Jan 29, 2015A Fresh Look at Circuit Training
The NSCA Education Team helps you unlock the power of circuit training and its potential for building strength, speed, and power.
Time is a precious commodity, which most of us do not have. As a coach, it is difficult to balance physical training with skill training and situational analysis. For athletes, it is difficult to balance class schedules with training while still meeting a social calendar that works.
So how is it possible to juggle everything and still give your athletes an effective workout? The answer is circuit training. Not just a typical circuit that the general fitness enthusiast would engage in, but rather, one that helps improve athletic performance through strength and conditioning.
Circuit training has been around for many years. Traditionally, circuits have consisted of either body weight or stack-machine exercises with low weight and high repetitions designed to increase muscle tone or muscle endurance. While this has been the norm, when designed properly, circuit training can be so much more: an effective way of increasing strength and power.
Designing a Power Circuit
The concept behind circuit training stays the same whether you are training for strength or strength endurance. A series of exercises are performed one after the other with little or no break between the exercises. The difference between power circuits and the traditional endurance circuits is determined by the overall training intensity and volume.
Intensity 
In order to increase strength, an athlete needs to work with at least 60 percent of their one-rep max. Usually, power circuits are performed between 75 and 85 percent of the athlete’s one-rep max. (Higher intensity places a greater demand on the nervous system, requiring more rest between sets, making it difficult to perform circuit style.) Endurance circuits are performed at less than 50 percent of an athlete’s one-rep max.
Volume
Volume is the total amount of work. It is calculated by adding up the total number of repetitions for each exercise. For example, if you performed six sets of five reps, that would constitute a volume of 30. The same volume could be reached by performing three sets of 10 reps.
For strength increases, the volume of training for each exercise is normally 15 to 40 repetitions. This does not mean 15 to 40 reps per set, but rather the total volume should fall between the ranges of 15 to 40 reps for each exercise.
Increasing strength is like a button on an elevator. Push the button and the elevator will come, but pushing the button more than once will not make the elevator come any faster. Increasing the volume in a training session will only lengthen the amount of time it takes to recover. As a general rule, when you increase the volume of an exercise for an athlete, they will need to decrease intensity to see optimal strength gains.
Speed
Movement speed is critical to power development, particularly during the concentric (or positive) part of the movement. While slow movements have their place in a training program, the attempt to be as explosive as possible during the concentric part of the movement is the key to power development.
This does not necessarily mean that the weight, particularly a heavy weight, will be moving fast–but the athlete should be trying to move it as fast as possible. In fact, Behm and Sale (1993) have shown that the attempt to move weights explosively, even when the actual movement speed is slow (due to the heavy weight), can improve power significantly. Still, the eccentric movement should be slow and controlled so that true power is developed.
Think Time, Not Reps
In order for a strength circuit to be effective you need to control fatigue. Fatigue during power training circuits will be caused by either a depletion of ATP-CP–the immediate source of energy in the muscles–or an accumulation of lactic acid. If fatigue is caused by depleting ATP-CP, that is fine because this energy system can recover very quickly (two to four minutes for complete recovery) and allow the athlete to continue to work at the right intensity and speed.
The recovery time from high levels of lactic acid can be as long as two hours. High levels of lactic acid will make it difficult to work at the appropriate intensity, decreasing the effectiveness of the workout.
To make sure that lactic acid is not causing fatigue, the duration of each station in the circuit should be kept to 15 seconds or less. Notice that we are not recommending a specific number of reps because this can vary from exercise to exercise, depending on the range of motion and the weight used. The goal is to do as many reps as possible in the 15-second time frame, using good technique and a controlled eccentric motion. When the whole circuit is completed, a two- to four-minute rest should be taken before the next round to allow for full recovery of ATP-CP stores.
Selecting the Exercises
The order of exercises in the circuit will also affect fatigue levels. Upper body and lower body exercises need to be alternated to spread the fatigue as much as possible. You should alternate push and pull exercises as well. For instance, if your circuit starts with a pulling exercise, like pulldowns, you could then move to a lower body exercise, like leg presses. Your next upper body exercise would then need to be a pushing exercise, like the bench press, followed by a lower body exercise, like leg curls.
This is a circuit designed to give a total volume of about 30 reps for each body part with an intensity of about 70 percent of one-rep max.The athlete should not be near a failure point on any of the exercises, which is fine since failure is not necessary to increase power.
The number of repetitions done in each 15-second set will depend on the exercise. Arm curls and calf raises have a much shorter range of motion than back extensions or leg presses, so more reps can be completed in the in 15 seconds.
When the athlete has achieved the desired volume for an exercise, 30 reps in this example, the exercise is eliminated from the circuit and they take a 15 second rest upon arrival to the next station. If you look at the calf raises, you will see that after two circuits the required 30 reps are done.
For the remaining circuits, have the athlete take a 15-second rest whenever they get to the calf raise station. Don’t have them continue to do calf raises because this will increase the volume too much and potentially overtrain the calves. Make sure they take the rest period. The program is specifically designed to improve power and endurance and is not intended to act as a body building method.
Get To Work
Ideally, you should try to have athletes complete this circuit in less than 25 minutes. Pre-planning the routine by setting up the circuit in advance will prevent the rest from getting too long. Have a back-up plan or alternate exercises selected in case your gym space becomes limited. This type of full-body power circuit can be done twice a week with two days rest between sessions, making it a very time efficient way to fit power training into a busy athlete’s program.
The National Strength and Conditioning Association is the worldwide authority on strength and conditioning, supporting and disseminating research-based knowledge and its practical application, to improve athletic performance and fitness. www.nsca-lift.org
References
Baechle, T.R. & Earle, R.W. (2008). The Essentials of Strength and Conditioning. Champaign, IL: Human Kinetics.
Behm, D. G., & Sale, D. G. (1993). Intended rather than actual movement velocity determines velocity-specific training response. Journal of Applied Physiology, 74(1), 359-368.
