Sitting, standing, walking, even putting on pants all require the coordination of your hip flexors—a group of three muscles working together to provide mobility and power. They stem from the upper thigh and move diagonally backward to the spine.
If you’re looking at an anatomy textbook, the hip flexors will fall under the Illiacus and, more so, the Psoas Major, sometimes combined as the Iliopsoas The third muscle is the Rectus Femoris, which runs parallel to the quadricep. They act as a bridge or hinge from your lower body to upper body. They are naturally built to endure a heavy workload, but if not stretched and cared for properly, they can wreak havoc on your daily life.
If you strain your hip flexor, you’ll know. It will feel tight, restricted, crampy, and your mobility will suffer. Many athletes confuse the hip flexors with the abdominals because of the way it runs behind the abdominal wall.
Let’s look at a common Pilates movement: the double leg lower and lift (demonstrated here on YouTube). Lying on your back, keeping the lumbar (lower) spine adhered to the floor, lift both legs straight up in the air directly above the hips. Then, keeping the lower back down, slowly lower your legs until your lower back tries to peel up. That’s your limit. Stop and reverse into a leg lift.
During this exercise, you’ll initially try to control the entire movement with your hip flexors. You’ll feel tension in the groin area and perhaps in the abdominal wall. Try it again, but this time mindfully squeeze your belly button into your spine and pressing your spine into the floor. Keep your legs long. You should feel less tension in the groin and more in the abs. This comparison demonstrates how easy it is to shift work into our hip flexors and ultimately our lower backs rather than allowing our lower abs to do it.
Athletes with hip flexor problems are often soccer players, kickers, sprinters, and weight lifters. They all demand a high level of function from the hip flexor, especially the fast twitch muscle fibers, which boost reaction time and speed.
The non-athlete can also experience hip flexor issues due to poor posture, including muscle imbalance, as well as a decreased level of fitness or joint stiffness. Our bodies are connected so intricately that compensation for an injury on one side of the body can affect the function on the other side.
For pregnant women and those who have had children, a slew of postural changes can cause lingering side effects, including hip flexor weakness. Unless properly addressed through patient stretching and isolation training of the hip flexors and lower abdominals, the post partum issues can become a constant problem. Read more about the changing musculoskeletal structure here.
When it comes to preventing or resolving hip flexor pain, look at the bigger picture. Stretch and care for all surrounding muscle groups before and after exercise. Break up your workout routine into an arrangement that will provide varying demands from your hip flexors. So, sprinting everyday or completing high intensity jumps, squats, or heavy weights, is not ideal.
When in doubt, stretch and rest.