How many repetitions are required for the "hundred" exercise in Pilates?

The "hundred" exercise in Pilates is specifically designed to build endurance, improve coordination, and enhance core strength. The standard for this exercise involves performing a sequence of 100 pumps, which typically corresponds to breathing in for five counts and out for five counts over the duration of the exercise. This rhythmic breathing pattern complements the actual pumping of the arms while lying on the mat, making a total of 100 arm movements or "pumps" through the course of the exercise.

Engaging in 100 repetitions encourages proper coordination of movement and breath, foundational principles of Pilates, and is central to the effectiveness of this exercise as it activates the core and warms up the body. Additionally, reaching the target of 100 pumps completes the essential goal of the exercise. This is why the answer indicating 10 breaths for 100 pumps is correct, as it reflects the traditional and widely accepted standard for performing the "hundred" exercise effectively in practice.