lol!! yeah Gyro is right. For maximum strength and muscle development, sets should be done with a weight great enough to cause muscle fatigue (the inability to do another repetition). So heavy weight over short reps will build muscle fibre, low weight over many reps will only tone muscle afaik.
I read in some health mag recently that a study had been done into short twitch muscle building. One group of volunteers used heavy weights and did a low number of reps SLOWLY (as youre normally shown down the local gym)
The other group did exactly the same, except on the 'lift' part of the rep they did it very quickly. On the lowering part of the rep they did it slowly the same as the first group..(i think lowering too quickly causes strain so be careful, eek!)
Then after a certain time period..can't remember..maybe a month... they looked at the two groups fast twitch muscle fibres. In the slow rep group the results showed that slow twitch muscle had been built (endurance muscles).
In the fast lift rep group they found that fast twitch muscle fibres had been built (the ones you want for short bursts of speed..say up to 30 metres).
Don't forget to warm up by doing aerobic exercise for about 20 minutes before lifting weights though or not only will you pull a muscle, your weight lifting will all be in vain too as the muscles need to be warm and elastic before you can stretch them sufficiently to build muscle fibre. And stretch afterwards too.
I looked into becoming a gym instructor once and even got an offer of a job at the local leisure centre...It was just about the time i was getting into paintball and they wanted me to work practically every sat & sun... Paintball won!! Good choice huh?