I want to know your thoughts and theories on the subject. I've been working out complimentary muscles on workout days for the past two years, i.e.: back/biceps chest/tri's deltoids/traps as oppossed to working out opposing: back/tri's chest/bi's I know it's always good to change up the exercises, so I tried opposing muscles for two weeks and have found it difficult to maintain since I like to hit up the gym several days in a row. So if I worked out chest/bi's one day, the next day it would be real difficult to do back exercises since my bi's were worn out from the day before. Ok so here's my question: is it really beneficial to switch up what muscles you workout in your workout plan? Or is it sufficient to stick to working out the same muscle groups I have been, but just switching up exercises? Please, if I am unclear just ask questions and I can try to clarify.