Introduction

Circuit training continues to be a popular form of exercise and can be found in health clubs and leisure centres across the globe. Circuit training is commonly perceived as an intense form of exercise that enables participants of similar and mixed ability to get a balanced and effective workout.

 

Circuit Training in the Market

Circuit training has been developed into a myriad of forms, however, the basic principles identified below still form the core of any circuit training session.

What is Circuit Training?

Circuit training can be used to progressively develop the muscular and circular-respiratory systems. Circuit training is considered a time cost-effective medium, where large numbers of individuals, at various stages of physical development can be trained together.  Circuits can be adapted to achieve a variety of fitness goals using a variety of equipment and can be adapted to indoor or outdoor areas.

An exercise ‘circuit’ is one completion of all prescribed exercises in the programme. When one circuit is complete, the individual begins the first exercise again for the next circuit. Traditionally, the time between exercises in circuit training is short, often with rapid movement to the next exercise.

History of Circuit Training

Elements of circuit-style training programmes were present early on in history. The modern form of circuit training was developed by R.E. Morgan and G.T. Anderson in 1953 at the University of Leeds in England (Sorani, 1966).

Morgan and Anderson developed this modern form of circuit training in order to enable individuals to work at their own intensity whilst also training with others. It was initially examined as a 9 to 12 exercise protocol where participants performed exercises at a moderate intensity (about 40% to 60% of 1 RM values) for a specified number of repetitions or amount of time. Once the repetitions were performed or time expired, the participant would move to the next exercise station with very little rest.

During the circuit training session all energy systems interweave to enable different intensity activities to be performed. This results in the aerobic energy system being more predominant during some exercises and the anaerobic energy system being more predominant in others.

Improvements in muscle strength and endurance were observed, as well as components of aerobic fitness (Kravitz, 1996). The efficiency of this type of training grew in popularity and expanded because of advances in equipment in the United States (i.e. selectorised and hydraulic equipment).

For years, a growing body of research expanded on the benefits of this highly efficient mode of training. Researchers have examined how increasing the intensity of this type of training by using exercises known to significantly elevate the heart rate and limiting rest time could elicit even greater gains in even shorter overall exercise time (Tabata et al, 1996; Gibala et al, 2006; Gibala & Little, 2010; Little et al, 2010).

Today, using body weight as resistance during circuit training may grow in popularity as financial means to special equipment and facilities access have declined for some. Body weight can provide an adequate training load as long as it results in sufficient aerobic and resistance training intensities.

This original formula has changed little over the years, and has benefited from occasional refinements rather than a complete redesign. For example, it is now common to see people performing circuits with fewer than 9 stations, and circuits where all exercises are themed (such as boxing in boxercise).

Why Circuit Training?

Circuit training sessions have a very low choreography level, there is no fancy footwork patterns or complicated arm movements. Circuit training provides a full body workout and individuals can work at their own pace.

Circuit training does not necessarily involve, as some people assume, high intensity exercise. It is a system of exercising in which each individual works at their own pace at a predetermined number of stations or exercises for a set period of time. Each individual can work at a level of intensity suited to them.

The best part about circuit training is that everyone can benefit. The only real restrictions are:

• The fitness level of the participants;
• The space available; and
• The imagination of the instructor.

Types of Circuit Training

There are three types of circuit training:

1. Coloured;
2. Controlled; and
3. Timed (circuit dose).

Coloured

Display cards show predetermined repetition and the circuit difficulty is graduated in repetition per colour, for example:

• Red    = 5
• Blue   = 10
• Green = 15

Start on a low colour circuit and move up a colour when this becomes easier. Different colours can be given to different exercises depending on their difficulty and/or ability of the individual.  This will prevent a lot of standing about before each change over.

Controlled

• Divide the class up between the exercises.
• Work individuals’ for approximately 10- 20- or 30 seconds per exercise (dependent on aim).
• The instructor controls the change, verbally, by use of a whistle or by using the time taken for someone to climb a rope or to complete a set number of shuttle runs.

