Sensible advice for aches, pains & injuries

Strength Training Surprises

Why building muscle is easier, better, and more important than you thought, and its vital role in injury rehabilitation

updated (first published 2006)
by Paul Ingraham, Vancouver, Canadabio
I am a science writer and a former Registered Massage Therapist with a decade of experience treating tough pain cases. I was the Assistant Editor of for several years. I’ve written hundreds of articles and several books, and I’m known for readable but heavily referenced analysis, with a touch of sass. I am a runner and ultimate player. • more about memore about

Strength training is more useful and more efficient than most people realize, and a valuable component of fitness and most injury rehabilitation — but not for the reasons most patients and professionals think. It is the gym-o-centric, load-bearing exercise that a few guys like to do — bodybuilding, pumping iron. 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! Much of strength training as you thought you knew it is probably a waste of time and even dangerous — but it definitely doesn’t have to be. In this article, I will spell out why strength training really matters and how to do it.

While I hope anyone who’s ever spent time in a gym will find this helpful, it’s mainly written for people with chronic pain and stubborn injuries who are wondering:

Where does strength training fit in to a recovery plan?

The best (and least advertised) benefits of strength training

Over the years, I have come to love strength training for fitness and rehabilitation, but — as always — not for the conventional reasons, some of which are useless or problematic (the classic example is core strengthening, covered below). Fortunately, there are some other reasons to work with your muscles:

A replacement for joint-bashing “cardio”

Contrary to the conventional wisdom, strength training is to some degree also a form of “cardio” or “aerobic” exercise. Fitness does not just equal a stronger heart — it’s primarily skeletal muscles that adapt to all kinds of exercise, get more metabolically efficient, do more with less oxygen and nutrients, and demand less from the heart.1

So muscle substantially defines fitness, and therefore considerable fitness can be achieved with strength training alone — and without the drudgery of relentless cardio workouts, and without their injury and re-injury risks. Such workouts — especially running, cycling, and swimming — are brutal on joints and tendons by nature. The risk of repetitive strain injuries are baked right into them! Strength training can keep you in shape, while also giving severely fatigued anatomy a badly needed rest — rest which is the single most important 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.

Doing “cardio” exercise for its own sake may be a worst case scenario: tediously slaving away on the stationary bike or Stair Master at the gym thinking that you are doing it for your heart, when all you’re really doing is eating up your day and grinding away at your joints, inefficiently training muscles that could be trained more efficiently and more safely by moving over to the weight machines.

I’m not saying cardio is useless — that’s would be a rather controversial claim, and hard to support with evidence! But I am saying that it has known and obvious risks, and meanwhile strength training is quite under-rated.

Where is all this coming from?

Some readers heads are spinning by now. There’s some pretty paradigm-nuking stuff in the paragraphs above. Taken to heart, some of it should change how you think about exercise and gyms forever. If you’ve never come across some of those ideas before, you’re not alone: few people have! In particular, the perceived value of “aerobic” exercise is deeply entrenched in conventional wisdom, along with blindness to its risks, and most people have never even considered questioning it.


Body by science

Five stars! This book reads like one of my own: science translated into practice. I learned more from this book than I have from any other book I can think of in years. The mind-blowing factor is high. Many myths well-busted.

But it’s easy to do! Each key point taken on its own is pretty straightforward: yes, runners get hurt, no kidding. And, yes, building your muscles is actually good for more than looking good in a tight shirt — so radical! And it’s easier than people think? That’s probably the most surprising point … but it also has a mountain of science backing it up. And it’s safer? Also very logical, and evidence-based. Every piece here is pretty easy to swallow.

The book Body by Science: A research based program to get the results you want in 12 minutes a week provides more information. It also has far more detailed and specific instructions for weight training. It’s certainly not a perfect book, and some critics think it needs debunking. I agree that they make too much of the idea that strength training is actually equal to cardio — too much speculation without getting down to the evidence. But it’s an interesting read nevertheless, with many good ideas that are well-defended, and aren’t so controversial.

Some quick definitions

Strength training is the only method of building muscle mass and strength, and it is the final, logical 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: lower load, higher reps, just to get comfortable with loaded movements again. And — when you are almost completely recovered already — strength training is an ideal final step.

