Can Stretching Really Help Fix What Ails Your Knee?

A brief update on last week's post: I had a few twinges and tinglings in my knees after my spirited workout (I got up to 349 watts while doing intervals on the stationary bike). That was probably to be expected, after three months of indoor cycling at a leisurely Sunday-at-the-park pace. Maybe it wasn't so bright to ramp up to time-trial intensity so fast. :) So I'm going to take a few more weeks to "break in" my knees for the 2011 cycling season. Who wants to ride in the cold anyway?

Now for the discussion on stretching, resumed:

WHAT'S WRONG WITH YOUR KNEES AND HOW DOES STRETCHING FIX IT?

Okay, I'm going to start with what was wrong with my knees, because my problem was fairly common -- and I have to start somewhere.

I had cartilage damage in my knee joints. That can cause pain mainly in two ways (as I explain in Saving My Knees): (1) tiny pieces of the soft and damaged cartilage flake off -- which you don't feel because the tissue has no nerves. They float in the synovial fluid and then migrate out to the synovium (the lining of the joint capsule) -- which you do feel, because the synovium is nerve rich. (2) cartilage that is thin or damaged fails to adequately cushion the underlying bone from pressure (such as from bent-knee sitting or walking). Bone endings also have plenty of nerves, unfortunately.

So my primary challenge (and the challenge of millions of others with pain from chondromalacia and osteoarthritis) is as simple and complicated as this:

How can bad cartilage be fixed?

This is where some doctors head for the exits, claiming it simply can't be done. That's just not true though. Even if you can't restore cartilage perfectly to its original state, you certainly can strengthen it and, if you do all the right things and are patient, even regrow it, I'm convinced. (NOTE: natural regeneration of cartilage has been shown through at least three scientific studies; I discuss the subject more here and here).

So then, how can the cartilage be fixed? Through a program of stretching?

This makes no sense at all. Just think about it. How would that even work? Would you stretch the cartilage? Of course not -- you'd stretch tissues around it, primarily muscles. But if you stretch your quadriceps, or your hamstring, how does that help repair or strengthen your damaged cartilage?

It doesn't. To change the health of the cartilage, I strongly believe you need to adopt a program of appropriate motion, that gradually intensifies over time. That's what succeeded for me.

MY IMAGINARY CRITIC LASHES OUT: "TALK ABOUT A 'STRAW MAN' ARGUMENT! WHO SAYS STRETCHING HELPS CARTILAGE! IT HELPS OTHER THINGS!"

Later we'll look at that: specifically, what's the rationale behind stretching for sufferers of chronic knee pain? For now though, it's important to start with the simple essence of the matter. Which is: If your problem is damaged cartilage, you need to improve the condition of that tissue. And stretching doesn't do that. How could it?

A more sophisticated rebuttal (from Mr. Imaginary Critic) might be that stretching helps you do the things that will fix the cartilage (such as engaging in lots of not-too-strenuous motion). Or that stretching redresses imbalances that are causing the damage in the first place (notice that, in this second scenario, stretching still doesn't claim to repair the tissue -- only prevent it from being chewed up more).

I'm skeptical about both assertions in the preceding paragraph, but that's for an upcoming post.

MY IMAGINARY CRITIC AGAIN: "YOU WANT SIMPLE, WHAT ABOUT THIS? I HAVE A BAD KNEE. MY BAD KNEE MAKES THE JOINT AND NEARBY MUSCLES FEEL TIGHT. STRETCHING HELPS ME LOOSEN UP AND FEEL BETTER."

The logic certainly seems straightforward. Stretching is about getting loose. Having bad knees is usually about feeling tight -- whether it's a "knot" in the joint, or tight muscles around it, or just an inability to move a knee through a normal range of motion. So isn't getting loose just common sense, in order to feel better?

That depends. What's the source of the tightness? And does stretching help take care of that?

It doesn't appear so.

Listen to Doug Kelsey, chief therapist of Sports Center, a guy who's much smarter than me:

If the muscle is tight from irritation of the joint (which is almost always the case), stretching proves to be exceptionally frustrating. You're flexible right after the stretching but within hours or days, you're just as tight as before the stretch.