Timed Circuit (Circuit Dose)

Timed circuit or circuit dose training is an ideal way to train groups that are together for long periods of time, for example:

• A platoon or company;
• The unit football team;
• A remedial group;
• A Unit Headquarters; and
• Outdoor fitness clients.

Formula

The formula for finding a circuit is as follows:

• Select exercises for the circuit.
• Work on exercise for 30 seconds.
• Record the amount of repetitions completed.
• One Minute recovery.
• Continue until all exercises have been completed.
• Half the amount of repetitions completed on each station (e.g. if an individual completed 30 press-ups then half would be 15).

The next time this group visits the gym get them to complete a full circuit, only doing half the reps on each exercise. This circuit is to be timed and a fraction of this total time is to be taken away e.g. one quarter.  Ensure the fraction is realistic. When the fraction is taken away from the total time, you are left with the target time. On subsequent visits, continue with the same circuit until the target time is achieved. Once the target time has been achieved, re-evaluate the target time by repeating the process. Table 1 provides an example circuit dose.

Circuit Training Variations

There are many variations of circuit training, listed below are some the more commonly used:

• Duplication: individuals are paired off with a partner of similar capabilities and motivation.  The apparatus to be worked on is also duplicated.  Each person competes simultaneously against each other in the number of repetitions attained in the pre set time.  All apparatus is worked.
• Triplication: apparatus is laid in triplicate, i.e. hard/moderate/easy. Each person follows the circuit around selecting their own intensity of work.
• Split Circuit: individuals move along the line of apparatus performing predetermined repetitions on each selected exercise in personal preferential order.  No rest allowed.
• Shaped Circuit: two or three triangles and/or squares of exercises within one circuit.  Triangles or squares can be made up of exercises for one muscle group or as for the normal circuit training.
• Chalking Circuit: individuals chalk up maximum repetitions completed.  The following person tries to beat the amount that is chalked on the mat.
• Coupling Circuit: over a pre-determined amount of time, pairs add together their repetitions after completing an exercise and make a note.  The following pairs try to beat the repetitions in the same allocated time.
• Hazard Circuit: an obstacle is to be completed between each exercise.
• Work or Jog: Pairs – One works, the other Jogs.
• Overtaking: Each individual starts off at intervals and tries to overtake the person in front.
• Colour coded: white easy, red hard.
• Team circuit: one team performs the other rests – time tried to be bettered, or set team in lines and all work together.  Move onto the next exercise when the whole team has finished.  Teams must be of similar ability.

Advantages and Disadvantages of Circuit Training

Advantages of Circuit Training

There are a number of advantages to circuit training and these include:

• Can be done in- and outdoors;
• Can be used were space is limited;
• Can be used with improvised or no kit;
• Individuals of mixed ability groups can work at the same time;
• Progress measured easily (i.e. clock/stopwatch);
• Large/small numbers worked at the same time;
• Can be adapted for most sports; and
• Can help to improve:
  • The cardio vascular system.
  • Strength.
  • Endurance.
  • Determination.

Disadvantages of Circuit Training

There are a number of disadvantages to circuit training and these include:

• Easy for individual’s to cheat (i.e. when the instructor’s back is turned);
• Can be difficult to supervise (depends on group size and layout);
• Bottlenecks can occur (i.e. fitter individual’s catching up with slower group members); and
• Can get boring (e.g. if continually using the same session).

Circuit Training in the Military

Fitness is paramount to being successful in the military, especially the army. Recruits are expected to be able to excel in all physical tests and meet the physical demands of being a soldier.

The key to this success is a training regimen aimed at increasing strength and cardiovascular capacity. As such circuit training in the military environment is designed to provide exercise to groups of soldiers at intensities which suit each individual’s fitness level.

Circuit training can promote fitness in a broad range of physical and motor fitness areas. These include cardio-respiratory endurance, muscular endurance, strength, flexibility, and speed. Circuit training can also be designed to concentrate on sports skills, soldiers’ common tasks, or any combination of these.

In addition, circuit training can be organised to exercise all the fitness components in a short period of time. A little imagination can make circuit training an excellent addition to a unit’s total physical fitness programme.

