Which Muscle Groups Do I Choose?

usually when i go to the gym i work out 2 muscle groups, i.e. chest and biceps, shoulders and triceps, or back and rear delts. my question is can you combine any two groups and work them out on the same day or are there some better combos than others? and why? thanks!
Jen

As long as you are working out all of your major muscle groups, atleast 2 times a week, you are good to go. How you pair them up isnt as important, but you have to make sure that you are working antagonist muscles equally. Antagonist muscles are muscles in opposing groups (usually on either side of a limb) like triceps and biceps, or quads and hamstrings. When one contracts, the other elongates and vice versa. If you get it done, cool, but I find its easier to make sure if you do them at the same time.

Its important these muscles are balanced or else you safety and range of motion may suffer. I see this most often in the core- people will work out their abs all day long, but completely ignore the lower back. This makes it difficult for momentum to travel through the core, because when it hits the weak spot, in this case, the lower back, it shifts directions, and causes pain in either the muscle or the connective tissue. Its important to keep you body balanced, so everything works together at the same level, keeping you efficient and injury free.