That tightness or fullness can be caused by swelling in the joint. Kelsey says that "as little as 20 milliliters of extra fluid in the knee [the equivalent of half a shot glass, he says] will intimidate the quadriceps muscle into near total inactivity." That swelling may not even be that visible.

So how effective is stretching in reducing swelling? Not very. Stretching may be effective in inducing swelling -- causing more swelling, when you overstretch -- but it doesn't relieve it. (As Kelsey notes, stretching may make you feel temporarily more flexible, but soon you tighten up again, especially if there's swelling in the joint. That was my experience exactly.)

How can you beat the swelling, and begin to eliminate the tightness, in a real, significant way? Kelsey suggests (1) elevating the leg and (2) light exercise, such as slowly spinning on a bicycle or walking in a pool. My opinion: that is what you need to focus on, not stretching.

(By the way, after quoting Doug Kelsey at some length, I should be gracious and point out that he has produced The Runner's Knee Bible, which contains many photos and videos and I'm sure is terrific.)

NEXT TIME: What are the arguments for how stretching benefits someone with bad knees?

My Personal Recovery: The Epilogue to "Saving My Knees"

I will return soon to the subject of stretching. Meanwhile, if you want a glimpse at the stretching controversy, just check out the "talk" page behind the Wikipedia page on stretching. True, many of the comments are semi-informed at best, but the back and forth suggests a citadel of belief may be crumbling ... :)

Today I want to do something I've meant to do all winter: provide an update on my knees and where they're at, post recovery.

Saving My Knees takes a reader to the end of April 2009, when I returned to the U.S. from Hong Kong. My knees were much improved. I made slow, steady gains through a joint-focused (NOT a quad-focused) regimen of appropriate motion. I was convinced better days lay ahead.

So what happened?

First, my knees did continue to get better (I returned to vigorous cycling by the late summer of 2009). I still noticed some discomfort while sitting during the summer of 2009. But by that fall I felt my knees were strong enough to return to full-time desk work. It took me a while to find a job (I ended up with my old employer, Bloomberg News, except in New York City).

I resumed my journalism career as a corporate finance editor late in December of 2009. Do the math, and that's 20 months since my attempt to heal my knees began at the end of April 2008. 20 months, and I'm not going to kid you -- there was still a touch of residual discomfort, while descending stairs or sitting at a desk for long hours. Not much, just a little.

I stuck to my motion-based program (a lot of cycling and walking), and sometime during the early or middle part of 2010 -- I can't even tell you exactly when -- the last reminders of my chronic knee pain went away.

Of course I was overjoyed. I cycled hard last summer, throwing caution to the winds. I'm sure that I ramped up too fast. I was riding to that happy point of total exhaustion. By November, I felt a little soreness in my left knee while on the bike. So you may be thinking, "Oh no! There it goes again!"

Nope. Whatever was going on with my knee -- I suspect a little tendinitis around the patella, but I'm not entirely sure -- this time didn't scare me. I felt as if I had the knee care manual in my back pocket. I was fortified with experience and knowledge. I also had the comfort of knowing I had a sore strong knee. That makes a lot of difference.

Still, a little slow-down intervention was needed. That came in the form of winter, when it's too cold to cycle outside here anyway. I vowed to dial back my intensity, keep cycling a lot, and wait for the soreness to subside. I developed a winter training plan. For instance, for all of January, I spun on the exercise bike at a very low resistance.

Over two months, the soreness disappeared. My knees feel perfectly normal now. During February, I started to pick up the intensity, preparing for a new cycling season. This month, I accelerated my training even more, because I want to start doing 50-60 mile punishing bike rides in April.

So where am I, this minute, in my post-recovery? To give you an idea, here is my knee-related workout program for the past week:

Tuesday: 45 minutes cycling. First, level 7 on the stationary bike (about 106 watts I think) for 10 minutes, then level 8 (about 20 watts higher) for 35 minutes.

Thursday: same as Tuesday.

Saturday: Time to get serious! 30 minutes cycling at level 7, then 30 minutes of intervals growing progressively harder, peaking at level 19 (that's 349 watts, for about 75 seconds, at more than 90 revolutions per minute).

Sunday: 60 minutes at level 7.

