Intensity, Density, and Muscular Failure

Disclaimer:  This is a bit detailed so please follow along.

In my last post I touched upon a few topics you may or may not have heard before and now I will explain what they are and what implications they have one your training and, more importantly, your results.

Intensity is a tricky word. It is deceiving. Mention “intensity” to anyone and they probably think of action movie explosions, the look in a fighter’s eyes before a title shot, or their last grueling Kettlebell Kamp workout. But, intensity, as I stated before and as it relates to training, is merely load over time. I will try to refer to what intensity actually is as load/time and what one thinks of as a “high-intensity workout” as a high-density workout hereafter.

Decreasing one’s time spent training rapidly increases load/time, and increasing the loads in the time you do spend training increases it, but not as quickly. To give you an example, snatching a 16kg kettlebell 100 times in 10 minutes (600 seconds) would produce a load/time of about 2.7. 16kgx100reps/ 600seconds=2.6666. This of course is not a PERFECT model because it does not take into account time spent at the “lock-out” position or “rack” position and instead assumes a constant degree of load, but it works in the case of the example and, more importantly, the theory behind varying degrees of intensity. If one performs the same load (16kg for 100 reps) in 400 seconds (6 minutes and 40 seconds), the load/time of their workout nearly doubles to 4! To produce this same effect by increasing the load, one would have to perform 100 reps in the original 10 minutes with 24 kg! That’s a 50% increase in weight.

So now that you have a clearer understanding of workout intensity, I will explain how it relates to high-density workouts and muscular failure. A high-density workout is a workout that reaches near the point of total muscular failure in the quickest time possible by employing a high degree of load/time. It is complicated, so I will try to break it down. This means performing exercise with the greatest load possible for a given time, or performing an exercise for the greatest amount of time with a given load.

The reason we perform multiple sets during a workout is because it is impossible to near total muscular failure with just one all out effort. If we were designed to give everything we had at once without the endurance and recovery to keep coming back, the human species simply would not have survived this long. Either way, a high-density workout must be performed to NEAR muscular failure.

But what is muscular failure, and what constitutes a “high-density” workout? Many people confuse the meaning of “training to failure” and how one should use it to workout. Failure, or the inability to complete another repetition at a given weight is NEVER a good thing to do when working out. It messes everything up: your designated load/time, workout density, and even your mentality as well. We were not programmed to fail, and your workout should reflect such. Think about it, if all that was needed to get results was failure, then you could just walk into the gym, perform an exercise that was heavy enough for you to perform for 1 repetition but not 2, and then attempt 2 reps. Then that would be it. You would go home thinking you performed the most effective exercise possible. But you wouldn’t have, and I don’t suggest anyone try to employ this method of training as I can guarantee immediately that it will not work.



Muscular failure, the goal of a high-density workout, is actually impossible to achieve. You can’t ever batter yourself so hard that your muscles will become completely useless and inoperable, otherwise you would have to be carried out of the gym on a stretcher as you would be unable to move! What you can do is push yourself so close to this muscular failure that your knees wobble going up stairs, or you have trouble opening doors for the next couple days.

And so in a nutshell: a “high-density workout” is one that nears muscular failure. Bodybuilders will often, mistakenly, utilize strictly high-density workouts by “splitting” the body into various parts. In theory, it sounds like a great idea, but in reality, the body functions as a unit and must be trained as such or it will atrophy. This is why the body should be trained in its entirety, even if certain workouts may place greater emphasis on different muscles. For example, high-density sprints will affect you differently than a high-density long cycle the next day, but both require you to use multiple muscle groups, as well as effectively engage your core muscles. Extreme high-density workouts should only be performed 1-3 times per week when training the entire body or over-training will result.

One must also use their muscles each day in some relatively low-density fashion. By low-density, I mean well above baseline resting, but nowhere near muscular failure. There are two ways to accomplish this. First: you can perform a workout with a high load/time, but with few sets to prevent nearing muscular failure. This would be like doing 4 100 yard sprints in your workout if you typically do 10 of them during a high-density workout. Another way to perform low-density exercise to keep one’s body stimulated is to utilize a much lesser load for a greater time. Using the example of running again, one could jog for a mile or more at a comfortable pace rather than attempt to reach muscular failure as quickly as possible. A week long bout of bed rest in studies has been shown to dramatically decrease protein synthesis, suggesting that it starts happening after a matter of only a couple days of doing nothing. The ramifications of not using one’s muscles are greater than the idea of only using the “most effective workouts.” Disuse leads to atrophy and the last thing anyone wants is for his or her hard earned muscle to start shrinking before their eyes. The only exception to this rule is after the NERVES have been over-taxed, rest must be allowed for them to grow and strengthen while one’s muscle may minutely atrophy. To prevent or minimize atrophy, it is recommended that you perform “active” rest during your “off-week.” This can be as simple as yoga or performing the same exercises with fewer sets or less weight. Any minor loss of muscle will be more than compensated for by the fact that now the force generated by your nerves will be stronger, thus stimulating more muscle, and allowing more muscle to strengthen and grow in the coming weeks of training. You may even find that your nerve force has so greatly improved that you experience a GAIN in strength after a week layoff!

Now that you have a better understanding of intensity, density, and muscular failure it is time for you to employ these concepts in your training and watch your results take off!