ACL Rehab

I just wondering did abdominal muscles helps in proprioception in knees? I've seen some of the ACL Rehab protocol require patient to strengthen their abdominal at the same time. Is this of any help with proprioception?

I think it unlikely that abdominal strength is related to knee proprio, however, I commonly teach athletes to activate their core muscles as part of an overall rehab programme. It provides a good opportunity for them to improve core stability and also adds variety to the regime.