Intensity, often referred to as strength, measures the degree of power or force exerted in a physical activity. In fitness, it indicates how hard a person is working during exercise, which can be influenced by factors like speed, resistance, and duration. Higher intensity workouts typically lead to greater calorie burn and improved cardiovascular fitness. In strength training, intensity can also refer to the amount of weight lifted relative to a person's maximum capacity. For example, lifting heavier weights for fewer repetitions is considered high intensity, while lighter weights for more repetitions represent lower intensity. This concept is crucial for developing muscle strength and endurance effectively.