Exercise is the closest thing there is to a miracle drug,12 and strength training is one of the best kinds of exercise, practically like magic: more healthy and more efficient than most people realize, and a valuable component of fitness and most injury rehabilitation, but not just for the reasons most patients and professionals think. It is the gym-o-centric, oomphy style of exercise that mostly guys like to do — bodybuilding, pumping iron, powerlifting. Nearly everyone else ignores strength training, except during occasional New Year’s resolution phases, or when prescribed and/or supervised by a physical therapist.
Please don’t dismiss it! In this article, I will spell out why building strength truly matters to ordinary folks, and how to do it — and technique is amazingly unimportant. Wearing muscles out, by any means, is usually good enough for the average person or even the average athlete.
While I hope anyone who’s ever spent time in a gym will find this guide helpful, it’s especially written for people with chronic pain and stubborn injuries who are wondering: Where does strength training fit in to a recovery plan? While it does have a vital role in rehab, it’s not a “treatment”: weakness is rarely the reason people are injured or in pain to begin with, and strengthening is rarely an effective prevention or treatment for injury. But it is a crucial part of load management — an ideal way of taking baby steps back to normal function and then beyond into better-than-ever territory.
The best (and least advertised) benefits of strength training
Over the years, I have come to love strength training for fitness and rehabilitation, but not for entirely conventional reasons, many of which are problematic. Fortunately, there are some other great reasons to challenge your muscles regularly:
- Strength training is more efficient and easier than most people realize, requiring less of a commitment. This particularly surprising point is covered in great detail in a separate article. It also has more lasting benefits than most people realize — permanently improved muscle cells!34
- Strength training is much better for general fitness, health, and weight loss than most people realize, and specifically it can partially replace so-called “cardio” workouts, which are highly repetitive and time-consuming and are a risk for all of the common repetitive strain injuries (RSIs like iliotibial band syndrome, plantar fasciitis, shin splints and several more). For instance, making muscles work hard is “essential” for people with diabetes, because there’s good evidence it controls blood sugar at least as well as aerobic workouts and probably better.5 It’s also anti-inflammatory and good for brain health, just as we have long known about exercise in general.6
- Strength training can be done safely and precisely, particularly aided by machines, so that you can pursue fitness without aggravating existing injuries or risking new ones — a critical rehabilitation advantage that is under-rated or missed entirely by nearly all professionals. Even many personal trainers fail to emphasize this. This makes it a great tool for “load management” in injury rehab.
- only a few key exercises per workout
- 1–2 sets per exercise
- sets separated by a couple minutes rest
- each set lifting about as much as you can keep in the air for a couple seconds, or 10–20 slow- to medium-speed repetitions per set
- about a week of rest between workouts (see below)
- Direct, simple injury has to be at the top of this list. It’s not as common as people fear — powerlifting is amazingly safe for backs, for instance — but it’s not exactly rare either. Bad things can happen when you are moving around heavy things, primarily muscle strains (tearing muscle), but also sprains, contusions, overuse injuries, and a long list of miscellaneous and straightforward accidental damage. But this list is more about the non-obvious possibilities …
- Misdiagnosis is a large category of ways that strength training can go wrong. Some problems that appear to be “simple” musculoskeletal problems, like back pain, actually have medical causes, some of them ominous, such as pain caused by a tumour, or a drug side effect. The failure to diagnose such things correctly can lead to prescriptions of completely ineffective or harmful strength training. Here’s just a few key examples, and there are probably dozens more (because there are so many surprising ways to hurt):
- While training to look the part of Spartacus, actor Andy Whitfield pushed through a lot of back pain, assuming it was a normal reation to the intense training, but it was actually a cancer that killed him a few months later. Such scary causes of back pain (and other pain) are rare, but not rare enough — the possibility should not be ignored. A benign back tumour tormented a personal friend of mine, pressing on a nerve, for about five years before it was diagnosed. During that time, he tried strength training a couple times, with predictable, miserable results … and then he was decisively cured by surgery.
- Another “tumour”: One of my readers had runner’s knee (iliotibial band syndrome) caused by a benign cyst stuck under his IT band like a rock in a shoe: good luck treating that with strength! All you’re going to do is piss it off.
- Hypermobility (hypermobility spectrum disorders and Ehlers–Danlos syndrome) is usually caused by complex genetic defects that have poorly understood effects on muscle and connective tissue. Patients are often chronically sore and suffer from a parade of miscellaneous “unrelated” musculoskeletal problems that can go undiagnosed for years, even a lifetime. It’s possible that strength training is doomed to backfire with these patients. Or perhaps they need strength training more than anyone? But only with much greater caution than average, and probably much more than they are likely to suspect the need for.
- Chronic fatigue syndrome (unexplained fatigue, also often overlapping with chronic pain, which is why I’m including it here): these patients may seem like ideal candidates for exercise therapy, but if the cause of the fatigue is myalgic encephalomyelitis — a nasty infectious neurological disease that routinely evades diagnosis — exercising can backfire severely,27 and might even make the condition permanently worse.28
- Facioscapulohumeral muscular dystrophy (FSHD) is a common and mild form of muscular dystrophy that can cause only minor symptoms for decades, including and especially weakness, soreness, and chronic musculoskeletal complaints … exactly the kind of trouble for which strengthening is often prescribed! And it might help mitigate the problem, but patients will certainly be much more vulnerable to exercise overdose, and of course their problems cannot actually be solved by strength training.
Aggravating RSIs. You can certainly go wrong getting strong if you have one of the common overuse injuries like shin splints or plantar fasciitis and you start doing too much training, too soon. Overloading cannot fix overloading! Strengthening is a risky activity before the tissue has calmed down enough to tolerate new challenges. And yet this an extremely common mistake. The belief that the injury was caused by a weakness and therefore can be fixed by “toughening up” — that’s the corrective exercise trap at work there — often leads to over-training in the early stages of rehab from these injuries.
It’s also worth noting that they are often driven by natural vulnerability to relatively normal loading — not “overuse” per se — and so anything less than extraordinary caution with dosing can easily make them worse. Patellofemoral pain is the canonical example: that joint is naturally biomechanically extreme, and can get overloaded even with normal use.
