Posterior pelvic tilt, while much less common than anterior pelvic tilt, still afflicts many people. With the posterior pelvic tilt, commonly referred to as “flat back,” the hamstrings and glutes are tight, pulling the back of the hips down, while the abdominals are pulling the front of the hips up. The quadriceps, hip flexors and spinal erectors consequently are weak, allowing for the imbalance to take place.
The first step to corrective exercise is foam-rolling and/or stretching the tightened muscles. To foam-roll the hamstrings, sit with the foam roll under the hamstring, applying as much pressure as you can handle. Hold each sore spot until the pain subsides (roughly 30 seconds). For the glutes: Sit on top of the roll, with one ankle resting on the opposite knee, lean toward the lifted leg, feeling for those tight spots. The abdominals cannot be foam-rolled but should definitely be stretched. After foam rolling, stretch the hamstrings and glutes to allow the muscles to return to their normal lengths.
To keep the pelvis from reverting back to posterior pelvic tilt, some strength exercises are required. Corrective exercises should include those that require the hamstrings, glutes, and quads to work synergistically rather than allowing the hamstring and glute dominance to continue. One example is the lunge. Lunges are particularly good because they break the work into two separate legs, allowing for even more focus on the correct muscle group. There also tends to be a bit of focus on the weakened quadriceps and hip flexors. To do a lunge, take a long stride with either leg forward. Keep your weight evenly distributed and lower your weight until both knees are bent at 90 degrees, then return to the starting position. Repeat the same number of repetitions on each leg.
The lower back muscles also need to be strengthened since they too are a part of the weakness that allows posterior pelvic tilt to be a problem. Any exercise involving spinal extension will help to strengthen the muscles of the lower back. One of the simplest and most effective is the superhero: Lie face down on the floor with arms extended out in front of you. Slowly, lift the arms and legs off the ground simultaneously (like a superhero during flight). Lower, and repeat for the desired repetitions.