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Cardio Limits Muscle Gains?


Currently I run for 90 - 120 minutes once or twice per week. Could this be limiting my muscle gains for weight lifting? Whenever I run, I'm careful to eat enough to offset any calories I burn while running. Also, I keep my bodyfat around 10%, so it shouldn't be necessary for my body to break down muscle to fuel running. Is this reasoning correct, or should I reduce my amount of cardio if I want to gain more muscle?

Thank you.


It burns off the fat so you can actually see the muscle. Once or twice a week is fine. I would always rather run sprints than do an endurance run but, thats just me.


It could possibly have an effect on leg strength.

Charles Poliquin has often talked about how cardio can morph fast-twitch fibers into slow twitch. He also stated that it can take several weeks or even months for them to morph back once lifting w/ out cardio resumes.

I remember when I first took up mountain biking, my squat poundages dropped a lot.


Once or twice a week is ok but why not just do some HIT or Tabata training on the bike. Less time in the gym and the same or better results.


Exactly. You need to keep your "cardio" workouts [u]short and intense[/u] in order to get all the benefits without losing muscle mass or strength.

It's the sprinter vs. marathon runner analogy. Read some of Ross Enamait's stuff (his books are great). He has some incredibly tough conditioning circuits that are short (20-30 minutes or less) but extremely intense. They will get you in shape, help you get leaner and help you keep your muscle and strength.

Renegade Training and Joe DeFranco follow similar ideas/methods.


I've always enjoyed the long runs, but I think I'll take your advice and try to do shorter, more intense running. Thanks all.


Also try strongman. It's a great way to build strength-endurance.


HIIT, Tabata's, and crossfit type endurance training will not interfere with strength training and can actually help build it.