In the absence of any good advice I have opted for core strength exercises and muscles in my upper half that I would use to push,pull and dangle myself with. I dont think going for 'meaty' would be much use.
My advice was pretty good for this kind of thing. I'm off for an offended cry in the corner now
.
As for weight, BMI is not based on build/muscle mass etc. Your weight is fine if you can pull yourself over things and run easy enough. It's true anything you have to do which is weight bearing or running for that matter can benefit from being lighter but on the flip side the leaner you are the more you feel the cold. First time I did a winter OCR I was the leanest I'd been in a long time. Wasn't great for cold water obstacles
. If you want to train specifically for an event then functional strength for getting over the kinds of obstacles you see on these kinds of courses. All your efforts will be body weight based. Local parks are great places if they have body weight exercise areas or big net climbs for older kids of have this kind of thing and you can get there in the morning before children want to use them. Practice climbing over walls and fences, monkey bars are good, chin ups on bars and/or football goal posts, rope net climbs etc. Run for a bit, do some obstacles/weight bearing exercises and then run some more. Get your feet and trousers wet in a stream and run some more, walk into the shower on the coldest setting for a bit before turning it up to your normal temperature etc.
Another issue I've seen for some people at the ones I've done was only water being available at feed stations. If you need simple carbs every 30 minutes you might struggle. This is obviously event specific but if you're used to training on water during exercise you won't suffer if there's only water.