- Frozen shoulder can get severely exacerbated by any attempt at strength training, no matter how careful. This condition can even flare up badly even just with range of motion exercises.
- Neuropathies — pain caused by trouble with nerve tissue — can be seriously exacerbated by resistance training. These conditions are often surprisingly subtle and undiagnosed, but misdiagnosis probably isn’t the main problem: it’s the underestimation of their vulnerability to exercise therapy in general and strength training in particular.
- Chronic achilles tendinopathy is prone to rupture, and can be triggered by rehabilitative strength training, especially rapid loading (eg plyometrics). While carefully managed eccentric loading might be therapeutic, it’s not totally clear, and exactly how much load these tendons can handle without breaking is largely unknowable.
- Sensitization often involves greatly reduced load tolerance … so much so that even cautious resistance training is ineffective at least, hazardous at worst. Since sensitization is probably a factor in most stubborn injuries, this is highly relevant to a lot of rehab, especially for the worst cases. Chronic widespread pain is related to sensitization (lots of overlap), may eventually benefit from building their strength, but often have such poor load tolerance that they just can’t handle resistance training — at first for sure, maybe never.
- Anxiety and hypervigilance. Some people are indoctrinated to believe that the point of strength training is to fix weakness (especially “core” weakness) that makes them vulnerable to injury. Belief in fragility can become a major factor in future episodes of pain, especially back pain, which is notoriously sensitive to such anxieties.29 It can also lead to a great deal of wasting time if people focus on training obscure muscles far beyond their functional needs.
- Trigger point exacerbation. The sore spots that most of us often develop in soft tissue are poorly understood,30 but they probably involve some vulnerability to physical stress, but anecdotally it seems like physical stress often does bother them, and it makes a certain amount of sense.31 They may flare up if you’re not careful, even if they respond well to cautious progressive training. I think quite a few “injuries” at the gym are not muscle strains (tears) but simply aggravated trigger points, which can be so acute that they feel like injuries.32
- blood flow is increased far more than any massage could ever do, capillaries open up wide, the entire system mobilizes resources to supply hungry muscles with oxygen and nutrients
- metabolic waste products are produced and washed away at a prodigious rate, probably including old stale ones still lingering in the dregs of trigger points that you mostly (but not entirely) got rid of in earlier stages of recovery
- coordination and neurological function improves with every workout as you “learn” how to actually recruit a respectable number of muscle fibres, which is responsible for most early strength gains
- rusty inhibitory and excitatory reflexes are exercised, normalized, balanced, which probably provides an injury prevention benefit
- Strength Training Frequency — Less is more than enough: go to the gym less frequently but still gain strength fast enough for anyone but a bodybuilder
- Endurance Training for Pain & Rehab — Why endurance training might be a wise alternative to strength training (especially when healing from an injury)
- Mobilize! — Dynamic joint mobility drills are an alternative to stretching, a way to “massage with movement”
- The Trouble with Chairs — The science of being sedentary and how much it does (or doesn’t) affect your health and back pain
- Micro Muscles and the Dance of the Sarcomeres — A mental picture of muscle knot physiology helps to explain four familiar features of muscle pain
- The Strength Athlete (thestrengthathlete.com). Good quality evidence-based blog, coaching, and other resources for powerlifters. A couple of articles of potential interest to PainScience.com readers: interviewed on their podcast in late 2019.
- Strength and Conditioning Research (strengthandconditioningresearch.com). Detailed analysis of exercise science, biomechanics, and applied strength and conditioning.
- The Glute Guy (bretcontreras.com). Great writing and critical analysis of strength science… with a butt focus. 🍑
Nothing’s perfect, of course. It is possible to hurt yourself or aggravate an existing condition, especially a repetitive strain injury, and I review a bunch of caveats in detail below. But, mostly, you “can’t go wrong getting strong.”
If you think lifting weights is dangerous, try being weak. Being weak is dangerous.
Bret Contreras, PhD, lifter, trainer, researcher, more, via Twitter
The corrective exercise trap: strengthening does not prevent or fix injuries
Tedious, specific, “corrective” or “therapeutic” strengthening exercises are a staple and tired cliché of physical therapy. Everyone assumes their rehab montage will involve a lot of disciplined strengthening of specific muscles. “The belief that physiotherapy exercises have to be different from simple strengthening exercises is still common,” writes physiotherapist blogger Adam Meakins. “This is both disappointing and sad.”7
This high-falutin’ use of resistance training is largely based on the simplistic notion that people are injured or in pain because something is weak and needs to be “toughened up.” And that in turn is routinely exaggerated into the more impressive-sounding assumption that there is something in-correct about patients — fragile, weak, crooked — which can be both identified and corrected by specific, expertly prescribed strengthening exercises (and stretching too). This paradigm was born in the 1950s when Dr. Thomas DeLorme was promoting strengthening for injured soldiers.8 “The consensus behind its use was the assumption that people in pain, and/or injured, were weak.”9
But you can “go wrong getting strong” — mostly by doing it for the wrong reasons. This has been called the “corrective exercise trap.”10 The belief that something needs fixing is the trap, the wrong reason. It’s mostly incorrect, and harmful for both patients11 and pros.12 It leads straight to overzealous coaching and training, doing too much, too soon.
There are many good examples of the mania for “advanced” rehabilitative resistance training. You can’t have technical exercise prescription without technical diagnosis, which is why Functional Movement Screen is so popular, even though it was never intended to be a diagnostic tool. Hip weakness is a fashionable cause of running injuries like iliotibial band syndrome or shin splints, and that is closely related to the more general paranoia about “dead butt syndrome,” which in turn is a more specific manifestation of the even more popular notion that we all need good “core strength” to fend off back pain and other injuries. There’s also the upper and lower “crossed” syndromes, posture bogeymen used to justify both strengthening and stretching.
All of those things are mostly nonsense. I discuss most of them more below or in other articles.
Implying that patients are weak and fragile with unnecessary strengthening prescriptions sends a message that probably does more damage than anything it’s allegedly helping. Fixing a “flaw” is a terrible rationale for resistance training… especially when there are much better, valid reasons to do it!
