Circuit training

Circuit training is a type of interval training in which strength exercises are combined with endurance/aerobic exercises, combining the benefits of both a cardiovascular and strength training workout. 'Circuit' means a group of activities and refers to a number of selected 'stations' positioned around the facility that are to be visited in rapid succession. The range of stations includes those comprising resistance equipment (e.g. hydraulic equipment or free weights), as well as allocated spaces to do squat thrusts, pushups, jumping jacks, sit-ups, and other exercises. Each person should complete the activity in one station before they proceed to the next station. They then continue until they have passed through all stations once or twice as required, or until a certain time requirement has been met.

History of circuit training and fundamentals

Circuit training is an evolving training exercise program that was developed by R.E. Morgan and G.T. Anderson in 1953 at the University of Leeds in England.

Fundamentals

Early in the original format of Morgan and Anderson, the circuit was made up of 9 to 12 stations. However, today, this number varies according to the design of the circuit. The program may be performed with exercise machines, hydraulic equipment, hand-held weights, elastic resistance, calisthenics or any combination. Themed circuits are possible, for example with boxing exercises (boxercise). A 15 second to 3 minute aerobics station is placed between each station, allowing this method to improve cardio-respiratory and muscle endurance during the workout.

A simpler form of the exercise has the group running round the gym with a trainer simply calling, for example, "ten push ups", "ten sit-ups" at intervals.

Studies at Baylor University and the Cooper Institute show that circuit training is the most time efficient way to enhance cardiovascular fitness and muscle endurance. Studies show that circuit training helps women to achieve their goals and maintain them longer than other forms of exercise or diet.

And research from Morgan and Anderson showed:

Perhaps a most profound finding of this study, from a health perspective, is that this investigation clearly shows that performance of this circuit of exercises, at this level of intensity elicited oxygen consumption values (39% to 51.5% of VO2max) that meet established guidelines of the American College of Sports Medicine (ACSM) for the recommended intensity (40% to 85% of VO2maxR) of exercise for developing and maintaining cardio-respiratory fitness (Pollock et al, 1998). Thus, this circuit not only provides a suitable muscular fitness stimulus but also helps to meet ACSM cardiovascular guidelines and the newly published Dietary Guidelines for Americans 2005 for physical activity.

Advantages of circuit training

• May be easily structured to provide a whole body workout.
• Does not require expensive gym equipment.
• Participants normally work in small groups, allowing beginners to be guided by more experienced individuals, as well as benefiting from the supervision of the instructor.
• Can be adapted for any size workout area.
• Can be customized for specificity; easy to adapt to your sport.

It's the most scientifically proven exercise system. It's time efficient and incorporates strength, flexibility and cardio in the same workout. (The Cooper Institute; Dallas, TX)

Disadvantages of circuit training

Circuit training is well suited for developing aerobic endurance or fat burning. It is, however, not so suitable for those wishing to build strength or muscle bulk. The duration of some circuit training stations can be in the region of 45 to 60 seconds, and in some cases as long as two minutes. These circuits typically mean that the number of repetitions performed on each station is relatively high, putting each exercise way out on the endurance end of the intensity continuum.

Those wishing to optimise increase in strength or muscle bulk (hypertrophy) can reduce the number of repetitions performed and increase the weight to be lifted or increase the intensity, when hydraulics or elastics are used. On the other hand, longer station length is quite appropriate for any cardiovascular (aerobic) stations included in the circuit.

Where all the participants have an adequate level of experience, the station times could be reduced to, say, 15 or 20 seconds. This will encourage the participants to lift heavier weights, aiming to achieve overload with a smaller number of repetitions, typically in the range of 4 - 8 or 8 - 12, depending on the specific training goals. However, this would provide little time for the instructor to supervise technique, posture and form to ensure that the activity remains both safe and effective.

Sources

• Kravitz, L. (1996). "The fitness professional's complete guide to circuits and intervals". IDEA Today, 14(1), 32-43.

• Pollock, M.L., Gaesser, G.A., Butcher, J.D., Despres, J-P, Dishman, R.K., Franklin, B.A., & Ewing Garber, C. (1998). "The recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness, and flexibility in healthy adults". Medicine & Science in Sports & Exercise, 30(6): 975-991.

See also

• Hydraulic resistance
• Curves for Women