Does anyone know any good methods for strengthening the SI joints? Right now they are painless and I injured both of them just over 3 months ago. Doctor was lagging it so I decided to try to fix it myself, or if I can't I'll make sure to wait and get physiotherapy.

I could do ab crunches but the back extension machine just irritates it and I think glute ham raises are too much for it too handle in this weak state. I also do very light deadlifts (less than 50 lbs) to help strengthen them. I injured the right one due to front squatting while not fully arching my back to stay upright, then the left one started aching from walking around while tilting my back to the left to compensate for the right one. Both are painless as of now, but does anyone have any experience with these injuries? If so, how did you rehab it.

I don't think I need mobilization by a physiotherapist as it doesn't hurt unless I lift something heavy, especially when bending over with an arched back.