Let this guy perform a pull up

If you post your project/.puppet, I can have a go at it.

Fun challenge! Hopefully someone like oksamurai​ will jump in with some advice for this more advanced sort of use case. (He knows all!)

Some suggestions in case helpful.

When trying to keep the position of something relative to the actual character, one thing I have seen is to include it in the puppet. That is, make the bar etc part of the puppet (a part of the arm). Then nail it down with pins etc so it does not move. That way the hands are glued to the bar because it is really the same artwork. You can change the opacity of the bar during a recording if you want to make them appear/disappear, or have a separate puppet (that looks the same) for with and without the bar.

Another approach is to put a dragged on the hands then touch that dragged once at the start of the recording. It will remember that dragged position and not let the hands move.

Sometimes I put draggers on the elbows too, to give me more control. If you don’t use them, they have no effect. I assume you would put draggers in the body to move the body up/down for the pull up. if the elbows flop the wrong direction, that is when I record a frame or two at the start so the elbows start in the right place.

Remember you can slow down the recording time to give you more precise control over draggers while recording. There is a drop down next to the record button in the scene window to change the record speed and playback speed. Can be helpful. I have not found a way to stop stretching from happening completely, but slowing down the recording helps. E.g. using sticks you can control better where stretches occurs. E.g. you would put normally put sticks down the arms to stop bends in the middle of an arm, but it will still stretch lengthways.

It is too hard to explain lots of options with sticks, but put simply, put sticks where you don’t want warping to occur. E.g. you might do one across the shoulders from arm joint to arm joint, with a small gap between the two arm bones and the shoulder bone. That might be enough.

It is also worth thinking outside the square. You can put sticks in the body and arms and legs, but put the origin near the shoulders maybe. Then put dangles on the feet. That way the rest of the body will flop around, dangling from the shoulders. You don’t have to tag them with “Arm” etc tags if you are not using the walk behavior. You can adjust the springingness of springs to affect how much the body will (or will not) stretch from the dangles.

But since you are doing something a bit different, expect to need to do some experimentation. Just remember that what is in front of other things is controlled by the ordering of the layers. So you need to nail that down first. E.g. the bar might really need to be two bars that just look joined in the middle, so one can be attached to the left hand and now to the right, where the hands are attached to one arm in front of the body and the other arm behind the body. 

It could be tricky if the head is meant to be behind the bar. Even more tricky if you then want the head to go in front of the bar (e.g. the chin). That is when you start looking at creating two puppets (e.g. a head only) so you can play with the depth arrangement easier.

Good luck!