Cardio – Before or after?

One of the most frequently asked questions I get regarding cardio is whether it should be done prior to or after resistance weight training.  First let me say that I am not a huge fan of doing cardio and weights during the same workout.  It’s too easy to think that since I am going to be doing more, I do not have to exert on the first portion of the workout.  Or, since I have already exerted so much for the first part, I can slack a little on the second. Experience tells me that one or the other will suffer.  I know that not everyone has the time to do this, but I prefer doing cardio and resistance training on separate days so I can put full effort into each; if not separate days, at least a few hours apart.   If you must do both on the same day, do resistance weight training first and then cardio.

Many studies have reported that concurrently performing strength training and endurance training will compromise strength and power (Chromiak & Mulvaney, 1990).  Rhea et al. (2008) studied the effects of plyometric training with concurrent cardiovascular endurance training on collegiate baseball players.  One group performed a combination of plyometrics and endurance while another group performed just plyometrics.  The combined group decreased in speed and power while the single group showed an increase in speed and power.  Nader (2006) suggests that this phenomenon, known as the interference phenomenon, is because certain enzymes that are needed for strength gains are mitigated by endurance training. 

Now for the physiology; the body utilizes three energy systems. The phosphagen system uses adenosine triphosphate (ATP) and creatine phosphate (CP) as fuel.  The glycolytic system is when glycogen (sugar) from the muscle or glucose (sugar again) from the blood is converted to ATP and used as fuel.  The oxidative system resynthesizes carbohydrates and fat into ATP.  The phosphagen system only supplies energy during short bursts that last for just a few seconds.  The glycolytic system lasts just a few minutes and the oxidative system is used for exercise durations longer than three minutes. 

The three energy systems of the body, phosphagen, glycolytic, and oxidative, work together and often overlap, however as mentioned, endurance training (aerobic) and strength training (anaerobic) will often elicit incompatible results.  Rhea et al. (2008) propose a fitness continuum that consists of neuromuscular power, muscular strength, muscular endurance, and cardiovascular endurance.  Training for the individual components in the fitness continuum will result in differing physiological outcomes.  It is also thought that the closer the components are in the continuum, the more compatible the training adaptations will be.  Similarly, the further apart the components are in the continuum, the less compatible the adaptations will be. 

In theory, to move into the oxidative system, you need to pass through the phosphagen (ATP-CP) and glycolytic (sugar) systems.  This leaves too little of the proper fuel for resistance weight training.  Where as performing strength exercises first and depleting the first two energy systems, one is ready to move into the oxidative system.  Bottom line, do strength training first and then cardio. 

Chromiak, J. & Mulvaney, D. (1990). A review: The effects of strength and endurance training on strength development.  Journal of Applied Sport Science Research, 4(2), 55-60.

Nader, G. (2006). Current strength and endurance training: From molecules to man. Medicine and Science in Sports and Exercise. DOI: 10.1249/01.mss.0000233795.39282.33. 

Rhea, M., Oliverson, J., Marshall, G., Peterson, M., Kenn, J., Naclerioayllo’n, F. (2008).  Noncompatibiality of power and endurance training among college baseball players.  Journal of Strength and Conditioning Research, 22(1), 230-234.