The Science Of Training: 7 Principles Of Exercise Selection By Menno Henselmans

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To paraphrase a wise man, “Small, weak, and injured is no way to go through life.” But if you design your workouts around the wrong exercises, that’s exactly how you’ll end up; dreadfully unmuscular, embarrassingly weak, and prone to chronic injuries.

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Proper exercise selection can be tough. There are countless lifts to choose from and most of them have several similar-but-different variations. Unsurprisingly, most people don’t have a systematic method to select their exercises. They just do what feels best, what looks best in the mirror or what others do. When they find out the latest hype exercise, they immediately plug it into their program without analyzing how it fits in. Fortunately, there’s a set of objective criteria to qualitatively rate exercises, which allows you to make the most effective choice between any group of exercises with the same purpose – like figuring out why an overhead extension is a better choice for triceps than a pressdown. I devised these criteria for bodybuilders and recreational strength trainees, but powerlifters and other athletes should also find some use for them. Admittedly, these criteria are incomplete, but they do apply to the vast majority of exercises.

Let’s take a look at exactly what these principles cover and then learn how to apply them to several basic exercises.

1) The Limit Factor

An exercise is most effective for a bodypart if that bodypart is a limiting factor in the execution of the exercise, overlooking the other criteria. If your grip always gives out first on deadlifts, then your posterior chain will remain understimulated and deadlifts end up being a poor choice for training your lower body. Similarly, your lower chest and the long head of your triceps are active movers during a pull-up, but they’ll never limit your performance in the lift, so pull-ups are not seen as an effective exercise for these bodyparts. This criterion removes almost all unstable exercises from the bodybuilder’s exercise menu. Standing on an unstable surface will make your balance or, at best, some small stabilizing muscles, the limiting factor in the exercise. This principle also applies to using unstable objects as weights.

Single-arm barbell overhead presses suck for shoulder training because your forearms and the stabilizers in the rotator cuff will give out long before your delts get the chance to do enough work.

2) Compoundedness

For any selection of bodyparts, a compound exercise is superior to more isolated exercises, provided the compound exercise fulfills the other criteria for said bodyparts. This isn’t so revolutionary. If you can train three muscles at once, why train them separately? Compound exercises put much higher neurological, hormonal, and cardiorespiratory demands on your body than simple isolation exercises. Compound exercises are more than a sum of their isolation exercise parts, which is why the guy with the bigger bench press will be more impressive than the guy focusing on flys and skull crushers. Compound exercises also allow your body to spread the external force over multiple joints, which is beneficial for joint health and strength. Basically, they’re a more natural way to move your body and they lend themselves to meeting the other exercise criteria better than isolation exercises alone.

That is not to say isolation exercises are useless. They absolutely have their place, but they can never rival compound exercises and should never be prioritized over them when it comes to getting big or strong.

You can certainly include curls in your program, but only if the program already contains compound pulling exercises. However, note the second part of this principle’s original definition: For any selection of bodyparts, a compound exercise is superior to more isolated exercises, provided the compound exercise fulfills the other criteria for said bodyparts. That means chin-ups are superior to the combo of Scott preacher curls and straight-arm pulldowns, because chin-ups train the lats and biceps in the manner that meets at least all the same criteria (which we’ll learn in a moment) and possibly some others. Chin-ups in this example are at least as good as the isolation exercises in every aspect and even better in some ways. An economist would say, chin-ups dominate Scott preacher curls and straight-arm pulldowns. However, when it comes to triceps work, the bench press is not superior to overhead extensions because the standard bench press doesn’t work the triceps through the full range of motion and it thus leaves the long head understimulated.

As such, overhead extensions and bench presses can’t be directly compared using the compoundedness criterion. They’re just different, like comparing a hammer and a screwdriver. Both can be good tools, but they can’t do each other’s job very well.

