Leg Curls are for Wankers
Written on March 14, 2007 at 11:08 am, by Eric Cressey
Q: I just read your article on leg extensions, and I’m wondering if leg curls are bad, too. I’m rehabbing a mild hamstring pull, and I’m wondering if light-weight leg curls are okay.
A: I’m not a fan of leg curls at all. Your hamstrings will never work in isolation like that; they’ll always be co-contracting with the glutes, adductor magnus, and smaller hip extensors. When you do a leg curl, you really just encourage an overactive muscle to tighten up even more than it already has.
In our Building the Efficient Athlete DVD set, Mike Robertson and I go into great detail on how when you see a muscle strain, you should always look for a dysfunctional synergist. Think about the functions of the gluteus maximus: hip extension, abduction, and lateral rotation.
If it shuts down, you can get hamstrings or adductor magnus strains (synergists in hip extension), piriformis issues (synergist in lateral rotation), tensor fascia latae (TFL) strains (synergist in hip abduction) or even quadratus lumborum tightness/strains (hip-hiking/lateral flexion to compensate for lack of hip abduction). You also might get lower back tightness or lumbar erector strains from lumbar hyperextension to compensate for a lack of hip extension range of motion (secondary to glute weakness not being able to finish hip extension). Finally, you might experience hip joint capsule irritation anteriorly because your glutes aren’t providing enough posterior pull to counteract the tendency of the hamstrings to allow the femoral head to glide forward during hip extension.
Yes, I know I’m a longwinded geek, but I do have a point. That is, always look for inefficiencies and dysfunction; don’t be lazy and just stop at pathology. Several pathologies can result from a single inefficiency/dysfunction/syndrome. If you understand how to identify and correct these inefficiencies, you can use comparable protocols to fix a lot of problems.
They say that one of the best ways to win people over is to take their pain away. If you’re a trainer or therapist whose income depends on getting people healthy, you NEED to know this stuff.
Oh, and as for your hamstrings issue, get the glutes firing with various activation exercises and stick to hip extension movements such as pull-throughs, deadlifts, forward sled dragging, box squats, and back extensions to get co-contraction of the glutes. It goes without saying that I would also include plenty of single-leg exercises. If you want to start training knee flexion, when the time is right, incorporate some glute-ham raises.