A replacement for “cardio”
Contrary to the conventional wisdom, strength training is just as good for general fitness and weight loss as aerobic exercise.13 Most people believe — ever since the “aerobics” fad in the 80s — that you have to train the heart to get in shape, and you can only train the heart with cardio, but it’s not true: it is primarily skeletal muscles that adapt to all kinds of exercise, get more metabolically efficient, do more with less oxygen and nutrients, and then demand less from the heart.14
So the condition of muscle substantially defines fitness, and considerable fitness can be achieved with strength training alone — and without the drudgery of relentless cardio workouts, and their injury and re-injury risks. Such workouts — especially running, cycling, and swimming — involve significant risk of repetitive strain injury. Strength training can keep you in shape, while also giving severely fatigued anatomy a badly needed rest — rest which is a hugely important but neglected factor in rehabilitation from many of the world’s most common injuries.
By all means, if you are a serious runner, cyclist or swimmer, resume your sport as soon as you can — for the love of it, and for the fitness, because those sports certainly also are good for muscle! But strength training is a valuable and effective substitute, because sometimes you just have to take a break to heal.
Strength training is the only method of building muscle mass and strength, and it is the final step in a progression of rehabilitative exercise intensity. Rehabilitation is all about breaking recovery down into “baby steps.” For the severely injured, the first step is the easiest of all possible exercises: simply moving. After that, mobilizing and stretching: slow, rhythmic, gentle tissue challenges. Then comes some endurance training (which is really just light strength training): lower load, higher reps, just to get comfortable with loaded movements again. And — when you are almost completely recovered already — proper strength training is an ideal final phase.
|Mobilize!||25–75||light, very easy|
|Strength Training||6–12||moderate to high|
Fun fact: for the first few weeks of regular strength training, any strength gains you experience are mostly due to simply learning how to actually contract the muscle you are exercising (“recruitment”). Only after a few weeks of sustained training do your muscle cells start to get bigger (not more numerous), a process called “hypertrophy.”
How to build strength
The physiological changes associated with strength training occur when you exhaust a muscle within a minute or two.15 If you’re not doing this, you might be doing something worthwhile, but it’s not strength training (or not the most efficient strength training).
When you’re training, you can either count repetitions or just go for as long as you can. I prefer the latter for a variety of reasons, but it’s far more common to count reps. I’ve asked for a second big wall clock in my gym, but the management is puzzled by that: I’m the only one timing my sets. Everyone else is just counting reps and doesn’t care how long the set takes.
There’s a never-ending scientific debate about how to optimize the variables for different types of people and different goals by fine tuning the number of sets, the length of the break between sets, the number of workouts per week, and so on — although the last of those, frequency, is quite settled down now. (Hint: less than almost everyone else assumes.)
Regardless, there are going to be individual differences for everyone — evidence strongly suggests that some people, for instance, are literally genetically incapable of strength training!16 — but most people will be just fine with the dials set like so:
|Aerobic||Lower-intensity exercise fueled by oxygen-burning metabolism (lower intensity, e.g. jogging is aerobic).|
|Anaerobic||Exercise too intense to be fueled by aerobic metabolism (e.g. sprinting).|
|Reps||Repetitions of one exercise. “I did 12 deadlift reps.”|
|Sets||A group of reptitions. “I did three sets of deadlifts.”|
|Failure||Exhausting a muscle to the point where it cannot do another rep with good form.|
|Hypertrophy||Increase in size of muscle in response to training.|
|1RM||Abbreviation for “one rep max”: the maximum weight you can move in a single repetition. Often used as a baseline.|
|Controlled lengthening of a muscle, e.g. the biceps while lowering a dumbell.|
What’s this about “exhaustion”?
It’s true, you will be tired after strength training — quite whipped! — but “exhaustion” has a more technical meaning in strength training. Exhausting muscle tissue, or taking it to “failure,” is essential for building strength.
Good, consistent exercise form is crucial in strength training not just because it’s safer — it is the simplest, best way of judging both exhaustion and progress. You know you’ve “exhausted” a muscle when you cannot repeat a contraction without losing good form. And exhaustion is exhaustion: it doesn't matter whether you get there by repeating an easier lift more, or doing a harder one a few times.
If you shake or wobble significantly and can’t stop it, you’ve lost form. If you can’t actually perform the action without squirming into a different position, you’ve lost form. If you can’t do it without bringing in a bunch of other muscles to “pinch hit,” you’ve lost your form.
And, of course, if you start doing fifteen repetitions instead of just twelve before you lose your form … you know you’re getting stronger!
Exhausting muscles requires recovery. How much recovery? How long should you wait before doing the next set?
Less is not less: strength training does not have to be as frequent as you thought!
Most people assume that you have to train muscles at least twice a week to make them stronger, and probably three times per week.
Believe it or not, scientists are actually pretty much unanimous in their agreement about this. In the last twenty years of research, there is barely a single dissenting note! Strange, I know. Exercise science is usually more controversial.
A lot of people are skeptical about this, and should be. But I have an entire article devoted to summarizing the research. If you doubt my word, please check for yourself: nine key scientific papers between 1988 and 2007 are cited, all showing clear evidence that most people can probably reduce their training frequency with little or no change in result. See Strength Training Frequency.
Once or twice per week for a given muscle group is adequate for most people, and three times per week definitely has a diminishing returns problem. Depending on the variables, some people could literally triple their gym time and effort, from 1 to 3 workouts per week, and get no additional benefit. Others might get some benefit, but minimal.
Such time savings are not trivial. Particularly for patients doing strength training only because it’s important rehab, the reduced commitment is truly important — it could easily mean the difference between doing it and not doing it. This is a guess, but it may also be even more appropriate — safer — for people with injuries to take more time for recovery between workouts.
Seriously, hire a trainer
If you are serious about using strength training to bulk up or to complete a rehabilitation process, you should definitely hire a personal trainer and/or a physiotherapist. Not only is it obviously safer to use heavy weights with guidance, you will simply get better results.17
However, do beware of trainers who push too hard and think that you need more than one workout per week.
