Ok, so in Muscular Tension Part 1 I looked at the topic of muscular tension in overview. What it is, what it represents and why it is important (i.e. as the primary initiator) in terms of muscle growth. This had to do with high-tension skeletal muscle contractions activating mechanosensors which turned on the protein synthesis pathway via mTOR .
This requires two factors which are recruiting the fibers and then exposing them to some (currently uknown) number of contractions to activate the mTOR pathway via mechanosensors.. This can occur in a number of ways including lifting heavy weights (80-85% of max or higher) which recruit all fibers from repetition 1 or by lifting lighter weights near or to failure. Both may end up achieving the same or a similar number of high tension repetitions.
All roads lead to tension. It’s just a matter of how you get there.
I ended up by addressing the idea of “effective reps” the number of reps of a set or workout that occur under full recruitment and activate mTOR. The idea being that only those effective reps really matter in terms of a growth stimulus, at least for the highest threshold muscle fibers. Effective reps can be achieved in a number of ways including multiple straight sets at an appropriate intensity with insufficient rest, rest pause and others. How you do it less important than that you do it acutely although I will still argue that there are better and worse ways to achieve that goal.
I also posited that workouts where the sets generate very few effective reps might explain why some research and training theorists are positing enormous volumes of training. When every set is so ineffective/inefficient, you have to do a on more than if you did fewer sets that were challenging or accomplished something.
And despite people’s hope that I was going to turn this into some deep molecular look at muscle growth, that actually wasn’t the purpose of my blathering. Part 1 was really just a longwinded background to explain why high muscular tension, regardless of how you get there, is the key to turning on growth.
I ended by pointing out that, practically we lack a way to measure muscular tension in the gym. You can do it in the lab, eventually some type of patch/APP might exist. So we need some sort of proxy for muscular tension, something we can track in a practical sense to at least guesstimate the amount of muscular tension
And I want to start today by looking at the proxy for tension that we have in a practical sense. More to the point, I want to look at not only some of the enormous mis-understandings that come out of the idea but places where using load without qualification is not a good proxy.
Weight on the Bar as a Proxy for Tension
While some number of effective reps under high tension overload is critical to the acute growth stimulus, we have the problem that we can’t measure tension in the gym yet. We need a proxy for muscular tension that we can measure beyond “I feel it/I got tired/I got a pump/I got sore, bro”. Something a touch more objective.
And as I gave away in Part 1 and as anybody who has read anything I’ve written already knows, the real-world practical proxy for muscular tension is weight on the bar, the actual external load being lifted. Yes, there are other factors here.
Lifting speed can impact this although it’s complicated, you get into peak and average forces and force/time curves and maybe I’ll write about that at some other time. Maybe some of the internal vs. external focus work. That sort of thing.
But ultimately the load on the bar is the best quantifiable proxy we have. By this logic, lifting 120 lbs requires more muscular tension than 100 lbs. More external load means more muscular tension. Except when it doesn’t which is in a lot of situations. Before getting to that, you ask what I am basing this overall idea on. How is weight on the bar/external load a proxy for muscular tension?
Remember that muscular contraction generates force. Also recall that force production is related, among other factors, to the physiological cross sectional area (XSA, effectively the size) of the muscle. Smaller muscles generate less force, larger muscle more force, at least assuming that the cross sectional area increases are made up of myofibrillar and not sarcoplasmic growth.
This relationship is just staggeringly strong, like one of the strongest in any biological system, nearly a straight line relationship. At least this is true if you’re looking at somewhat artificial lab measures of force output under controlled conditions in the lab. Even outside the lab, the relationship is incredibly strong with lean mass correlating staggeringly well with 1 repetition max: more lean mass means a higher 1RM.
It’s simply that once you get outside of the lab where you’ve attached an isolated muscle fiber to tension meters, it gets more complicated. You can’t go from a muscle is X size to this weight Y can be lifted. There are factors of biomechanics, fiber typing and neural factors that will all determine what actual external load can be lifted for a fixed amount of muscular force output. Two individuals may lift different weights if they are the same size and one person may lift more by changing technique (i.e. high-bar to low-bar squat).
But this says nothing about the actual force output of the muscle. It simply points out that a given amount of muscular force/tension may move varying amounts of weight in the real world. So for 100 arbitrary units of force out of the biceps, a guy with shorter forearms will lift more weight than a guy with longer. It’s a physics and lever arm thing.
And when people see that a seemingly smaller guy with better mechanics outlifts more than a bigger guy with worse mechanics, their simplistic conclusions is “Lyle is an idiot, muscular tension and load on bar have nothing to do with one another.” But this is not the argument, comparing two individuals to one another. It’s about the relationship for one individual between bar weight and muscular tension. Their limb lengths don’t generally change although technique can (again, high-bar vs. low bar squat).
For the time being the statement being made is that the load on the bar will be related to the amount of tension generated/required by the one individual’s muscle mass for a given individual in a given exercise.
So if you take Lyle the Crocodile, high-bar squatting 275X5 will require more force output and expose the muscle to higher tension than Lyle high-bar squatting 225X5. What Lyle might do in a low-bar squat doesn’t matter. What Bob the Builder does in either movement is irrelevant. I’ll address some of these issues later in the series in more detail.
But this is far from the last time when external load on the bar and muscular tension may diverge: where the external load isn’t representative of actual muscular tension. I examined one of those in Part 1 and will do so again here.
The Repetition Range Contradiction
Astute readers may already see a contradiction with something I wrote in part 1 which was that you can reach high tension in a muscle via multiple paths: heavy weight for fewer reps, moderate weight for moderate reps or light weights for high reps with all three potentially leading to the same/similar numbers of effective reps per set. But the weights being lifted will be very different.
Assuming a 100 lb 1 rep maximum, you might be using 85 lbs for 5 reps, 70 lbs for 15 reps and 30 lbs for 30 reps (i.e. 85%, 70% and 30% of max). Clearly 85 lbs is heavier than 70 lbs and both are heavier than 30 lbs. Aha “Lyle is an idiot, load and tension aren’t equivalent.” And I didn’t say that they were.
But I never said that you had to expose the muscle to high LOADS but rather high TENSION and these are just different ways to reach high tension. And while my idiot status may remain in question, this is still missing the point. It simply requires further qualification. The mistake here is comparing different rep ranges in absolute terms. All three situations lead to full recruitment and absolute load and tension are not equivalent.
