What is the primary definition of physical activity?

The primary definition of physical activity focuses on bodily movements produced by the contraction of skeletal muscles, which leads to an increase in energy expenditure. This definition encompasses a broad range of activities beyond formal exercise or structured workouts. It includes everyday tasks such as walking, gardening, or even activities like standing or moving around, highlighting that physical activity is any movement that requires energy expenditure. The emphasis on skeletal muscle contraction is crucial, as it distinguishes physical activity from other forms of energy expenditure that do not involve muscle movement, such as digestion or resting metabolic functions.

In contrast, the other choices narrow the definition of physical activity in various ways. Some focus on specific aspects like temperature increase, structured fitness routines, or recreational elements, which do not encapsulate the full spectrum of what constitutes physical activity.