That is actually what a tendon-y hand does when all the muscles are pulled. It gets like this from low body fat, eating a lot of pastry/oats/soja and a lot of moving around and manual work involving predominately upper body, or alternatively, focusing on a lot of push-ups when working out.
Yup. Aerobic excercise is the one you do for development of slow-twitch musculature. That's most of the torso and generally smaller muscles, and tendons everywhere else. Tendon is the section of the muscle that connects it to the bone, this makes muscles in tendonous musculature look round and flat. It's very visible on legs of people who walk or run a lot, mountain climbers especially, how the muscle jumps out of the pelvis right where the tendon starts, makes a nice line down and visibly falls right back to the bone by the knee and jumps out again under it. Fast-twitch muscles, on the other hand, are the middle sections and if you need immediate strength and work on them, they are going to make the muscle look bulky. This gets usually lost to vision though, because fat fills in the cracks. If the body sees that endurance is what you need, though, obviously weight would get in the way. Notice how archers or horseback riders are all skin and bones though they are really strong esp. in fingers, while fighters(not soldiers) or lifters tend to have loose skin with bit of fat under it. Important effect for what I said up there is that fast-twitch musculature sort of expands(widens) when the muscle gets pulled, but tendons stick to the bone or muscles under it and actually can make everything look smaller.
This is dumbed down, most people have it very varied everywhere around the body depending on what sort of life they lead, but this is basically how it works. I love explaining stuff. And I left chemistry out, too.