Why is it important to keep your knees straight during the flutter kick?

Keeping your knees straight during the flutter kick is essential for achieving better propulsion in the water. When the legs are extended and the knees are straight, the kick generates a more streamlined motion, allowing for a more effective transfer of energy from the legs into the water. This streamlined position reduces drag and enhances the powerful backward movement necessary for propulsion, contributing to efficient swimming.

In contrast, bending the knees can create more resistance, leading to less effective kicking and potential slowing down of movement through the water. This can also lead to improper body positioning, which further complicates propulsion. Overall, maintaining straight knees allows for a more effective and powerful flutter kick, optimizing forward movement.