When I started to work out, I just did. I had no idea about anything and it felt that there were too many sources to exactly know what to learn. With this series, I want to share my known experience in terms of gym / fitness and nutrition. I'm into this pretty heavily since 2011.
A common understanding for different training definitions is important. This way you exactly know what the person is talking about. Also, having knowledge can help you build something from a basis. That time I'm explaining different intensity techniques in terms of fitness and gym.
In general, intensity techniques are an addition to your workout, that will intensify it. As the name already says, they can get really intense. Some cut down the time between sets and reps, other increase the weight in a specific schema. I will also describe what I do for myself, which fits best for me and my time.
Super sets
One of the most known intensity technique are super sets. The basic idea is that you make one additional set (without a break, only some gaps), directly after your usual set.This saves time and exhaust you faster (which is probably the reason behind working out). Important to notice is that if this second set is for the same muscle group, you must cut your weight. For example, you do 8 reps of triceps cable push down, finish the set, cut down the weight by 50% and directly do another set with the same reps. You usually do one to five super sets in the end of your workout, otherwise you may get exhausted too fast.
There exist special derivations of that, including switching of exercises or doing more than two sets as one super set. In my experience, having two sets in a row is mostly exhausting enough (especially if it is for the same muscle group).
Drop sets
Another really common and famous intensity technique are drop sets. The idea is to gradually drop weights between your sets, without having a break in-between. You usually do this until you cannot do any more reps (or shortly before that). The important thing to notice here is that you should do this at a machine, or use a training partner that can quickly support you or help drop your weights.
Start with a weight that you are able to do 8 to 12 reps with. Let's say you do 10 reps, finish the set and directly drop the weight by 10 percent. Without having a break, you do another set with as many reps as you can. This principle will continue, until you are exhausted. I personally never liked drop sets and never really did, since the work you do is hard to track for progress, as well as the exhaustion is not correlated to muscle growth.
Pyramid system
The idea behind the pyramid system is that you increase your weights until a certain point (your personal limit) and then usually go down again. I never liked that, because there was too much thinking / planning involved and I do not see the advantages. Also, the pyramid system and drop sets are more to destroy your muscle, but we rather want to stimulate them (which is not the same).
Timer under Tension
The longer your breaks between time are, the better should be your power. So time management is critical, also in sports. Timer under Tension is a training method that defines, how long you should perform a set. This relies on the theory that muscle have a tension time, in which they have an optimal growth. I've heard that this set-time is around 40 to 60 seconds.
For systemising this technique you can split your reps into different movements (which you do anyway) and time them. The first movement is towards your body (excentric phase), then you stop, followed by a move from your body, ending with a stop. Now you could say that you do a 2-1-2-1 scheme, which means that you do stops for 1 second and movements for 2 seconds each. If you would do 10 reps per set, you would get a time under tension value of 10 * (2+1+2+1) = 60.
In my experience, this can help you get out of a stagnation or when you want to do something differently. I always do a controlled workout (intentionally), meaning that I'm conscious about these times, but do not track them. At some exercises, I do stops for 1 or 2 seconds. This can definitely help you preventing a 'bounce' of the weight, which may screw up your progress tracking.
Blood Flow Restriction
There exist some techniques that help you do your training with less weight, but still bring enough intensity for a good muscle stimulation. Blood Flow Restriction (BFR) training is one of those techniques. The idea behind it is that you restrict the blood flow in the veins for a specific body part, and do a huge amount of reps per set.
It is said, that this technique is very good if you are injured. Especially if you have problem with your legs (knee pain), this might be very helpful. However, if you feel uncomfortable trying this, I recommend talking to a trainer. However, I have never tried it, probably because I was never (seriously) injured. But there exist good studies on BFR that show the effectiveness of this technique.
MYO reps
MYO reps rely on the fact that the most important reps in a set are the last few, since they are the most effective ones towards muscle growth. Fatigue is a really important thing to notice here. When you do a 12 reps set, the first 8 should be the ones who accumulate fatigue and the last 4 will then be the important ones.
Start a MYO rep set with a set that gets you nearly to muscle failure. Then you continuously do a little break for no longer than 20 seconds and start right away with a mini set of usually 3 to 5 reps. You continue this for 3 to 5 rounds, or until you are exhausted.
What I do
In the past years, I have experienced a lot with intensity techniques. Most of the times, I have added them randomly at the end of my workout, as recommended. If you are capable of doing them every time you work out, you probably do something wrong (not enough overall) or you don't train naturally and thus have a higher recovery.
I train every muscle at least twice a week, by splitting my whole body into two workouts. The idea is to train each muscle in a higher frequency, so that the protein biosynthesis stays high enough. I will describe my plan in another article. Most important is that I try to do as much as possible my workout. Muscle groups who don't heavy relate to another can be trained in a super set. For instance, you can make a set for chest and without a big break (maybe 10 seconds), go on and do a back set. This can even be extended with a third set for another muscle, but the idea will be the same.