Weight on the bar is still a proxy for tension, however. 100X5 requires more tension than 85X5, 85X15 requires more than 70X15 and 45X30 requires more than 30X30. Within a comparable situation, external load is a proxy for tension.
Now I’ve already given a few of this series’ points away, qualifying some places where absolute load on the bar and muscular tension are not identical. Load is only a proxy for tension with certain qualifications in place. And I’ve only scratched the surface of some of those qualifications. There are places where a heavier load leads to less tension and a lighter load to more tension and I’m gonna look at a bunch of them in this series.
Now, there is actually another, bigger issue to consider, one that might have fit into Part 1 but I didn’t have space. Because while acute tension overload sufficient to stimulate adaptation in the sense of a single workout is critically important, there is a factor that is more important over the long-term.
Progressive Tension Overload
While high muscular tension and a sufficient number of contractions/effective reps is the key to an acute training stimulus (i.e. within a workout) that’s not all there is to the topic because that’s just addressing an acute training stimulus. Most of us train more than once in our lives and what matters is how all of this works in the long-term.
So let’s back up, we do it all right in the weight room, turn on the FAK/PA/mTOR thing, protein synthesis (which I’m told I don’t understand hahahaha) occurs, hopefully outstrips protein breakdown and the muscle gets bigger and stronger over time.
What are the implications of this?
One is that the tension overload that was sufficient to activate the mTOR cascade previously will eventually be insufficient to trigger that same pathway. So consider someone lifting 70% of max for 15 reps with 2 reps in reserve (and they do enough sets to stimulate growth). Say it’s 100 lbs right now. Over time the muscle gets bigger and stronger and that 100 lbs now only represents 60% of their maximum. Boom, we’re right back to ineffectual training where the number of effective reps is too low to be a good stimulus to further adaptation.
The weight that was a stimulus a week or two weeks or two months
ago is eventually no longer sufficient to stimulate growth.
But you argue, what if they now take that new 60% weight to failure? Won’t it accomplish the same thing? Probably. But eventually 60% becomes 50% and on and on. I guess eventually that 100 lbs goes from being a heavy set of 8 to a set of 30 although realistically this would never actually happen for reasons I can’t be bothered to explain.
And if you wanted to go that route it might work at least over the short term. Except that constant training to failure eventually burns people out and most people reading this don’t have a clue where failure really is to begin with which is the topic of another forthcoming article series. There is also the fact that nobody actually trains this way and most just pump out the same reps with the same weight. 225X8 stays at 225X8 forever and so does their muscular size.
So I’ll work in this section from the assumption that you’re targeting a specific repetition/intensity range. And eventually the muscle adapts and what was a sufficient tension overload acutely isn’t. The weight that was an overload for a heavy set of 8 isn’t anymore (or is less effective as a set) because it’s dropped from 80% to 70% of maximum. Now what?
Some would argue to do more sets That is, if you cut the number of effective reps per set in half as you adapt, why not just do twice the volume? That is, if 4 effective reps per set becomes 2 after you’ve adapted, just do twice the volume. When it drops to 1 effective rep per set, double it again so you’re doing 4 times as many sets as before. And when the stimulus per set is zero effective reps, you can do infinite sets and still not grow.
Which would probably work but will also double your training times and just has you doing endless extra work (cutting into recovery) that just going heavier would accomplish more easily. Eventually you’ll get zero effective reps per set and MUST increase weight anyhow. Even the biggest “volume is the primary driver of growth” hardhead I know has written that “adding weight in the 6-12 rep range is THE key to long-term growth”. So rather than just tacking on sets to the limits of your tolerance, why not just add weight in the first place?
Yes, fine, blah blah, when you’re very very strong adding weight can be problematic but I’m not saying do it every workout or week to begin with. Past the intermediate stage, it might be 4-6 weeks before a load increase is needed. Consider that elite PL’ers train for 4 months to add 5 lbs to their lifts. This isn’t a fast process beyond a certain point.
Then again by the time this matters, when you’re lucky to gain 0.25-0.5 lbs a month of muscle and a few pounds per year to begin with, you’re pissing into the wind training anyhow. Adding volume won’t grow you any faster than adding weight either unless the added volume is what’s in your syringe. You might as well quit at this point because now you’re just fighting the slow slog to death and decay. But I digress.
At the end of the day, no matter what else you do, to generate further growth, you need to increase the tension overload/requirements. Yes, there are other progression methods. But progressive tension overload in terms of increasing the load is the primary one over the long-term. This isn’t even debatable even if folks continue to debate it.
And literally every study, no matter what they say they are studying, has progressive tension overload built into the protocol. The methods always describe that loads are being adjusted during the workout and throughout the study. It’s an assumed part of the protocol because without it nothing happens.
And this means that what these studies are actually asking is “What happens if we compare these different frequencies or volumes WHEN PROGRESSIVE OVERLOAD IS ALREADY PRESENT.” Everything else being examined, EVERYTHING ELSE, is a secondary factor of study even if nobody but me seems to have noticed it.
Now, the occasional study has worked on a base of not increasing load. The Haun et. al study I seem to be picking on lately (even if it was done methodologically very well) is one of them. So far as I can tell it didn’t add weight to the bar across the 6 weeks, it simply added sets to a fixed (piss-ass intensity) load. And the results, or rather non-results bear me out. The growth was sarcoplasmic rather than myofibrillar.
Because all of the low-tension work in the world doesn’t stress the actual myofibrils because the number of effective reps (full recruitment under high tension) is so close to zero. it was also only 6 weeks long and over a longer time frame, what the fuck do you do? 32 sets/week, 48 sets/week, 64 sets/week? Yes, this is a bit of a strawman so spare me the bitching, I know nobody is suggesting that.
But I think it’s a bullshit progression when you could have just started with a proper intensity set (i.e. not 10 reps with 4RIR), done 8 proper sets 2X/week and added weight to the bar instead. And I ASSURE you that a second group that had done that would have experienced actual myofibrillar growth without spending all day in the gym doing repeat warm-up sets every 8-10 minutes.
