and are you talking about the thing with the spring? i own one of those and i can say it takes practice to better your grip with those. it may hurt now, but at some point you'll find that it's starting to get easier

ahh i see. hand and arm strength are important for that. now, obviously some people are lighter than others, so they'd be able to hold on to their weight easier, but since most of the weight falls on your arms hanging, you gotta have more arm strength. for hand strength, you'd just be able to hold on for longer without your hands getting as achy easily (if you already knew this then that's nice, i just felt like typing lol)