Modern sports medicine shows there is NO benefit from stretching before working out and, in the case of cold muscles, stretching may make them more prone to micro-tears.
I swear I remember years ago reading somewhere that Tohei said there should be no need to warm up.
Those "exercises" at the beginning of aikido classes - if they're done and approached correctly - are not warm up exercises
. It's chi/nei kung. It's the internal aiki. But most people have no clue - often even the teachers - and they approach it in a Western mentality of stretching out and getting things warmed up. And that approach, not only robs people of the gold inside all of this, but it makes people more prone to injury.
I am 51 years old. I've been training aikido for 25 years. I need no warm up at all to go right straight in to anything anyone wants to throw out. Right now, I could walk outside and breakfall on the concrete. Randori - bring it on. 5-6 people. Let's go. Training with rolls and falls on a hardwood floor - one of my favorite things to do. Hardwoods and concrete don't lie. Mats can and do.
I'm not even a manly man. I'm a musician and artist, voracious reader, and sort of a renaissance type. And I smoke, too. Sometimes a lot. I have no problems keeping up in training when the volume gets turned up, and I can throw big 20-30 years olds around like rag dolls. I attribute this to having made the internal alignments and energies - that have been available in aikido and other martial arts - part of not only the core of my training, but the core of how I move, sit, stand, and walk in everyday life.
There's a big difference between training any kind of movement system in a rote and repetitive and half-catatonic state - and approaching it from a truly intelligent mindset. The ego loves to feel like it's really doing something, and is quite receptive to a kind of Neanderthal training approach found in many dojos. These arts, when approached with more validity, are based on intrinsic power, effortless movement, and energetic precision. There really is a superman inside all of us - but it will never come out unless it's developed.
I remember Sugano, who I'd trained under, and who was actually a family friend, gave a workshop in Sweden in the mid-90's. He was moving around like a little kid on the floor. At some point, he stopped everyone - probably 75 people - and said. "You're not getting this. You're not doing Aikido. If you keep going like that, you'll train for years, and all you'll be doing are making movements."