I would welcome your explanation of why it is beneficial for beginners and those with bad backs to bend the knees in uttanasana and related postures. I feel that it is right and would like to be able to express what is happening using the language of muscles and bones. Thank you for the sharing that takes place on this forum. Namaste
Hi Helen,
It is important for some people to bend their knees during Uttanasana if their lower back is higher then their sacrum. If this is happening they will probably be feeling the stretch primarily in their low back and not in their hamstrings where this stretch is designed to open. By bending their knees they are able to gain more mobility in their pelvis, as the hamstrings are able to relax, and the pelvis can tip forward. They also ensure that the muscles of the lower back, such as the Quadratus Lumborum and the deeper Spinal muscles do not get over stretched.
I posted this reply on our blog; you might find more useful information there if you have a browse.
Jen
I have some low back problems and It feels much safer and better for me to start with a bent knee position, and slowly extend the knees, than forcing the forward bend from a straight leg position.
That’s why I do not visit the local yoga class, because they usually just try to force you to do the ideal form of the exercise, which might not suit you as well as a slightly modified version. Hence, the importance of a personal trainer or, if you can’t have that, a sound judgement, and pacience, paired with self awareness. But the trainer is better, helps you avoid a lot of potentially harmful beginner issues.
Forward bending, for those with lower back maladies/ailments/dysfuntion can adversely affect said condition(s). Another way to say this is that forward bending may be contraindicated for those with lower back pain.
Conceptually speaking, Uttanasana takes the same shape as Paschimotanasana (rotated 90º). Paschimotanasana is the most dangerous pose for the lower back. Unlike it’s standing cousin (Uttan) there is no out in the pose. The out in Uttanasana is bending the knees.
Consider that the hamstring connects the sitting bones (ishial tuberosity) to the tibia. When the legs are straight (hip flexion; knee extension) the hamstring is at tension (I’m generalizing in an applied yoga anatomy way here) like a guitar string. Thus it pulls on the sitting bones and that asks the pelvis to go with it (to some degree) creating tension in the lumbar spine. The more bend in the knee the less asking of the pelvis by the hamstrings. Whent he student’s hamstrings are very very tight, as they often are in beginning students, the tension I mention above and the subsequent synergies may happen even whenthe knees are slightly bent, in which case they need to be bent more or the student needs to do another pose instead. When the hamstrings open then poses of this sort are more available in their classical expression.