I dunno if you're into motocross, water skiing, or jet skiing (hard hard riding though), anything like that

But I've found alot of my upper/lower body strength came from those activities, it's like lifting a weight except you have the adrenaline pumping so you're not getting tired. Basically you're working out more than you'd normally be able to but you're having so much fun it's easily ignored. Of course this is just a longshot, not everyone has those toys. Another great way to get overall body strength is surfing, but not everyone lives by the water

Damn all these variables