Strength athletes, such as powerlifters, american football linemen and shot putters care about maximizing their muscular development because there is a well proven and direct correlation between muscle cross sectional area aka size, and strength output, while muscle size isn’t the only factor to influence strength, it is one of the most important.

Bodybuilders who are judged on their muscular development and symmetry also have reason to care about getting maximum muscular development.

Over time, personal trainers and coaches have developed a variety of specialized training techniques, things you can mix into your training which, according to gym lore, will help with that goal of maximizing your muscle gains.

If you’ve spent much time in the gym, odds are good you’ve heard of some of them.

These tricks like performing heavy negatives, drop sets, supersets, and forced reps have all been touted as ways to get even more muscle growth out of your workouts. But are they really better than just training the usual way in normal sets and reps? Well luckily there is research on the topic

Quick physio lesson, when you lift a weight, use a machine, or do a bodyweight exercise, the rep can be broken into 3 parts.

First is the concentric portion, this is the part of the rep where your muscle is contracting and becoming shorter, during this portion you are usually moving either a weight or your own body against gravity.

In a bicep curl, the concentric portion is lifting the weight up in a pushup… well it is the up part.

It is called concentric because your fibers are in the process of contracting.

What happens though if you pause anywhere through the range of motion and just hold the weight, well your muscle is no longer continuing to get shorter , so it isn’t concentric.

This is the second part of the rep, and is called an isometric contraction. If you pause at the top of a bicep curl, or the bottom or top of a push up, you are contracting your muscle isometrically.

Some exercises are just one long isometric contraction, a plank is a great example of this. Where as some people seem to skip this portion all together and switch direction almost instantly.

But most importantly for this video is the eccentric portion, also sometimes called the negative, this is the part of the exercise where the target muscle lengthens, some see this is the “easy” part.

Imagine lowering the weight back down from a bicep curl. Your muscle is lengthening, but although you are working with gravity, your muscle is still doing something. It is slowing the speed of the weight as it drops.

When people talk about doing a negative, they are referring to taking a heavy weight sometimes even heavier than they can lift up in the first place, and slowly lowering it down, doing just the eccentric part of the rep.

You’ll notice a lot of people in the gym when they are doing regular reps , look at this portion of the rep as the unimportant part, but this is exactly the part that we should be interested in if we are going to determine whether doing heavy negatives gives you an advantage.

First is a study from 1991. They set out to figure out just how important that eccentric negative of a rep really is.
(https://www.ncbi.nlm.nih.gov/pubmed/1...)

The researchers took a group of Middle-aged males, and divided them into three groups. Each group got a different training program.

All three training programs had each group perform leg press, and leg extension exercises two days each week, they also all chose a weight which they could only do between 6 and 12 times before failure.

One group trained with normal reps that included a concentric and eccentric portion, they pushed the weight up, and then lowered it back down under their own power.

To figure out how important that lowering eccentric portion was the researchers developed a special hydraulic device which could take the weight and lower it back down for the participants after they reached the top of each rep.

This way a second group could test out what happens if they only performed the concentric push, without the eccentric negative.

The thing is though, if the second group is only doing the up part, anyone can see that their muscles would be doing at least a bit less work, so the researchers did something even more extreme. they took a third group, and instead of just taking away the negative, they made them do a second concentric to make up for it.

The group that did only concentric but twice as many reps increased their type 2 fiber size by an impressive 27%, which would be more impressive if it wasn’t for the fact that the group which did half the reps, but included the eccentric portion, increased in type 2 area by 32%.

What’s crazy is the group that did the same number of reps with only the concentric portion, their type 2 fiber area didn’t even measurably improve after the 4 weeks of detraining.