For optimal strength & conditioning, many fitness aficionados believe that cardio training and weight training should not be combined with a single workout; or if combined, that one or the other must come divided separately. The theory behind these claims states that each variance of exercise physiologically interferes with the other, potentially dulling the desired training effects.
Cardio or Weights First?
But the best scientists disagree as discussed in a interesting study published in the Journal of Applied Physiology of young healthy volunteers who vigorously rode special stationary bikes by using just one leg and then completed various resistance exercises using both legs. The experiment required one limb actively demonstrating both types of exercises while the other had done only weight training. Interestingly, from five weeks of training, both legs had grown equally for strength and size and cycling done first had not reduce or change the impacts of weight training.
A similar study was done to sedentary, middle-age men and learned that after a session of cycling the volunteers developed specific molecular changes in their leg muscles that were distinct from the volunteers who participated lower body weight training on the alternate days. But when the men demonstrated both forms of exercise one after the other, but doing half as much of each, their muscles robustly developed both types of molecular responses.
Scientist found that there was no indications of interference. Perhaps most revealing was the order of the exercises in the research was immaterial. In the 2014 research, the men rode and then did weight training; in the second study, they weight trained and then rode. The muscles can not tell the difference.
Set your workout to what works best for you!
So don’t worry too much on which exercise comes first, but better set up a workout regimen that happens to be best fit for you.