published 12/14/06, updated 7/23/10

Strength Training and Injury Rehabilitation

Everything you need to know about strength training for rehab

by Paul Ingraham, Vancouver, Canada MORE
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Credentials and qualifications

I am a writer and retired Registered Massage Therapist (unusually well-trained for a massage therapist, a 3000-hour program). I’m almost done with a Bachelor of Health Sciences degree. I am a peer reviewer for The Natural Standard, and a copyeditor for Science-Based Medicine. My most important qualification is more than a decade of workaholic post-graduate study, clinical experience, and constant conversations with readers from around the world, including many experts who have provided countless suggestions and criticisms.

For more information, see: Who Am I to Say? More information about my qualifications, credentials and professional experiences for my readers and customers.

Strength training is weight training, bodybuilding, pumping iron: “high load, low reps.” But it is also a common therapeutic exercise, routinely prescribed by physical therapists to help people recover from injury and pain problems. Much of this activity may be futile and risky, however.

Strength training has value, but there are quite a few “gotchas” that I wish were more widely understood by health care professionals and the general public. I’ll outline these here, and also spell out just exactly when strength training actually is appropriate, and how to do it.

While I hope anyone who’s ever spent time in a gym can get something valuable out of this article, it’s mainly written for people with chronic pain, with injuries that just don’t seem to ever heal, who are wondering where strength training fits in to their recovery plan.

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 endurance training: low load, high reps. And — when you are almost completely recovered already — strength training is the ideal final step to consolidate your gains.

	Repetitions	Loading	Challenge
Spectrum of intensity of rehabilitative exercises
PF-ROM Exercises	25–100	extremely low	painless
Mobilizing!	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 several weeks of strength training, any strength gains you experience are mostly or entirely 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 six to twelve consecutive repetitions.1 If you’re not doing this, you might be doing something worthwhile, but it’s not strength training (or not the best strength training).

If you’re not exhausting muscles in 6–12 reps, you’re not strength training.

A batch of repetitions is called a “set,” and there’s a never ending scientific debate about how to optimize strength training 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. It’s important to understand that it’s different for everyone — evidence strongly suggests that some people, for instance, are literally genetically incapable of strength training!2 — but most people will be just fine with 3 sets per muscle or muscle group, allowing 3–4 minutes of rest between each set,3 and 2–4 days of rest between workouts.4

What’s this about “exhaustion”?

It’s true, you will be tired after strength training, but “exhaustion” has a more technical meaning in strength training. Exhausting muscle tissue, or taking it to “failure,” is essential for buildings 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 a fifteen repetitions instead of just twelve before you lose your form … you know you’re getting stronger!

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.5

Is this you?

Your physiotherapist has prescribed a long list of therapeutic exercise that you are supposed to do every day.

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.

Your physiotherapist has prescribed a long list of therapeutic exercise that you are supposed to do every day.

But it’s supposed to be hard, right? That’s 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,6 7 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.8 9

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 muscle in question are usually not ready for strength training yet,10 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.11

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” idea. While I appreciate the “use it or lose it” aspect of this, which seems sound to me, I have to say it’s not otherwise well thought out. It’s 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!

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” idea.

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.12

Or is this you?

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 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.14 So it’s off to the gym.

But your results range from underwhelming to disastrous. A few of you will get good results. But several will also end up in severe pain thinking “What was I thinking?” And most simply won’t get results. You will feel exhausted, old, vulnerable … discouraged.15

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.

Each of the three most common sources of soft tissue pain responds 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 professional 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 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 — 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 enormous and numerous:

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, probably significant protection from future

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.

For a lot of people, especially guys, challenging themselves with weights has huge psychological and emotional benefits.

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, although I have spent a good amount of time in them anyway.)

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.

Your own body weight can be more than adequate for strength training.

However, it must be said that a thorough strength training program simply cannot be done without at least some apparatus. However, a small investment in a few barbells and exercise bands or tubing (large, colourful elastic bands or tubes) allows for almost infinite number of strength training options.