“Blowing off steam” psychologically is one of the great benefits of strength training
Endurance training is probably the king of exercising as an outlet for frustration, but it’s certainly one of the important side-benefits of strength training too — and lower loads and higher reps and moving briskly from one exercise to the next can easily crank your heart rate well up (which is probably what’s needed for this purpose). Although everyone knows that exercise is good stress management, the interesting explanation for it is not widely known. It’s actually firmly grounded in biology and science: basically, exercise simulates a reaction to a stressful emergency which then also triggers the relaxation and recovery mode that follows. Robert Sapolsky:
The stress-response is about preparing your body for an explosive burst of energy consumption right now; psychological stress is about doing all the same things to your body for no physical reason whatsoever. Exercise finally provides your body with the outlet that it was preparing for.
Why Zebras Don’t Get Ulcers, by Robert M Sapolsky, 255
I think this is one of those really great little “user’s manual” things to understand about our own nature. The biology of stress is all about mobilizing biological resources for intense, life-saving activity, like running like hell from a predator, or (eek) fighting one. The curse of being human is that the same emergency biology can be triggered by abstract concerns, no predators required. But stress and anxiety are still preparing us for an emergency. So go with it — act like there’s an emergency!
The practical problems with “corrective” strength training
Strength training probably can aid rehabilitation in a few cases. For instance, two papers have shown that strength training was effective for treating neck pain,1819 which probably proves at least this much: almost any activity is probably better than no activity. Another pair of studies showed that painful shoulder muscles respond well to strength training, getting both stronger and less painful.2021
However, these benefits are probably the benefits of exercise in general rather than the benefits of strengthening anything in particular.
Strength training as therapy often fails. Why? Three main reasons:
It’s barking up the wrong tree, because of the corrective exercise trap (discussed above). The problem isn’t that people are weak and just need to be toughened up. While I appreciate a certain amount of “use it or lose it,” it’s also kind of like the cause of a headache is not the absence of Aspirin. Strength training probably isn’t the magical missing ingredient when someone is in chronic pain. Almost no one gets into much painful trouble in the first place because they were weak. Weakness is not, by and large, the cause of pain and injury.
It’s too tedious! In my experience the huge majority of people simply cannot stick to a no-end-in-sight regimen of fiddly little strength training exercises. When physiotherapists prescribe large batches of these things, they are simply not coming to terms with the realities of human psychology. In medical science, this is the difference between “efficacy” and “effectiveness”: how things work in theory versus practice.22
Too much, too soon. It tends to lead to poor load management, especially with overuse injuries. There are some ways that strength training can backfire, some that are inevitable, but most are easily avoided by staying in the Goldilocks zone … and encountered regularly when you don’t, which happens all too often, especially due to overzealous coaching and encouragement from personal trainers and physical therapists. I will review many of the specific ways that things can go wrong below, but the point here is just that it can go wrong, and it may not be an overt backfire: often it just subtly sabotages progress, prevents it from doing any real good.
Strengthening your core to no avail!
Probably the ultimate example of therapeutically irrelevant strength training is trying to treat/prevent back pain by strengthening your “core” — muscles around the pelvis, lower back, and abdomen.
Your back hurts. You are generally healthy but, dammit, your back really hurts — and why is that, anyway? You’re generally fit. You take care of yourself. You can’t possibly be a weakling.
You don’t trust doctors with your back (which is smart, you shouldn’t23), and in fact you’re not that keen on seeking help for this kind of thing in general. You’re independent, competent, so you take matters into your own hands. Back hurts? Exercise it.
You’ve heard lots about core stability. That has got to be important for your back. “Core stability” just sounds so good — cores should be stable, right? So it’s off to the gym.
But your results range from underwhelming24 to making a bad situation worse. A few of you will get good results. But several will also end up in pain thinking “What was I thinking?” And most simply won’t get any clear results at all. You will feel exhausted, old, vulnerable … discouraged.25
“You can’t go wrong getting strong” … or can you? The hazards of strength training
Many independent, motivated people in pain will go to the gym hoping to train their pain away, only to discover that it isn’t quite that easy. Some succeed, others fail… and some who fail actually make it worse.
Maybe they heard that “you can’t go wrong getting strong.” The idea that strengthening is almost perfectly risk free is a surprisingly popular concept in rehab and chronic pain treatment, but it’s naive. There’s certainly truth in it, probably more than just a kernel, but it’s wrong a little too often for comfort. That clever rhyme may not be a great thing to tell a lot of patients.
Most risks of strength training go away if you just add one simple caveat: “You can’t go wrong getting strong … with good load management.” Keep the intensity in the Goldilocks zone, no big spikes in intensity, don’t rush it, and most of what might go wrong probably won’t.
There are some pathologies that are deal-breakers for resistance training, but those are mostly irrelevant in the context of typical musculoskeletal medicine. When it comes to working with garden variety aches ‘n’ pains, there is almost no such thing as “going wrong” with strength training if you don’t go too far, too fast. But if you do? With poor load management, you can easily go wrong strength training. And of course a lot of people do overdo it, for many reasons, but chiefly because of that no-pain-no-gain attitude, so extremely prevalent in amateur fitness culture.
We have a theory versus practice problem here that probably accounts for a wide range of opinions on this:26 if you assume sensible dosing and competent coaching, then it really is hard to go wrong getting strong. But, if you focus on the prevalence of amateurish and reckless training “in the wild,” then going wrong is all too likely.
Exactly what can go wrong with strength training
This is a list of specific examples of how strengthening can go significantly wrong without exercising extra caution, which is sadly rare in practice.
The gym is not a perfectly safe place.
Now back to the good news…
Escaping the corrective exercise trap: strength training as a load management tool
Yes, there is good news! Strength training can be extremely valuable in rehab, and it can be done safely. In fact, the whole point is that it’s the ideal way to control how much tissues are challenged — to make sure it’s a “challenge” you can adapt to, rather than a harmful stress you cannot.
Although overloading cannot fix overloading, when you’re ready for it strength training can and should become a valuable component of rehab from nearly any kind of injury or chronic pain problem. It is your most important load management tool. It is extremely flexible and can be performed in a wide range of intensities, and easily customized to stimulate only what you want to stimulate.
