I do see what you're talking about Amos, but with respect, I do not equate Shumatsu Dosa with the Triangle pose. The one is for learning how the hips and hands coordinate can lead to more issued power, and it all arrives like a freight train. The other is one of my favorite hip opening exercises.
Shumatsu Doza Ichi.
There's another area that Yoga and Aikido are a little different Clare, but it still comes down to intention. Your teacher is the person you have put in a position of judgement over yourself. While I remember yoga being a very supportive and affirming activity, martial arts can be for the opposite reasons. No one was there to give me affirmation when I worked for EMS, or the Fire Department, nor when I worked in Corrections, and not when I work in the hospital now. People are scared and angry - and can I move forward anyway? Our clients, business partners, and opponents aren't always making us feel supported. Even our friends and people we trust don't always leave us feeling better about ourselves. In a combat situation, the opposite party is there to make me feel bad on many different levels!
Stress and emotions do change how you move - and how you sleep, digest, focus, breathe, fight infections and a thousand other things. Part of what martial arts are for is moving forward anyway. There's always another patient in the next room who deserves better than me melting down, the bills don't stop coming, and my family is still there and needing me. It's not easy and it doesn't make anything suck any less.
Someday you'll fall and you'll not be doing a generalized startle reflex when you lose your balance and the fall will just be a fall instead of a slurry of thoughts and emotions overwhelming you and spilling into muscle movements. Someday, you're going to be in front of your teacher who has power over you and can judge you or fail you, and you'll just stand up and turn anyway. Maybe a whole audience cheering you on, or who won't be on your side, or who aren't even paying attention, and you'll just do your best anyway.