Our hip flexors serve many vital functions. The goal of the hip flexor is to make it easy to for joints to move through their full range of motion smoothly. They’re responsible for important aspects of motion, like our ability to bend, run, or kick. Without our hip flexors, controlling the movement of our legs would be virtually impossible. Our hip flexors also work to stabilize the joints of the hips and lower body.
Take a step back and think about where you spend most of your day. If you're a young athlete, you probably spend most of your time at school or maybe work or practice and even a little time at home, if you're lucky. Now think about what position your body is in during those periods. I would bet that you spend most of your day sitting down. You may walk to class or run in practice, but the majority of your day is spent in a seated position.
Another way to look at it, if you stretched a short and tight muscle and it regained length, it shouldn’t get tight again, should it? Whereas if the muscle wasn’t technically “tight” but rather holding excessive tone in order to keep your spine from looking more like a losing game of Jenga, stretching it will just give more opportunity for low back pain, and quickly lead to the muscle tensing up again to defend the spine. This is the problem with conventional hip flexor stretches.
When a muscle contracts, it shortens. Take the biceps for example. Without getting too technical, the biceps are attached at the forearm and shoulder. When your biceps contract, they shorten and bring those two points closer together. When you rest, the muscle returns to its normal length, and the two points move farther away. Constantly contracting your biceps over a long period of time would cause them to get shorter, even at rest.
Like quadriceps, the hamstrings are 2-joint muscles. Unlike the quadriceps, though, the hamstrings reside at the back of your thigh. They attach at the siting bones, which are located on the underside of your pelvis. When the hamstring muscles contract, the effect is a pulling of the back of the pelvis down toward the back of the thigh, or a bringing of the lower extremity back behind you.
The pectineus is an accessory hip flexor. This short muscle originates from the front of the pelvis, crosses the hip joint and inserts near the top of the thighbone. In addition to hip flexion, the pectineus works with other muscles to move your thigh inward. The pectineus may be involved in groin strains, which occur commonly among players of sports that require rapid acceleration and position changes.
How to: Get on your hands and knees, in a tabletop position (a). Slowly widen your knees out as far as they can go and bring your feet in line with your knees. Your shins should be parallel with one another (b). Flex your feet and ease yourself forward onto your forearms. (If the stretch is too intense, try putting your arms on a block or firm pillow.) Hold for eight to 12 breaths (c). If holding the stretch for longer, try slowly moving your hips forward and backward to bring the stretch to different parts of your hips.