Hello mate,
Reference to the original post being, some hints you may find usful.
When you get down the gym grab one of the massive weights that goes on the end of the squatting/benching bar, hold it down to your side and just lean sideways so it goes down to about kinee level... do this both sides, 5 sets of 6-8 repititions and that will strengthen you up in no time.
Failing that any dumbell will work or even a bag of cat litter or dog biscuits if your at home and dont have gym access.
For the lactic acide problem, get down to Holland and Barratt and pick up some creatine capsules. 3 caps 30 mins before workout/paintball session and 3 caps after and 3 a day for the couple days before and after workout to get it in the system. Long and short of it is the creatine buffs off the latcic acid so you can work harder for longer without the pain.
remember if you go for creatine (and it says it on the packet) drink lots of water otherwise they'll bung you up.
Hope that helps and as say worked for me
JJ
I also notice your in Maidstone, if you coming to Tonbridge on the 24th keep an eye out and we'll have a chat.