There is a common phrase you might hear yoga instructors say during class -‘tuck your tailbone’. I asked one of my fellow teachers, who is a Rolfer/Massage Therapist, and in my opinion, an anatomy expert, to explain why it is not appropriate to use that cue. Here is her response – thank you Beth B!
Tucking the tailbone, a well intentioned but misguided cue…. You can’t tuck your tail and have your bandhas engaged, they are mutually exclusive. The cue tucking the tailbone results in engaging the most superficial of the abdominal muscles rather than the deepest. There is a neuro-muscular relationship between these muscles (core and sleeve) so that when the superficial muscle is doing the work, the deeper muscle will be insufficient. This tail tucking recruitment of the lower portion of the rectus abdominal muscle, curls the pubic bone towards the belly button and shifts the center of gravity back to the heels preventing full movement of the respiratory diaphragm and full extension of the spine.
I am visual so I thought I would include a picture of the spine so you could see when you tuck the tailbone (sacrum/coccyx), you would change the structure of the body, be out of neutral spine and therefore would not have the foundation needed to have a strong, safe posture. (The picture on the left is person in Samashiti -equal standing- with neutral spine.)
If a student is overarching the lower back, the teacher might give a more specific cue to bring them to neutral spine or Samasthiti because when you tuck the tailbone you would then come beyond neutral spine in the opposite direction. As a teacher it is important to say WHY you are giving a particular cue so if it is not a cue that is appropriate for all students, then each student can assess if the cue is for them and make the alignment correction, when necessary. Another example – when students are in forward bend, teachers may mistakenly give a general cue to the entire class — ‘bring your weight to your toes’. In this example, the teacher could say, IF your weight is not evenly distributed and you have more weight in your heels, shift your weight toward your toes. It is important to consider that no matter what the class ‘level’ is, there will be students of all levels in all classes and it is helpful to give as much detail as possible, while allowing some silence for students to ‘be’ in the posture.