Circuit training is a type of full-body fitness training that involves a combination of high-intensity aerobics and strength or resistance training exercises. You do each exercise briefly, often 60 seconds, before moving on to the next exercise without a break. The heart rate is elevated throughout the circuit, and participants can burn as much as 30 per cent more calories than lifting weights or doing cardiovascular exercises alone.
Increased Aerobic Fitness
While 30 minutes of circuit training does not increase your aerobic fitness as much as 30 minutes of running or cycling at a comparable percentage of your maximum heart rate, the benefits are comparable to interval training. Interval training is when you alternate periods of high-intensity work with rest or low-intensity work. Circuit training with only brief rest periods -- about 10 seconds -- provides the greatest improvements. Huge improvements are seen in anaerobic endurance levels in circuit training regimens, meaning increased speed, strength and power. The body becomes better able to handle elevated levels of lactic acid, which builds up in muscles from repetitive motion.
Circuit training provides approximately the same levels of improvement in strength as a traditional weight-training routine when the participants use comparable weight loads. Higher weight loads, often used in strength-training regimens, provide faster improvements in strength and power due to using a higher percentage of muscle capacity. Circuit training builds strength moderately while also helping improve anaerobic endurance, which is why many athletes use it in the off season for maintenance.
Changes in Body Composition
People who want to maintain their weight while toning may find the results they seek through circuit training. Aerobic exercise alone usually leads to a decrease in total weight, with the amount of lean body mass remaining the same. With circuit training's combination of aerobic fitness and building muscle mass, the fat lost from exercise is replaced by lean body mass. Because muscle burns more calories than fat, by replacing fat with muscle, participants have an easier time maintaining their newly toned figures.
Circuit and strength training improve the way participants feel about their bodies even before they see results. According to the Journal of Sport Behavior, participants who added only two days a week of strength training to an otherwise nonexercising lifestyle had improved body image as well as an improved sense of overall well-being. Women who do home circuit-training three times a week feel much more positive about their bodies than women who walk for exercise with the same frequency.