Circuit training is doing a set of an exercise then moving to the next exercise then the third, fourth or as many exercises as you want. The main benefit of training in this way is allowing your body to recover between each set. Ideally each exercise should work a different muscle group or the same muscle group being worked should be spread out.
The best routine for circuit training involves either a full body workout or upper/lower split workout routine. It’s good to give your muscles a few to several minutes to recover between sets of that particular exercise. The big benefit here is called total work capacity and specifically the number of quality reps you can perform is greater when you follow a circuit routine. The other big benefit is your total work out time should be less as you need a shorter rest period between your sets because you are working different muscles.
If you are only working one muscle group you will not really benefit from a circuit because going from one exercise that works the triceps to another exercise that also works the triceps will not really give your muscle any added recovery time and as a result your total work capacity and quality reps will not increase.
If you are working two antagonist muscles this is a great approach. I like to do a mini circuit for a chest then back exercise or vise-versa. Some other great combinations for this are quadriceps and hamstrings, biceps and triceps.
Recent research has shown that our muscles grow better as they are stretched. This concept known as stretch mediated hypertrophy has been shown in some studies to produce up to three times greater muscle growth. Beyond increasing your range of motion in the lifting exercises you perform. You can also do a combination circuit of two antagonistic muscles to increase the muscle stretch. For example you stretch the triceps as you do a bicep exercise which allows you to take advantage of stretch mediated hypertrophy when you follow up your bicep exercise with a tricep exercise resulting in greater muscle growth.
Keep in mind gym etiquette. You should be respectful of other gym members so if the gym is busy consider not doing a circuit or alternating between only two exercises. Nobody likes to wait for exercise equipment that you haven’t used in even as short as a few minutes. If you really want to follow a circuit then simply let others use the exercise equipment when you are not then go back to do another set when it is free again. Essentially you are not hogging the equipment but you may have to wait for it. When alternating between two exercises choose two that are close by or even a cable machine that you would use different attachments for each exercise. You should leave a towel or bottle by the machine or equipment you are not using if you are alternating between two exercises so for example you are on exercise machine A leave your bottle/towel by exercise machine B. Then switch to machine B and leave your bottle/towel by machine A and keep alternating until you finish up all of your sets for those two machines. Just be sure to not leave either of the machines unattended for more than a few minutes as people don’t like to wait for a machine you are not using.
Thx