Make 1 pood feel like 3

I read somewhere that ex world champ boxer Kostya Tszyu (light welterweight) used Kettlebells regularly in his training leading up to a fight.
One thing he would do was carry a 1 pood for an hour and perform a lot of different exercises with it, without putting it down for a full hour.
Today I thought I’d give it a go and shoot for 1/2 hour as it was my first attempt.
I thought I’d start slow and pace myself.
For the first 5 minutes I just walked around and changed hands about every minute.
Then I did a few 1 handed swings and added a few throws to the other hand at the top.
After walking it out for a while I did about 10 snatches with each hand and then walked again.
Less than 10 minutes and the little one pood was getting heavy.
5 minutes practicing racks without putting it down with both hands and it was time for another walk.
During the walk I was starting to invent things to do with it as it was getting heavy.
I cranked out 33 swings (not pulling on the downstroke) just easy ones but my grip was starting to weaken, so I went for another walk.
After that a windmill was almost a relief as didn’t have to hang on so hard, but it was a bit wobbly.
Another walk, changing hands constantly and the 1/2 hour was up.
I don’t know what he did for an hour but for endurance training it’s hard to beat.
Not for evryone but it is a good gauge of endurance.