If you take Pilates classes or fitness class you might hear the phrase, stay out of your hip flexors. What does that mean? And can you do it?
First, the hip flexors are a group of muscles that bring the thigh and trunk of the body closer together. You use your hip flexors in many daily activities like walking, stepping up, and bending over. Technically, the hip flexors are the illiacus, psoas major, pectineus, rectus femoris, and sartorius muscles. Obviously, we need our hip flexors. But we usually don't need them as much as we use them in ab exercises.
Here is the problem: When we exercise to target the abs, as we do in Pilates, we do exercises that decrease the distance between our thigh and trunk - think situps, roll up, leg lifts. Now the hip flexors are a strong group of muscles, and they try to take over. So we end up working our hip flexors more than our abdominal muscles! This is one of the ways that you can do 500 situps and not have a single one of them truly target your abs.
You know the kind of situps where you put your feet under something that holds them down and do a whole bunch of situps with an almost flat back? Guess what? Mostly hip flexors. Pilates people run the same risk with the many flexion (forward bending) exercises we do.So how do I get out of my hip flexors?
The answer isn't simple. A lot of us have to work on the hip flexor habit constantly. For one thing, you can't really leave the hip flexors entirely out of most ab exercises. They are still an important part of the picture. The idea is to get the abs involved as much as you can and to keep the hip flexors from taking over.
Our first line of defense is always awareness. When you do Pilates or other ab focused work, put your attention on your abdominal muscles. Start to figure out for yourself what feels like abs and what feels like hip flexors. It might help to familiarize yourself with the abdominal muscles and their functions. Work also with being aware of how over tucking the pelvis can bring the hip flexors in to play.
Low back pain and soreness in the groin area may be signs that you are weak in the abs and over-using your hip flexors. Another clue is not being able to keep your feet and legs down when you do a sit up or roll up. Do you see the logic in that one? What's happening there is that the abs aren't strong enough to do their up-and-over contraction, but we've told the body to get the trunk and thigh closer together, so the hip flexors take over and the feet fly up. (Tight hamstrings play a role too)
The other side of hip flexion is hip extension. It is important to have the muscles of hip flexion and hip extension work together in a balanced way and many of us have weak hip extensors. That discussion is in this article: The Basics of Hip extension.
Next, Pilates exercises that increase awareness and set the foundation for body mechanics that balance ab and hip flexor use: