The hip rotators not only rotate the thigh on the pelvis but more functionally rotate the pelvis on the weight bearing fixed thigh. Activities such as swing a golf club, and even just walking require some rotation of the pelvis on the weight bearing leg. While we don't need that much range of motion to walk, activities such as running, dancing, tennis, and many other sports can require more hip rotation.
If your hips are killing you, you probably spend a lot of time sitting—in the car, at work, on that SoulCycle seat—which puts your hips in near-constant "flexion", says Cori Lefkowith, NASM-certified personal trainer and owner of Redefining Strength in Orange County, California. Even running involves a repetitive flexion movement that can cause pain.
For example, your quadriceps muscles are a group of four that are located at the front of the thigh; one of the group members, the rectus femoris flexes the hip, which brings your lower extremity (thigh, lower leg, and foot) forward, in front of you. On the other hand, your hamstring muscles are located at the back of the thigh. When they contract, they extend the lower extremity, bringing it behind you.
You’ve heard the saying: it’s all in the hips, but for many of us, our hips – or more precisely, our hip flexors – are tight, stiff and inflexible. If you’re an office worker you can probably thank sitting down at your desk 8 or more hours a day for your tight hip flexors. Habitual sitting causes your hip flexors to tighten and shorten – adjustable standing desks, anyone?
Now, that we have decreased some of the tension in the back, we can focus on strengthening the front. There are loads of awesome core exercises, but let’s take a look at the most common one and make a couple modifications for this postpartum population. Just keep in mind, these are things to look for in a woman that’s 8 weeks or 8 years postpartum. Just because it’s years later doesn’t mean she fully recovered.
You're more likely to get a hip flexor injury if you've had one in the past, you don't warm up properly before engaging in athletic activity, your muscles are already tight or stiff, or your muscles are weak from being overused. If, while exercising, you try to do too much at once in too short an amount of time, you can also put yourself at risk for a hip flexor injury.