Here’s how I did it:
- I started somewhere I could step up to full contraction (in a gym). I lowered myself back to the ground, unsupported and as slowly as possible. I stepped back up so my chin was over the bar again. I lowered myself down again. I did this to exhaustion.
- As I got stronger, I started jumping and continuing to pull myself up. I’d then use the prop to push me the rest of the way up. I’d then lower myself down unsupported.
- Sometimes I’d find someone to spot me. The key here was for them to just apply the tiniest bit of force to help me past my sticking point, which usually happened when the bar was around forehead level. I’d lower myself unsupported.
- As I got strong enough to do a few on my own, I’d do that to exhaustion, then switch to spotted or assisted ones to exhaustion, then do one more where I just hung as long as I could.
It seemed to work for me, and I did it this way because a trainer told me that we build strength quicker with eccentric contractions, when we’re using the muscle to resist motion rather than perform it. I’m not sure if that’s true, but if it is, it would explain why lowering yourself down in a chin up appears to help people to chin ups sooner than increasing weight lat pull-downs. I haven’t read any research on this, and can’t verify any claims.
An alternative I learned later when I took up judo:
- Find a hip- or chest-height bar, say, at a playground.
- Sit underneath it and pull yourself up. Your bum will come off the ground and your heels will stay down.
- When you can’t pull any higher, push with your straight legs.
- Relax your legs to lower down.
- To progress, slide your bum forward over the ground and recline a bit before you start. You may have to cheat to get in position the first time, if you can’t reach the bar, but then put your legs back out in front.