The first weekend in April, my goal is to be back with my cycling group, powering down the flats and charging up the hills of western Long Island. If I were living scared, I suppose I wouldn't do this. I'd stick with slow recreational rides. But the thing is, I'm pretty sure I know my knees well at this point. And I think they're strong enough to cycle hard.

Worst-case scenario, I'm wrong and I end up taking it easy for a year or two. I've developed a plan on "cartilage time" before. You have to make your peace with slow progress, but there's nothing wrong with that if the gains are real.

To Stretch or Not to Stretch, Part I

So I'm in the gym where I work out and see a sign to this effect:

"Please Ask A Personal Trainer About Assisted Stretching."

And I'm thinking, sort of wryly, "Yeah, there's a full-employment act for personal trainers -- not only do you need to hire them to show you the stretch, you need to keep them on, in perpetuity, to help you with the stretch."

Okay, that sounds a bit snarky. It's not that I dislike personal trainers. My sister-in-law is one, and she's one of the nicest people I know. But during my recovery from chronic knee pain, I had the opportunity to investigate the benefits of stretching. And what I discovered left me distinctly underwhelmed.

PREPARE FOR A GLORIOUS JOURNEY ...

I'm going to spend a few weeks blogging about exactly why I turned into a stretching skeptic.

This is a moment I've sort of dreaded, just because stretching is such a big topic and there are so many stretching advocates out there (and they can all touch their toes, and they're so damn proud of it :)). I'll probably end up annoying the hell out of someone. Stretching has become a quasi-religion in the world of physical fitness. Stretch before exercise! Stretch after! If you have knee pain: stretch, stretch, stretch!

But what are the arguments for all this stretching? What is the actual evidence about its benefits? Does stretching really make sense if you have knee pain? In other words, what are you trying to fix, and how does stretching help you fix it? Who was the first human anyway who said, "Hmm, I'm going to run across that field, so maybe I better stretch my quads first?" And if stretching turns out not to be that useful (as I believe), why has it become so solidly entrenched in our physical fitness culture?

I plan to cover most of those questions (I'm not sure about the "first human" one :)) in a series of posts. Hopefully, anyone who perseveres with me to the end will be inclined to accept that, at the least, the benefits of stretching have been (as I say in Saving My Knees) greatly oversold.

STRETCHING CAN HURT YOU

Even if you think I'm nuts, and you're loathe to give up your four or five favorite stretches, be careful. While cruising the KneeGuru bulletin boards one day, I came across an object lesson for stretching fanatics.

"Phrank" (his nom de message boards) started a thread "Can Certain Stretches Damage the Knee?" His story, in brief (I've edited his post down for length and readability):

First let me explain my history with my right knee. In 1992 it was dislocated, sept 2008 i had a lateral release and debridement ... it was also supposed to fix my knee instability ... In Jan 2010, I needed another surgery to correct my knee instability ... I would also like to include that I also suffer from I.T. Band syndrome ... In May of 2010 I began to jog, i was doing great, i slowly got up to jogging 3 miles non stop ... no pain, just i.t. band stiffness/soreness alone with muscle soreness. About two weeks ago I was doing a new stretch that a co-worker told me about that would help stretch my tendons and IT Band ... the last time I did it ... it felt fine when I was stretching it, I felt releif, nothing popped, nothing gave way ... so i sat back done to continue my work, got back up 10 mins later to get something, As i stood up I felt so much knee pain. It was really intense ... Now two weeks later my knee makes popping sounds when i get in and out of bed or sitting down and getting up from a chair.

Was the stretching necessarily to blame? Obviously, it's impossible to be sure, especially since we have only Phrank's account to parse. But he did include a diagram of the stretch he was performing. When I saw it, I just shook my head. Check this out:



In a reply I made to his post, I suggested that another name for this might be the "Just Asking for Trouble Stretch." Because look hard at this image, and think about what Mr. Knee Pain Sufferer is doing. He's putting torque-like pressure on an unstable knee joint in an unnatural position.

Let's break down that bold type:

1. putting torque-like pressure: For this stretch to work, you need to push down on that knee, and since the leg being stretched is bent and folded over the other leg, the knee is subject to a bit of twisting pressure. Ugh. My knees have healed, and I just started to try this stretch, and quickly abandoned it out of fear.

