Flutter Kicks and the Exercise Police

Who are the exercise police?  They are the people who try to ban all of the effective exercises!  Flutter kicks have been used by many military groups for a long, long time.  They are a favorite at dive school and rescue swimmer school.  I like flutter kicks.  However, the exercise police have proclaimed them to be unsafe.  They are wrong.  Flutter kicks are not unsafe....if they are performed correctly.  In fact, they are a great exercise if done right.  The problem is that when you lie on your back and extend your legs out and off the ground, there is a large rotational force that attempts to pull your pelvis into anterior tilt.  If your core is weak, your pelvis rotates forward, causing a hyperextension of your lower back (image C below).  This is a problem, but it is easy to fix.  There is no need to throw out a perfectly good exercise due to this issue.  The way we fix it is to try to assume a posture like position B in the image below.  In reality, you will end up in position A (which is ideal), but try for B.  We find that if people try to get in position A, they end up in C (not good).  What you think your body is doing and what it is actually doing can be different.  During flutter kicks, rotate your pelvis posteriorly until your lower back is flat on the ground.  There should be no space between your lower back and the ground.  This does flex your spine, but it is not loaded significantly in this case so it is no problem at all.  By flexing your spine a little, you prevent hyperextension (image C), which is a problem.  When you cannot hold this position any longer, either bend your knees a little to take off some of the load, or stop.  Don't allow yourself to go into lower back hyperextension (anterior pelvic tilt).

 

In fact, the tendency for this position to pull you into anterior pelvic tilt is the best thing about flutter kicks!  By resisting this rotation, you are building a very strong core and learning to brace and control your hips appropriately.  If you do lots of flutter kicks (why not?), consider doing some hip flexor stretches afterward and be sure to include some training for the opposing muscle groups (glutes, hamstrings) like stiff legged deadlifts, glute bridges, or lunges. 

The other movement that the exercise police are wrong about....deep squats....but I'll save that for another post.