Hundreds of abs exercises exist, and everyone claims to know which one is best for a strong middle. But, no single exercise can really claim to be "best" over all the others — not even the very challenging flutter or scissor kick.
This move, done by lying on your back and scissoring your legs, uses your rectus abdominis, the main ab muscle, and your obliques, the side ab muscles, for stabilization. But, you'll also feel the very fronts of your hips burn during the exercise. This is because the hip flexors work hard along with your abs to hold your legs just off the floor and kick.
If your back is healthy, then the flutter kick might be one of many exercises you include in your ab-training regimen to foster a more stable core, even if it alone isn't the "best."
Flutter kicks are not THE best ab exercise. But they're not a bad choice to add to your roster of ab moves.
What Is the Flutter Kick?
A proper flutter kick is easy to perform as you need no equipment, except for a gym mat.
- Lie on your back on a gym mat with your legs extended and your arms alongside your hips, palms down, says Valdosta State University. Or nestle your hands underneath your rear to elevate your hips.
- Lift your legs 4 to 6 inches off the floor. Squeeze your abs to keep your back from overarching.
- Keep your legs straight as you rhythmically raise one leg higher, then switch. Move in a fluttering, up and down motion.
- Perform for 15 to 20 repetitions. Alternatively, flutter kick for a period of time, such as 20 to 30 seconds.
- Try this variation according to ACE Fitness: Prop yourself up on your elbows and do the flutter kicks in slow motion.
To vary the move, cross the legs over and under each other rather than flutter them up and down. This change doesn't markedly alter the muscles used during the exercise; it's just a fun variation.
Muscles Flutter Kicks Work
Your rectus abdominis — the front sheath of your abs — works when you flex, or bend, the torso at the waist. During the flutter kick, no bending happens so these ab muscles work as stabilizers only.
The hip flexors, which attach the pelvis, back and legs together, are the primary movers. Secondary muscles worked are those in the thighs. The obliques, at the sides of your abdomen, and quadriceps stabilize the activity along with the rectus abdominis.
Possible Stresses to Your Body
Hovering your legs off the floor to perform the flutter kick can cause stress to your back. To make the move easier on your back, ExRx.net suggests letting each heel hit the floor as you scissor up and down. If you feel pain, skip the kicks and choose more back-friendly core moves, such as front planks and crunches on a stability ball. These exercises place more focus on your ab muscles and less on your hip flexors.
If you do flutter kicks consistently at every workout, you could develop back pain due to overly tight hip flexors. When these muscles at the front side of your hip attachment become tight, they pull on the muscles of the lower spine. Over time, this leads to imbalances that can cause serious discomfort and even lumbar disc disorders.
Flutter kicks aren't the only ab exercise that contributes to tight hip flexors. The classic sit-up and straight-leg hanging leg raise are two other hip flexor-tightening moves. Sitting much of the day at a computer or driving a long commute are other reasons your hip flexors may be tight.
A Mix Is Best
Part of the reason flutter kicks can't be the "sole" best ab exercise is because to thoroughly train all the muscles of your abdomen you must include a variety of movements such as rotation (or anti-rotation), overall stabilization and flexion. Flutter kicks and planks are stabilization moves so, as long as they don't bother your back, you can combine them with other exercises such as bicycle crunches and cable woodchops to train functional rotation and work your obliques, and crunches as an example of flexion.