2. unstable knee joint: Now imagine your knees are unstable. That makes this a double bad idea.

3. unnatural position: Now for the kicker: You're not even helping your knees adapt to some motion you'll be undergoing later. Look at this weird position! What physical activity does this replicate? When do you, in some sporting or life activity, swing your bent leg up over your other leg, and push down on it? What about, like, never? There's value to putting some pressure on your knee joint, say by climbing up stairs, if you want to train your joint to better climb stairs. But here you're putting pressure on your knees for no other reason than you think you need to stretch some muscles/tissues and can't find a better way to do so.

Stretching can be dangerous! Even seemingly benign stretches can lead to small tears in the muscles or tendons being stretched, especially for people who are weak (from short-term or chronic injury or whatever)/out of shape/healing from injuries. So even if, after reading all I have to say today and in upcoming posts, you continue to stretch, please be careful.

NEXT TIME

What's wrong with your knees? And how does stretching help fix that?

Update on "Saving My Knees," the Book

I realize there are a certain number of you out there finding this blog for the first time, feeling that you've dropped in during the middle of a conversation.

Nothing wrong with that. That's what a good blog should aspire to being: a lively conversation.

However, I imagine you first-time readers may be wondering: What is this book, Saving My Knees? Is it worth my time to buy, especially if I don't have a Kindle already?

Saving My Knees is my story of beating chronic knee pain and how I discovered much of what I was told to do, as a patient, was demonstrably, provably WRONG or MISGUIDED. The book is an argument (for a certain approach to overcoming knee pain). The book is a refutation (I hope) of the standard treatment regimen for chondromalacia/patellofemoral pain syndrome.

It has been on sale through Amazon.com for more than a month and has done better than I expected. What's more, a handful of copies have gone to buyers abroad, which really makes me happy, as it shows that the dissemination of my message isn't being constrained by geographical borders.

So who am I anyway? Not a doctor. Not a physical therapist. But I am a longtime journalist, a fairly bright guy, an analytical thinker with the ability to synthesize knowledge, and someone who is open-minded enough to know that the experts aren't always right ...

If you are a smart, discriminating person, willing to question authority when appropriate (I slavishly followed the advice of my physical therapists and doctors until I realized their advice didn't make sense), and you have knee pain, you should read this book. I don't mean to sound arrogant with the preceding characterization -- it's just that I've spent a lot of time lately on knee pain message boards. And I know there is a certain kind of person my book won't reach. Even though physical therapy has failed, that person has either jumped on the surgery merry-go-round (and once you're on that carousel, you often stay on it, I'm afraid) or can't quite wrap their head around the idea that current medical practices could be wrong.

These are the same kind of people who, 200 years ago, were being bled into bleeding bowls to cure problems such as acne and who weren't questioning why their acne wasn't getting better. (A colorful analogy I like to trot out from time to time -- medical science at any given moment in time will be imperfect; that's simply reality!)

I wrote Saving My Knees because there are NO OTHER books anywhere written in the first-person that chronicle how someone triumphed over knee pain after being told his knees would never get better. I wrote it because I followed a rigorous, fact-based approach to healing that I knew would be relevant for other knee pain sufferers. I wrote it because, selfishly, I wanted to plant a flag, on January 2011 (the publication date), showing that I was in the early vanguard of people who figured this out years before everyone else does.

Yes, I'm pretty confident that a lot of the thinking about knee pain treatment is going to evolve significantly over the next two or three decades.

So, if you're on the fence about buying Saving My Knees, you can:

Go here to read my (rather long) KneeGuru thread announcing the release of the book (and what it's about).

Go here to read my (really, really long) KneeGuru thread about my success story beating knee pain.

Go here to find out how to read an electronic book, if you don't have a Kindle (hint: it's easy).

And if you want to just hang out at this blog for a while, making up your mind, that's fine too ;).

A Scientific Investigation: What Effect Does Physical Activity Have on Knee Joints?

After last week's ultra-long post, I'm going to go short this week.

So today, without a lot of elaboration, we'll look at the latest scientific roundup on how activity affects knee joints.

