How hard you should train is an important variable in training and I think many people lose a lot of time durdling around at the gym without making any progress because they fail to implement enough intensiveness. But does everybody have to go “balls to the wall”, or are there finer nuances to it? And what are the drawbacks of high intensiveness? Well, let’s take a look!
Intensiveness vs. Intensity
First of all we have to define two terms that are often used interchangeably but really have two different meanings.
- Intensity is the amount of weight that is used for an exercise, commonly described as a percentage of a 1 rep max.
- Intensiveness describes how hard you train, often measured as “reps in reserve” (RIR) or on an exertion scale (RPE). It gives an estimate how close you get to muscular failure during a working set.
So if your 1RM in the back squat is 100kg and you do 1 rep with 100kg, you have both maximum intensity (100%) and maximum intensiveness (0 RIR).
If you do one rep with 90kg, you still have a high intensity (90%), but much lower intensiveness, as you would, in theory, be able to do more reps with this weight (~2 RIR).
If you do 6 reps with 80kg and you cannot do one more rep, you have a (relatively) low intensity (80%) but again maximum intensiveness (0 RIR).
Mechanisms of Intensiveness
Our body is an homeostasis machine. It wants to stay the same and keep every process in the body the same whenever possible. If we want to improve our body, we have to disrupt homeostasis and force our body to adapt. Little disruptions are often too small for our body to register and therefore we need to push harder. That’s where intensiveness increases.
The main mechanism of intensiveness is increasing fatigue of muscle fibres and building up greater metabolic stress. This, at least in theory, increases muscle fibre recruitment, making those last reps that you squeeze out before failure, more effective. Sounds good, doesn’t it? But everything has a cost, in this case, it is fatigue.
Fatigue increases exponentially the closer you go to muscle failure. This makes training to failure inadequate for very high training frequencies, as you simply cannot recover in time anymore. On the flip side, it is a good idea to get the most of a training session if you can not train that often (or want to, which is okay).

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Surely you now have the question “how much intensiveness do I need?”. To answer this question, we have to take into account what your goals are. Strength or hypertrophy?
Training for strength
If you are mainly training to increase strength, it is a good idea to stay relatively far away from muscle (and form/technique) failure. Strength is a skill and you want to get many reps with perfect form to practice your strength skill as often as possible. Anywhere from 1-4 RIR or a RPE of 6-9 is generally considered to be effective. This is backed up by research that shows no advantage of going to failure.
Perfect practice makes perfect! Going to failure with strength training can be programmed occasionally for strategical reasons, but your bread and butter should be high quality reps without reaching failure. The loads you have to use for strength training are no joke and small technique mistakes, which are bound to happen at high intensiveness, impose a high risk of injury. Injury is the enemy of progress as you can not train if you are injured, at least not the injured structure.
Training for hypertrophy
The research we currently have shows no real advantage of going to failure even for hypertrophy training. Case closed, we stay away from failure, right? Wrong! Anecdotally we see that people who train harder, make better progress. People who read the newspaper while doing leg extensions never have impressive quads! Why is this so? Probably because many people have no idea how going to failure feels and therefore are incapable of estimating how far away they are from it. This way they never get the positive effects of “stimulating reps“!
When training for hypertrophy, we have the luxury of using relatively low weights, which aren’t that “hard” on the body, making them safer to perform. This makes training to failure much safer, but also necessary as we need failure to make sure we stimulate the muscle enough to grow. Note that high rep sets make it very hard to gauge how close you are to failure. On the leg extension I regularly think at repetition 10-12 that there isn’t much more in the tank, but when I actually keep pushing, I am able to perform 10-15 more reps.
Because we use lighter weights, more reps, isolation exercises and machines, bodybuilding makes it necessary to train with a lot of intensiveness. This doesn’t mean that you have to “go to war” and reach failure on every set of every workout, but experiencing it more often than not, is probably a good idea.
Bodybuilding is not just about light weights and a lot of reps. You should also implement heavier weights on a 5-8 rep range for hypertrophy (or even 3-6 reps), especially on the compound movements like squat, romanian dead lift, bench press etc. For the sake of safety and health, you shouln’t go over technical failure on those on a regular basis. Keeping a true 2RIR is a good compromise as the weights are heavy and your body should recruit more muscle fibres. Be sure to have your form in check regularly (videos and/or a coach are your best friend here) because even minor errors may result in tedious injuries in the long term.
Experiencing failure
Most people fall into the “training for hypertrophy” camp and therefore need to learn how to train to failure. Even if you are training for strength, it makes sense to implement phases that are closer to failure so you learn how it actually feels when you hit failure.
This is a mistake I made in my early training days, I thought that I trained with 2 RIR (which was the common guideline at those days), but much later, when I actually trained to failure, I realised that this probably was more of a 4 RIR. This explains why I struggled a lot with progressing my physique.
Going to failure alone isn’t enough alone. You have to keep up good lifting technique and get in high quality repetitions. This “quality” is hard to explain, but if you ever watch a bodybuilder train, you can see this quality and intent with every repetition. You don’t just go through the motions, you feel, you focus on the contraction, you control the movement. This is a skill, so make sure you take the time needed to improve it.
To sum it up
If you are training for strength, stay 4-1 reps away from failure. Get those high quality reps in and stay safe while doing so.
If you are training for hypertrophy, go “all out” more often than not. There is little reason to hold back, just make sure lifting technique is still good and you get high quality reps in.
Not matter what your goals are, if you are a beginner, you have to learn proper movements first and, as soon as you have that, experience failure to learn how to estimate how close you are to it.
I hope this article was helpful to you and you now have a better understanding of what intensiveness is and how hard you should train. If you liked the article, share it with your lifting friends and help me spread the beary knowledge. And don’t forget to eat well and train hard ❤ !
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