Progressive overload is THE BASIS of all training and every sport requires it in some form or fashion. The stimulus that is sufficient today won’t be after some amount of adaptation and must be increased. And, in the context of muscle growth, given that high tension/effective reps is the stimulus to turn on protein synthesis, that means that tension overload has to increase over time. And the implication of that is:
If we start from the standpoint of using weight on the bar as a proxy for
tension, the implication is that increasing the weight on the bar is a
proxy for progressive tension overload.
Because if the 100X15 you were lifting a month ago is no longer a sufficient tension stimulus because you’ve adapted, that means that increasing to 110X15 (or whatever) will be required to create a sufficient new stimulus. And when that is no longer sufficient, you go to 120X15. If you never move up from 100X15, there is no further overload. Adaptation stops at the point it’s an insufficient tension overload and you get insufficient numbers of effective reps to turn on the FAK/PA/mTOR pathway.
And ultimately, the idea of progression is far more important than what is being done acutely. Yes, the single workout stimulus is critical because without it adaptation won’t occur at all. But what happens over the long-term is more critical. It’s not the weight on the bar right now, it’s that weight is added to the bar over time.
Importantly, you can only measure progression from the starting point of a given situation. Whether you go from 120 to 150X5 or 100 to 120X15 or 30 to 45X30 over some time frame, you’re applying progressive tension overload over time.
The starting point doesn’t matter in an absolute sense outside of needing to be a sufficient stimulus for adaptation acutely. If 30X30 isn’t a stimulus in the first place, you won’t have to increase the load to keep growing because you won’t grow in the first place. You won’t even get “toned”.
It’s that progression that applies progressively increasing tension loads
so that the FAK/PA/mTOR pathway is activated and maintained such
that growth continues over time.
Back in the Real World
People continue to argue against the above, especially in the era of “Volume is the primary driver on growth” bullshit. I am told that one brain surgeon argued that adding weight to the bar is a negative because it reduces his volume and I will laugh and laugh in 6 months when he has seen no progress and realizes I was right all along.
I already mentioned that every study showing effective growth, outside of what it thinks it’s studying (frequency, volume, etc.) is done on a base of progressive weight overload. It is FUNDAMENTAL to the training process. Load is adjusted day to day and week to week because apparently “labcoats” understand the training process better than gym dipshits and Internet rocket scientists who think progressive tension overload isn’t the key part of stimulating growth.
You can prove this all to yourself easily. Go to your gym and pick out a few regulars and note their current training poundages. Come back in a year. The guys who are lifting sufficiently heavier weights will have grown. And the guys lifting the same weights have not grown no matter how much volume or frequency they throw at it. They will be doing the same bullshit 2 hour chest workout every Monday with the same weights and look exactly the same as a year before.
Ok, that’s not true. For some gym trainees, they will get bigger if they don’t add weight to the bar but focus on volume. But in this case it’s their volume of anabolic steroids. Trust me, double from 600 mg/week to 1200 mg/week and you’ll grow better than doubling your set count OR adding weight to the bar. Drugs beat out all of this.
And I think if you look at a lot of arguments that volume is the primary driver on growth on growth, what you will find is that it’s not the training driving the bus but rather the special sports supplements being used. As I said in Part 1, a lot of goofy/stupid/inefficient/ineffective bullshit works pretty well when your dosage is high enough. And when you want to grow more, it’s easier to take more than to train more.
Or consider how altogether too many women training: all the volume at worthless intensities and with no progression. And nothing happens for years. Then they cut volume, go heavier and work on progression. BOOM, they see more progress in 2 months than in the last 2 years. There are lessons to be learned here folks.
Look at your own training: if you haven’t added weight to the bar for a year, you haven’t grown either. A ton of volume might have worked for a bit and that was it. Researchers know that adding weight to the bar is fundamental no matter what else is being done. How can anybody still be arguing against this in 2019?
No matter what you want to argue or believe,when the rubber hits the road:
No progressive tension overload over time means no long-term growth.
In practice, that means adding weight to the bar.
Or look at good NATURAL bodybuilders. In most (read: all) cases they are pretty damn strong. They aren’t powerlifter strong by and large (though some of the good naturals come from a powerlifting background). But that’s because they don’t usually practice very low reps and use different lifting techniques (another article for another day).
Mind you, if you transition a bodybuilder to powerlifting, they tend to be extremely good at it. They’ve got the muscle mass (and hence strength potential) and once they get efficient with more efficient PL’ing techniques and get the necessary neurological adaptations, they move huge weights.
But show me a big natural bodybuilder and you’ll show me someone who is pretty damn strong in the big picture, especially relative to smaller guys. You just don’t see good naturals farting around with light weights although you may see this among juiced bodybuilders who just let the drugs do the work. But some of the hugest pro bodybuilders (i.e. Dorian or Ronnie) who are immensely strong.
Though remember I said you can’t really compare people like this. Comparing two natural bodybuilders, the guy squatting 405 isn’t automatically bigger than the guy squatting 315 because biomechanics and stuff all play a role. But the natural bodybuilder who went from squatting 225X8 to 315X8 will be bigger than he was.
Far more importantly than their absolute strength is the fact that they have gotten stronger over the course of their career.The difference between being strong and getting strongER is another critical distinction people fuck up regularly and leads to one of the common misunderstandings of this topic. I’ll look at this in detail in Part 4.
Hell, go back and look at all the big guys of the early 20th century, they mainly trained to get strong as hell because their main game was strongman performances. Specific bodybuilding training wouldn’t come until much later and the guys in the pre-steroid era just focused on getting strong as hell. And they got big as a consequence because in progressing from squatting 225X5 to 365X5 over several years, your legs can’t have not grown. Because nobody can add that much weight to the bar through simple technical and neural mechanisms.
Snarkily, I find it interesting that one individual who will trot out these old timey guys to “disprove” the 25 FFMI cutoff is currently writing training programs meant to pander to current fads which have NOTHING to do with how those guys actually trained. They sure as hell didn’t train a muscle five times per week to “do more volume” and you shouldn’t either. They trained to get strong as fuck with relatively moderate volumes and frequencies and they grew as a consequence of that. There are lessons here folks.
Now, don’t misread this. If you go from 250X5 to 260X5 and there may be no meaningful difference in muscle size. I’m not saying every pound you add to the bar equals some amount of growth because that would be stupid. I’m also not saying that there will be a linear 1:1 ratio of muscle gain to strength or vice versa (which seems to be a rather dumb assumption made by a fairly specific research group/individual) since there are clearly other factors involved. But beyond some point, as you build up the weight on the bar in a moderate repetition range, the muscle has to get bigger.
