We took Middle Son to his neurologist appointment last week. He's now 5'7" and 165 pounds. At age 13. I didn't hit 165 until my senior year in high school.
Middle is lean and very strong. We're fortunate that he is generally a calm, happy child. If he was combative we'd have trouble managing him.
I remember of the therapists that worked with Middle when he was young. In early elementary school she said that she was concerned that Middle might need two-on-one care as an adolescent to keep him (and everyone else) safe. At the time he would bang his head on the walls when he was upset, and occasionally on other people. We had holes in the wall all over the house, so many that we'd stopped fixing them.
Now we only worry about aggressive or injurious behavior when we give him a haircut. We cut his hair last month. We gave him sedatives and waiting for them to take effect. Then we had four people (one on each limb) restraining him and one working the clippers. It was the easiest, or anyway the least difficult, haircut we've given him in a long time.
If Middle was regularly that agitated, I don't think we'd be able to keep him living at home. It wouldn't be safe for him or others.