3 Reasons You Should Do Strength Training Before Cardio
The Focus Factor
Many cardio workouts, like pedaling an exercise bike or walking on a treadmill, requires little focus or concentration. You might spend the time letting your mind wander as you feel the stress melt away. But when you train for strength, you may handle heavy weights where the risk of injury is higher. Who wants to drop a weight on their foot? Ouch! So, strength training requires more focus and brainpower.
If your mind and muscle are exhausted from a cardio workout, your brain might not be as up to focusing on the mechanics of strength-training exercise as when you’re fresh. Using good form is critical for safety and for getting the most out of exercise, so you want to be in the proper mindset and not have brian fatigue. It’s also important to focus on how you breathe when you lift and not hold your breath. Strength-training typically takes more mental focus than repetitious cardiovascular exercise, where you do the same movement over and over. So, get the more mentally demanding stuff out of the way first, while your mind is still fresh and your ability to focus is at a peak.
The Muscle Fatigue Factor
Strength training forces your muscles to handle more weight than they’re accustomed to. Otherwise, you won’t get stronger or increase the size of your muscles. One of the main reasons people fail to make significant strength and muscle gains is they don’t push their muscles harder over time. After a cardio workout, the muscles in your lower body are fatigued and less able to handle as much weight. So, you likely won’t perform as well when you strength train and that can limit your gains. Fatigue will be most pronounced for the muscles in your lower body since those are the muscles you use for cardio while the impact will less for your upper body. Therefore, upper body strength will be less affected since your legs do most of the work during cardio.
The type of cardiovascular exercise you do matters too. A study published in the Journal of Strength and Conditioning Research found that stationary cycling doesn’t interfere with muscle growth as much as running. The difference may lie with the type of contractions each emphasizes. Running is an exercise that uses more eccentric contractions, which cause greater muscle damage and muscle soreness. In contrast, cycling places a stronger emphasis on concentric contractions that creates less muscle damage and exhaustion.
The Fuel Factor
Another factor to consider when deciding which form of training to do first is the type of fuel your body taps into when you do each form of exercise. During heavy strength training, your muscles use carbohydrates as a fuel source in the form of muscle glycogen. In contrast, during moderate-intensity cardio, your body uses fat and carbohydrates as fuel. The lower the intensity of a cardio session, the more your body uses fat as opposed to carbohydrates as fuel, but if you’re working out at a moderate to high intensity, your muscles use more carbohydrates in the form of glycogen. If you jump into a cardio session before strength training, you’ll deplete your muscle’s glycogen stores and have less available for strength training. So, again, your performance may suffer.
The Bottom Line
Now you know how doing a cardio workout can affect your performance when you strength train. If you want to maximize strength gains, do strength training before cardio or do strength and cardio on separate days. If you must do strength training and cardio on the same day and like to do cardio first, keep the intensity of your cardio session low to avoid excessive muscle fatigue.
J Strength Cond Res . 2012 Aug;26(8):2293-307. doi: 10.1519/JSC.0b013e31823a3e2d.
Doma, K., & Deakin, G. 2013. The cumulative effects of strength and endurance training sessions on muscle force generation capacity over four days. Journal of Australian Strength and Conditioning, 21 (Suppl. 1), 34-38.