As Dante Trudell put it so brilliantly “The key to growth is getting stronger in a moderate repetition range.” That sums up training for size.
Note: I will maintain that irrespective of it’s other strengths (and there are many) Doggcrapp training “worked” for people because Dante got lifters to stop fucking about with the pump and volume and all of that irrelevant bullshit and got them trying to “Beat the training log and add weight to the bar over time.” That is, to get stronger in a moderate repetition range over time. And when they did that and ate, they grew. Because all of the fucking about without adding weight to the bar doesn’t work. QED.
So as I mentioned in Part 1, let’s work from an early qualification that we are talking about moderate or higher repetition ranges. Three is at the low end and you have to do a lot of sets to get it done but 3-5 reps per set and higher up to about 30 reps per set near or to failure is where we’re talking about here.
A Mid Article Summary
So here are the key things to remember so far:
- High mechanical tension for a sufficient number of “effective” contractions is the initiating factor in muscle growth via the FAK/PA/mTOR pathway
- We can’t easily measure mechanical tension in the gym
- Weight on the bar is, to a first approximation, a proxy for mechanical tension
- Adding weight to the bar means an increase in mechanical tension which stimulates growth in the long term
Where 3 and 4 are really the key focus of this series. And they are absolutely true except when they aren’t. Or rather they have to be qualified a bit. You can’t compare two individuals in terms of load on the bar, the absolute load may differ between rep ranges even if both can lead to the same high tension stimulus. They may be relatively more or less efficient at getting there but they all get there. In a sense it doesn’t matter because of #4. Progression is more important overall: where exactly you start is less relevant than where you end up. I mentioned others as well.
One of which was the idea of comparing two different exercises and this leads me to one the common mis-understandings of the concept of “higher load means more tension” along with a favorite dumb-assed argument you see sometimes. To really address that, I need to bore you with some physics.
Lever Arms, Torque and Force Production
So remember back to high school physics, with free body diagrams where you had to keep track of different forces on a system and figure out what they were and stuff. I loved those things, like working a puzzle. I also love putting Ikea furniture together so take that for what it is.
Anyhow, we can look at weight training through that concept although we only need to focus on two forces: the force generated by the muscles pulling on the bone and the force required due to the resistance being moved (air resistance doesn’t matter and we’ll ignore friction although it can matter on poorly maintained machines). Most things we do in the weight room rely on gravity for resistance but there are exceptions.
Tubing pulls along the line of the tubing regardless of the direction and cable stacks allow the up and down gravitational pull on a weight stack to be changed to an angled or horizontal resistance. Many movements that don’t work with free weights such as the standing horizontal DB rotator cuff exercise works with tubing or a cable.
There are also mechanically braked isokinetic machines, those old stupid pneumatic things, some electronic machines and water resistance is weird as hell because it pushes back in any direction the opposite of how you push against it. But that’s just detail mongering to shut down the nitpickers (I deliberately left out one current technology just so someone can bring it up and dismiss my entire article because they think I’m out of the loop. I’ll mention it in Part 4 for lolz).
The key here is that, however you set up the external force of resistance, the force the muscle has to generate to complete the movement depends on the force that is opposing it. So if the force required to lift a weight is 100 arbitrary units, your muscles have to generate at least this much force to complete the repetition. And this is true regardless of how the resistance is created. I’ll just use gravity based movements to keep it simpler.
Ok, so we have muscular force pulling against the force due to gravity and, in that sense, the heavier the weight being lifted the more force that is required to move it. Lifting 300 lbs requires more muscular force to move than 200 lbs. Well, kind of.
Because there is an added complexity and this gets us into the concept of a lever arm. This is defined as the perpendicular distance from the axis of rotation to the line of force (in the case of weight training, this is the force due to gravity acting on a weight).
This is shown in the image below which you can think of as representing a biceps curl.
It actually shows two lever arms. The long one is the lever arm of the resistance from a weight held in the hand to the elbow and the down arrow is the resistance of gravity pulling on the weight (or whatever). The short one is the lever arm of the muscle, from the biceps to the elbow and the up arrow is the force pulling up.
What you can see is that in different parts of the motion, both the lever arm of the resistance and biceps pull is changing length. Note how the resistance force is always straight down (gravity always and only points down) although the biceps line of pull changes slightly from straight up in the far left to the steepest angle in the middle.
And simply, the longer the lever arm, the higher the effective force at the axis of rotation and vice versa: the shorter the lever arm the lower the effective force. When the forearm is perpendicular to the floor, the lever arm is at its longest and for any fixed weight, the force requirements will be the highest (this also defines the sticking point of the exercise). Early and late in the movement, that lever arm is shorter which is why it’s easier to start and finish a biceps curl than to get it through the middle.
Note: There is a hugely critical practical training aspect that comes out of the fact that maximal tension only occurs at the point of the maximal lever arm but I don’t have space here to get into it (and it’s sort of tangential to the point of this series). Essentially the only time the muscle can experience maximal tension is at the sticking point. It must be lower at every other point in the movement, at least with free weights. Other types of resistance can work differently (i.e. cams try to alter resistance to match the force curve, chains overload the top). But it has some implications for exercise selection in terms of possibly selecting movement which stress a muscle maximally at different parts in the movement by changing where the maximum lever arm occurs. Another article for another day for sure.
Anyhow, technically we are not concerned with forces, we are concerned with torque, a force that tends to cause rotation (like a torque wrench). Torque is defined as the force times the lever arm (the perpendicular distance between the force and the axis of rotation). For any given load or force, the longer the lever arm the larger the torque and vice versa. And this is a critical concept for the weight room.
Torque in Weight Training Movements
So in weight training, the axis of rotation is the joint that moves. And this is super easy to understand for isolation movements. In a biceps curl or triceps pushdown, rotation occurs primarily around the elbow. In a leg extension or the leg curl it’s the knee unless you are doing something very strangely. In a pec deck or DB flye it’s the shoulder (and the forearm if you use bad form).