3) Range of Motion

The more an exercise moves joints through their full range of motion, the better it is, overlooking the other criteria. It has been empirically demonstrated that lifting with a full range of motion (ROM) is superior to a partial ROM for building strength. For size there was also a trend towards significance in the one study that measured it. Another study found that full ROM training is better than partial ROM training even when you use a partial ROM exercise for all parts of the full ROM. So full ROM bench presses are generally more effective than heavy partials in the bottom, middle and top position combined. Furthermore, using full ROM increases your mobility for that movement pattern and increases the muscles’ length and it does so more effectively than stretching.

Increasing the ROM also increases the compoundedness of the exercise.

Partial squats are only somewhat effective for training the quads and maybe the spinal erectors, but full squats effectively involve the entire posterior chain. Lastly, training with a full ROM is easier on your nervous system and your joints because lighter loads can be used. Wait, what? Using less weight creates a better exercise? Yes. If absolute, maximal weight was all that mattered, everybody would be doing isometric-only or eccentric-only exercises and they’d be outgrowing clothes faster than a Kardashian marriage. But that’s clearly not the case. We all know that, ideally, the bar should touch the chest when we bench press and shallow quarter squats are only done by frat kids in between sets of curls, but few people realize that the ROM principle is actually applicable for all exercises. For almost every pulling or pushing movement, whatever implement you’re gripping (bar, dumbbell, cable handle) should touch your body at some point during the exercise. That includes pull-ups, rows, and overhead presses. The ROM principle also dictates that the optimal grip for most exercises is near shoulder width. The way most human bodies are built, right around shoulder width offers the greatest ROM for pushing and pulling movement patterns, unless your hands actually become an interference to the ROM, like during the military press, in which case your hands have to move slightly outward.

In short, cutting down the ROM on an exercise demands a damn good reason. And for the record, “a shorter ROM lets me go heavier, and that gives me an ego-boner,” is a damn silly reason.

Featured Athlete: Kelechi Opara

4) Tissue Stress Distribution

The more an exercise’s stress is applied to its targeted structures, and the less stress is applied to peripheral tissue, the better the exercise, overlooking the other criteria. Evidence for the tissue stress distribution principle comes from many sources, including studies on EMG activity, isolation versus compound movements, open versus closed chain movements and machine versus free weight movements. Targeted exercises should stimulate your muscles maximally and target other tissues, like tendons, only insofar as their adaptations are required for maximum muscle growth. Factors like bone density, tendon strength, and cardiovascular health tend to take care of themselves if you do high-intensity compound exercises, so you don’t need to worry about actively strengthening anything other than your muscles. For more information on how to maximally stimulate individual muscles, see my previous Muscle Specific Hypertrophy articles (Part 1 and Part 2). Applying this criterion further is generally done on an individual exercise basis and partially depends on a person’s anthropometry (that is, body proportions), but some generalizations can be made.

The following are essentially sub-criteria of this principle:

  • Your body isn’t structurally adapted to pushing against things that are behind your body; it’s unnatural and causes unnecessary shoulder stress. As a result, exercises such as dips, behind-the-neck presses, and behind-the-body side or front raises should be excluded due to this criterion.
  • The “core” is structured to stabilize the spine, not move it. Spinal movement, especially flexion, is unnecessary for bodybuilders. Never round your back: keep it flat or arched. Anatomical position is almost always the optimal position for force transfer, maximal core muscle activation, and minimal peripheral tissue stress, such as spinal shearing forces.
  • The more an exercise forces your body into a specific movement pattern, the worse the exercise, overlooking the other criteria. So, dumbbells are more favorable than barbells which are more favorable than machines. Free weights generally have a very acceptable tissue stress distribution, while machines rarely do.
  • Closed kinetic chain exercises are superior to open kinetic chain exercises, overlooking the other criteria.

Use this simple test to see if an exercise has an open or closed kinetic chain. When you apply force to an object, either you move or that object will move.

