Long Muscle Length Training Is Overrated

Imagine you're completely new to viewing fitness content. What might you conclude about muscle-growth based on the what content creators are talking about?

Well...if you’ve viewed any social media lifting content in the last year, you’ve probably been repeatedly assaulted by phrases like “make sure you get a DEEEEEP stretch” and many similar derivatives.

And this isn’t necessarily a problem on its own - rather, it's the gross extrapolation and hyperbolic nature with which content creators are talking about this subject that is.

So back to the original question: if you were an unknowing, brand new consumer of fitness content, you'd probably think that anything other than stretch-focussed training was a complete waste of time; and you'd probably be quick to conclude things like "leg extensions are the worst quad exercise", as many science-based content creators myopically preach (yes, this is actually a quote).

This is a phenomenon I’d like to define as the long-length panacea. It's basically the content creator's cheat-sheet to faking answers to every lifting question.

• Not growing your chest? You're not getting enough stretch.
• Not growing your calves? More stretch.
• Feeling joint pains all the time? You're probably not getting deep enough stretches in your lifts.

The long-length panacea is a scenario in which all techniques one uses and all decisions one makes ultimately lead back to loading and getting a deeper stretch on the target muscle. All roads lead back to making sure that - forever and always in every context - you get a “DEEEEEEP stretch”.

All of this has come from a recent body of research which suggests that training muscles in more lengthened positions (with a stretch loading emphasis) promotes more growth.

And some of you may (rightfully) raise some eyebrows at this whole thing.

What about the squeezed (shortened) position? What about that "peak" contraction?

Since the 70s, Arnold has been talking about how the pump and the squeeze was better than (or at least as good as) sex. And people back then seemed to have built muscle just fine…

But since new research has indicated that longer-length training may (on average) yield a more robust muscle-growth response, stretch-biased training is all the rage.

So, what’s the truth? Why do longer-length exercises seem to yield more growth? And where’s the nuance?

More Length = More Strength

Since the research on longer-length training became popular, many have speculated different reasons for why stretched positions yield better results.

Some chalk it up to the increased contribution of the passive elements of contraction.

Others focus on the theory of “stretch-mediated hypertrophy” (which is a theory you can safely ignore if you've never heard of it - the concept lacks the necessary human-based evidence to substantiate the associated claims).

So, for now, I’ve chosen to assume the simplest explanation is the most likely (shoutout to Occam's Razor), which is that we’re simply stronger in more stretched positions.

Think about a muscle like a rubber band: the more you stretch it, the greater its potential to recoil away from the stretched position. 

For example: I perform single-leg leg-extensions at my gym. When I use the “full range of motion”, I can complete ~8-10 repetitions using 200lbs. However, when I just use the bottom half of the aforementioned range, I can complete ~12-15 repetitions using 240lbs (there are confounders here such as machine mechanics, but still the output difference is surprising).

In other words, you’re simply able to do more in lengthened positions. More is more (until it's not, like if someone gets injured).

So, The Squeeze is Useless?

Naturally, you might ask the question…so, if stretched position motions allow me to do and get more, then why wouldn’t I just do ONLY stretched position work all the time?

Connective Tissue Adaptation

More is more, up to a point - if you can do more while still recovering from that extra work (assuming your nutrition, sleep, and overall stress levels are in-check), you’re likely to “get more”.

But here's the problem: more is still more - everywhere, not just in muscles.

Because we live in a very muscle-centric culture, we tend to forget about the fact that muscles only exist to create force around joints. And joints can only function properly when they are supported by…connective tissue (ligament, tendon, bone, cartilage, etc.)!

Connective tissue structures do not adapt at the same rate that muscles do. Connective tissue gets stronger, much like muscle does, but it adapts much more slowly (meaning that connective tissue has a longer recovery window).

What does this have to do with making gains with stretch-focussed exercises?

If you only choose to load the stretched positions of every muscle, you’re also choosing to load connective tissue structures in the same way: repeatedly, and in relatively higher magnitudes.

Let’s make this more concrete: imagine we’re comparing the leg extensions and sissy squats to train the quads.

The leg extension trains a shorter relative muscle length of the quads, while the sissy squat trains a longer relative muscle length.

But this isn’t the only difference, from a joint-perspective, between a leg extension and sissy squat.

