Intro 

The progress of the ‘human world’ is often leads to changes that are way way faster than what our biology can keep pace with. It is fairly obvious that we have not had time to adapt to the modern western diet (if that’s even possible).

A tragic example is how difficult it has been for many indigenous groups to adapt to the ferocious pace of change our species sets for itself. Especially changes in diet   https://www.mja.com.au/journal/2007/186/1/nutrition-related-disorders-indigenous-australians-how-things-have-changed  As Europeans blazed across the globe, the changes that they imposed on the diet, disease profile and environment alone made for near extinction level events among some indigenous populations. This is a stark reminder of how our species can affect change that is hard for our biology to keep up with. 

For us, the evolution of our physical bodies happens at a snails pace, not only compared to ‘human progress’ but also relative to many of the life forms on the planet. Did you know for example that 15 generations of certain gut bacteria live and die their whole lives while you are asleep at night? That means that in their tiny world the equivalent of 2000 years of human evolution go by in a night. 

For gut bacteria a 100 years is tens of millions of generations and a great deal of evolutionary adaptation. For us humans they live inside of, 100 years is less than 2 generations, and the blink of an eye in evolutionary terms. 

150 years (a mere 2 generations) is about how long our bodies have had to try and adapt to living and walking on hard flat surfaces. By hard flat surfaces I mean the concrete, paving and tarmac that we live on in our homes, towns and cities After 20 years of treating pain and obsessively trying to understand its underlying causes I have come to believe that this is a major cause of back pain, hip pain, knee pain, ankle pain, ankle sprains and plantar fasciitis. I have come so far down this path that I believe hard flat surfaces like concrete and paving are as significant to joint pain, muscle pain and connective tissue pain as sugar is to dental decay. This is more than likely not something that you have considered so I will try and bring it to life with a quick visualisation for you.

Imagine you are stood on a seawall looking down at 2 metre drop onto soft sand, now imagine jumping down and with straight legs let your heels sink into the sand as you land. Now picture standing on a 2m wall somewhere near your house, jump down in your minds eye and again with straight legs let your heel contact the pavement first. If you are in possession of an imagination you should be able to get a sense of the fact that the second experiment was probably not a good idea. This is a small window into a world of massive life long microtrauma that is inflicted on your skeleton during a lifetime spent on very hard flat terrain. 

There are 2 key problems the natural terrain we lived on for millions of years when it is compared to the brand new urban terrain we now live on. 

Hardness 

When the human heel strikes hard ground the strain that occurs in the joints and soft tissues is many times greater than on soft ground. It is part of why running on pavement feels so different to running on grass or sand. On natural surfaces energy is absorbed whereas on concrete energy is deflected back into the tissues of the body. 

paving slabs are extremely hard and offer no natural support to human feet.

To be understood, this additional stress that occurs in a single heel strike on paving must be multiplied over millions of steps, in every year lived in the urban environment. The spread of pedometers and apple watches has shown us just how many steps we actually take, even the most sedentary of us sit around 10 thousand heel strikes per day. This is a supreme recipe for repetitive strain. 

Tissues that generate stubborn pain are tissues that are suffering from persistent strain. Knee pain, hip pain, ankle pain, foot pain and plantar fasciitis are to a large extent repetitive strain injuries inflicted by the unnatural hardness of our urban terrain. 

Flatness 

Take a moment to reflect about what the ground is like when you are in the big outdoors. When you are ‘off trail’ whether it be in forest, on grasslands, on beaches, in mountainous regions the ground is almost never dead flat. Even when there are no obstacles in the form of rocks, fallen limbs and vegetation it is almost never dead flat.. almost never. Salt flats, certain beaches and a percentage of dry river beds are flat but apart from the Mother Nature is constantly curvaceous. 

the flatness of modern urban surfaces leads to weakness in our knees, hips and backs.

If you live on a constantly shifting and changing terrain full of natural obstacle the amount of muscle activity in your hips, core and legs is many many times what it is if you just cruise around town. Mother Nature gave your ancestors a workout like no other, we are adapted to rely on that constant stimulation to maintain muscle mass in our hips and lower back. The legacy of all this flatness is muscle wasting in the lower half of our bodies. The reason that this is great significance is that it is the strength of healthy muscles that prevent pain and injury in our joints and connective tissues.

