Circuit Training: What is it? Why do it?

What is circuit training?

Circuit training involves performing a series of strength training exercises with less than the normal amount of rest. The rest between sets is purposefully not enough for complete recovery.
There are many ways to design a circuit. You could pick ten exercises and do one set of each with no rest. You could go several times through a circuit with no rest. You could do a series of exercises with work intervals and rest intervals. Circuits can be intense and as short as 12 minutes or they can be as long as an hour. The variable are limitless so it may seem confusing but the main point is to do more work in less time than you would in a “normal” weight training session.

What is circuit training good for?

• increasing work capacity (the amount of work you can do and recover from)
• some increase in cardiovascular fitness
• increasing strength endurance
• adapting to acid buildup in the muscles
• mental toughness
• team building
• favorable changes in body composition (can lose fat without losing muscle)

Sounds great! Is there anything circuit training can’t do?

• you will not get much stronger on circuit training unless you are a beginner
• circuit training will not make you faster
• nor will it help you jump higher
• in my opinion, circuit training becomes less useful as athletes accumulate years of training

How does it work?

Circuit training falls under the broad category of metabolic training. Metabolic training responds to the volume of work done. Cardiovascular training is a type of metabolic training for example. In contrast, max strength and max speed training are not metabolic in nature. In general metabolic training and maximum intensity (central nervous system) training are incompatible with one another. This is why circuit work will not make you faster or help with your power production. Circuit training DOES accomplish two goals.
1. Circuit training causes buildup of lactic acid in the body. Circuit training is challenging because accumulating lactic acid is unpleasant and can even make athletes nauseated.  The benefit is that the body learns to better buffer the acidosis and this leads to much better strength endurance.
2. Circuit training causes growth hormone release in the body. It is theorized that the growth hormone released allows fat loss with minimal muscle atrophy and this is why circuit training is effective at creating favorable changes in body composition.

When should I do circuit training?

Circuit training is best used:

• in the off season to maintain work capacity,
• in the pre-season to increase work capacity
• to foster team unity/mental toughness if needed
• if you are out of shape and looking for gains in general fitness

Two Protocols for Circuit Training

1. The Survivor Circuit

This protocol is based on training that Mike Arthur did with the University of Nebraksa football team in the 80’s. The premise is that performing sets of 10RM intensity with one minute of rest releases the greatest amount of lactic acid and induces growth hormone release.

Nine exercises are chosen. Athletes to three sets of 10 reps with a minute rest in between each set. One minute of rest is allowed between exercises. The Survivor Circuit should take about 36 minutes to complete.

Michael Boyle describes a modification of the Survivor circuit in Advances in Functional Training.  In Boyle’s modification he uses more full body exercises that use large muscles (like squats) rather than single joint exercises (like bicep curls).

In my modification of the Survivor circuit I found it to be difficult to stay on time but it was a challenging full body workout.
Here is my modification of the Survivor Circuit:
1. squat
2. hip thrusts
3. bench press
4. pullups
5. right leg lunge
6. left leg lunge
7. deadlift
8. close grip bench
9. dumbell row

2. 30s work/30s rest

The premise behind this protocol is that a 30s work/30s rest ratio is what invokes the largest release of human growth hormone. This protocol is endorsed by Vern Gambetta in Athletic Development. There are a large variety of example circuits in his book.
I modified one of Gambetta’s power endurance circuits and found it to be very challenging. I chose three exercises (db high pull, db pull to press, and squat and press). The circuit was repeated three times the first week, four times the second week and five times the third week. Doing three rounds of the circuit takes only 9 minutes. The first week I was surprised at how difficult the workout was. In the fourth week, I was surprised by how easy (relatively) it had become.  Overall this protocol feels more difficult and has more of a cardiovascular training effect than the survivor circuit.
(*note. The high pull to press is slightly more technical in nature. Do not do this circuit without proper training and supervision)

Summary and application

Circuit training involves a series of strength training exercises with incomplete recovery. The goal of circuit training is to accumulate lactic acid and release growth hormone in the body. You can expect to see increases in work capacity and muscular endurance but not increases in speed or strength.
In designing a circuit, choose exercises that work the large muscle groups and that do not require much skill or coordination. Form will be difficult to maintain under conditions of fatigue. If you feel nauseated, stop the workout early and increase your rest intervals next time you do the workout.