What batsmen like me do for fitness is often a bit different to what bowlers like Jimmy Anderson or Stuart Broad do but everyone in the squad has a big focus on core strength. It is really important for batting, bowling and fielding. You need a strong core and spine so your movement isn't restricted out there.
I remember getting hit in the ribs when I was on about eight or nine in my first game, and everyone rushed over, quite concerned. The umpire said to me afterwards, 'If anyone had appealed I would have had to give you out LB!' I ended that innings about nine not out off about 15 overs. I was already digging in - Yorkshire style.