At the same time, it can provide both fun and a challenge to soldiers’ physical and mental abilities. Almost any area can be used, and any number of soldiers can exercise for various lengths of time.

Practical Tips

Points to Consider When Planning a Circuit

There are a number of practical points to consider when planning a circuit training session:

• Determine Objectives: the designer must consider specific parts of the body and the components of fitness on which soldiers need to concentrate.
• Select the Activities: the circuit designer should list all the exercises or activities that can help meet the objectives.
• When do you require the circuit for;
• Amount of time allocated;
• Numbers of individuals to be trained;
• Number and sequence of stations;
• Number of times a circuit is completed;
• The group’s standard of fitness (i.e. trainee soldiers, trained soldiers or mixed-ability group);
• Space and equipment available (indoors/outdoors).
• Are there safety factors to consider?

Points to Consider When Conducting a Circuit

There are a number of practical points to consider when conducting a circuit training session:

• The exercises are laid out in the correct order;
• The exercises are clearly marked and easy to follow;
• Avoid exercises that demand skill;
• Teach the exercise on the first visit; and
• Test on 2nd or 3rd visit.

Points to Consider After Circuit Training

Once the circuit training session has been completed the following points should be considered:

• Record your times; and/or
• Adjust your standards and targets as necessary.

Safety Factors

While injury is always possible in any vigorous physical activity, few calisthenic exercises are really unsafe or dangerous. The keys to avoiding injury while gaining training benefits are using correct form and intensity.

Further, individuals with low fitness levels, such as trainee soldiers or new clients, should not do the advanced exercises highly fit soldiers/individual can do. For example, with the lower back properly supported, flutter kicks are an excellent way to condition the hip flexor muscles. However, without support, the possibility of straining the lower back increases. It is not sensible to have recruits/new clients do multiple sets of flutter kicks because they probably are not conditioned for them. On the other hand, a conditioned Royal Marine Commando company may use multiple sets of flutter’ kicks with good results.

The key to doing calisthenic exercises safely is to use common sense. Also, ballistic (that is, quick-moving) exercises that combine rotation and bending of the spine increase the risk of back injury and should be avoided. This is especially true if someone has had a previous injury to the back. If this type of action is performed, slow stretching exercises, not conditioning drills should be used.

Some individuals complain of shoulder problems resulting from rope climbing, horizontal ladder, wheelbarrow, and crab-walk exercises. These exercises are beneficial when the individual is fit and conducts these exercise in a regular, progressive manner. However, a certain level of muscular strength is needed to do them safely. Therefore, individuals should train progressively to build up to these exercises. Using such exercises for unconditioned individuals increases the risk of injury and accident.

References

Gibala, M.J. & Little, J.P. (2010) Just HIT It! A Time-efficient Exercise Strategy to Improve Muscle Insulin Sensitivity. Journal of Physiology. 588(18), pp.3341-3342.

Gibala, M.J., Little, J.P., Essen, M.V. (2006) Short-term Sprint Interval versus Traditional Endurance Training: Similar Initial Adaptations in Human Skeletal Muscle and Exercise Performance. Journal of Physiology. 575(3), pp.901-911.

Kravitz, L. (1996) The Fitness Professional’s Complete Guide to Circuits and Intervals. IDEA Today. 14(1), pp.32-43.

Little, J.P., Safdar, A., Wilkin, G.P., Ranopolsky, M.A. & Gibala, M.J. (2010) A Practical Model of Low-volume High-intensity Interval Training induces Mitochondrial Biogenesis in Human Skeletal Muscle: Potential Mechanisms. Journal of Physiology. 588, pp.1011-1022.

Sorani, R.P. (1966) Circuit Training. Dubuque, Iowa: William C Brown Publishers.

Tabata, I., Nishimura, K. & Kouzaki, M. (1996) Effects of Moderate-intensity Endurance and High-intensity Intermittent Training on Anaerobic Capacity and VO2max. Medicine and Science in Sports and Exercise. 28(10), pp.1327-1330.

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