The AstroTurf Example 

One relatively niche example of a hard man made surface that is newer than most is AstroTurf. Within a very short space of time AstroTurf become globally notorious as a cause of sports injuries. Groups of professional soccer players have even filed a lawsuit for the right to play on natural grass in the 2015 Women’s World Cup.

astroturf.. a recipe for pain and injuries?

This 2014 survey.  https://www.ncbi.nlm.nih.gov/m/pubmed/24581229/ of US Major League Soccer over 95% of the respondents said they had greater muscle and joint soreness playing on artificial pitches. 90% said it took them longer to recover; and 89% said they were more likely to get chronic injuries from playing on artificial turf as opposed to grass.

Fortunately for my theory there is sufficient interest and financial incentive for this area to be researched fairly extensively. The research data definitely makes for interesting reading, for those of us with an appetite for such dry biscuits. There is evidence that early hard styles of AstroTurf were a greater risk factor for injury, and that risks may have reduced as technology improved, with the addition of tiny rubber pellets. There is also evidence that certain kinds of sports injuries do happen way more often on modern artificial turf.

Some studies like this one  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5544152/ have suggested that the transition from in-rubberised AstroTurf styles to those infused with rubber lead to a decrease in injuries of the knee and ankle. 

Papers like this one   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4590909/ which looked at numerous other studies, have  shown variable injury risks related to AstroTurf which they note may be explained by the evolution towards rubberised turf designs over time. 

One very large study found  https://journals.sagepub.com/doi/abs/10.1177/0363546519833925 that there is a significantly increased risk of knee injuries on AstroTurf. Interestingly it was more discerning than some other papers as it isolated the exact kind of knee injuries that AstroTurf pre-disposes.

There are many other strands to the research, and as is always the case with such complex issues (with so many variables) it is not 100 percent conclusive as to whether AstroTurf is as bad as so many athletes and coaches have claimed. Regardless of the details,  I feel there is enough noise here for us to confidently make a ‘no smoke without fire’ call on this topic.

Within all this furore over astroturf I may have my only semi-measurable piece of evidence for my theory on hard surfaces. There wasn’t anyone gathering data on the frequency of ankle sprains among the generally public in Victorian England during the transitions from cobble stones to paving after all. In my view the AstroTurf example may form a solid piece of circumstantial evidence at least. We are only talking about a very small number of people spending a very small amount of time on these surfaces to have caused a fair amount of uproar. 

In many ways it may be every bit as relevant that athletes report more aches and pains on AstroTurf as it is that they have a greater number of confirmed posterior cruciate tears on that surface. This is because in theory we are talking about ‘repetetive strain’ when we discuss the link between concrete and knee pain, hip pain, back pain, ankle pain and plantar fasciitis. Repetitive strain does not show up in our bodies as massive tears so often as it does aches and pains. The increase in pain reported by athletes on AstroTurf to my mind is a very clear suggestion of increased strain on their tissues regardless of what the incidence of cruciate ligament sprains is. 

A Pain Epidemic 

It is debatable of course whether my theory about hard surfaces being a major contributor to knee pain, ankle pain, plantar fasciitis, foot pain, hip pain etc. is correct. One thing that is for sure though is that we live in the middle of an epidemic of lower body pain. The statistics for lower back pain, foot pain, plantar fasciitis, knee pain, hip pain, ankle pain and hip pain in or culture boggle the mind. And all this in an age of extremely sophisticated health technology. 

knee pain.. common as concrete!

We also live in a time where osteoarthritis affects virtually everybody, it’s just a matter of at what age  and where (sorry if that’s a shock). It’s my belief that this epidemic of back pain, hip pain, knee pain, ankle pain and foot pain earlier in life is part of a species wide early warning system which heralds the undeniable epidemic of osteoarthritis we suffer later in life. If we look at where all this wear and tear occurs we can see it is all too often in the weight bearing joints of the body. If you know someone who has had a joint replacement or fusion it will most likely be their knee, hip or ankle. 

It is totally up for debate whether a meaningful amount of this pain and wear & tear is caused by our failure to adapt to life on hard surfaces. The elephant in the room is that we know people had osteoarthritis and pain before we invented paving stones, the question is where and how much. It would be crazy to make it out that this is a simple topic. Diet, genetics, occupation, injuries, activity levels and stress all afterall have a major part to play in the genesis of pain and injury… and presumably always have done.

