Flutter kicks: what exactly are we talking about?
Flutter kicksAbdominaux / Core
Flutter kicks are alternating leg beats performed lying flat on your back. You will also hear them called vertical scissors or alternating leg raises. We will use both names here, since they show up interchangeably in gyms and online programs. The movement comes straight from swimming: the swimmer kicks the legs to move forward. On the floor, that same action turns into a brutal core exercise.
The muscles worked during the movement
The rectus abdominis takes most of the load, especially its lower portion. The obliques stabilise the pelvis. The hip flexors, the psoas in particular, drive the kicking action itself. The quads and the lower back chip in too. That broad recruitment explains why the flutter kicks exercise shows up in so many ab sessions.
Flutter kicks exercise: the correct position, step by step
Lie on your back. Slide your hands under your glutes, palms facing the floor. Lift your shoulders slightly off the ground. Raise both legs about twenty centimetres off the floor, knees straight. Now beat your legs up and down, never letting your heels touch down. Your lower back stays pressed into the floor: that rule is not negotiable.
The mistakes that ruin the movement
- An arching back, a sign your legs are too low.
- Too much range, which burns out your hips before your abs.
Holding your breath from the first rep to the last.
Chin crushed into your chest, which tightens up your neck.
The four-count cadence
Military training often counts in fours: right, left, right, then "one". That slow cadence makes every rep far harder. A video or a demo gif helps you lock in the rhythm before going it alone.
Variations for abs, CrossFit and swimming
Sit-upsAbdominaux / Core
Lowering your legs makes it harder. Raising them makes it easier. The hollow version, arms stretched out behind your head, raises the bar again. In CrossFit, the exercise often gets paired with sit-ups or hollow rocks inside a timed circuit. Platforms like Darebee offer free routines that include it with no equipment at all. In swimming, the same kick is trained with a kickboard to improve propulsion and body alignment.
Scissors or flutter kicks: what's the difference?
The two movements look very similar. In scissors, one leg crosses over the other, horizontally. In flutter kicks, the path is vertical, with no crossing. Scissors recruit the adductors and obliques more. Flutter kicks hit the lower abs far more directly.
Benefits and practical guidelines
A more solid core, a steadier posture, a direct carryover to running and swimming: the payoff is real. Volume and frequency depend on your level. Three sets of twenty to forty seconds is plenty to start with. You can include this exercise two to three times a week. Once you're past the learning phase, stretch the sets out. If you get lower back pain, it's better to talk to a personal trainer to adapt the position, and to browse our strength training tips.