-the aim is to stretch the fascia (outer layer of the muscle) to enable more muscle growth
-the regular sets are followed by a 7-set series with the aim to pump blood and nutrients in the muscle
FST-7 is a brainchild of Hany Rambod, celebrity coach of some of the best bodybuilders of all times (Phil Heath being one of them).
The method is based on assumption that muscle growth can be limited by the outer layer of the muscle (called fascia) and it may be necessary to stretch this layer to enable further volume increase.
Let’s say, you can’t park a big car in a small garage. And are we supposed to make the garage larger? By inflating it. Yes, the idea behind FST-7 is that by doing additional 7 sets of 8-12 reps with only short break between the sets (30-45 seconds) you inflate the fascia and make more room for muscle fibers.
Those 7 sets are not really added to grow volume. Volume will be increased by smaller number of repetitions (ideally 4 to 6) with longer breaks between the sets (like 2-3 minutes) and with less than 7 sets (possibly 1-3).
Those 7 additional fast sets are really just a pump. You pump and pump and pump the blood and nutrients in your muscle to stretch the fascia as much as possible.
FST-7 is a very demanding and also a very effective form of training. It’s not for everybody. OK, Hany Rambod says it is and offers numerous variations for absolute beginners, women etc. But let’s say the basic version is really more suited for advanced bodybuilders.
One very interesting aspect on FST-7 is that it can actually explain the success of German Volume Training (GVT) based on 10 sets with 10 reps. After several scientific studies have shown that the optimal number of reps per set is in the range between 4 and 6, with only a few sets, most bodybuilders have left the GVT and similar methods. FST-7 could help rehabilitating it somewhat.
Another interesting aspect of FST-7 is that is that people with thick fascia will be less inclined to grow really huge, round muscles. Some even speculate that people of African ancestry have thinner fascia which enables them to increase the muscle mass more effectively.
So what weight should one use for the 7 “pumping” sets? Not the heaviest you can work with because you are not going to totally exhaust your muscle by every set but also not very light so that you will feel pretty close to failure. In another words, you may be able to do another 2-3 reps but not more than that.