Without getting too deep into the weeds of knee mechanics, the sissy squat creates much higher forces on patella-femoral compression compared to the leg extension (this is the force that your quads create between your knee cap and femur when they contract) .

So although the sissy squat on a per-set basis may be more of a robust stimulus to the quads, it also comes with the cost of significantly higher levels of joint compression and tendon stress. 

Of course, there are other differences between leg extensions and sissy squats - that are probably obvious to many of you - which I'll touch on in a later part of this article.

Anyway...if you extrapolated the current body of literature to make the conclusion that you should only perform sissy squats (and other lengthened-quad work), you’d be ignoring the potential downside of repeatedly stressing the same connective tissues, over and over in the same way, in the highest of possible magnitudes.

Including a more balanced approach of using both the leg extension and the sissy squat will still allow you to reap the benefits of the stretch-focussed work while also creating enough differentiation in joint force in the knee so you aren’t constantly stressing the exact same patterns and positions.

In other words, using a variety of exercises with different loading parameters and muscle lengths provides a similar muscular stimulus while altering joint stress, making your program more sustainable over the medium to long term.

I like to use a silly analogy to understand this: imagine if someone instructed you to bang your hand with a hammer repeatedly for 60 seconds.

Would you rather bang one spot on your hand for the entire 60 seconds, or would it make more sense to subtly alter the spot on your hand that you were banging?

Hopefully the parallel is clear: altering the spot that you hit your hand would distribute stress enough so that no single part of your hand got damaged excessively - but you’re still able to achieve the goal of hitting your hand for the entire 60 seconds while not breaking anything.

Distributing stress in slightly different ways will make your training more sustainable. You may be able to get away with repeatedly stressing the same pattern for short time periods, but eventually, your rate limiter may come from single joint structures rather than from your muscle’s ability to recover from workout to workout.

In addition, you may be able to accumulate MORE total volume - and therefore the potential for more progress - with less total downside, because you’re not digging out of the exact same hole every time you train a particular muscle or muscle group.

Anecdotally, I've heard from many of you in my audience who say something a version of the following: "I swapped most exercises I was doing for their stretch-biased alternatives and everything was going well until I started getting pain in all my joints a couple of weeks later".

Of course there are confounding variables here, like whether exposure was graded appropriately, whether recover was as good, and whether life stress was the same, but I've heard this kind of story too many times to ignore the emerging pattern here.

Muscle Length Adaptation

Differentiation joint stresses is perhaps the most important reason you’d want to train a variety of muscle lengths across a week, as opposed to only the stretched position.

But another compelling argument in favor of short-position training relates to the benefit of getting stronger at multiple muscle lengths and in multiple joint positions.

Every muscle has an end-range lengthened position and an end-range shortened position. At either end of these extremes, different qualities of contraction and different portions of a muscle are emphasized more or less.

For example, research suggests that the quality of hypertrophy we receive from a stretched versus a shortened exercise may be slightly different.

Put another way: there is nothing more appropriate for getting strong in a position than training that position itself. This involves both the neurological coordination of all muscles and connective tissues involved in controlling specific joint positions as well as the differences between active and passive contraction (which someone else is likely better equipped to explain than I am).

In other words, if you want to make your knee joint more stable in the fully locked position, the most specific way to do that would be to use a leg extension (an inherently shortened-biased movement).

While doing squats undoubtedly have the potential to make the fully-locked knee position stronger, squats do not load the quads when the knees are straight at the top (at least, very little compared to the leg extension).

And on the flip side, there is no leg extension on earth that will load the fully knee-bent position, which is undoubtedly useful for getting stronger in the fully knee-bent position.

Skill-Specific Adaptation

It is easy to forget that every exercise we perform is a skill that may or may not have carry-over to other skills we may want to improve.

For example, a golfer may find it beneficial to train trunk rotation motions to improve their golf swing strength (not the silly mimicking of a golf swing with more load, but rather the stabilized training of the obliques in rotation in a cable or machine setup).

Training both long and short positions of dominant muscles within each sport in these cases could potentially help athletes for all of the above reasons.

Pain Management

This conversation is intimately related to the one we’ve already had, but I wanted to double-down on it because I think it’s important.

Many patients with knee pain or in early stages of rehab, for example, have a very difficult time loading the fully knee-bent position.

