Resistance Circuit Training: The Benefits

What is Circuit Training?

Essentially, circuit training is just interval strength training. A strength exercise is performed for reps or time, a rest interval is then given before the performer moves onto the next exercise. It is the primary mode of training for developing strength endurance, raising work capacity, and changing body composition¹. It is a very effective method for training teams or large groups because everybody can train at the same time. Circuit training can also be used to target specific parts of the body (such as legs, core, upper body), or can be used as a total body workout. The circuits can be tailored to satisfy every fitness level through modification and progression of the selected exercises.

Health & Performance Benefits

Scientific research on the benefits of circuit training have focused on four main areas relating to health & performance. These are:

·         Improvements in oxygen consumption (VO_2max)

·         Improved body composition (body fat %)

·         Transformations of physiological health markers (cholesterol, vascular function, blood sugar)

·         Strength Improvements

Oxygen Consumption (VO_2max) is the maximum amount of oxygen that can be delivered to the working muscles during exercise. It is an important marker for heart function and endurance exercise capacity, and provides an indication of the efficiency of the aerobic system to supply energy. The best effects of circuit training for improving VO_2max are seen when implementing a circuit of 3 sets of 8-10 exercises 3 times per week², displaying improvements in VO_2max in excess of 18% in previously untrained adults and 12% in trained college aged athletes.

Body Composition is positively affected in terms of total body mass, lean body mass and body fat percentage (%). These beneficial changes have been shown to occur across a wide range of intensities³ (ranging from 40-75% of 1 repetition maximum) with the largest improvements witnessed when the work:rest ratios are between 1:1 and 2:1 and the rest interval is less than 1 minute. A combination of aerobic and strength exercises in the same circuit has also shown reductions in skinfold measurements, waist:hip measurements, and waist circumference in both men and women⁴.

Physiological Health Markers such as blood glucose, cholesterol (both HDL and LDL), and vascular function (blood flow, blood pressure) are improved after both acute and chronic bouts of circuit training. Significant increases in HDL cholesterol can be seen within 1 hour of a circuit training session, similarly decreases in LDL cholesterol occur as a result of repeated training bouts. Increases in the rate of blood glucose disposal indicate that circuit training may be the ideal method of training for Type 2 diabetics and people with Impaired Glucose Tolerance (Pre-Diabetes)⁵. Positive benefits in both resting and exercising blood pressure are also widely reported with increased blood flow during exercise and reduced resting blood pressure attributed to circuit training.

Strength Improvements depend on the training status of the participant and the intensity of the exercise (% 1 repetition maximum). Untrained individuals (both male and female) using loads of less than 60% 1RM for 1 circuit 3 times per week for 10 weeks showed increases in strength ranging from 15-42%^6,7. When using circuit training for training athletes it is advisable to increase the training intensity in order to elicit the desired strength adaptations, thus loads in excess of 75% 1 RM is recommended for this population.

Circuit Training Target Population

Circuit Training is the ideal mode of training for the general population, especially those looking to improve body composition and overall general health. Athletes can use this method of training to improve VO_2max, and improvements in Lactate tolerance also occur. Well trained athletes may be better served utilizing traditional strength training methods if improvements in strength are of primary importance. The work:rest ratio can be manipulated to provide a progressive overload for continued improvement. Overall, circuit training provides a great total body workout and the flexibility of exercise selection ensures that no two workouts need be the same, thus providing both mental and physical variety to the workouts.

1. Gambetta, V. (2007) Athletic Development: The Art & Science of Functional Sports Conditioning, Champaign: Human Kinetics.
2. Alcaraz, P.E., Sanches-Lorente, J., and Blazevich, A.J. (2008) 'Physical performance and cardiovascular responses to an acute bout of heavy resistance circuit training versus traditional strength training', J Strength Cond Res, 22, 667-671.
3. Hass, C.J., Garzarella, L., DeHoyos, D., and Pollock, M.L. (2000) 'Single versus multiple sets in long term recreational weightlifters', Med Sci Sports Exerc, 32, 235-242.
4. Maiorana, A., O'Driscoll, G., Dembo, L., Goodman, C., Taylor, R., and Green, D. (2001) 'Exercise training, vascular function, and functional capacity in middle-aged subjects', Med Sci Sports Exerc, 33, 2022-2028.
5. Dunstan, D.W., Puddey, I.B., Beilin, L.J., Burke, V., Morton, A.R., and Stanton, K.G. (1998) 'Effects of a short-term circuit weight training program on glycaemic control in NIDDM', Diabetes Res Clin Pract, 40, 53-61.
6. Haber, M.P., Fry, A.C., Rubin, M.R., Smith, J.C., and Weiss, L.W. (2004) 'Skeletal muscle and hormonal adaptation to circuit weight training in untrained men', Scand J Med Sci Sports, 14, 176-185.
7. Marx, J.O., Ratamess, N.A., Nindl, B.C., Gotschalk, L.A., Volek, J.S., Dohi, K., Bush, J.A., Gomez, A.L., Matezzi, S.A., Fleck, S.J., Hakkinen, K., Newton R.U., and Kraemer, W.J. (2001) 'Low-volume circuit versus high-volume periodized resistance training in women', Med Sci Sports Exerc, 33, 635-643.