Which of the following is NOT a key component of physical fitness?

The correct answer identifies speed as not being classified as one of the key components of physical fitness. While speed can be an important attribute in certain sports and activities, the primary components of physical fitness are generally categorized into cardiovascular endurance, muscular strength, body flexibility, and muscular endurance.

Cardiovascular endurance refers to the ability of the heart and lungs to supply oxygen to the muscles during sustained physical activity, which is fundamental for overall health and fitness. Muscular strength refers to the maximum amount of force a muscle can produce, which is essential for performing daily activities and developing overall body strength. Body flexibility enhances the range of motion in the joints, which contributes to balance and injury prevention.

Speed, while valuable, is typically considered a skill-related fitness component that supports performance in specific athletic contexts rather than a foundational aspect of general fitness. As such, speed does not fall under the primary components used to assess overall physical fitness in a broad application.