Circuit workouts are a time-expedient and fun way to get fit. If you’re not familiar with them, circuit training workouts consist of a series of resistance exercises, usually 6 to 9, that you do in sequence with little or no rest between each exercise. You pause only long enough to set up for the next exercise, in most cases, although some people rest as long as 60 seconds between exercises, especially when doing high-intensity moves. An average rest period is usually around 30 seconds.
For the resistance exercises in a circuit workout, you might use resistance bands, barbells, dumbbells, your own body weight or a combination of any of the above. You can also include cardio intervals in a circuit workout to keep your heart rate up and burn more calories. For example, you might do 10 burpees, 30 seconds of high knees, butt kickers, jumping jacks or other cardio exercises after every 3rd or 4th resistance exercise. The beauty of circuits is you can customize each workout to meet your objectives and change the exercises you do for variety.
You’re doing resistance exercises when you do a circuit workout, so you might wonder whether circuit training offers enough of a stimulus to promote muscle growth and strength gains. Can it be a substitute for conventional weight training?
Can You Build Muscle with Circuit Training?
The best formula for promoting muscle hypertrophy is to use moderate resistance, a weight that you can lift between 8 to 12 times (70%-80% of one-rep max) before exhausting the muscle. According to research, using greater volume, 3 sets or more of each exercise, is best for stimulating muscle growth. However, some research shows a single set to failure or near-failure can also increase muscle size, although it’s not necessarily ideal.
With circuit training, it’s customary to use a lighter weight for each circuit, usually around 50% to 60% of one-rep max and to do a higher number of reps. In some cases, you do AMRAP, or as many reps as possible for a specific time. For example, you might designate 30 seconds for each exercise and you do as many reps as you can in that time-period before moving to the next exercise. This type of low resistance, high-rep training is optimal for increasing muscle endurance rather than size. Still, you will likely get some hypertrophy if you use a weight heavy enough to reach near failure when you complete the last rep. Because you’re not resting for long between sets, it’s best to alternate between upper and lower body exercises so one set of muscles can recover while you work the other.
Also, unless you repeat the circuit several times, you’re only doing a single set of each exercise, which isn’t ideal for building muscle size. If hypertrophy is your goal, cycle back through the same exercises 2 or 3 times to increase the volume of work you place on each muscle group.
Circuit Training for Hypertrophy: What Does Research Show?
Can you make gains in strength and muscle size through circuit training alone? In 2011, researchers asked a group of healthy, resistance-trained men to do a resistance workout in a circuit fashion with minimal rest between exercises for 8 weeks. The men did 6 repetitions of each exercise using a weight representative of their 6-rep max and rested 35 seconds between exercises. The second group of guys did a similar number of sets but rested 3 minutes between each one, similar to traditional weight training for strength and hypertrophy. Both groups worked out three times per week.
Was one approach more effective than the other? Both groups experienced similar increases in strength, lean body mass, and power. Plus, the guys who did the sets circuit-style lost more body fat. So, it seems that circuit training CAN increase muscle size, strength, and power, based on this study. A circuit approach also may be more effective for fat loss. That’s not surprising the short rest periods increase the rate at which you burn fat.
Tweaking Circuit Training to Meet Your Goals
Circuit training is highly customizable. Not only can you customize the exercises you do during each circuit but you can tweak the resistance and volume to make it more conducive to gains in strength, hypertrophy, muscle endurance or fat burning. For the former, use a greater resistance, about 75% of your one-rep max and include at least 30 seconds of rest between exercises. For more aerobic and fat-burning benefits and to focus more on muscle endurance, use lighter weights (50% to 60% of one-rep max), more reps, and little or no rest between exercises.
As mentioned, you can also increase the number of sets you do for each exercise (to increase volume and favor hypertrophy) by choosing fewer exercises and cycling through the same circuit three times.
Do You Still Need to Do Standard Weight Training?
Although you can gain muscle size with circuit training, if you’re using a relatively heavy resistance, you’ll make more gains by varying the stimulus you place on your muscles. The longer recovery periods between sets that you use with traditional strength training (1 to 5 minutes), gives your muscles more recovery time. This helps you do more volume on the next set. Circuit training is ideal for overall fitness and for days when you have limited time to train. Its biggest strength is that it gets your heart rate up more than traditional strength training and you get more done during the time that you have due to the short rest periods. It’s a condensed workout for days that you’re short on time.
Can circuit training replace traditional strength training? It depends on what your objectives are. If you’re not trying to build significant muscle size but just want to get fitter in general, circuit training might be all you need. However, if you’re trying to get significantly stronger and more defined, stick with traditional strength training. That doesn’t mean you can’t circuit train but don’t make it your only form of training.
J Strength Cond Res. 2011 Sep;25(9):2519-27. doi: 10.1519/JSC.0b013e3182023a51.
ACE Fitness. “Circuit Training Basics”
Exercise Biology. “Can Circuit Training Increase Strength and Muscle?” October 2011.
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