lbb

There are a lot of "shoulder muscles"; for good aikido mechanics, the typical person needs to learn to use some of them less and others more. "Relax" is the opposite of "contract"; you cannot perform movement if everything is "relaxed". Again, mechanics: when dealing with the extremities, the mechanics are flexing and extension. A lot of aikido mechanics depend on extension, but whether you're flexing or extending, it's all being done by muscle contraction. Muscle relaxation doesn't make anything happen.