Hi there, i m new here n havent been working out for a long time due to a knee injury (partial acl tear). My muscles are all weak now, core is weak, arms n thighs are weak. Any recommendations on where i should start first? I looked for the pre/post partum series but there is only 1 video. I really like the sculpt series but my knees couldnt take it, any standing modifications for that? Thanks.