Whether it is scissor or flutter kicks, move your legs underwater. For the former, facing up, extend your legs in a V shape, bring them quickly together with one ankle on top of the other, then switch quickly. Your quads and inner thighs should feel the burn. Your abs are also targeted because they will work to keep you from floating or sinking. The latter exercise seems like a lot of fun for kids because you’re splashing. Hold on to something and kick your legs briskly behind you. Try to move them faster, not higher.