Pedants will point out that there is often small movement around other joints even in single joint movements. People will curl their wrist slightly on biceps curls or extend them on triceps in an attempt to shorten the lever arm and make the movement easier. The shoulder may move in a curl and the elbow or wrist may move on a pec deck or flye. All true but not relevant here as I’m focused on the axis of rotation for the relevant muscle. If the goal is training the pecs, the axis of rotation that matters is at the shoulder.
Note: Real pedants will note that the axis of rotation moves around a little bit in the joint throughout the movement. This is true but the effect is miniscule, the practical effect irrelevant. It’s a bit of biomechanical nerd trivia that is interesting and nothing more. And knowing it won’t get you laid.
This is a lot harder to picture for compound movements where there are multiple muscles acting at multiple joints all at once and you can technically define moment arms for all of them. So in a squat there is movement around the ankle, knee and hips with glutes, quads, hamstrings, adductors, calves and low back all playing a role. There are multiple lever arms and multiple muscular contributors, etc. I made the mistake of writing a term paper in college on squat biomechanics. Ugh.
In a bench press there is movement around the shoulder (often in multiple planes depending on elbow position) and elbow with pecs, delts, triceps, lats, serratus anterior and others all contributing. For shitty benchers who bridge up off the bench there’s movement at the hip too. I fondly remember an article by Charles Staley about bench pressing for the hamstrings. Funny stuff.
Ignoring that, in weight training movements, both the weight being lifted and the muscle are acting in the above fashion: at some lever arm relative to the axis of rotation. In most situations, the muscle is closer to the joint than the weight which means a shorter axis of rotation/lever arm for the muscle than for the resistance/weight being lifted.
The biceps attaches closer to elbow than the weight in you hand. There’s a couple of weird exceptions, the calves are one (and I think one of the jaw muscles) and this gets into a bunch of stuff about 1st, 2nd and 3rd degree levers that I never remember because that’s what textbooks are for. These are just details.
All of this goes to a point I made above which is the mistake in comparing two lifters. Even if they have similarly sized or strong muscles, they may lift drastically different external weights due to having different levers around a joint. A guy with a short forearm will curl more for the same muscular force output than a guy with a longer arm because the lever arm is shorter.
The Real Implication of Lever Arms
But there is a much more important implication of lever arms. The effect of the lever arm means that two entirely different loads (generating force due to gravity) can generate an identical torque at the axis of rotation. Remember that the resultant torque is the external force times the length of the lever arm.
So say you’re lifting a weight that would require 100 arbitrary units of force to lift at a lever arm of x length so the torque is 100x. If you move that same weight to a point that is half as close to the axis of rotation the lever arm is now 1/2x and the torque is cut to 50x. The absolute load is the same, the torque at the joint is not.
By the same token, if I double the force at the halfway point, the resultant torque at the axis of rotation will be identical to half the weight at the original position. I’ve shown this in the drawing below. AOR is the axis of rotation and I’ve shown a 100 unit force at distance x from the AOR and a 50 unit force at distance 2x from the AOR.
A smaller force applied at a longer lever arm can have the same or a higher resultant torque than a larger force at a shorter lever arm. It’s the whole you can lift the world with a long enough lever. It’s also why a longer handled wrench makes it easier to turn a frozen nut. For any given amount of muscular force, the longer handle means a longer lever arm and a higher effective torque at the nut.
And in a muscular sense, that means that the absolute weight on the bar can’t indicate what tension it requires/exposes the target muscle to without considering the lever arm. And this leads into not only that bit of confusion but one of my truly favorite dumbshit Internet arguments.
The Compound Exercise Mistake
I could also call this the exercise comparison mistake but I like this title better since it’s usually an argument couched in the idea that, if load on the bar is a proxy for tension, and higher loads mean more tension, compound exercises MUST be better for growth because the weight on the bar is higher.
I think the most common way I’ve ever seen this stated is like this:
“What’s better for the shoulders, an overhead press with
300 lbs or a lateral raise with 30 lbs?”
Which has so much wrong with it it hurts. It could be made for most other compound to isolation exercise comparison (i.e. what’s better, a 315 bench or a 30 lb DB flye). It actually works the opposite for squat and leg press since everybody can move more weight on the leg press than in the squat but I’m not getting into the vector math or physics of it because I’ll get it wrong. I’ll focus on the shoulder example since I see it most commonly and it’s just dumb as shit.
First, how many legitimate 300 lb OHP’s have you ever seen? Unless you train with strongmen or elite powerlifters, I’m going to say roughly zero. Just like you haven’t seen many legitimate 400 squats, 300 benches of 500 lb deadlifts in the average gym. So it’s kind of a stupid example even if it’s only meant to illustrate a point.
Second, those numbers are an idiot exclusion of the middle. Anybody who can OHP 300 lbs should be able to lateral raise more like 50-75+ lbs per hand (100-150 lbs total) depending on their mechanics and I’ll show you how I reached that conclusion below.
Find someone with a huge OHP and have them do heavy laterals and you’ll see a similar relationship and it won’t be a huge OHP and a pitiful lateral raise. The example as it stands simply fails the reality check. Anybody who could OHP a ton can lateral raise slightly less than that ton but still a ton.
Yes, I know, the people saying this are making a point between BADASS powerlifters and LAMEASS gym bros but it’s still a stupid example because the numerical comparison has no basis in reality. It’s an example containing the implicit conclusion that they want to make. And it’s dumb.
Someone will counterargue that PL’ers lift all the weights and lots of gym bros never go above 30 lbs in the lateral. Which is true but making a different point which is about the bullshit nature of most gym bros training since they never add weight to their movements because the think things like the pump, or the squeeze or doing a shit ton of volume per se is more important than adding weight to the bar over time.
Adding weight to the bar over time is the end metric for powerlifters and, frequently, they grow better than gym bro bodybuilders in my opinion (another article for another day). But again it’s tangential to the idea that a 300 lb OHP MUST be superior to a roughly equivalently heavy lateral raise. It’s only superior to a dumbass comparison example.
Because what the example is really trying to say is that the higher absolute weight on the bar MUST be better for growth than the lighter weight used in the lateral raise. Because this is America and bigger numbers are better than smaller numbers. 300 is more than 30 (or 100 or 200) hence 300 is better.
But in doing this it’s confusing absolute weight on the bar with actual muscular tension (remember I said that the key isn’t high LOADS on the muscle but high TENSION). The confusion is worse with the dumbshit weight comparison of 300 to 30 lbs since it’s a false dichotomy.
