20 back squats benchmark

In the gym we’re supposed to try a long, hard set of heavy lifts once in a while, such as 20 squats at your 10-rep max. By definition this would be hard… and would show that your 10-rep max is bigger than you thought.
Recently I did 11 back squats at 60 kg as part of a workout, so I decided to make my first 20-rep workout weight be 70 kg. It was a pretty good guess. I had little doubt upon hitting 10 that I could make 20, but it was hard. If you haven’t tried this, it feels a lot like carrying a heavy backpack up a steep mountain trail. You’re breathless and you want to put it down, but you can’t!