Muscle Flushing Training Principle
The flushing principal was the building block for all advanced techniques like superset and tri-sets. It started with the realization that when the muscle is flooded with blood the muscle hypertrophy increases because of the flushing effect delivering urgently required nutrients while taking away toxins like lactic acid.
If we think of getting the "pump" in our arms from super-setting a pulling movement (biceps) with a pushing movement (triceps), we would be flushing the muscle with all it needs to increase in size. Talking about flushing the arms is easy because we can see and feel the results.
Bodybuilders who try the flushing training principal for the first time get hooked easily because they can see and feel the difference. The flushing principal can be applied to any bodypart. Let's say that you are going to train legs and the high volume workout that you are going to do is designed to engorge and flush all the muscles in your legs completely.
We obviously cannot flush our whole body because it would take hours. Science has shown us that anything more than an hour of high intensity training will eventually turn catabolic and you will lose muscle. There is a good reason that sports science tells us to train HIIT for only 45 minutes.
We are therefore required to do split training routines when using the flushing principal. This will probably mean concentrating on one body-part for each workout with an isolation movement at the end of the workout. If we go back to our leg day, we see that all the movements are designed to draw blood to the lower body.
Whether you are doing leg extensions pumping the blood into your legs and lunges working your whole lower body, you will feel the pump on your legs. Science has now clearly demonstrated that this engorging of the muscles with blood increases muscle repair (protein synthesis).
The flushing principal needs to be treated carefully because over-flushing a muscle group will not get the results you are looking for. You need to learn how to listen to your body, no one else can know how many sets and reps you need to do, it is something only you will know from trial and error.