Final answer:
Option A, having one's leg moved by a therapist, is NOT an example of physical activity for the person receiving the therapy, as they are not voluntarily moving their muscles.
Step-by-step explanation:
Physical Activity Identification
When determining which of the options is NOT an example of physical activity, it's important to understand what physical activity entails. Physical activity is any movement that is voluntary and requires energy. Therefore, having one's leg moved by a therapist (option A) would NOT be considered physical activity for the person receiving the therapy since they are not actively using their muscles to move their leg, but rather it is being moved for them. On the other hand, juggling (option B), walking (option C), and threading a needle (option D) all involve voluntary muscle movements and thus qualify as physical activities.