Weight Bearing and Weight Shifting

I am writing this for two reasons; one everyone has been asking how Jason's physical therepy is going and two when I was searching the Internet trying to understand why he wasn't moving around much I didn't find anything that helped. So here's hoping this post turns up in the google search of someone in need.
Jason is sensitive to weight bearing and weight shifting. This a common cause of gross motor delays in healthy babies. Our physical therepist said "often parents report those babies have always hated tummy time and that they get carried frequently throughout the day. Generally they have very pleasant, easy-going personalities." That is Jason to a tee!
I told her tummy time just isn't working. I have been putting a towel under his shoulders for months but as soon as the towel is gone he won't make any attempt to lift himself up. So she said he probably doesn't like feeling of pressure being put on his joints. You have sensors in your joints that give feedback with pressure (standing, kneeling, and pushing through hands), and touch receptors that give feedback to touch. Some kids do not like these sensations and will cry to avoid those positions. But with simple desensitizing exercises you can work through this and get your baby ready for crawling!
We are desensitizing his knees by having him kneel at a couch cushin and I kneel behind him so his legs don't spread out.
We have been desensitizing his hands by working with lots of textures by playing with sand, shaving cream, and pudding and whatever else I can think of.
We are working on weight shifting too. Jason didn't know how to get out of sitting safely so we did an exercise to help with that. I would sit on the floor with him in between my legs. Then hold his arms and steer them down to the ground and then adjust his legs if needed.
We have been working on those exercises for the past week and a half and Jason has mastered getting out of sitting, he rolls onto his belly and his happy to stay there once he is on his belly, and he lifts up onto his hands when he is on his belly, he has even scooted a little bit. I am seeing such a big difference since we have been working on desensitizing him to weight bearing and weight shifting.
I am so excited about the progress he is making and shocked at how quickly it is all happening.
So, Jason is doing great. :)