The answer to this is pretty straightforward, and anyone who is not a novice to hitting the gym and exercising knows that if you are strength training, you should always do cardio after. This is intuitive, considering that when you are trying to get stronger, you need the energy to push your muscles harder. If you run 5 miles, then try to lift, you will not see the power gains you hope for.
However, all you need to do is a little digging on fitness websites or in the MySpace fitness groups to find there are many people who pose the question, “should I do cardio before or after I strength train?” If it is so obvious to the people who have been doing this for years, then you must wonder why novices might be so clueless. Well, it is not completely their fault.
For one thing, not all weight training is the same. Some people lift to get bigger, some to get stronger, and some people weight training may actually be trying to get leaner. One of the things that I have heard people (trainers included) say, is that intense cardio before gets your heart rate up such that when you lift, your body is in more of a fat burning mode. This does make sense if you wish to get leaner/your objective is to burn calories. Of course, if you have been strength training or bulking up, you are probably burning more calories by default because of the added muscle. Still, many people, train to get leaner/lose weight, so intense cardio before might not be such a terrible idea. When I am trying to get leaner, though, I still will lift before my cardio; I just do much more cardio than I normally would, and lift lighter/more reps.
Less experienced exercise freaks, though, may not even identify this type of goal when they workout; they just want to get “in shape.” The masses generally believe that cardio before is the way to go, and as such, they do this first. I think one of the reasons for this fallacy is because of the “warming up” aspect. I never think of a warm up as the same as cardio. The purpose of the warm up is to get the blood flowing and your body stretched and ready to really pump it, but not for much more. On one MySpace post I read, a person decided to include her warm up as part of her cardio, though the majority of her cardio was going to be completed after her strength training.
What works best for me is to split my workout times, once for strength training, and once for cardio. This is great if I can train twice a day, once in the morning, once in the evening. Unfortunately, I don’t always get this chance, so when I do workout once, I do a slight warm up, then lift, then kick my ass with some intense cardio. Normally, I have so much energy after the cardio that I can do more abs or whatever else I feel like. But, this only works if I have done my main strength training first.
In any event, energy is the most important factor in improving at the gym, and doing cardio before saps you of it. I would suggest to anyone who asks this question to first evaluate what their true objective is, other than merely “getting in shape.” I would be very hard pressed to suggest doing any real cardio before serious strength training.