You should do strength training when you have already paid your dues doing easier work first. You should do it to cover that last, crucial step from “recovered” to “better than ever.” You should do it to test your tissues, to reveal remaining vulnerability, to demonstrate to yourself that you really are better. It is a powerful way of demanding the highest possible function from your tissues, the most potent way of “using it” instead of “losing it.” The physiological effects are significant and numerous:
Strength training does not just happen in gyms
Some people don’t like gyms. I’m one of them, actually — or used to be, anyway. I have gotten comfortable in them over the last decade.
You should consider trying to overcome gym shyness because (a) the people there are probably nicer than you think, (b) strength training is fairly efficient and you probably don’t need to spend as much time there as you fear, and (c) the precision and control of universal gym equipment has many advantages.
Nevertheless, there are some excellent, creative alternatives to gym training. Your own body weight can be more than adequate for strength training many large muscle groups. Slow deep knee bends, push ups, chin ups, and abdominal roll-ups are all good examples of body-weight-only exercises that many people cannot do many of — good places to start strength training without gym equipment.
However, it must be said that a thorough strength training program simply cannot be done without at least some apparatus. A small investment in a few barbells and exercise bands or tubing (large, colourful elastic bands or tubes) allows for an almost infinite number of strength training options.
Can strength training prevent/treat athletic injuries like runner’s knee?
Early in the article, I questioned the major role of strength training in injury prevention and rehab, but that was a general discussion about the problems with the “corrective exercise trap.” In this section, I’ll go over a few specific examples. What does rehab research have to say about the role of strengthening in preventing injury?
On the bright side, strength training probably can reduce the risk of tearing a muscle, an extremely common sports injury (muscle strain). It makes more sense, and there’s some evidence supporting that.33 But that’s probably the only prominent example.
Repetitive strain injuries in particular — like plantar fasciitis and patellofemoral syndrome — are often seen as a price that active people pay for being weak in some way. Although this has always been a popular view, it’s been given new life since the early 2000s by a lot of hype about hip weakness specifically, which supposedly makes athletes vulnerable to running injuries. This idea started with IT band syndrome, and has spread to virtually every common repetitive strain injury in the knees and ankles and feet.
And so it goes. Unfortunately, hip weakness is just a pet theory that got out of hand.
A 2014 meta-analysis is the best reference available to support a more general claim that resistance training will prevent/treat overuse injuries.38 Unfortunately, “the best” is not very good: the authors’ conclusion about injury prevention is based on data from just four studies of questionable/limited relevance …39 and there is definitely some contrary evidence as well.40
Strengthening might ward off some overuse injuries, but that’s an untested hypothesis, and Lauersen et al simply does not provide meaningful support for it—not even remotely. There are all kinds of other reasons to train your muscles. Use those reasons. You don’t need this one.
About Paul Ingraham
I am a science writer in Vancouver, Canada. I was a Registered Massage Therapist for a decade and the assistant editor of ScienceBasedMedicine.org for several years. I’ve had many injuries as a runner and ultimate player, and I’ve been a chronic pain patient myself since 2015. Full bio. See you on Facebook or Twitter, or subscribe:
Some good strength training resources around the web (mostly for readers who are pretty serious about their strength training):
What’s new in this article?
Eight updates have been logged for this article since publication (2006). All PainScience.com updates are logged to show a long term commitment to quality, accuracy, and currency. more
When’s the last time you read a blog post and found a list of many changes made to that page since publication? Like good footnotes, this sets PainScience.com apart from other health websites and blogs. Although footnotes are more useful, the update logs are important. They are “fine print,” but more meaningful than most of the comments that most Internet pages waste pixels on.
I log any change to articles that might be of interest to a keen reader. Complete update logging of all noteworthy improvements to all articles started in 2016. Prior to that, I only logged major updates for the most popular and controversial articles.
See the What’s New? page for updates to all recent site updates.
2020 — Added a citation about anti-inflammatory and neuroprotective effects of resistance training.
2020 — Another batch of miscellaneous improvements.
2020 — Lots of general editing and modernizing, plus a bunch of new stuff about the “corrective exercise trap,” and idea that was represented here before, but too haphazardly. It’s now much more focused and relevant.
2019 — Minor but nice addition of a “good news” reference about the permanence of a key exercise benefit.
2018 — Added an important point about efficacy vs. effectiveness (see Beedie et al and several more examples of adverse effects of strength training.
2018 — New section: “You can’t go wrong getting strong” … or can you? Some hazards of strength training.
2018 — New section, “Can strength training prevent overuse injuries?”
2016 — Added “Why is exercise healthy?” sidebar.
2006 — Publication.
- Academy of Medical Royal Colleges. Exercise: The miracle cure and the role of the doctor in promoting it. AOMRC.org.uk. 2015 Feb. PainSci #53672 ❐
This is the primary authoritative source of the quote “exercise is the closest thing there is to a miracle cure.”
- Gopinath B, Kifley A, Flood VM, Mitchell P. Physical Activity as a Determinant of Successful Aging over Ten Years. Sci Rep. 2018 Jul;8(1):10522. PubMed #30002462 ❐ PainSci #53004 ❐
If you want to age well, move around a lot!
We already know that physical activity reduces the risk of several of the major chronic diseases and increases lifespan. “Successful aging” is a broader concept, harder to measure, which encompasses not only a reduced risk of disease but also the absence of “depressive symptoms, disability, cognitive impairment, respiratory symptoms and systemic conditions.” (No doubt disability from pain is part of that equation.)
In this study of 1584 older Australians, 249 “aged successfully” over ten years. The most active Aussies, “well above the current recommended level,” were twice as likely to be in that group. Imagine how much better they’ll do over 20 years …
- Schwartz LM. Skeletal Muscles Do Not Undergo Apoptosis During Either Atrophy or Programmed Cell Death-Revisiting the Myonuclear Domain Hypothesis. Front Physiol. 2018;9:1887. PubMed #30740060 ❐ PainSci #52684 ❐
Why is it easier to get back in shape than it is to get into shape in the first place? Some adaptations to muscle training are temporary and vanish quickly if you don't keep working out. But others, like the addition of extra muscle nuclei, appear to be more or less permanent. Nuclei are added as you train so that they can build and manage more proteins in a plumper muscle cell. When you stop training, the cell slowly deflates — atrophies — but the nuclei helpfully remain, dormant, waiting until you are ready to exercise again. See Alex Hutchinon’s more detailed analysis of the study.
