Circuit training employs a series of exercise stations that consist of various combinations of weight training, flexibility, calisthenics, and brief aerobic exercises. Circuits may be designed to accomplish many different training goals. With circuit training one move rapidly from one station to the next and performs whatever exercise is to be done at that station within a specified time period. A typical circuit would consist of 8 to 12 stations, and the entire circuit would be repeated three times.
Circuit training is most definitely an effective technique for improving strength and flexibility. Certainly, if the pace or the time interval between stations is rapid and if workload is maintained at a high level of intensity with heart rate at or above target training levels, the cardiorespiratory system may benefit from this circuit. However, there is little research evidence that shows that circuit training is effective in improving cardiorespiratory endurance. It should be and is most often used as a technique for developing and improving muscular strength and endurance.
Some free exercises have an isometric or holding phase instead of using a full range of motion. Examples of these are back extensions and sit - ups. When the exercise produces maximum muscle tension, it is held between 6 and 10 seconds and then repeated one to three times.
