Java's still a managed environment, and in either case, Rust shows it's not strictly necessary anyways. Wouldn't mind some software engineer unions, though.
Running is not as extreme as you think, a lot of it is just carrying on the momentum of the truck after you jump off, other tham that it's mostly just brisk walking.
The heavy stuff depends, regulations typically impose a limit on weight but a lot of people don't follow it. You learn to use proper lifting form quite quickly though or you'll get a hernia
Funny story actually. After year 1 I was in peak condition, year 2 was normal, year 3 I gained weight.
Year 1 I worked slowest and year 3 fastest. I just became way more efficient :p