Will Cardio Interfere with Our Ability to Maximize Muscle? New Research

For decades, the oft-repeated assumption was that when an exerciser performs both cardio-respiratory and strength training exercise, an “interference” effect exists.  Specifically, trainees who were focused on increasing lean muscle tissue were counseled to avoid cardio due to the detrimental interference effect that cardio had on our muscle-building capabilities. 

A group of Canadian and Australian researchers recently published a study in the Journal of the Federation of American Societies for Experimental Biology that provides our most current understanding of the effect that cardio has on our strength training results. 

The researchers divided participants into three groups:

Group 1: Strength training only

Group 2: Strength training + high-intensity interval cardio (with a 3-hour rest in between the strength workout and the cardio workout)

Group 3: High-intensity interval cardio + strength training (again, with a 3-hour rest in between)

The results? 

Combining cardio with strength training had no negative impact on the molecular signaling involved in increasing lean muscle tissue.  Additionally, the order of cardio or strength had no impact on the molecular signaling.

Take home message: If we are serious about our strength training and building lean muscle tissue, we do not need to avoid cardio for fear that our muscle-building results will be compromised.