- Moberg M, Lindholm ME, Reitzner SM, et al. Exercise Induces Different Molecular Responses in Trained and Untrained Human Muscle. Med Sci Sports Exerc. 2020 Aug;52(8):1679–1690. PubMed #32079914 ❐
Muscles “remember“ strength: when you train, “key regulatory genes and proteins… are influenced by previous training history.” See also Schwartz.
- Codella R, Ialacqua M, Terruzzi I, Luzi L. May the force be with you: why resistance training is essential for subjects with type 2 diabetes mellitus without complications. Endocrine. 2018 May. PubMed #29730785 ❐
Dr. Brad Schoenfeld‘s comment on the study: “The title says it all. Many modalities of exercise are beneficial, but resistance training is the most important activity you can do for overall health and wellness. 💪🏻”From the abstract:
Anaerobic, intense physical activity, such as that of strength or power sports disciplines, is not univocally recognized as safe and simple to realize, however, it is important in stimulating energy and glucose metabolism. According to recent evidence, high-intensity training may be prescribed even in the face of cardiovascular diseases, peripheral vascular disease, or osteoarthritis. Some studies have shown resistance training to be more efficient than aerobic exercise in improving glycemic control. This review explores the most up-to-date indications emerging from literature in support of the beneficial effects of strength stimulation and resistance training in patients with type 2 diabetes without complications.
- Liu Y, Chu JM, Yan T, et al. Short-term resistance exercise inhibits neuroinflammation and attenuates neuropathological changes in 3xTg Alzheimer's disease mice. Journal of neuroinflammation. 2020 01;17(1):4––4. PubMed #31900170 ❐ PainSci #52495 ❐
Lifting weights: good for Alzheimer’s? Good chance. This study clearly showed a neuroprotective effect from resistance training in mice. Compared to mice who were not given cute little barbells!
It has been clear for many years now that exercise in general is neuroprotective — that is, it has an anti-inflammatory effect in the brain and slows down Alzheimer’s disease progression — but that insight mostly comes from studies of aerobic exercise. This study extends that effect to resistance training. Specifically: “improved cognitive performance and reduced neuropathological and neuroinflammatory changes in the frontal cortex and hippocampus of mice… [and] inhibition of pro-inflammatory intracellular pathways.”
Obviously a human study would be more persuasive, but it’s still early days for studying neuroinflammation. Lots of what we now know about exercise physiology we learned from mice initially. It’s likely that the effect will be confirmed in humans as well.
And now, just for fun… how exactly do you strength train mice? A ladder with a treat at the top, and teensy weights attached to their tails! I am not even joking: that really is how they did this. “The mice were motivated to climb up the ladder to a total of 15 times, with progressively heavier weights attached to their tails and a 2-minute rest in between each climb.”
There are many other studies I could have chosen to support the general claim that resistance training has broad health benefits. This is a good example of a particularly valuable effect that is still being illuminated by research.
- The whole post made by physiotherapist blogger Adam Meakins:
The belief that physiotherapy exercises have to be different from simple strengthening exercises is still common.
Physios love to give over complicated, under loaded, corrective exercises in a belief they are superior and more effective.
Then there is the argument that physio exercises are more functional as they are focused on ideal alignment and motor control!
But in my experience these corrective functional exercises are anything but corrective or functional.
Instead these exercises are better described as subversive distraction exercises.
These exercises tend to occupy patients usually just long enough for natural history to kick in and make physios look effective.
The idea that physio exercises have to be different from standard strengthening exercises is due to physios desire to appear different and highly specialised.
This is both disappointing and sad!
- Todd JS, Shurley JP, Todd TC. Thomas L. DeLorme and the science of progressive resistance exercise. J Strength Cond Res. 2012 Nov;26(11):2913–23. PubMed #22592167 ❐
- Lagerman P. Reasoning exercise dosage for people with persistent pain. In Touch. 2018 Autumn;(164):30–35. PainSci #52992 ❐
Lagerman paraphrasing The End of Physiotherapy and Eriksen et al:
Exercise is a key component of the physiotherapist's management repertoire, and physiotherapy has, historically, neglected a broader holistic view of the patient in favor of a reductive perspective of the body which has resulted in treatment exercise being focused on pathology. While this view is the mainstay in the treatment of most acute musculoskeletal conditions, it is ineffective in the management of those patients with persistent pain where causal links to pathology cannot be substantiated.
- Tumminello N, Silvernail J, Cormack B. The Corrective Exercise Trap. Personal Training Quarterly. 2017 Mar;4(1). PainSci #52905 ❐
Tumminello, Silvernail, and Cormack decisively but gently and diplomatically tip over this most sacred cow of personal training and therapy:
In order to spot a physical flaw that needs to be corrected, one must begin by having a reliable measure of whether or not it is actually problematic in the first place.
Spoiler alert: there is no such reliable measure! Corrective exercise is built on wishful thinking. Screening for movement dysfunctions has been failing one fair scientific test after another. The importance of posture has been wildly exaggerated. The importance of anatomical variation has been virtually ignored.
These authors all have excellent credentials and top notch clinical reasoning skills. These are smart guys tackling several thorny sub-topics like postural dysfunction, movement dysfunction, core stability, and — most important of all, I think — the “nocebo concerns” with corrective exercise: “when clients are told such things about themselves from an authority figure (as they might be during some corrective exercise evaluations), that this potentially makes one’s clients less resilient and more prone to injury and pain.”
- Exaggerating the importance of defect-correction is actually dangerous for the patient (nocebic). Tumminello et al again: “When clients are told such things about themselves from an authority figure (as they might be during some corrective exercise evaluations), that this potentially makes one’s clients less resilient and more prone to injury and pain.” Translation sans diplomacy: stop #%&^ telling patients they are fragile and weak!