But even if you make a much more reasonable comparison, say a 300 lb OHP to a 75 lb lateral raise (75 lbs in each hand or 150 total pounds), the assumption that 300 lbs requires a force output or subjects a muscle to inherently more muscular tension than 75 lbs/hand 150 total pounds has problems.
Now I’ll assume here that the goal is to build the delts. Pedantic assholes will invariably comment “But OHP is better for delts and triceps” or “overall growth” or “all of those real world activities where you lift stuff overhead” or some bullshit but that’s not the point of my discussion or the stupid ass quote.
The statement as made is talking about shoulder growth only and that is my singular focus. None of the rest of it matters. And the problem with the comparison is that it’s conflating the absolute LOAD on the bar with the TENSION experienced by the muscle. And there are two problems with this.
Problem 1: The Lever Arm Issue
Ok, so here’s a picture of me doing a DB OHP and a DB lateral raise at the longest lever arm that will be experienced. I did my best to line up the pictures top to bottom to make the comparison reasonable and fair.
The red vertical line running through my shoulder is meant to indicate the axis of rotation. The red arrow dropped down from the weight is the force of gravity acting on the weight. And the green line is the lever arm, the perpendicular distance from that force and the axis of rotation.
And what you can see is that the lever arm is roughly three times as long in the lateral raise as the OHP because I have long assed arms and a long forearm relative to my humerus.
Note: I can see someone with a biomechanics background composing their critique of this right now. “It is clear that Lyle McDonald doesn’t understand this system since he is ignoring movement in other planes during the OHP and lateral raise and how that impacts on the resultant lever arm and torques. He’s an asshole and should be ignored.” Yeah, well, see here’s the thing. I am well aware of this but this isn’t an article about the physics of lifting and I’m trying to stick with concepts more than math. Assume that the humerus is in the same position in both movements (i.e. mid-scapular plane) so that is fixed in the system and the only consideration distance along the arm from shoulder to the weight.
Anyhow, I have no idea if this is normal biomechanics or I’m just a weirdo. But let’s say the distance from shoulder to elbow is x and from shoulder to hand is 3x based on the extremely scientific method of eyeballing it. That is, the lever arm is three times as long for a weight held in the hand versus having it applied through the elbow.
Ok, crap, I have to qualify something else which is that I’m trying to compare a movement done with two hands to the weights held in one. And this will end up getting confusing. Assuming the lifter is symmetrical, the weight being lifted with two arms is effectively split in half with each arm. OHP’ing 300 lbs means that each arm is having to put out 150 lbs of force. And that force will be applied at the elbow assuming it’s the forearm is perpendicular to the upper arm.
What this means is that, with my roughly 3:1 lever arm length:
150 pounds at the elbow generates the identical torque at the shoulder as 50 lbs held in the hand: 150x.
So if I have the muscular force to OHP 300 lbs, 150 lbs in each hand essentially, I should be able to lateral raise at least 50 lbs/hand. And the torque at the shoulder will be identical. And so will the muscular tension.
If the lever arm of the OHP was closer to 1/2 that of the lateral raise (and for anybody able to OHP 300 lbs it probably is), that 300 lb OHP which is 150 lbs per hand should allow for a 75 lb per hand lateral raise, at least to a first approximation. Because both will create an identical torque of 150x at the shoulder.
Ok, it’s probably not absolutely identical for some obtuse biomechanical reason that someone will dredge up but just consider this as a back of the envelope calculation and focus on the point: two completely different loads can generate an identical resultant torque at the axis of rotation.
Lifting 150 lbs at 1/2 the lever arm is the identical torque to lifting 75 lbs at twice that lever arm.
Yeah, comparing that 300 lb OHP/150 lbs in each hand to a 30 lb lateral won’t achieve that. The effective torque here would be 150x vs. 60x (or 150x vs. 90x for my long arms) and clearly the OHP is superior. But it’s a dumb comparison because anybody who can OHP that much will be able to lateral raise a lot more than 30 lbs.
For an equivalently loaded lateral raise, the muscular tension requirements will be roughly identical despite the OHP having twice the external load.
And once again we might rough estimate that the guy who can OHP 300 lbs, 150 in each hand might be able to do a lateral raise with about 75 lbs assuming double the lever arm.
And while a physics teacher would have an absolute aneurysm over this, I’m going to write this in the next section as the 300 lb OHP with 150 lbs in each hand as having an effective force requirements of 75 lbs. Clearly this is dumb and wrong, 150 lbs can’t be 75 lbs but I’m tired of writing out arbitrary torque values. What I mean by this is that the 150lbs per arm that is being lifted is roughly equivalent to the 75 lbs per hand lateral at twice the lever arm. It’s just shorthand to save me some typing.
But let’s start from a slightly different assumption, that the guy who can OHP 150 lbs/hand can only lateral raise 60 lbs in good form. Now the resultant torques becomes 150x vs. 120x and the OHP is still superior. Put in my weirdo wrong terminology, the effective 75 lbs of the OHP is still higher than than 60 lb requirement of the lateral.
The case is made, compounds rool, noob. Or do they?
Because there is more to consider.
The Muscular Involvement Issue
In addition to the lever arm issue, there is another to consider which is that the OHP uses multiple muscles to complete the movement: delts, triceps, pecs have a minor contribution, serratus and there are probably others. Which means that the total torque requirement for the OHP is not isolated to the delts: it’s spread out across multiple muscles.
Now, how much is being contributed by each I couldn’t begin to rough estimate. It will depend on relative strengths of the muscles and such and I’m sure someone can find some obtuse EMG study on it to math it out. I don’t care. This is a concept discussion about the problems with the simplistic assumption that compounds are superior to isolation due to higher absolute loads on the bar.
The point is that the total torque requirement of the OHP (and really any
compound movement) is spread across multiple muscles.
Again, I’m assuming that the 300 lb OHP is equal to 150 lbs per hand with an effective force requirement of 75 lbs due to the 1/2 as long lever arm. If the delts contributed 100% of the force requirements, that would be 75 lbs. Certainly they contribute a majority, that’s what prime mover means. But it’s not 100% no matter what.
