erm... u don't burn 300 calories sprinting 100m! apart from that it sounds like a good way to stay in shape
i can see you burning about 200-400 cals during sex, but wanking? can't see it somehow... would be funny to see all the peeps on this diet nipping to the toilets about 4 times at work, then come out looking a bit happier than when they when in there
its hardly the same tho. sprinting you run as fast as you can in 100m. i can do it in about 12-13 secs so thats 1.2 metres per second. thats quite alot of work for the muscles to do in such a short space of time. where as joggin is fuck all really. practically walk about.
still not gonna be anywhere near 300kcal tho... thats 30g of fat, or 50g or carb.... an theres no way you can us that in 15s of exercise!