The terms “circuit training” and “interval training” are often used interchangeably, but they are not the same workouts. The two workout types use different exercises, require different energy systems, and promote different results. Both are efficient, time-effective workouts, however, that you can easily add to your weekly routine to boost your fitness benefits.
Circuit training is a resistance-training workout. You choose nine to 12 exercises and rotate through stations for a pre-determined length of time.
For example, perform a chest press, lat pulldown, shoulder press, bicep curl, triceps extension, squat, lunge, calf raise, and abdominal crunch for 30 to 45 seconds each. Then, you repeat the circuit for the duration of your workout.
In contrast, interval training is an aerobic-based workout. You choose your aerobic exercise and add intervals of increased speed or resistance. For example, during a brisk walk, add a one- to two-minute sprint, then return to your brisk walking for an equal amount of time.
The more popular style of training these days is Tabata Izumi Tabata and his colleagues at the Japanese Institute of Fitness and Sport designed an experiment to measure how two different types of interval training sessions taxed the aerobic and anaerobic energy systems (‘Metabolic Profile of High-Intensity Intermittent Exercises’, Tabata, I, Irishawa, K, Kuzaki, M, Nishimura, K, Ogita, F, & Miyachi, M, Medicine & Science in Sports & Exercise, 29(3), 390-395, 1997).
The conclusion was that high-intensity bouts and very short rests are very intense workout that maximally stresses both aerobic and anaerobic systems. While longer rest periods, do not stress both the anaerobic and aerobic energy systems as much, so more work can be done until fatigue.
The results of this research by Tabata et al clearly show that two different intervals of workouts have different demands and therefore training effects. I1, with 20-second bouts with 10 secs rest at 170% VO2 max places the aerobic and anaerobic systems at peak stress. Therefore it would be a fine session for improving both aerobic and anaerobic capacity. Events, where both aerobic and anaerobic demands are high, are, for example, 400m, 800m, and 1500m running, sprint cycling, canoeing, rowing, and speed skating. This kind of workout would be great for these sports. Games players may also want to use the I1 workout as an intense training method for improving aerobic and anaerobic fitness.
The I2 workout doesn’t put either system at peak stress. However, it does allow more high-intensity work to be done in total. With the long recovery, I2 has a greater contribution from the PCr energy stores. (Phosphocreatine ) So this kind of session will be better for developing the PCr system, improving maximal power. In addition, by allowing greater rest periods, the session can help improve recovery mechanisms.
Based on his findings, it is recommended that for anaerobic training, both types of interval sessions are used, one with very short rests, and another with long recoveries. However, the athlete’s sport will determine which type of session is most important. Incidentally, if you want to use interval training, remember that to get the kind of benefits described you must perform the workouts to exhaustion. Interval training is about setting a demanding intensity level and working at that level for the prescribed work/rest ratios until you cannot continue. If you do that, you have reached overload and the training will be effective. Without overload, there is no adaptation.
Happy Workouts !!!