Spectrum of intensity of rehabilitative exercises
PF-ROM Exercises 25–100 extremely low painless
Mobilize! 25–75 low mild discomfort
Endurance Training 12–50 low to moderate moderate exertion discomfort
Strength Training 6–12 moderate to high strong exertion discomfort

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 it’s done

The physiological changes associated with strength training occur when you exhaust a muscle within a minute or two.2 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!3 — but most people will be just fine with the dials set like so:

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.

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.4

However, do beware of trainers who push too hard and think that you need more than one workout per week.

Bored with tedious strength training prescription? You’re not alone!

Is this you? Your physiotherapist has prescribed a long list of therapeutic exercise that you are supposed to do frequently.

Almost immediately, it’s boring — and difficult. Many of them are what I call “ear wiggling” exercises: it’s hard to contract the muscles that you are supposed to contract. Either you can hardly do the exercise at all, or you can do it but the muscles are small, and it’s weird and frustrating how quickly such a small movement becomes totally exhausting.

But it’s supposed to be hard, you rationalize. That must be the point. The fact that you can just barely lift that 2-pound weight ten times must mean you really need this.

So you keep at it.

For a while. But the problem doesn’t really get a lot better, the exercises never really seem to get much easier, and in fact — honestly — you actually feel kind of gross after most sessions, sometimes even downright worse. And there are so many of them. And there’s no end in sight.

It’s like a life sentence: it seems like you are supposed to do these exercises practically forever, especially because you’re not really getting better …

Why physiotherapeutic strength training exercises often don’t work

Rehabilitative strength training probably does aid rehabilitation in many cases. For instance, two papers have shown that both strength and endurance training were effective for treating neck pain,56 which probably proves at least this much: almost any activity is probably better than no activity. Another pair of studies from 2008 and 2010 both showed that painful shoulder muscles respond well to strength training, getting both stronger and less painful.78

Nevertheless, physiotherapeutic strength training is probably risky. I see an awful lot of clients who are still in pain, despite doing lots of physiotherapy. What could account for this? There are at least three significant problems I can think of …

It’s premature. The muscles in question are usually not ready for strength training yet,9 and are more or less traumatized instead of trained. Specifically, they almost always harbour myofascial trigger points — muscle knots — that sap strength and endurance, yet will be aggravated by overexertion.10

It’s not really relevant. There is a kind of simplistic mentality behind the prescription of strength training exercises — it tends to come from a bull-headed “this part isn’t working so let’s make it work, make it tougher” idea. 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, a cause of pain and injury.11

It’s 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.

And that’s why I see an almost continuous stream of clients who are in various stages of disillusionment about their physiotherapy exercises. I almost never have to tell them stop — most of them already have — just to stop feeling bad about it.

Finding the right balance between too much and too little is a theme that runs through all my articles about therapeutic exercise.

Or is this you? Strengthening your core to no avail!

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 all a weakling in general.

You don’t trust doctors with your back (which is smart, you shouldn’t13), 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 of 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 underwhelming14 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 well. You will feel exhausted, old, vulnerable … discouraged.15

Some 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.

Each of the three most common sources of soft tissue pain can probably be aggravated by strength training. Most pain is probably caused by joint problems, muscle “knots”, and fibromyalgia or other nervous system “freakouts.”16 Moderate, well-chosen exercises can probably be helpful in every case — which partly explains why some people who go to the gym (women, say), those who are a little less gung-ho and focus more on aerobic training, actually tend to do fairly well with it. This was probably the case in each of the four studies references above — there’s an excellent chance that the strength training was cautious and professionally supervised, much less likely to be excessive than what people tend to do on their own. But intense and erratic strength training may be useless and even dangerous.

In particular, you need to beware of trigger points. Joint problems and fibromyalgia aren’t exactly rare, but muscle knots … well, they’re everywhere. There is scarcely any kind of pain or injury problem that they aren’t involved in, either causing it outright, or making it worse, or flaring up in response to it. And significant trigger points make it difficult to do strength training — there are probably neurological, metabolic and straightforward mechanical reasons why muscles with trigger points simply do not necessarily do well when challenged in this way. See Micro Muscles and the Dance of the Sarcomeres for more detailed information.

That said, some people clearly do get good results, so it’s not like you should be afraid to try — just cautious and aware of the possibility of a backfire.

Now — finally — back to the good news

Yes, there is good news! Strength training can be useful, and it can be done safely.

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. When you are ready for it, strength training 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:

And, of course, if you do enough of it you may even get some vanity benefits, hypertrophied muscle cells, “big guns,” a stomach with speed bumps. Wouldn’t that be nice?