And we can contrast that to the lateral raise with 50 lbs in each hand where it is basically the delts contributing 100% of the force. Yes, traps play a role but that’s shoulder elevation, not humeral ABduction. I’m sure someone will point out a minor neck muscle. Whatever, there is no true isolation movement where only ONE muscle works. It’s just a matter of degrees: single joint movements are more isolated to a single muscle/group than a compound exercise which uses a bunch.
For all effective purposes, the delts are the only muscle really contributing to the movement in the lateral raise. So they have to generate the entirety of force/torque requirements. If the lifter could do a 75 lb lateral raise, I’d state categorically that the lateral raise would expose the delts to more tension than the 150 lb/hand OHP with an effective 75 lb force requirement due to the lever arm and this is reduced further due to the delts not being the sole producer of force. Because the OHP would require less than 75 lbs of force output from the shoulder.
But even at a 60 lb lateral raise, with the longer lever arm and only the one muscle effective working, the medial delts might still be exposed to more tension in the lateral raise than in the OHP. I’m not saying they absolutely are or are not and that probably depends on a host of factors such as the lifter’s mechanics and relative strength levels.
Let’s wank about this mathematically. If the delts only contribute 90% of the OHP, the 75 lbs effective force becomes 67.5 lbs which is about 12% higher than the 60 lb lateral raise. At 80%, it drops to 60 lbs which is exactly the same as the lateral. And anything lower than 80% and the OHP will require less force than the lateral raise. I am not saying that any of these numbers are correct, this is a concept discussion, making a point about how the comparison as it’s stated is based on bad logic.
But irrespective of the exact numbers, my point is this: the differences in muscular tension between equivalently loaded movement with severely different lever arms is not nearly the differential implied by the absolute numbers of 150 lbs and 60 lbs per hand (or 300 lbs and 120 lbs total).
Because clearly the OHP isn’t requiring 2.5 times the force output (and hence exposing the muscle to 2.5 times the tension) in the delts as the lateral because 150 lbs is 2.5 times higher than 60 lbs. Depending on your assumptions about relative muscular contributions, it’s more like 5-10% different in either direction.
The shorter lever arm cuts the resultant torque/effective force requirements which is then spread out across multiple muscles which further reduces the force requirement of the TARGET MUSCLE.
Yes, I’m beating this dead horse because the assumption that compound movements are inherently superior for growth because you use more weight is utterly flawed.
And that is what we are interested in here: the force requirements of the target muscle since that will determine how much tension/force they must generate and what tension load they are exposed to.
Which is a very long way of making the point that while external load is a proxy for tension, you have to think about the situation a bit. You can’t just look at the load on the bar and draw conclusions about anything. In this case the qualification has to do with the mechanics of the movement itself.
If one movement lets you lift twice as much due to having half the lever arm and more muscles contributing, it may require similar, slightly more or even a little less tension in the target muscle than another. It’s not inherently superior (outside of impressing Internet idiots) just because the number on the bar is higher. It might be. But it might not be.
This actually brings up another issue that is often unconsidered.
What Muscle is Experiencing Optimal Tension Overload?
Recall that growth occurs when the muscle we’re targeting experiences high tension for enough contractions to activate the mTOR cascade. This means that far more important than performing an exercise in such a way as to generate effective reps per se, we want to expose the target muscle to the appropriate stimulus.
If our goal is to train the delts for hypertrophy, the goal is to expose the delts per se to sufficient effective reps to trigger the FAK/PA/mTOR pathway.
And this means that we have to consider what muscle is failing during a movement. So if you are performing a heavy set of OHP and your triceps fail early, you may or may not expose the delts per se to a sufficient tension overload or enough effective repetitions to turn on mTOR. That 150 lb/hand OHP with a 75 lb effective force requirement due to the lever arm might or might not be sufficient for the delts per se because there are other muscles which are involved.
I’m not saying it will or it won’t and that will depend on a lot of factors such as mechanics and relative triceps strength. Someone with long arms or weak triceps will get less of an effective delt stimulus out of OHP than someone with short arms and strong triceps.
And when you start to look at who responds to certain exercises what you see is this. People built to do certain movements get a lot out of them for the target muscle (i.e. bench for pecs). People not built to do them do not. And this is very likely to be a big part of why.
But if your triceps are severely limiting and fail early, the delts might not get an optimal stimulus or less effective total repetitions. Certainly, the triceps got that stimulus but if you’re using the OHP to train the triceps, you’ve missed the point of this discussion. We’re talking about training the delts for hypertrophy. Not the triceps, not the OHP as a movement itself. We are concerned with training the delts for hypertrophy and nothing more.
So consider a hypothetical situation where the weight you’re using for an OHP is such that the triceps are fully recruited from repetition 1 but the delts don’t reach full recruitment until repetition 6. On a set of 8, the triceps will get 8 effective reps but the delts will only get 2. Compare this to a lateral raise with the equivalent weight where full delt recruitment will occur in the delts from rep 1 and all 8 reps are effective reps.
Even in the tension requirements are slightly lower in the lateral raise,
if the triceps fail early, the effective stimulus from the lateral
raise may still be superior.
Again, I’m not saying that it absolutely will or won’t be. Rather I’m just making the point that the differential in tension isn’t nearly what the 150(75 effective weight) vs 60 lb values imply at face value when people simplistically look at the load on the bar. And even if the lateral raise still requires slightly less tension output from the deltoids, it may still allow for more total effective reps and a better stimulus for the delts since it’s not limited by the failure of accessory muscles.
Note: People with some training experience have probably noticed that different types of exercises tend to “fail” in different ways. In compound movements, it’s most common for the movement to slow and get grindy and then fail at some part in the middle of the movement. So on a final rep of bench you might get it partway off the chest and then it stalls in the middle. Or you get it through the middle and still don’t make lockout. Same with OHP.
In contrast, isolation movements often seem to just fail. It’s like one rep goes and the next won’t even start. It’s an on-off switch. And this is probably due to what I talked about above, the issue of multiple muscles contributing to the compound exercise versus only the one in the isolation movement.
In the OHP, when your triceps start to fatigue but your delts are still relative fresher, your body can utilize different recruitment strategies to keep going and you can grind another rep. When your delts are cooked in a lateral raise, your delts are cooked and there is no movement to be had.
