My advice is find a physiotherapist that rides. I had a major injury a while back and was having problems with my therapist because she didn't know what I was trying to accomplish to get back on a horse. Together we did some research and found a therapist that was a rider and I started going to him instead. He taught me exercises and streches to do that helped me to get my strength back but also corelated to me getting back in the saddle sooner. Even if you are not seeing a therapist right now a few sessions with a good one that rides may help you to find exercises to loosen up! As for the video, I agree that you are jumping ahead, your release looks ok for the size of the jump but as you jump higher you are going to want to work on releasing more.