The idea behind the exercise is to present the muscle with a new, and greater challenge each time you perform each exercise. When the muscle gets fully exhausted, and is presented with a challenge that it cannot meet, there is a strong message sent to the muscle that it needs to get stronger. This change to become stronger is referred to as an adaptation. This adaptation is what allows exercise to be productive, and bring about real change.
But to comprehend what full muscle exhaustion is, you have to examine how the muscles work. With each exercise that you perform, there is the concentric and eccentric. Don’t be too intimidated by the terms. From now on we’re going to refer to them as “positive” and “negative.” The positive (concentric) part of the movement is when you are moving the weight with your own force. The negative (eccentric) portion of the exercise is when you are letting the weight back down. If you haven’t noticed, letting the weight back down is a lot easier.
Let’s say you are doing a pushup with somebody sitting on your back. It’s easy to lower down to the floor with control. You have the strength to do that. But try to go back up again? Much harder. Likewise, there are parts of the movement that are easier than others. You are much stronger in the last 6 inches of locking out a pushup than you are when your chest is only an inch or two above the ground.
So if you do pushups until you can’t go from the floor to a locked out position, have you really worked your muscle to its limits? No. You have gone to what is referred to as “positive failure.” But there is still a lot of muscle strength left, especially for doing the negative part of the movement. A good way to think of it is to think of the positive and negative like they are too separate arms. If you tire out one arm, are you out of arm strength? No! You’ve got a whole other arm that’s rested and fully capable of doing more work. There’s a masturbation joke in there somewhere, but I’ll leave that alone.
You also have static strength – where you may not be able to move the weight any further, but you still have enough muscle strength left to hold it steady in one place.
So if you are really wanting to challenge your muscles, really make sure that you are triggering the elusive “adaptive response,” it’s good to take an exercise to positive failure, hold it in that spot as long as you can, and then lower the weight as slowly as possible to tax the negative strength as well. When you perform repetitions this way you are wearing out the positive, negative, and static strength of the muscle – not just the positive, which is more like the first stage of muscle fatigue.
Even more interesting is the prospect of doing just the negative portion of an exercise, because that’s where your greatest strength lies. So you really make an effort to exhaust the muscle as completely as possible. And, perhaps more importantly, when you do just the negative portion of the exercise, you can use a buttload more weight. Sometimes double the weight or more. Most report that this is phenomenally more effective for strength increase than using far lighter weights and completing the positive portion of each repetition. While this type of training isn’t very practical if you don’t have a partner with you (to help you get the weight through the positive portion when you are too weak to do it yourself), it does have some distinct advantages, and you’ll probably see/hear/read more about it in the future – especially as more and more exercise equipment is designed to have this functionality.
Anyway, that’s the negative part of the exercise, and why it’s important. Play around with it some and see for yourself. A good place to start is doing the negative portion of a chinup/pullup if you are not strong enough to do one. Do the negative part, then climb up on a chair and repeat. There’s probably no faster route to completing your first, full, unassisted pullup. Here’s ol’ Doc Smith bringing it…
And here’s some weighted negative pullups as part of a Body By Science workout…
In the next exercise-related post, maybe we’ll talk about static strength, and how static exercise can be useful for the very same reasons. It has some advantages over negative-only sets because it is more practical for doing without a workout partner. Although I must say, I’ve always lifted weights alone for the most part, and having a workout partner lately has been totally fun. We go in and do our workouts one at a time, alternating who does their workout first. The role of the wingman/sidekick is to help complete the last positive rep so that a full negative (or two) can be performed for full muscle exhaustion.
Here are some videos of the future of exercise equipment, where the muscle can be fully loaded to its maximum through each portion of the full range of movement. The weight is lighter through the weaker parts of the movement, and then the machine puts more force on the muscle in the strongest part of the range of movement, particularly at the very beginnings of the negative portion of an exercise. Total work is monitored on the CZT machine, so you can see and monitor those very fine improvements you make from week to week as you get stronger and stronger (and the gains come more slowly). Not that you have to now panic and go find one of these machines to have hopes of getting in a good workout. This is just to demonstrate this principle. You can still have amazing workouts on your own without any specialized equipment. But hopefully this makes you more consciously aware of the huge variation in strength in various stages and ranges of a repetition of any given exercise – allowing you to exhaust your muscle just a little more than you would have otherwise.
Don’t be too afraid of Chuck’s brother. He’s scary. But this video is just too intense and awesome not to include – especially considering that I’ve met this dude (hopefully Keith will come and comment on this, as he has a great deal of expertise with this type of training)