Even today after years of research and application, some still maintain the belief that weight training lacks any aerobic benefit. The fact is, lifting weights increases blood pressure and heart rate, representing some aerobic stimulus. However, with the existing definition that aerobic exercise involves continuous nonstop activity performed for an extended period of time (minimum of 20 minutes), while maintaining a heart rate between 70-85% of maximum, with the chief energy sources being oxygen and body fat, conventional weight training cannot claim to offer similar aerobic benefits.
For those who are interested in obtaining the benefits from both worlds – aerobic stamina with low percentages of body fat and anaerobic strength with impressive muscular shape, the manner in which weight training workouts are conducted is what links the two together. Certain sports, such as tennis, already combine elements of both.
Since muscles can only contract for long periods of time when sufficient amounts of oxygen are available, mental focus during circuit training becomes directed toward the proficiency of the heart and lungs, as opposed to just the muscles during conventional weight training. The cardiovascular and respiratory systems feed our working muscles with oxygen-filled blood that is eventually fueled by body fat. ('Eventually', because the ATP, CP and LA anaerobic fuel cycle has to become significantly depleted before the body will burn fat as workout energy).
By performing circuit training / aerobic resistance activity, you'll never give your heart or lungs a chance to relax. You will reap the benefits of increasing heart and lung condition (enhancing your ability to utilize oxygen and burn fat) and gain impressive muscular shape and strength.
Conventional methods for lifting weights recommend that each exercise set be followed by an adequate rest period before proceeding to the next routine. Following this ritual, heart rate and blood pressure peaks during each exercise but dramatically tails off during rest intervals. This method enforces plenty of intentional inactive time in order to replenish ATP and other anaerobic fuel, and to psyche-up for those heavy weights. However, it prevents the aerobic system from effective participation.
Circuit training has been around for decades and offers an unlimited matrix of applications and benefits. This system of working-out is performed differently both mentally and physically. In this method, the subject performs one set of one exercise then immediately performs other exercises in succession without rest, one after the other. Exercises are sequenced in a variety of combinations which isolate single-muscles, regional groups of muscles, or total body training all in one workout.
If you're in a crowded facility, or at home and have to change equipment for every exercise (both time consuming factors), aerobic benefits will be sacrificed when the body becomes less or inactive. Your mission is to stay moving. Try doing sit-ups or pushups or jump rope if you're forced to stop.
After each circuit (which is traditionally 8-12 exercises), a 1-5 minute rest is optional to replenish your mental and physical energies. If your goal is to lose body fat, expend this time on the stair machine or stationary bike. This will recuperate your muscles from the weights while your cardio/respiratory system remains active using fat as fuel.
After completing a circuit training workout, you'll feel refreshed and less sore. Circuit training promotes the removal of toxins which build up in the body during rigorous activity. During the deceleration periods in conventional methods, toxins become trapped within the tissues as the less active heart slows down the rate of blood flow. Circuit training's continuous cardiovascular requirements flushes toxins out from the tissues with the forcing of blood through the tubal pathways of the cardiovascular system. Your muscles become cleaner and recuperate immediately after each workout.
Since circuit training is continuous, resistances automatically become substantially lighter. The reduction in total weight lifted is compensated by eliminating any inter-set rest intervals (keeping the muscles fatigued). The higher number of repetitions suggested for each set during circuit training forces your muscles to rely on lighter poundages.
By performing more repetitions in each set (10-20), the duration required to complete each set is substantially lengthened. As the subject remains active, the muscles can work just as hard as during conventional methods but now the added responsibilities from the heart and lungs add to the benefits.
Conventional methods suggest that the applicant handle heavier resistances with 6-10 rep sets. Inter-set rest periods of up to 6 minutes replenish the ability to lift more weight but, at the same time, can subject the lifter to possible injuries. Injuries can occur from extended rest periods which cool the tissues. Over-emphasization of heavy resistances can place too much stress to the muscles, tendons and ligaments instead of prioritizing muscular activity to an extended duration activity.