>>47838723 sets and as many reps you can do.
I do 3 sets of 8-12 reps.
>>4784324I use a towel that's about a metre long with a rough texture for a proper grip.
Make sure it's not a thin towel so it doesn't suddenly rip off when you're hanging from it.
But using two small towels like in pic related should be fine as well.