Conclusion

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.

Notes

Kisner et al. Therapeutic Exercises. 1996. Return to text.
A 2005 paper presents evidence that there may be genetic differences between people that account for a surprisingly wide range of responses to strength training (see Hubal). 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.”
Return to text.
Kisner et al. Therapeutic Exercises. 1996. p60. Return to text.
Kisner et al. Therapeutic Exercises. 1996. p85. Return to text.
Mazzetti et al. Medicine & Science in Sports & Exercise. 2000. From the abstract: “Directly supervised, heavy-resistance training in moderately trained men resulted in ... greater maximal strength gains compared with unsupervised training.” Return to text.
Nikander et al. Medicine & Science in Sports & Exercise. 2006. 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.” Return to text.
Ylinen et al. Journal of Strength & Conditioning Research. 2006. Similar to Nikander, researchers compared women with chronic neck pain who did strength training, endurance training, or no training. They specifically noted that “evidence-based guidelines do not explain what types of exercise” should be recommended for chronic neck pain. They found that “neck and shoulder muscle training was shown to be an effective therapy for chronic neck pain.” Return to text.
Andersen et al. Journal of Applied Physiology. 2008. 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. Return to text.
Nielsen et al. Muscle Nerve. 2010. 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. Return to text.
Simons et al. Muscle Pain, p216. “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.” Return to text.
Simons et al. Muscle Pain, p214. “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.” Return to text.
See The ‘Use It Or Lose It’ Principle. Return to text.
Most doctors are well aware that there are serious shortcomings in the medical management of most musculoskeletal problems, especially chronic pain cases. Dr. Jonathon Tomlinson, an instructor at St. Leonards Hospital in Hoxton, explains that “undergraduate training is focused on hospital orthopedics (broken bones and anything else that’s amenable to surgery) or rheumatology (nasty inflammatory diseases) which comprise a minority of the aches/pains/strains and injuries that people actually suffer from.”

Medical researchers have done many studies showing that most doctors do not understand aches and pains or heed expert recommendations. A good recent example is a paper in the Archives of Internal Medicine showing that family doctors frequently ignore guidelines for the care of low back pain — see Williams et al.

More generally, the Journal of Bone and Joint Surgery, and the Journal of the American Osteopathic Association, have both published papers recently showing that physicians simply do not have an adequate understanding of musculoskeletal medicine. In 2002, Freedman et al felt that “It is ... reasonable to conclude that medical school preparation in musculoskeletal medicine is inadequate.” Then again in 2005 in JBJS, Matzkin et al concluded that “training in musculoskeletal medicine is inadequate in both medical school and non-orthopaedic residency training programs.” Most recently, in 2006, Stockard et al wrote “82% of allopathic graduates ... failed to demonstrate basic competency in musculoskeletal medicine.”
Return to text.
Smeets et al. Disabil Rehabil. 2006. This 2006 review of scientific literature is painfully vague about the importance of low back muscle condition in chronic low back pain. Although there is certainly some evidence that suggests that core stability training is good for back pain (see O'Sullivan for instance), it’s nowhere near as strong as it should be, considering how popular the concept has been for the last fifteen years. Consider that the authors found that “no study examined the effectiveness of cardiovascular training specifically” — an incredible and frustrating gap. They also conclude that “general and lumbar muscle strengthening are equally effective as other active treatments,” meaning (I think) that researchers have not yet been able to show whether or not strength training and core stability training is any more worthwhile than any kind of activity — which does not exactly encourage me to tell my clients to try to strengthen their backs, especially when I know full well that some of them may have adverse reactions caused by irritation of their trigger points. They point out that there is “only moderate evidence” that intense strength training in the lumber muscles is more useful than moderate training, another strange gap. 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! Return to text.
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. Return to text.
Mense et al. Muscle Pain. 2000. Return to text.