SAS Australia star and Olympic swimmer Shayna Jack!WATCH: Cate Campbell swim the 4 x 100m freestyleThe 22-year-old has received a reduced sentence after being barred from the sport when she tested positive for doping 17 months ago.The athlete took to Instagram to share the exciting news with her 31k followers and express her relief at being found “innocent” of knowingly using prohibited substances.Shayna was found guilty of doping 17 months ago.“The Court of Arbitration for Sport has tonight