What is defined as the ability to exert muscular strength quickly?

The ability to exert muscular strength quickly is defined as power. Power combines both strength and speed, allowing an individual to apply force in a rapid manner. This can be seen in activities such as sprinting, jumping, or explosive lifting where both the magnitude of the force and the rate at which it is applied are crucial.

In contrast, agility refers to the ability to move quickly and change direction with efficiency, which, while related to performance, does not specifically encompass the concept of strength. Speed is about how fast a person can move from one point to another, and while it pertains to rapid movement, it doesn't include the element of muscular strength. Endurance focuses on the ability to sustain prolonged physical activity, emphasizing stamina over the quick exertion of strength. Thus, power is the correct term that embodies the concept of exerting muscular strength swiftly.