This is - at least in part - due to what I mentioned earlier about patella-femoral stress and how we’re stronger in more lengthened positions as compared to more shortened positions.

There may be times where you or a client are dealing with joint/muscle pain or injury, wherein you can only tolerate a certain threshold of loading.

Because shorter position training is generally less stressful and therefore easier to recover from, it is often a more appropriate place to begin the rehab process or to decrease overall levels of stress so that someone can recover while engaging substantially in other activities (training predominantly short positions during an athletes season, for example).

Specific Muscular Bias

Training certain muscles in more shortened positions can also allow us to be more specific to biasing a given muscle, just as lengthened position training can do the opposite.

For example, if I perform a flat dumbbell press, all of the different portions of my chest are capable of pulling my arm forward from the bottom position (which of them is doing the most work is dependent on how one sets up and executes the motion). A flat dumbbell press therefore can challenge all of the different pecs quite substantially, especially if sets are taken to failure.

However, if I perform a cable chest flye, the story can be quite different. 

Why?

Imagine the end points that each of your pecs pull your arm to. It is easiest to think about how differently the upper (clavicular) and the lower (costal) pecs pull the arms at their end-range shortened positions; the upper pecs basically pull the arm toward the chin, while the lower pecs pull the arm down toward the nipples.

Because these muscles become more differentiated in their functions the more shortened they become, performing short-position exercises for certain muscles allows you to isolate that specific portion more than others. This is especially relevant in an instance wherein someone wants to prioritize a specific part of their chest (typically the upper chest), for instance.

This is part of the reason that short position training for certain muscles is less fatiguing - you simply have fewer things contributing to the motion, and therefore less total stress on the involved joints in such cases.

There are also instances wherein training shorter or longer muscle lengths changes the secondary contribution of muscles involved, which is another confounder to consider (for example, think about the secondary muscle involvement in a stiff-legged deadlift compared to a lying leg curl).

Last, But Certainly Not Least

Recall the first example I gave in relation to sissy squats versus leg extensions.

Other than muscle length and joint-force differences, there are many other variables in exercise selection worth considering.

For instance:

• How stable is the exercise? 
• How easy is the exercise to coordinate and learn?
• How seemless is progression on the exercise?

Put another way: how practical is the exercise?

Do you imagine that coordinating a sissy squat is as easy as coordinating leg extension?

Do you imagine that loading and progressing a sissy squat is as simple as loading and progressing a leg extension?

Do you imagine that sissy squats would be as immediately comfortable or adjustable as leg extensions?

These things really do matter. They are anything but trivial; and yet these questions are often completely ignored when your favorite influencer makes their latest and greatest exericse tier list video on what exercises are "best" for every muscle group.

The practicality of exercise selection is perhaps the most important variable. It should go without saying that an exercise's shelf life is one of the most relevant considerations of all, much more so than what specific muscle length an exercise emphasizes.

So What Do I Do?

I recommend that, for every muscle group you train (however you divide your muscle groups), you have at least two exercises: one that challenges a relatively longer length, and one that challenges a relatively shorter length.

For example: instead of doing leg presses and sissy squats, perhaps do leg presses and leg extensions.

Instead of doing 6 sets of seated leg curls, perform 3 sets of seated leg curls and 3 sets of lying leg curls.

Instead of doing 8 sets of pressing for the chest, perform 4 sets of presses and 4 sets of cable or machine flyes.

The list goes on.

Use a blend of exercises so that you can make your training more sustainable.

In addition, create an order of priority in your exercise selection that looks something like this:

1. The target muscle is targeted and the exercise is comfortable.
2. The exercise is stable enough and you can load and progress the exercise seemlessly.
3. Appropriate resistance - how much of the total range of the target tissue (versus other tissues) is loaded 
4. Adjustability - it might feel good today, but what changes can you make?
5. Rep range potential - can you adjust reps upward and downward? Is the exercise in question limited substantially to one end of the range or another?

Note how none of the 5 different levels to this pyramid include muscle length. All of these other variables are clearly bigger movers than the precise muscle length one trains at. 

It's not that muscle length is unimportant - it's simply that we should not prioritize muscle length at the expense of these other, more important considerations.

Do not lose sight of the forest for single trees - no one who has made substantial progress in muscle growth has done so simply by stretching their muscles more in every exercise.

-Ben

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