Strength Before Cardio: It's Not a Universal Law
We’ve all heard it before: if you’re doing strength training and cardio in the same workout, do strength first. Unless cardio is your sport or otherwise a huge priority for some reason, pretty much everyone will get more out of doing strength work first and cardio second. However, there are some details to this issue that need answering, and some were answered in a recent study in the Journal of Strength and Conditioning Research.
Personally, I've always had questions about the practice of strength training before cardio, and this study helped answer them. For example, I always found that I could do more pull ups after running a few miles than I could with a standard gym warm up. This begs the question: what happens if I’m doing cardio that focuses on a different part of the body than my strength training? Namely, if I’m running or cycling, and thus doing cardio primarily with my legs, perhaps the strength-before-cardio rule isn’t true if my subsequent strength workout is only upper body.
The role of muscle activation is probably even more important. The strength-before-cardio rule is based on the idea that cardio is likely to reduce your ability to lift heavy weights, but your heavy weights probably won’t slow down your cardio as much unless it’s a heavy squat day. However, new studies suggest exercise is a bit more nuanced than that. For example, recent reports have demonstrated occlusion can increase gains and fatigue has no relationship to muscle recruitment, which should have every athlete second-guessing when their muscle fibers are actually being recruited. Strength is recommended before cardio because peak strength will be reduced by doing cardio first, but we can’t say for sure that muscle recruitment will be, too.
To address these questions, the researchers in the new study took fourteen men and put them through four different workouts in a random order. One workout was just a bench press. Another was a back squat. The other two workouts were either the bench press or the squat preceded by thirty minutes of cardio. The cardio was performed at seventy percent of predicted maximum heart rates, which, for the moderately fit participants of this study, would amount to a leisurely jog.
No surprise to anyone, doing cardio first hindered the back squat. However, it made no statistically significant difference to the bench press. In fact, after doing the cardio, there was a slight improvement to the bench press. It didn’t even amount to an average of one rep more, which was nowhere close to statistical significance, but I found it interesting in light of my own experience with doing pull ups after running.
As far as fiber recruitment goes, on the other hand, there were no differences in conditions. What that means is that even though the lifters couldn’t get as many reps out of their squats after doing cardio, they recruited just as many fibers as they would have if they hadn’t done cardio. So from a muscle building perspective, it’s possible that the order doesn’t matter.
In the end, the advice to do strength training before cardio remains, albeit as a shadow of its former self. It seems to matter much less when different muscle groups are worked, and, indeed, it’s a good idea to try out your upper body lifts after lower body cardio a few times to see if there’s a benefit. Otherwise, emphasize the type of exercise that’s most important to you.
1. Jeremy Tan, et. al., “Effects of A Single Bout of Lower Body Aerobic Exercise on Muscle Activation and Performance During Subsequent Lower and Upper Body Resistance Exercise Workouts,” Journal of Strength and Conditioning Research, DOI: 10.1519/JSC.0000000000000413
Photo courtesy of CrossFit Impulse.