If you move, the exercise’s kinetic chain is closed. If the object moves, the exercise’s kinetic chain is open. The classic example is to think of a push-up compared to a flat dumbbell press. In the first, you’re moving (closed chain), and in the latter, the object is moving (open chain). Closed chain exercises allow your body’s structure to determine which joints move and how much, which takes stress off of the joints and lets the muscles do the work instead. This finding has been replicated many times and is hugely underrated. Closed chain exercises are better for your joints and your muscles. This is why squats are superior to leg presses and pull-ups are superior to pulldowns. It’s also why rows, bench presses and military presses aren’t perfect. As a final illustration of the tissue stress distribution principle, consider bench pressing using a barbell or the smith machine. Many bodybuilders intuitively think the bench press activates more stabilizer muscles, but the smith machine activates the prime movers more. Wrong.

Using a barbell does increase stabilizer muscle activity, but the stress of the extra weight that can be used in the smith machine goes to your joints and prime mover activity is actually the same.

5) Dynamic Contraction

Exercises that consist of an eccentric and a concentric portion are superior to exercises that are purely isometric, concentric, or eccentric, overlooking the other criteria. Long-term studies that measure increases in cross-sectional area (muscle mass) consistently support this concept.

Contrary to popular belief, the hierarchy of muscle building according to a systematic review and meta-analysis is:

  1. Eccentric-concentric contractions
  2. Isometric contractions
  3. Concentric only contractions
  4. Eccentric only contractions.

Dynamic contractions, a term I use here to describe movements with a concentric and eccentric portion, are also easier on your joints and allow for higher force production during the concentric phase. This principle reinforces the same theme that’s been present in many principles so far. “Natural” movements, in the sense of a movement being dictated by the structure of your body, are best. You’re strongest on the concentric when it’s immediately preceded by the eccentric phase of a movement.

That’s how you naturally jump, kick in doors, and throw heavy objects at people doing curls in the squat rack. Oh, and it’s the most effective way to do most exercises, too.

6) Strength Curve = Resistance Curve

The closer the resistance curve of an exercise approximates a healthy trainee’s strength curve, the better the exercise, overlooking the other criteria. If an exercise’s strength and resistance curves don’t match, some muscles involved in the lift will remain understimulated. You know how you usually fail exercises at the same point? Ideally, that point shouldn’t exist and muscle failure should only occur at points where your underdeveloped bodyparts can no longer apply enough force. That way, the exercise would allow you to develop all the muscles used in the lift in a perfectly, structurally-balanced manner. Note the explicit mention of a healthy trainee in the principle. If you routinely fail to lock out your deadlifts, that’s not a problem with the deadlift itself. It’s a problem with your structural balance. You, most likely, have disproportionately weak glutes, which are creating the sticking point at lock-out.

Exercises that satisfy this criterion would more or less automatically balance you out, because, in the case of the deadlift, your glutes would receive a greater training effect than the other muscles used.

The resistance curve for many exercises is flat, meaning there’s a constant resistance. The weights don’t change mass and gravitational acceleration is constant, unless you’re training on a space station in orbit. Exercises that require the weight to move vertically (directly opposed to gravity’s line of pull) therefore have a constant resistance curve. Exercises in which the weight moves in a “circular” fashion (think leg extensions and barbell curls) normally have resistance curves that have maxima where the moving body parts are horizontal and minima where the moving body parts are vertical. For example, the biceps are under minimal resistance at the bottom of a dumbbell curl and they’re handling maximal resistance at 90-degrees flexion (the midpoint).

That may seem easy enough, but to determine the exact resistance curve for other movements, you may need a solid understanding of physics.

How do you determine your strength curve?

