There is the “tuck” and the “tilt”. In all yoga poses, the pelvis is doing something in order to accommodate the shape. Just when things are getting good and the body has found it’s groove, the teacher gives the instruction to change the tilt of the pelvis. You might hear “drop” or “tuck” your tailbone. Whaa?
I believe the body has innate intelligence and it does. It’s usually best to let the body to do what it needs to do. Usually, but not always. For example, in back bends, the lower back needs to bend. Simple. The shape and function of the lumbar spine (lower back) is to bend backward (and forward). When backbending, “allow”, not force, your lower back to bend into the dome shape. Tucking or lengthening the tailbone gives the body the opposite information. Here’s another example. When taking the arms up, the body needs to raise the shoulder blades too. Once your arms are up, being asked to pull them down is counterproductive.
In mountain pose (tadasana) it’s sometimes tricky to find the correct position of the pelvis, especially because some of us have some pretty bad posture. Years of sitting and slouching or carrying heavy purses or wearing fancy high heeled shoes has skewed the way we stand. I’m included, for sure. The body’s innate intelligence has been hijacked by fancy chairs, airline seats, and book-filled backpacks (especially kids) So, it’s no wonder, when we try to “stand tall” in mountain pose our bodies wonder “how?”. Our default pelvic position may not be optimal. Some of the cause may also be structural, like tight hamstrings, stuck hips, and residuals from previous injuries.
The print and online magazine, Yoga International, has a great article on the specific subject of the pelvic tilt in mountain pose.
In mountain pose, then (and in other neutral-spine poses such as tabletop, plank, chaturanga, chair pose, downward facing dog, and staff pose), the pelvis should be tipped forward until the lower back curves in gently. “Tucking/scooping the tailbone, as commonly taught in these poses, is not beneficial to the function of the spine. In fact, that instruction, often given ‘to protect the back,’ makes it harder to engage the transverse abdominal muscle and the multifidus muscles which stabilize the back.”
Many of us are “stuck” in either a posterior or anterior tilt, according to the article. There are animated gifs that illustrate how the pelvis moves to a neutral position. I recommend you take a look.
You’ve seen the posterior tilt: the lower back flattens, the thighs, head and shoulder move forward and the chest collapses. This is pretty common. While standing in line at Whole Foods, Just look around. Check out your own posture. I’m constantly having to correct myself. As a yoga instructor, I see it all of the time. Here are the cues, which I like, that Yoga International offers:
“Tip your tailbone until the lower back curves in.”
“Stick you butt back”
“Press the tops of your thighs back”
or even “Widen your sitting bones”
If you’re a student of yoga, you know we move everything, especially the pelvis. Cat/Cow, forward folds and bridge pose all change the tilt of the pelvis. This is compared to other activities like like running, walking, cycling or swimming, which carry a fairly stable pelvic orientation. That’s why yoga should be a part of everyone’s movement regime.