How long do U rest between sets & wait until your 2nd same body part exercise?

[vinylgroover]

Generally around 2 minutes

 

[Mindwraith]

errrr....fatigue doesnt make your muscles grow dude. Overload does. Making your muscles push heavier weights than they have ever been used to. You can only get the energy to make your body attempt to push these weights with 3 mins rest the whole time. 30 seconds will just make the next set useless IMO.

Joker is correct, so is Zyg. Shorter rest periods between sets with lower reps and heavy weight is best for gaining mass through muscle fatigue. Overload can build strength as well if done with longer rest periods. I've actually experienced this first hand in the past 4 weeks of experimenting with this. There's a post by Zyg today, close to the top of the page.