Well, other than paying attention and simply feeling where you’re strongest and where you fail during an exercise, it helps to think of a muscle’s length-tension relationship. A decent rule of thumb is that muscles are strongest in their natural anatomical position (think military posture) or when in a moderately stretched position. For pushing exercises, your strength is generally lowest at the beginning of, or halfway through, the concentric part of the movement. This is why, in the case of the overhead press, bench press, or squat, you’re more likely to fail at the bottom of the rep or before reaching the halfway point. For pulling exercises, you’re generally weakest at the end portion of the concentric. This is why, for example, so many people find it nearly impossible to actually touch their chest to the bar when doing pull-ups.

Note: This is not giving you a cop-out for such an inability. If you can’t touch your chest, you’re weak or fat. Either build some mid and lower trap strength or cut some fat, pudgy.

So how do we match our strength curve to the exercise’s resistance curve?

Many people take the easy way out and simply avoid the hard parts of exercises. The trouble with this “solution” is that it violates the ROM principle.

Reality check: You look like a spaz when you’re doing your quarter-ROM pull-ups.

Power of the chains

An actual, useful solution would be to use accommodating resistance like chains or bands. Several longitudinal studies have found that adding chains or bands to the bench press increases strength gains and a meta-analysis and systematic review of the literature found that studies with variable resistance, intended to equalize the resistance curve to your strength curve, result in considerably greater cross-sectional area growth than studies using exercises with a constant resistance. While it’s also true that some studies have found no differences, that’s most likely because it can be difficult to determine the optimal amount of chain or band to use.

Apply too much added resistance and you negate all the benefits by creating a new sticking point. Apply too little, and you can still squeak out some benefit, but it’ll be sub-optimal. Just like Goldilocks, the right amount will be somewhere in the middle, making the resistance curve equal to your strength curve.

Almost every exercise can benefit from using chains or bands to make the exercise’s resistance accommodate to the optimal strength curve. Of course, you’d sometimes have to get crazily creative to implement this knowledge, and it’d be a constant process of estimation and fine-tuning to determine the right amount of band or chain resistance. If chains or bands aren’t an option for your gym, you can rely on the stretch reflex to train in accordance to this principle. As I mentioned for the dynamic contraction principle, when a muscle lengthens, the strength of subsequent contractions are increased. Popular theory holds that this strengthening is due to elastic energy from the stretched muscle, as occurs when you stretch an elastic band – the farther you stretch it, the harder it pulls. Though that theory is partially correct, comparing the stretching of muscles to that of elastic bands is extremely simplistic and the stretch reflex is, in fact, primarily a neural process.

Muscle lengthening increases signaling for motor neuron activity, so it’s still your muscles doing the work.

If it really were a process of elasticity, it would occur even without an active subsequent contraction. You can easily test this. Dive-bomb down during a squat and see how far you “effortlessly” bounce back up. (Okay, on second thought… just imagine dive-bombing down on a squat. Your patellar tendons will thank you.) Activating the stretch reflex is a good technique that can be used to accommodate an exercise’s resistance curve, especially for pushing exercises. It can also be used for some pulling exercises where strategic momentum can help you to overcome weak points in the movement. Face pulls, for example, have a strength curve that decreases as you move along the concentric portion, making the exercise uselessly-easy at the start and increasingly more difficult as the bar approaches your face. Therefore, they benefit greatly from using momentum. Don’t just pull on the handle. Heave it and make sure it practically brushes your eyebrows at the end.

However, you need to be structurally balanced and injury-free before using any type of strategic momentum. If you aren’t, you’ll just exacerbate your imbalances by allowing the underdeveloped muscles to avoid training stress.

