This routine can not fail in building muscle, because it hits every muscle group twice a week, once in the low rep/high weight range (intense workout) and once in the high rep/low weight range (moderate/going for the pump workout). Advantages: 1.if you skip one training day, at least you will still train that particular muscle group that week. 2.some people react better to high weight, others to high reps, either way, doing them both / week ensures growth. Important: 1.Try to never skip a day...but, if you do, do not skip the same body part twice in a week. 2.You will be tempted, when training with low weights, due to funny looks around you to add more weight, and arrive somewhere in the +-13rep. range rather than +-20rep. range. Don't! Train like this, feel the burn, enjoy the pump, eat, rest and watch yourself grow. 3. Stick to this program for at least 3 month to see visible results.