How do you get better at sit starts when bouldering?

Climbing on the moon board really helped with my sit starts, something that I was fairly bad at. I just couldn't get myself off the ground.

After dedicating a few months to climbing on the moon board, besides getting stronger in my core and grip strength, sit starts became much easier for me, since, at least in my gym, the moon board sit starts are much harder than the regular routes sit starts.

Besides that, I believe that supplementing climbing with weight training can help a lot with it.