- Tumminello et al: “The danger here is that many fitness professionals might end up making their training process more about a formalized evaluation procedure and less about good personal training.” In other words, the professional gets stuck in the self-serving belief that this “technical” approach is inherently superior to basics like exercise in general and good load management during rehab. And so they waste their time (and the patient’s) focusing on the wrong thing, cooking up “expert” exercise prescriptions.
- Clark JE. Diet, exercise or diet with exercise: comparing the effectiveness of treatment options for weight-loss and changes in fitness for adults (18-65 years old) who are overfat, or obese; systematic review and meta-analysis. J Diabetes Metab Disord. 2015;14:31. PubMed #25973403 ❐ PainSci #54044 ❐
Resistance training is an excellent method of improving body composition (ratio of muscle to fat) and markers of health (risk of cardiovascular disease). This meta-analyis concluded that weight-loss methods “utilizing exercise were more effective than those that employed just a hypocaloric diet,” and that combining diet with resistance training (weight lifting) was specifically more effective than combining it with endurance (aerobic) exercise. This flies in the face of the popular belief that endurance training is “heart exercise.”
- Your heart and blood vessels themselves do not significantly adapt to any kind of training, but your muscles most definitely do. This critical point has been proven in various ways, but my favourite is the experiment that trained only one leg in cyclists, leaving the other leg out of shape and weak. Their aerobic fitness was great when using the trained leg, but lousy with the untrained leg: clearly, it wasn’t their hearts that changed! (Citation needed. I’m not sure why there isn’t one here. I remember the study, but cannot find it!)
- Kisner C, Colby LA. Therapeutic exercises: foundations and techniques. 3rd ed. FA Davis Company; 1996.
- Hubal MJ, Gordish-Dressman H, Thompson PD, et al. Variability in muscle size and strength gain after unilateral resistance training. Med Sci Sports Exerc. 2005 Jun;37(6):964–972. PubMed #15947721 ❐
This 2005 paper presents good evidence that there may be genetic differences between people that account for a surprisingly wide range of responses to strength training.
- Mazzetti SA, Kraemer WJ, Volek JS, et al. The influence of direct supervision of resistance training on strength performance. Med Sci Sports Exerc. 2000 Jun;32(6):1175–1184. PubMed #10862549 ❐
From the abstract: “Directly supervised, heavy-resistance training in moderately trained men resulted in ... greater maximal strength gains compared with unsupervised training.”
- Nikander R, Mälkiä E, Parkkari J, et al. Dose-Response Relationship of Specific Training to Reduce Chronic Neck Pain and Disability. Med Sci Sports Exerc. 2006 Dec;38(12):2068–2074. PubMed #17146312 ❐
Similar to Ylinen, researchers divided 180 female office workers with chronic neck pain into three groups: one group did strength training, another did endurance training, and a third did nothing. They found that “both strength and endurance training decreased perceived neck pain and disability.”
- Ylinen J, Häkkinen A, Nykänen M, Kautiainen H, Takala EP. Neck muscle training in the treatment of chronic neck pain: a three-year follow-up study. Europa Medicophysica. 2007 Jun;43(2):161–9. PubMed #17525699 ❐
There are only a handful studies of long-term strength training for neck pain: two by this research group (Ylinen 2003, Ylinen 2006), plus their three-year follow-up to the first. They found that a year of regular neck strength or endurance training meaningfully reduced pain and disability. These benefits were sustained for three years in over a hundred women, even though many people didn’t continue training after the first year.
There are only a handful of other studies of exercise for neck pain, which have all failed to detect any of lasting benefit to exercise for neck pain. The results of these studies suggest that “most training studies seem to have been too short-term producing notable physiological changes.” But duration is the key, not intensity: “a relatively small training load is high enough to produce these changes, as there was no significant difference between the strength and endurance training groups with regard to the primary outcomes,” pain and disability.
Although these results are certainly good news, it’s important to keep in mind that not all patients improved completely, and even those who did achieve lasting results had to exercise diligently for a year (although six months might have done the trick, we can’t tell from this data). So strengthening is not a reliable or easy fix for neck pain (the efficacy vs. effectiveness problem strongly applies, see Beedie).
- Andersen LL, Andersen CH, Zebis MK, et al. Effect of physical training on function of chronically painful muscles: a randomized controlled trial. J Appl Physiol. 2008 Dec;105(6):1796–801. PubMed #18948442 ❐ PainSci #54962 ❐
This simple test of strength training as therapy for shoulder pain had positive results in 42 women with shoulder pain, researchers found that “specific strength training relieved pain and increases maximal activity.” Indeed, their pain was reduced 42–49%, and this result was less than 5% likely to be due to random chance.
- Nielsen PK, Andersen LL, Olsen HB, et al. Effect of physical training on pain sensitivity and trapezius muscle morphology. Muscle & Nerve. 2010 Jun;41(6):836–44. PubMed #20513105 ❐
In this experiment, 62 women (40 with shoulder pain, 20 without) participated in either a general exercise program or specific strength training for their shoulders. Pain tolerance and strength increased response to strength training in the women who started out with pain. In those who had no pain to begin with, both general exercise and specific exercise training were beneficial.
- “Efficacy” is how well a treatment works in ideal circumstances, such as in a carefully contrived scientic test. Unfortunately, real life is rarely ideal! (You may have noticed.) “Effectiveness” is how well the same thing works in typical clinical settings and patients’ lives. Which is what matters to most patients. A 2015 editorial in the British Journal of Sports Medicine explains that exercise (in a physical therapy context) is well-known to be efficacious, but often is not effective. That is, it works well when tested in the lab, but not so much for real patients. Again, effectiveness is what matters to patients! If effectiveness is low, only a few lucky and/or disciplined people can realistically expect to benefit.
- Doctors are unqualified to care properly for most common pain and injury problems, especially the stubborn ones, and this has been proven by other doctors: Stockard et al found that 82% of graduates lacked “basic competency” in this area. For more information, see The Medical Blind Spot for Aches, Pains & Injuries: Most physicians are unqualified to care for many common pain and injury problems, especially the more stubborn and tricky ones.