An article on exactly that subject (just released online) is slated for March publication in the journal Medicine and Science in Sports and Exercise. What's more, it's a systematic review -- double gold in my eyes, because a systematic review aims to synthesize the evidence from a pile of existing studies.

Such a method reaches a more certain truth because, as we all know, individual studies can be confusing, as they sometimes contradict each other.

The article's researchers, led by Donna Urquhart, examined a total of 28 studies. Here are their conclusions (with my comments afterward). I've ordered the list from least to most interesting to build up a little suspense.

(1) There is limited evidence that there is a positive relationship between cartilage volume and physical activity.

Good news! And not surprising! (I suspect future studies will supply even more evidence). So this means people who are physically active have more cartilage in their joints than their lazier brethren.

(2) There is strong evidence that there is no relationship between joint space narrowing and physical activity.

At last, it's time to shut up the "tut tut" birds. You know the ones: they look at you askance and warn that with advancing age, running/cycling/playing basketball will just hasten the inevitable breakdown of your knee joints. For example, running will lead to deteriorating cartilage, and that means eventually the bones will be brought into closer proximity (joint space narrowing), until you're in danger of having bone scrape painfully on bone ...

Great Halloween horror story. But not necessarily true, it appears.

(3) There is strong evidence that there is an inverse relationship between cartilage defects and physical activity.

Hooray! In other words, the physically active have fewer cartilage defects. I'll go even further and predict what a systematic review may find in another 10 years or so: not only do physically active people have fewer defects, but more of those defects will be shown to improve over time than among the general population.

(4) There is strong evidence that there is a positive relationship between osteophytes and physical activity.

Okay, this is the one that should have surprised me greatly, except I had read this New York Times piece a while back. Osteophytes (or bone spurs) don't have to be bad; they can be of the good "protective" variety, it turns out. Spurs are sometimes just a way the knee adapts to the forces pulling on the joint. "There is ... evidence to suggest that osteophytes can develop without explicit injury to cartilage," according to this latest article.

Yet more good news ...

Time to get active!

Comment Corner: Can Even Badly Damaged Knee Cartilage Heal?

Before the regularly scheduled programming begins: If you've read Saving My Knees and enjoyed it, please drop by the book's Amazon page and post a review. There's no crack team of publicists working the phone for this book -- I'm relying on good old-fashioned word of mouth.

Now here's the second installment of "Comment Corner" (okay, it's a bit hokey as a name), in which I answer a reader comment at some length. Buckle your seat belts; this one is a bit of a long ride!

Last week I was talking about strengthening the knee instead of the surrounding muscles, and exactly what that means. That prompted this comment:

I'm curious about the repair capability of severely damaged cartilage. I had a microfracture procedure in my left knee. My symptoms were primarily mechanical -- my kneecap would catch painfully every time I moved it through a certain angle.

When I got the pictures from the arthroscopy, I noticed that the damaged cartilage almost looked like hair. It looked "fuzzy", with hundreds of tiny strands that had clearly been torn apart. It's hard to describe unless you've seen pictures of it. Mine was worn down to the bone in places.

Do you think cartilage damage of this type can heal naturally through gentle movement? I'm having trouble imagining the mechanism that could promote healing in this case. The chondrocytes are captured in their lacunae, presumably within the loose strands of visibly damaged cartilage. How can they possibly "capture" the free-floating ends of the torn fibers in order to reattach them? I guess I'm having trouble understanding the mechanism that would allow badly damaged or torn cartilage, as is seen in Outerbridge grade 3/4 lesions, to heal. It's easier to understand how it might work in earlier-stage chondromalacia where the cartilage is still contiguous but is soft and has stopped providing adequate shock absorption.

Good questions. I recognize a kindred soul, trying like crazy to figure things out, as I once was.

First, normal cartilage looks like this (images borrowed from emedx.com). Nice and smooth, like a baby's bum:


Then you have "horror show" cartilage. Degenerated, fibrillated, like a fright wig:


Yow! No wonder knee pain patients staring at photos of their scoped joints feel a sickening little roll of the stomach. How the hell does image #2 ever improve and turn back into #1? That would seem about as unlikely as your broken vase, lying on the floor, jumping up and spontaneously reassembling itself.