7) Microloadability

The more precisely an exercise’s resistance can be determined, the better the exercise, overlooking the other criteria. The best mass-building exercises lend themselves both to high absolute loads and small incremental loads. Ideally, we want to choose exercises that allow us to increase the max weights used, but we need the ability to take baby steps towards those maxes. Absolute, or maximum, load is generally a limiting factor in bodyweight exercises. Handstand push-ups, for example, are superior to overhead presses with respect to their kinetic chain (closed vs. open), but they’re far worse than overhead presses with respect to their absolute loading. Once you’ve reached beast-mode and you’re doing handstand push-ups for reps, maybe even using a weighted vest, you’ll keep adding resistance how? Yeah, exactly. Incremental loading is actually a limitation for many exercises. Machines have fixed weight increments in their stacks and most gyms only have dumbbells that increase five pounds at a time. Even barbell exercises can only be loaded with the smallest plates in the gym multiplied by two, because lopsided bars are a bad idea, no matter how “small” the extra is on one side. While beginners and intermediates may be able to progress with such rigid increases, the ideal incremental load should be measured in a percentage of the working weight, not necessarily a strict 5 or 10 pounds.

While five pounds may a good incremental increase for squats, it can be inefficient and excessive for shoulder isolation work. This is why small magnetic add-ons, like PlateMates, can be so beneficial. If you have them, be sure to use them. If you don’t have them, put them at the top of your list of “Lifting Toys I Gotta Buy.”

Practical Application of the 7 Principles

Now that you’ve made it through the list, it’s time to see the rules at work.

Let’s apply the exercise selection criteria to a few basic movements.

1) We’re hitting triceps today. Should we do two-arm kickbacks, rope pushdowns, or standing overhead extensions with a rope?

Well, they all have the triceps as the limiting factor, they’re all dynamic contractions, and have no significantly different tissue stress distributions, although ropes are generally easier on the joints. The microloadability depends on your gym’s equipment, specifically the dumbbells and weight stacks, but kickbacks require such small weights that incremental loading is almost always a problem, unless you’ve already ordered those PlateMates. Overhead extensions are the most compound, because the overhead position puts you in full shoulder flexion and allows the long head of the triceps to participate fully, which is not the case in the other two exercises. All three exercises have the potential to use full ROM, but overhead extensions lend themselves best to using it because the resistance curve better approximates the human strength curve. Kickbacks and pushdowns have very little resistance in the stretched position. Overhead extensions also have an increasing resistance curve along the eccentric, which allows you to use the stretch reflex. Therefore… drum roll please… overhead extensions are the best exercise of the three.

2) Everybody says that deadlifts are magical must-have mass-builders, but how does the deadlift really score against the criteria?

I know I’m going to upset a lot of people with this, but deadlifts are not a good mass building tool. First, they are purely concentric and don’t involve dynamic contractions, which is a huge downside. Secondly, deadlifts put the legs through a limited range of motion which is arbitrarily determined by the radius of the standard 45-pound plate. These issues can be partially resolved by not resetting between reps, using a very wide grip, or using an extended range of motion (from a deficit or with smaller plates), but even then, the exercise doesn’t satisfy the limit factor principle. Even with those changes, the grip muscles or the erector spinae are most likely to give out first. Still, deadlifts aren’t even ideal for these muscle groups because they’re both slow-twitch dominant and require relatively-high volume for optimal growth, but working deadlifts with such a high volume will leave your nervous system fried and extra crispy. Deadlifts are a great jack-of-all-trades exercise, but that also makes them a master of none. Bodybuilders are better off using more specific exercises that satisfy all the 7 principles.

However, this isn’t to say that all deadlift variations are bad for bodybuilders. Romanian deadlifts and unilateral deadlifts, for example, remain good exercises.

Final Words

By now, you’ve hopefully absorbed enough to start making more deliberate and intelligent exercise choices. As with the optimizing of all training parameters, exercise selection should be a systematic process based on objective criteria. It’s tempting to do the convenient and comfortable exercises, or the ones that make you feel like a badass, but those feelings are short-lived. We know that the “fun stuff” isn’t always the useful stuff, and vice versa. The physique you build from smart training should be the walking billboard to your dedication to the iron.

I always tell my clients, “Do you want to look good for the one hour you’re inside the gym or for the 23 hours you’re outside of it?” So put the time into analyzing your exercise selection, do the hard work and earn the results.


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