All of this is just great … when you’re ready for it.

The psychological edge

Some people can probably benefit from the gym sooner than others, even in spite of trigger points. For a lot of people, especially guys, challenging themselves with weights has huge psychological and emotional benefits — so great that, for a certain type of person, they can outweigh the risks, even when muscles may not be quite ready for strength training.

The same can be true for anyone who has gone through a rational, well-managed rehabilitation process. If you are impatient, if you like endorphins, if you have already tested yourself with endurance training and do not feel too held back by trigger points, then you might be able to exploit strength training sooner — before other people would be considered “ready.”

Strength training can “blast through” the limitations of trigger points in such cases. I’ve seen it a few times, even experienced it occasionally. Obviously, you should not try to do this without being alert for warning signs.

Not just the gym

Of course, some people don’t like gyms. I’m one of them, actually — or used to be, anyway. 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.


Muscle knots are significantly involved in almost every injury or pain problem. And strength training, by definition, demands exactly the worst possible conditions for muscle knots, namely severe muscle fatigue — so please be careful when strength training. If it aggravates your symptoms or leaves you feeling drained … go back to endurance training!

But strength training is an important final step in rehabilitation for those who are ready: either when trigger points are mostly under control, or perhaps a little earlier for those who really enjoy hard exercise.

About Paul Ingraham

Headshot of Paul Ingraham, short hair, neat beard, suit jacket.

I am a science writer, former massage therapist, and I was the assistant editor at for several years. I have had my share of injuries and pain challenges as a runner and ultimate player. My wife and I live in downtown Vancouver, Canada. See my full bio and qualifications, or my blog, Writerly. You might run into me on Facebook or Twitter.

Related Reading


  1. 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 various ways, but my favourite is the experiment that trained only one leg in cylists, 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! BACK TO TEXT
  2. Kisner C, Colby LA. Therapeutic exercises: foundations and techniques. 3rd ed. FA Davis Company; 1996. BACK TO TEXT
  3. 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. In a fascinating radio interview about the paper (see Exorcizing Myths about Exercise), co-author Dr. Eric Hoffman says, “If we take two friends and enter them into a resistance training program, you could find that the one friend would trip all their muscle strength, whereas we have cases in the study of the other friend who either gains no strength, and we have some subjects that even lose a little strength.”

  4. 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.”

  5. 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.”

  6. 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 oflasting 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 reduce 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 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).

  7. 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.

  8. 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.

  9. Mense S, Simons DG, Russell IJ. Muscle pain: understanding its nature, diagnosis and treatment. 1st hardcover ed. Lippincott Williams & Wilkins; 2000. p. 216. “EMG studies indicate that in muscles with active trigger points, the muscle starts out fatigued, fatigues more rapidly, and becomes exhausted sooner than do normal muscles.” BACK TO TEXT
  10. Mense S, Simons DG, Russell IJ. Muscle pain: understanding its nature, diagnosis and treatment. 1st hardcover ed. Lippincott Williams & Wilkins; 2000. p. 214. “Disturbances of motor function caused by trigger points include weakness of the involved muscle function, loss of coordination by the involved muscle, and decreased work tolerance of the involved muscle. Weakness and the loss of work tolerance are often interpreted as an indication for increased exercise, but if this is attempted without inactivating the responsible trigger points, the exercise is likely to encourage and further ingrain substitution by other muscles, with further weakening and deconditioning of the involved muscle.” BACK TO TEXT
  11. Howls of protest! But consider one of the most trendy of all strength prescriptions: hip strengthening to treat lower body injuries, because allegedly hip weakness causes them in the first place. It’s been in all the glossy running mags, and it is touted as being science-based … and yet the actual evidence is pathetic if you go looking, and the connection is definitely not clear, let alone proven. See Does Hip Strengthening Work for Runner’s Knee? The popular “weak hips” theory is itself weak: hip weakness is not clearly a cause of problems like IT band pain or patellofemoral pain. BACK TO TEXT
  12. 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. BACK TO TEXT
  13. 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 — and 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!

  14. 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. BACK TO TEXT
  15. Mense S, Simons DG, Russell IJ. Muscle pain: understanding its nature, diagnosis and treatment. 1st hardcover ed. Lippincott Williams & Wilkins; 2000. BACK TO TEXT