Okay, let's look at the prospects for healing bad cartilage -- really bad cartilage that looks like a hairy crab. We'll do this in two parts, because there's Stuff I Know and then Stuff I Think Might Be Right.

Stuff I Think Might Be Right

So how does this "cartilage hair" reattach itself, as Anonymous wonders, to make your cartilage whole again?

Thought experiment: Imagine taking a cheese grater (don't really do this!) and barking it a few times, quite roughly, against the skin on your forearm. What's your arm going to look like after you finish? Probably you'll have a lot of little pieces of skin hanging off.

How does this skin then reattach itself to make your skin whole?

Answer: It doesn't, of course. The irregular bits eventually fall off. Over time the surface of your skin heals.

My guess is that something similar probably happens with raggedy cartilage that succeeds in healing. In fact, my best theory of what was going on with my joints -- I had a lot of problems though an MRI detected only "mild" chondromalacia -- is that I had some of this "cartilage hair," at least in certain places.

Now if I'm correct, the "cartilage hair" is just going to flake off. You have to accept that. Further, as it does, little bits of cartilage detritus will migrate to your synovium and make your knee sore. That, too, you have to accept.

What you have to focus on is the underlying cartilage that's intact: That stuff is too soft. It is in prime "hair-making" mode. It will eventually fissure too, turn into synovial seaweed, and go the way of its surface brethren if you do nothing. Which is what a lot of people do: nothing.

The intervention I believed was necessary: strengthening and stiffening the existing cartilage, very slowly. While this process occurs, there will be some pain associated as the bad stuff flakes off and migrates away through the joint. But you need more resilient tissue and the only way to get it is through motion coupled with appropriate load (a big hat tip to Doug Kelsey!).

You may be wondering: what about the chondrocytes (cellular cartilage-making factories) that are trapped in the "cartilage hairs." My guess is they go bye-bye. But if that unduly stresses you (I can tell Anonymous is doing the "extra-curricular reading" and is aware that chondrocytes are not that plentiful to start out with, scattered throughout the tissue), these cells have apparently shown an ability to regenerate.

This is from a prolotherapy Web site -- I'm not saying I'm a fan of prolo, or that I agree with everything on this page (though much of it makes sense), but the cited study is paywalled so I can provide only the prolo summation:

... data suggest that under circumstances of chronic injury, such as is seen in osteoarthritis or trauma, chondrocytes are capable of mounting a significant reparative response and can replicate their DNA to form new cells.

Okay, the above is Stuff I Think Might Be Right. Anyone with more knowledge/insights, please weigh in. Now for:

Stuff I Know

I know that cartilage doesn't have to heal completely, to pristine condition, in order for knee pain sufferers to escape their torments. Most of the population over 30 has some damaged cartilage in their knees. So first thing: the bar you have to jump over is lower than you may think. You don't need normal cartilage again, just cartilage that functions well and doesn't hurt.

I also know that very damaged cartilage has been shown to heal over time. I think the scale being used in studies I've read has been on ICRS grading, not Outerbridge, but if you look at these photos here, the two are similar (e.g., an ICRS Grade 3 is basically an Outerbridge III).

Here are some interesting numbers from a report published in Rheumatology magazine in 2006 entitled "Factors Affecting Progression of Knee Cartilage Defects in Normal Subjects Over Two Years."

Initially, there were 14 locations at Grade 3 (less than 50 percent thickness) in the subjects' knees. Three remained the same and five went to bare bone -- that's the bad news. However the good news is that almost half of them improved: four became Grade 2 and two Grade 1, which is nearly normal!

There were five sites at Grade 4, or bare bone. Now you'd expect at the end of two years, those five sites would still be at Grade 4, absent surgical intervention (such as a microfracture). But one ended up Grade 3, two were Grade 2, and one even healed all the way to Grade 1!

I'm willing to bet that, if these knees with Grade 3 and Grade 4 lesions had been scoped, you'd see plenty of that "cartilage hair."

So far I'm telling a wonderful story, but caveats are in order.

As careful readers no doubt noticed, these were normal subjects. Also it's not clear how big their lesions were. Still, I think the big takeaway is that cartilage can heal, even when you've got no more than exposed bone to work with. That's a really great, inspiring message.

