Modifications. People seem to dislike doing them. A lot. To paraphrase Gollum, "We don't's like'em, we does. Nasty modifications." I think it is because modifications are perceived as a sign of weakness. A non-verbal confession admitting they can’t do this aspect of the pose while their neighbor can. Doing a modification when the rest of the class (or so it seems) is doing the full expression of the asana is embarrassing.
So why do we offer modifications? Why do modifications?
One, it allows the practitioner to build the pose from the ground up. All poses should start from a firmly grounded foundation, allowing you, the practitioner, to find your center - your center of balance and your breath. This allows the practitioner to build strength and flexibility over time. As David Swenson likes to say, there is always someplace to work towards. I say, don't be in such a rush to get there.
Two, injury prevention! I can’t stress this one enough. Yoga, especially the Ashtanga practice, can be intense on the joints and muscles and only the practitioner knows their body best. Wonky knee(s)? Modify the pose to prevent over-extension or aggravation. Carpel tunnel issues in the wrists? Modify to prevent strain on an already sensitive spot. Rotator cuff problems? Go easy on that shoulder. There are many places to work from and still be able to progress in the practice.
Three, recovery from injury, surgery or pregnancy. The body simply isn’t capable of jumping right back into a practice after an injury, surgery or pregnancy. It needs time to recover and to rebuild. By returning to the foundations for the pose, the practitioner can safely work their way back. As the body re-learns the muscle memory and regains strength, the practitioner will see their practice grow. Granted, this depends on what your injury was. The practitioner might *not* return to the full level they were working on pre-injury, but by coming back to the foundation and working from there you will have a safer and more fulfilling practice.
Four, it allows the practitioner to build strength over time. I lead a beginning/intermediate Ashtanga class with a wide variety of students from all walks of life. Modifications are a huge part of this class and I see the desire to be at a higher level, but their bodies just don’t respond yet. Frustration sets in, because “they can’t do that”. It. Takes. Time. Look at how far you've come in the practice, then look at where you want to go and then, ask yourself, how do I get there? Patience is a must and it all comes back to number one: build the pose from the ground up.
And sometimes, the practitioner just has to admit to themselves that they will not be able to do X, Y, Z pose because of previous injury, short arms, excessively tight hamstrings, whatever. However, this does not mean they should abandon all hope and stop practicing right then and there. Practicing yoga means the practitioner understands that this is where their body is and this is where they need to practice.
Modification’s aren’t about what "can’t" be done, but are an acknowledgment that you, the practitioner, know where you need to work to move to where you would like to be. It is an acknowledgment that you can set your ego aside and practice each pose precisely where you need to be that day. When the instructor comes around and suggests you move into a lower level, it is because they see your body from the outside and can see that perhaps today, this is not the place for you to be working. Too much potential for injury.
However, next week...is a different week.