great points by Dswithers.
Also, you should be able to get a very adequate workout done in 60 mins. If you MUST go longer, you're either resting too much, dicking around too much, or simply trying to do too much at the gym.
working out to increase size is a simple concept: you lift weights to damage the muscle fibers a little, and then the body builds them up a little bit bigger than before so they can handle the stress of the workout next time.
Working out longer, and doing more damage to the muscle does increase results, but only to a point. very quickly you cross a thresh hold where too much just slows you down, because the body cannot repair it as quickly.
its for this reason that you see full body workouts happening 3 times a week - the workout is hard, but doesn't have a ton of exercises, or sets. but, you hit every muscle 3x a week, lightly.
Then you have the bodybuilder who reads FLEX magazine and thinks the only way to get huge is to do 32 sets for biceps, and then don't work the arms for a week. Well, they are right in that 32 sets for the small bicep muscle group would require a retarded amount of time to recovery fully.
The question is, would one really hard workout that takes a week to recover from really be 'better' or 'more effective' than doing a lighter workload, but more frequently?
the verdict is still out, but more people believe that a higher frequency with the right volume and intensity is indeed more effective than low frequency with a very high volume and intensity.
this is likely because most research is done with normal people, while most pro bodybuilders are using steroids to assist their body's ability to recover better from those 32 sets of bicep curls.
its for these reasons that one workout does not 'fit all' needs, or individual abilities, and why some people can barely workout and look awesome, while others have to try very hard in the gym to get average results.
