Which From of Cardio Won't Hinder Your Muscle Gains?

Whether an individual is an aspiring bodybuilder or merely a weekend warrior, the importance of cardiovascular fitness cannot be overstated.  Good conditioning is helpful in any ahtletic pursuit, and promotes a healthy heart, which can lead to a longer life.  Additionally, cardio training increases one's metabolism, aiding in promoting appetite in those wishing to gain weight and helping to burn calories for those looking to lose weight.

So why do many bodybuilders look at cardio training as a sort of necessary evil?  In addition to the fact that cardiovascular training is not the most enjoyable experience in the world (a few hours on the treadmill? No thanks.), some strength athletes are concerned that cardio may run counter to their goals of muscle-building.  If one is performing too much cardio, precious calories needed for growth may be burned in the process, while muscles such as the legs may be 'overtrained' from the combination of heavy squats, deadlifts and other strength exercises with running or cycling.

This concern is legitimate - but luckily scientists have done some investigation on which types of cardio provide the least interference with strength training goals.  In a study published this month, researchers compared the effects of two popular cardio choices - cycling and incline treadmill walking - on body composition and the development of lower body strength.  Participants in the study were randomly assigned to one of three groups: resistance training only; resistance training and cycling; or resistance training and incline treadmill walking.  Each of the groups were subjected to an identical stregnth-training routine lasting nine weeks (1).

At the end of the experiment, there were significant differences between the groups in terms of body composition.  The resistance training group (without cardio training) was the only group to gain weight, although percentage of body fat did decline, suggesting a positive change in body composition.  Both resistance and cardio training groups lost an average of around 1 kg (2.2 lbs), with the treadmill group losing slightly more body fat on average.  Interestingly, though, the women in the cycling group lost more body fat than the women in the treadmill group (1).

Measures of strength also yielded significant differences between groups.  As one might expect, the resistance training group experienced the greatest increase in strength, adding nearly double the amount of weight to their one-repetition maximum than both of the other groups.  Out of the cardio and resistance training groups, the cycling group had greater strength improvements, adding slightly more than 2 kg (~4.5 pounds) more to their one-repititon max than those in the treadmill group (1).

So which is the better mode of cardio for those engaged in strength training?  It depends.  If one's primary goal is to shed body fat, treadmill training is very slightly preferable.  If increasing strength is the primary goal, cycling is superior.

SOURCES:

1. Gergley, Jeffrey. Comparison of Two Lower-Body Modes of Endurance Training on Lower-Body Strength Development While Concurrently Training. Journal of Strength and Conditioning Research, 2009; 23(3):979-98.