Let’s face it: seated forward folds can be awkward, uncomfortable, and even slightly irritating. Tight hips and hamstrings can make it nearly impossible to sit comfortably on the floor, let alone fold forward. Some people who are tight in these areas may even feel embarrassed that they aren't able to fold more deeply.
Anatomically, the position of the pelvis plays a pivotal role not only in the alignment of seated forward folds but also in their effectiveness. Think of your pelvis as a bowl, the two halves (or hip bones) joined together in the front by a cartilaginous disc between the right and left pubic bones and the joints on either side of the sacrum in the back. Your hamstrings, as well as your inner thigh muscles, are attached to the sitting bones on the underside of your pelvic bowl, while the muscles that run up and down your vertebral column are attached to the upper outer rims of the hip bones (known as the iliac crests) on the back of the pelvis.
The position of the pelvis plays a pivotal role not only in the alignment of seated forward folds but also in the effectiveness.
Tight hamstrings pull the sitting bones down toward the back of the knees, tucking the pelvis under and rounding the low back. Lengthening the muscles along the vertebral column (i.e., straightening your spine) pulls the upper-back side of the pelvic bowl forward, anteriorly tilting the pelvis and lifting the sitting bones up, which lengthens the hamstrings.
In seated straight-legged forward folds like paschimottanasana, the low back naturally wants to round—rocking the sitting bones under—in order to give slack to the hamstrings or inner thigh muscles that you’re trying to stretch. You could reach and reach, taking the shoulder blades off your upper back and rounding the spine even more, but you might never stretch your hamstrings with your sitting bones tucked under. Not only can that be frustrating, but you may also be compromising the health of your low back.
When you set up for your fold in dandasana (staff pose) ideally you want a neutral pelvic bowl, one that is not pouring out backward or forward but in which your sitting bones are directly beneath you and there is a slight lift in and up through your low back to protect your lumbar spine. (Note: If you’re at all tight in your low back, hamstrings, or hips, which most of us are, it’s a good idea to prop your seat up on a blanket or two, allowing your pelvis to tilt forward slightly in order to get the lift through your low back.)
To achieve a neutral pelvis, begin by organizing your legs. When the legs turn out (externally rotating), the pelvis doesn’t have a choice but to tuck under, rounding the low back. So, take one hand to your inner upper thigh and one hand to your outer thigh, hug both inner and outer thigh muscles against the bone, and internally rotate your thigh bones, turning your inner thighs down, widening your seat, and lifting your sitting bones back up. Repeat the process on the opposite leg so that you’re seated upright on both of your sitting bones. Next, as a general rule in straight-legged seated forward folds, you want your second toes and the four corners of your kneecaps pointing up.
Once you’ve aligned your legs and pelvis so that your low back goes slightly in and up, you need to engage your legs to stay aligned (not always easy to do once your legs are not bearing your weight). You will get so much more out of your seated forward folds if you actively press down through the backs of your legs, inner thighs, and heels. Rooting down through the legs in this way also facilitates the lift and extension of the spine, per the “root to rise” principle, which reminds us that rooting our weight down through the lower parts of our body activates the muscles above, lending us greater lift and stability.
Now, as you begin to fold forward at your hip creases, resist the urge to reach out with your hands and the urge to pull your face down toward the floor. Instead, as you start to hinge forward, plant your hands firmly on the floor slightly in front of you (wherever they comfortably land). Press your hands down into the floor to create resistance, extending your sternum forward and up and lengthening your spine.
However, given the length of your hamstrings, you may not need to hinge forward at all to find a deeper stretch in the backs of the legs. Rather than forcing your torso forward, you can stay upright with your fingertips alongside your outer hips, pressing down through your legs and hands while lifting up through your spine.
Once you’ve extended your spine, you can begin to fold deeper. Note that some rounding will occur as you deepen your fold, but do continue lengthening the back of your neck. Remember, the secret is length, not depth, so if you want to get the most out of your seated forward folds, keep your legs active and your spine as long as possible.