Is Cardio Killing Gains?

Is cardio killing gains?

Are you training everything, doing cardio, so that you’re ready for anything? It’s the way forward isn’t it? But are you slowing down your progression? Is cardio killing gains you’ve made?

As the start of the senior season draws closer, more and more of us are adding in that extra conditioning (well we should be at least). Is this inhibiting those precious gains? I would like to say no it’s not, but it honestly might be.

It comes down to the body’s response to different stimuli. Cardiovascular work (e.g. Rowing, Running and HIIT) fires up a pathway called AMPK.

The mentioned pathway allows cardiovascular adaptations to occur, such as an increase in mitochondrial mass and capillaries density. On the other hand, we have mTOR. That is stimulated via resistance training (e.g Barbell and Dumbbell work) and allows the muscle to increase the cross-sectional area of its fibers.

The problem

Problem is AMPK is the dominant pathway. This means if mTOR was activated, via resistance training, it will be shut down by AMPK, via cardio vascular training. Therefore, no muscular adaptations occur, leading to lower levels of muscle growth (Thomas & Gordon, 2005).

Ways of combating these interfering effects:

Elevated levels of AMPK has been shown to occur for only three hours post-cardio. However, this is assuming that those three hours are spent resting and nutrition, as well as, hydration standards are met (Wojtaszewski et al., 2000). Thus implying mTOR is free to activate after that period.

In the perfect world, we’d get our conditioning session done in the morning and go about our day. Then we would return three hours or more later to perform our resistance training.


Obviously, we don’t all have the luxury of working out twice a day. So, what if we need to cram in everything in the one session? Jones (2014) found that performing the resistance session before the conditioning, greater muscular progress was observed when compared to conditioning first.

By Dan Smith, Strength Coach at AFU
IG: @Mrvanitysmith


Jones, T. W., Howatson, G., Russell, M., & French, D. N. (2017). Effects of strength and endurance exercise order on endocrine responses to concurrent training. Physiology and Nutrition, 17(3), 326-334. doi:10.1080/17461391.2016.1236148

Thomson, D. M., & Gordon, S. E. (2005). Diminished overload-induced hypertrophy in aged fast-twitch skeletal muscle is associated with AMPK hyperphosphorylation. Journal of Applied Physiology, 98(2), 557-564.

Wojtaszewski, J. F., Nielsen, P., Hansen, B. F., Richter, E. F., & Kiens, B. (2004). Isoform‐specific and exercise intensity‐dependent activation of 5′‐AMP‐activated protein kinase in human skeletal muscle. The Journal of Physiology, 528(1). doi:10.1111/j.1469-7793.2000.t01-1-00221.x


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