If you're Anonymous, though, what you face is fairly challenging. You've got to give your knees enough motion, and the proper amount of load, without blowing them out, so to speak. This will not be easy. This will take a lot of time, I bet (maybe four or five years).

But, if you can see yourself gradually getting better over that long stretch, it's certainly better than the alternative: resigning yourself to a life of constant pain. Remember, there's always hope.

What Does "Knee Strengthening" Mean Exactly?

My belief is that, to heal bad knees, you need to focus on strengthening the joint -- that's what's causing you trouble after all -- and forget about obsessing over your leg muscles. (You can build up your quads all you want, until they're as thick as tree trunks, after you fix your knees!)

That's how I succeeded in my recovery, which I describe in my just released book, Saving My Knees.

But what does it mean to "strengthen" a joint? In my case, I had to contend with bad cartilage. An MRI revealed I had "mild" chondromalacia (though I had not-so-mild pain symptoms, so I suspect that the problems lay deeper than the MRI could see). So my mission became to restore that cartilage to better health, to make it stronger. But how?

I began digging around in the world of articular knee cartilage. What constitutes weak or poorly functioning cartilage anyway? Obviously, if it's worn down or damaged structurally, the tissue won't work as well. But then I learned something curious: bad cartilage is generally too soft.

Now here's where things can get confusing. If you cruise the Net long enough, you'll find at least one instance of a doctor pooh-poohing the diagnosis of "chondromalacia," saying that the term makes no sense because it means "soft cartilage," and cartilage is supposed to be soft. That's a rather disingenuous thing to say though.

Because chondromalacia means an "abnormal softening of cartilage." Cartilage is somewhat soft because it must act as a rubbery shock absorber, compressing and then bouncing back to its original shape. Cartilage-as-a-brick wouldn't function too well; a brick has no ability to deform to absorb shock, then recover to its original state.

The issue arises with a kind of excessive and unhealthy softness that (at its extreme) is captured in this delightful bit of imagery from the book Heal Your Knees: "If a man in his eighties tears a meniscus, it wouldn't make sense to try to repair it, because that would be like trying to put stitches in a Boston cream pie."

You don't want Boston-cream-pie cartilage, certainly, that can't hold a stitch -- or bear the burden of a walk up a hill. To better understand why, consider this excerpt from Disorders of the Patellofemoral Joint, by John Pryor Fulkerson (my bold):

Closed chondromalacia is common and may or may not be symptomatic ... it consists of simple softening of articular cartilage, which begins in a very localized area and then extends progressively in all directions ... softening, which may at times appear fluctuant, may be present in varying degrees of severity, from simple softening to a more advanced form in which a type of "pitting edema" can be observed after digital or blunt instrument pressure. This loss of elasticity, which this softening represents, decreases the function capacity of cartilage and explains the reaction of adjacent subchondral bone to which the compression forces are transferred abnormally.

There we go. That supplies the needed clarity. Soft = loss of elasticity. Loss of elasticity = not very good shock absorber. Since cartilage's key role is to lessen shocks/forces transmitted through the knee joint, too much softness means lots of problems. Plus there's this to consider: soft tissue is more prone to flaking, fraying and tearing. Flaking off bits of cartilage can be a source of pain, as they migrate through the synovial fluid to the nerve-rich synovium. And I hardly need to belabor the point that you really want to avoid tearing your cartilage.

So my calculus was simple: I didn't want to prematurely have Boston cream pie (or anything resembling it) in my joints. That meant I needed to strengthen and stiffen my knee cartilage (here I'm talking about indentation stiffness, and not brittle stiffness), through a long program of high-repetition "exercise" that gradually increased in intensity.

I knew that approach could work, from a Swedish study ("Positive Effects of Moderate Exercise on Glycosaminoglycan Content in Knee Cartilage"). Moderate physical activity boosted the content of glycosaminoglycans (GAGs) in the cartilage of participating subjects. Having more GAGs in your cartilage is great; they contribute to making the tissue healthier and more resilient.

So for anyone trying to understand how I healed, that was one important, basic insight. I knew my cartilage was weak/damaged/soft. And I knew I had to make it stronger.

And I did, and by doing so, strengthened my knees.