This might explain part of the agony I'm currently feeling:
Stiff legs, bruises, sore neck (karting isn't supposed to be a contact sport right?) - after the racing we (work mates) headed off for 10 Pin Bowling where I prompted felt the tendon in the back of my foot go 'snap' like a rubber-band taking me out of the game - doh.
Thankfully there doesn't seem to be any serious damage (although admittedly I've not seen a doctor yet which I will if the pain continues) and there doesn't seem to be much pain or swelling remaining (other than stiffness).
Needless to say I don't think I'll be playing 10 Pin again for awhile...