The Nature Of Wear & Tear 

To highlight my personal take on how all this may fit together I want to talk you through a small thought experiment on the subject of hip pain, knee pain osteoarthritis and wear and tear.

wear and tear..complex.. but a normal part of life

I have a friend.. let’s call him Gary.. because that is his name. Gary has always been an extremely active bloke, hunting as a hobby, forestry work for an income. During his thirties Gary has some brief but unpleasant episodes of hip pain and sciatica, his sciatica wasn’t disc related, it was caused by muscle spasm in the back of his hip. All his scans and x rays were clear. 

In his late 40’s Gary found that if he began to get consistent right sided hip pain and knee pain after longer walks. Hunting days that he used to take literally in his stride had begun to leave him with a deep ache in the back of his right hip that lasted several days on each occasion. It gradually go to the point where he would take painkillers at the end of a days walk in anticipation of the pain that was to come. He also began to get more frequent stiffness in his lower back on the right side. 

To cut a pretty long and miserable story short let’s fast forward to Gary’s 65th birthday. By this point he had reached a level of disability and frustration that men like Gary always struggle with psychologically as well as physically. He was still hunting occasionally, over short distances and never to any of his favourite spots which were all too long of a walk for him. Every time he did hunt he suffered terribly for days and sometime weeks afterwards. Gary has also developed a consistent limp which was the thing that’s affected him the most because along with the pain it made him permanently feel like he was 85. He felt self conscious about moving like he was old and crippled when he still felt like he was pretty young at heart. By Gary’s 65th birthday he had already had the osteoarthritis in his right hip and knee confirmed on x rays and was waiting for a joint replacement surgery on the hip. 

So here is the thing…. like the vast majority of people in Gary’s situation his left hip and left knee had no arthritic change whatsoever and had not caused him a single day of pain in his whole life. 

Now let’s be super clear headed about this pain free hip of Gary’s for a moment. For 65 years his pain free hip had exactly the same DNA, the same job, the same hobbies, the same mileage, the same diet, the same environment and the same mattress. And yet his left hip showed no signs of osteoarthritis, while his right hip by age 65 has been hurting for 35 years and was completely worn out. How can we explain this? 

The only possible factor I know of that could determine the wearing out of right hip like Gary’s is mechanical strain…. either through injury or through persistent repetitive strain. Given that Gary has never injured that painful right hip we are left with the repetetive strain explanation. 

Gary’s right hip had worn out very very slowly and uncomfortable over 4 decades while his left hip remained fine. It seemed like a mystery until he was exposed to computerised gait analysis which revealed a severely fallen arch on the right side. For all those years his right arch had been collapsing with every step and without him knowing, and over millions of steps it had caused not only pain but catastrophic damage to the knee and hip joint. 

Now if we go back to the environmental factors that are the main order of business in this article.  It is abundantly clear that despite spending most of its life on hard ground that Gary’s left hip had not worn out. And this is to remind us that these things are never simple. 

You can eat a huge amount of sugar over a long period of time and find many of your teeth will still  be spared from decay. Similarly, you can stomp around on concrete and paving for a lifetime and many of your joints will be spared. Bodies and their interactions with environmental stress are complex. The fact remains (my view) in both instances that the sugar and concrete were both hugely significant factors in what occurred. In Gary’s case it was the long standing weakness and misalignment in his right leg that lead the joints to wear out, while the left was in a good state of alignment and was spared. If Gary had known what custom orthotics and rehabilitation exercise could have done for his weak side it would not have happened. This was the equivalent of him having poor dental hygiene against a background of sugar consumption.  

Closing Thoughts  

So the theory is that hard flat surfaces are as stressful to our joints and soft tissues and sugar is to teeth. And, if it is combined with weakness or misalignment in the body it can easily lead to back pain, hip pain, knee pain, knee injuries ankle pain, ankle injuries, plantar fasciitis, foot pain and even osteoarthritis. 

Perhaps surprisingly, the Gary case (and the untold millions like it) act as good news stories for those of us who are willing to work on acting preventatively on strength and alignment to avoid back pain, hip pain; knee pain, ankle pain, foot pain, plantar fasciitis and possible even osteoarthritis. This is because there are things we can do to sustain and nurture alignment and strength .. as there are things we can do to successfully mitigate the damage of sugar in our diets. Afterall we eat more sugar now than we ever have and yet we have less tooth decay than ever.