How do you do that without over training?
It is not as hard as you think. The capacity for the human body to do work is much higher than most people realize.
If you look at in season training for most college football teams, for example, they lift weights for an hour 2 or 3 days per week. They practice 2-3 hours per day. They play a 3 hour game every week.
The best teams show up for a voluntary workout the day after the game.
And this is not counting any pre-hab / re-hab work or conditioning being done.
On the low end that is 15 hours of work per week. On the high end it is 21 hours of physical work.
From a strongman standpoint, not all training is heavy event training or heavy weight lifting. There are lots of things a strongman can do in training to increase work capacity, base strength, and in some cases speed up recovery time.
All of these things take time, and if you want to be great, time has to be spent getting better.
I will finish with a quote about Ryan Vierra, a multi-time world champion in highland games, when people were speculating whether or not Ryan was using performance enhancing drugs-
"Try wearing through the soles of your shoes and the bottoms of your feet from doing so many drills, or wearing out 3 VCR's watching film. Then start talking about why Ryan is winning all the time."