Upper body strength really isn't the issue unless you're talking about holding the gun up for a long period of time (which just isn't the case at a range which you usually have a bench).
As an example, I was shooting 12 gagues competitivly when I was on an all girls skeet team (I was 13 years old and my team members were usually under 16) and wasn't more than 5 foot and 100 pounds. And those guns were 9ish pounds, much less than my AR which was about 6ish pounds before I added all the accessories.
And I HATE pink. HATE HATE HATE.
WTB: multiautomatic ghost gun with a .30-caliber clip to disperse with 30 bullets within half a second. Must include shoulder thing that goes up.
Memberships/Affiliations: CERT, ARRL ARES, NRA Patron Member, HRC, CGN/CGSSA, Cal-FFL