In reply to Lukas V-L:
Nothing on their website < strange!
Adapt their rock ring dead hangs to suit your needs.
If you can make the target time for a hang then split up the rep into intervals.
I.e a 1 min hang becomes 2 x 30 second hangs with a 5 second rest
A similar principal is used by marathon runners. They don't train for a marathon by running marathons in their spare time. Instead they train using smaller distances with a higher frequency.
Look up interval training.
An alternative could be to perform 3 hangs for the maximum amount of time your can stick. You will need a fair break in-between. Pick your longest time and work with doing repetitions of 80% of this max time as a training target.
Good luck!
