Q: Low reps,heavy weights or high reps, light weights. WHich one is better for muscle growth? And dont both methods increase muscle mass anyway?

A: In general, heavy-to-medium weights and low-to-medium (12 or fewer per set) reps to failure or near failure.

Best year-round programs will have a lot of variation and changes of intensity to let your body recover and not get overtrained. The easiest way to achieve variation is to simply change training routines every two months or so (I have several sample routines in the Weightlifting article). The easiest way to prevent overtraining is to take 1-2 week breaks from lifting every two months or so.

I also want to make a special note of 20-rep squats and deadlifts -- very tough and potent exercises which you may miss out on if you only stick to 6-12 rep ranges. I highly recommend you incorporate these into your routine in at least one or two of your two-month programs throughout the year. You would perform these using weights that would normally cause failure in 10-15 reps, but you would take rest-pauses in the middle of the set (not putting the bar down) until you squeeze out the full 20 reps. Of course as always when performing squats and deadlifts, be careful to maintain PERFECT FORM and DO NOT REACH ACTUAL FAILURE. Instead when you are starting to feel that you can no longer maintain perfect form, take a 5-10 second pause and then continue again.