- Smeets RJ, Wade D, Hidding A, et al. The association of physical deconditioning and chronic low back pain: a hypothesis-oriented systematic review. Disabil Rehabil. 2006 Jun;28(11):673–693. PubMed #16809211 ❐
This 2006 review is painfully vague about the importance of low back muscle condition in chronic low back pain. Although there is some evidence that suggests that core stability training is good for back pain (see O’Sullivan), it’s nowhere near as strong as it should be, considering how popular the concept has been for the last fifteen years. Cardiovascular training for back pain has barely been studied, and the authors found no high quality studies of that at all — an unfortunate gap. There is only a little evidence of wasting of the deep multifidus muscle (which many assume to be deconditioned in back pain, though it could easily just be a symptom of being in pain, not a cause of it). They also conclude from the available evidence that “general and lumbar muscle strengthening are equally effective as other active treatments,” and the authors believe that it is “more promising” to study “the interplay between biological, social and psychological factors.” Not exactly a resounding endorsement of going to the gym for your low back pain!
- When I read this, it sounds like I am trying to use scare tactics to make my point, and I know that the research evidence shows that many people with low back pain do feel better when they exercise. But what can I say? I cannot ignore my own experience, subjective as it is: I’ve met a lot of clients who did not feel better for working out. A thousand things could account for the difference, starting with the fact that people who participate in scientific research are having a different experience in so many ways than the independent person training without guidance. This may be why Smeets et al. thought that it was “more promising to further explore the interplay between biological, social and psychological factors” than it was to study the connection between muscle deconditioning and low back pain. The bottom line is that the jury is out — and there is obviously something risky about going to the gym when you have low back pain.
- I conducted informal polls on both Facebook and Twitter, and responses were quite diverse. As expected, at least some pros clearly truly believe that you literally “can’t go wrong.”
- These waters have been muddied by the infamous “PACE” trial, a big British experiment which concluded that graded exercise therapy was helpful for myalgic encephalomyelitis patients. But the PACE trial has been tainted by scandal and harshly criticized as “uninterpretable.” There are good reasons to believe that PACE got it disastrously wrong, and exercise actually hurts ME patients: see Shepherd.
- “We hypothesize that these crashes, or episodes of heightened fatigue, may have a cumulative effect on a patient’s health, and may compromise the patient’s potential for a full recovery.” From: Instructions for Stanford Chronic Fatigue Syndrome Patients.
- Ingraham. The Mind Game in Low Back Pain: How back pain is powered by fear and loathing, and greatly helped by rational confidence. ❐ PainScience.com. 1446 words.
- Ingraham. The Trigger Point Identity Crisis: The biological evidence that a trigger point is a lesion in muscle tissue. ❐ PainScience.com. 3775 words.
- The “integrated hypothesis” of trigger point formation, while controversial, describes a tissue state that might very well impair strength and make the muscle more vulnerable to mechanical strain. Even more specifically, the metabolic state of a trigger point, and the idea that it’s a micro-cramp, are both plausible specific reasons why trigger points might not combine happily with strength training.
- Even if you discard the idea of trigger points entirely, you can easily just cite the more generic idea or “functional” muscle injury or “fatigue-induced muscle disorder,” which is basically something between normal post-exercise soreness and outright trauma. Certainly not all muscle injuries are as pathologically straightforward as you might think. See Mueller-Wohlfahrt et al, and I discuss this in detail in my muscle strain book.
- Tyler TF, Schmitt BM, Nicholas SJ, McHugh MP. Rehabilitation After Hamstring-Strain Injury Emphasizing Eccentric Strengthening at Long Muscle Lengths: Results of Long-Term Follow-Up. J Sport Rehabil. 2017 Apr;26(2):131–140. PubMed #27632842 ❐
- Ingraham. Does Hip Strengthening Work for IT Band Syndrome? The popular “weak hips” theory is itself weak. ❐ PainScience.com. 3722 words.
- Becker J, Nakajima M, Wu WF. Factors Contributing to Medial Tibial Stress Syndrome in Runners: A Prospective Study. Med Sci Sports Exerc. 2018 Oct;50(10):2092–2100. PubMed #29787473 ❐
The researchers measured hip strength in a couple of dozen athletes and then waited (two years) to see who would develop medial tibial stress syndrome (a prospective study, which is the right way to do it). The runners who developed medial tibial stress syndrome originally had weaker hip abductors (that’s the muscles on the sides of the hips). It wasn’t a dramatic difference, but it was detectable and clinically significant… if it’s real.
- Yagi S, Muneta T, Sekiya I. Incidence and risk factors for medial tibial stress syndrome and tibial stress fracture in high school runners. Knee Surg Sports Traumatol Arthrosc. 2013 Mar;21(3):556–63. PubMed #22875369 ❐ Although hip strength was studied, it wasn’t even mentioned in the summary of results: no detectable link.
- Luedke LE, Heiderscheit BC, Williams DS, Rauh MJ. Association of Isometric Strength of Hip and Knee Muscles With Injury Risk in High School Cross Country Runners. Int J Sports Phys Ther. 2015 11;10(6):868–76. PubMed #26618066 ❐ PainSci #52536 ❐ “Hip and knee muscle strength was not significantly associated with shin injury.”
- Lauersen JB, Bertelsen DM, Andersen LB. The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis of randomised controlled trials. Br J Sports Med. 2014 Jun;48(11):871–7. PubMed #24100287 ❐ PainSci #53226 ❐
- All the 4 studies are of the lower limb, two of them about hamstrings and eccentric training, both of which have limited applicability to the question of preventing overuse injuries (most injuries of the hamstrings are not overuse injuries, and eccentric training is not typical resistance training). The third was a study of ACL injuries, which are traumatic, not overuse, so that doesn’t contribute to the case for preventing overuse injuries. And the final one was for patellofemoral pain, which does count, but its results are hardly decisive (see Coppack et al).
- Brushøj C, Larsen K, Albrecht-Beste E, et al. Prevention of overuse injuries by a concurrent exercise program in subjects exposed to an increase in training load: a randomized controlled trial of 1020 army recruits. Am J Sports Med. 2008 Apr;36(4):663–670. PubMed #18337359 ❐