Kristie, I am not aware of any studies that found it is better to do cardio before strength or strength before cardio. I believe in the past I read about some studies that found it really makes no difference which is performed first. For most of my clients and for myself, I do weights before I do cardio. When my clients do strength training they are tired when they are finished but not exhausted. They have energy left to finish their workout with cardio. If they start with cardio first, then they are usually quite tired. They often do not have much energy left to give a good effort when performing strength exercises. I am the same way. I have always been a distance runner. When I return from a long run, I have no desire to hit the weights. However, I can work with weights and then go out and still get in a good run. A trainer who once worked for me lifted very heavy. When he completed his lifting there was nothing left for him to do cardio. He found it much better to do his cardio workout before he lifted.