Originally Posted by
Jeff Illingworth
The two big issues are tightness/bracing and that your elbows appear to be flared out too far. For tightness, it will help if you can get your feet a little higher up by putting a weight or block under each so you can get some leg drive. It also looks like your head is sort of hanging off the bench which isn't helping (this may only be an illusion caused by the film angle). Pull your shoulder blades back, together and down.
For your rack, go ahead and put some weights on the legs to help keep it from tipping. That will help until you get a more permanent fix.