can still be beneficial to health and fitness. This perspective is consistent with broader public health recommendations, which advocate for incorporating various forms of physical activity into daily routines for optimal health benefits.

In contrast, the other options restrict the definition of physical activity to more formal or intense formats. Regularly scheduled strength training, structured workout programs, and high-intensity interval training all represent specific types of physical activities but do not encapsulate the full breadth of what physical activity can be. By recognizing occasional walking or stair climbing, we acknowledge a more inclusive approach to understanding how physical activity can vary in intensity and structure.