Which I think indirectly points to part of what I was saying above: in many cases,the nature of muscular fatigue and what is fatiguing first in a compound movement often results in a poorer overall stimulus compared to the isolation equivalent where only the target muscle can fatigue and be trained. But I digress.
Because lest we forget, this is still within the context that progression more than acute training stimulus is the more important issue. Regardless of which is superior acutely, progressing the OHP or equivalently loaded lateral over time should result in growth.
This brings up a practical issue that I’ll get more into in Part 3 but should at least mention here.
The Practical Issue of Progression
In that progression more than acute loading per se is the critical factor in long term growth, we face the often difficult issue of progressing lateral raises compared to OHP (or any isolation movement compared to a compound movement). Where adding 5 lbs to the OHP may cause no problems but adding 5 lbs to the lateral turns it from strict to a technical shitshow where not even 1 good repetition can be done.
This is an issue of percentages and load increments. In most gyms, 5 lbs (just under 2.5 kg) is the lowest increment most can increase a weight. And this represents a vastly different percentage increase depending on the base weight of the lift. On a 100 lb OHP, 5 lbs is only 5%. On a 30 lb lateral, it’s 16%. If you added 16% to the OHP, it’d get ugly too. Microplates can get around this but often a lateral raise is very hard to increase in weight while maintaining anything approximating technique.
In which sense, the OHP might be arguably superior in a progression standpoint. At the same time, there is the technical nature of the OHP where you often have to dick around getting the bar around the face although again, this is practical issue not a tension one. This whole thing can be avoided by using a Hammer BTN press machine but everybody knows that machines are for noobs.
And of course this pretty much applies to any compound to isolation exercise comparison. The lighter weights in the isolation movement make progression a practical issue. But that’s irrespective of the physiology.
I’d note that women have this issue almost across the board in the weight room with only a few exceptions: the weight increments are invariably a much larger percentage of the weight being lifted compared to the same increment for men. Finding a way to microload exercises is often mandatory for female trainees in a way that it isn’t so much in men. The weight jumps available are simply too large.
But these are both practical issues, not related to the specific discussion at hand in terms of bar weight and muscular tension not being synonymous. Knowing my nitpickers, I just like to cover all my bases. I’ll go into more detail on the above, in a different context in Part 3.
Back to the Compound Exercise Mistake
I won’t bother getting into it but all the above holds for many other movement comparisons. Bench press versus flye or pec deck for example. In the bench, the load is heavier but the elbow is bent and the effective load is 1/2 or 1/3 as close to the shoulder as in a flye or pec deck with the weight in the hand. That’s on top of bench using pecs, delts, triceps, a little lats while the pec deck uses the pecs.
And triceps are likely to fail before pecs so someone with long-arms or weak triceps may get a wonderful tricep stimulus and an ineffective pec stimulus. Those people ALWAYS grow better pecs from more isolation movements because they are able to get a sufficient training stimulus for the pecs that way.
It gets harder to examine for other movements without a lot of free body diagrams. I wanted to try to compare squat to leg extension but it’s way harder in the big picture to do so and I’m super lazy. Squat mechanics are much more complex, depth impacts on what muscles are being most challenged (most bench full range) and I can’t be bothered to try to show how it all works.
How you squat, the depth and your levers all determine what muscles are most challenged and what tends to fail first. The same logic holds, just because someone can squat more doesn’t automatically mean that the tension on their quads is higher or that the growth stimulus is superior than in an equivalently heavy leg extension.
Really the key factor to take away from this discussion is this:
An absolute higher load on the bar may not mean a higher tension in the
target muscle when comparing two different exercises.
Lifting 300 lbs in one exercise does not inherently require or generate more tension on the target muscle than lifting 120 lbs in another if that 300 lbs has a much shorter lever arm and 6 (whatever) versus one muscle generating force. Quite in fact, the compound movement might expose the target muscle to less tension than with an equivalently loaded isolation movement. Even if it doesn’t, it might generate less effective reps per set for the target muscle due to early failing of accessory muscles.
There are actually other implications of the above but I’m going to bump them to Part 3 for space reasons.
Summing Up Part 2
Ok, so that got out of control to cover only a single issue but perhaps you’re seeing the point of all of this already. High tension overload is the key to turning on growth acutely. Over time we have to increase that tension overload to maintain the stimulus. Since we can’t measure tension directly, we need a proxy.
And the easiest proxy we have is the weight on the bar. To a first approximation, the load on the bar will be an indicator of tension on the muscle. But only with some qualifications in place. You can’t compare two individuals to one another as their mechanics will change how much weight is lifted for a given amount of muscular force.
You can’t compare different repetitions in absolute terms either. And you can’t compare different exercises where, due to changing mechanics, lever arms and muscular contributions, the absolute load being lifted will not indicate per se how much tension a given muscle experiences.
A 300 lb bench is not inherently more tension than a 100 lb pec deck/flye (yes, pulleys, yadda, you know what I mean) since the lever arm at the pec is 1/2 to 1/3rd as short and you’ve got multiple muscles contributing versus one. It might or might not be but the idea that 300 is inherently more tension than 100 because the number is three times as large is based on simple logic. And simple logic is almost always wrong.
On the compound movement, smaller muscles will usually fail before larger so while the triceps or anterior delt might get a sufficient stimulus from the set, the pecs might not depending on the relationships between muscles. Guys built to bench which usually means thick chest and short arms can get a great pec stimulus from bench because their pec and triceps strength is closer. Guys with long arms or just weak relative triceps don’t get much out of the flat bench.
And the same holds for most movements. Guys built to squat think they are GREAT for legs and for them that might be the case. And people not built to squat can toil for years at the movement and get jack shit out of it for growth of their legs. Their low back on the other hand. And neither can usually understand the other.
And much of this is sort of irrelevant in a long-term sense. Progressive tension overload is more important than the acute stimulus. In the sense that weight on the bar is a proxy for tension, adding weight to the bar is therefore the proxy for increasing tension requirements.
As I’ll discuss next, there are other places where heavier weights may mean less tension, lighter weights may mean more tension, etc. And this is true even within the context of the same individual performing the same exercise in the same repetition range and applying progression. Tune in next time, true believers!
- Combining Metabolic and Tension Training – Q&A
- Muscular Tension Part 3
- Reps Per Set for Optimal Growth
- Categories of Weight Training: Part 5
- Muscular Tension Part 1