Our April NOInote Summer is Coming – Frozen Shoulder has been our most read post on NOIjam this year. In it we highlighted a wonderful paper from Max Pietrzak reviewing frozen shoulder and positing an underlying aetiology of metabolic disease, chronic low grade inflammation, a dysregulated autonomic nervous system and a failure to fully utilise the evolutionary function of the shoulder for throwing.
A recent piece on the Nautilus website picks up on the notion of the unique evolution of the human shoulder:
Did Our Ancestors Become Bipedal So They Could Throw?
Paleontologists since Darwin’s time have noted this culmination in the fossil record—a distinct shift in anatomy of the arm, hand, and shoulder away from a configuration suited to swinging through trees to one for throwing stones and spears.
Indeed, the human shoulder’s defining characteristic is its variability, says Nathan Young, an associate professor of orthopedic surgery at the University of California, San Francisco. “The shoulder is almost as unique as a face,” he says. Much of this variability is found in the scapula, which in humans can vary widely in shape, size, and orientation. By comparison, Young notes, the shoulder blades of tree-dwelling primates show little variation.
That uniqueness of form hints at the shoulder’s supreme versatility. After all, we don’t just use our shoulders for throwing—digging and rooting may have also played a role in changing the shoulder’s geometry, Young says. But when we do, the throwing motion transforms it, along with the rest of the arm, into a sort of high-precision anatomical slingshot.”
At the Cave of Hearths, in South Africa, Wilson’s team found 227 spheroid stones at a site dating back to the Early Stone Age, about 1.8 million years ago. Based on projectile motion simulations, they found that 81 percent of the stones could, if thrown, inflict “worthwhile damage to a medium-sized animal over distances up to 25 m.” That’s a bit more than the distance Bumgarner traverses from the mound to home plate—18.4 meters. (emphasis added)
Reading these descriptions of the shoulder – a high precision anatomical slingshot capable of bringing down medium sized animals at distances up to 25 metres with a spheroid rock raises a few thoughts and questions for me:
- Wow! Shoulders are versatile, strong and really quite robust
- I wonder if our ancient ancestors developed rotator cuff tears?
- People experiencing shoulder pain might benefit from knowing about some of this
- Could this information change how we treat pain experienced in the shoulder region
- In the realm of occupational/work health in particular, where the predominating idea to look after shoulders seems to be to do less (less movement, less range of motion, less load etc) is there more harm being done than good?
Thoughts?
-Tim Cocks
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LAST CHANCE TO GET ON AN AUSTRALIAN EXPLAIN PAIN OR GRADED MOTOR IMAGERY COURSE FOR 2016
Gold Coast 30 September – 2 October Explain Pain and Graded Motor Imagery **FULL**
Perth 15 – 17 October Explain Pain and Graded Motor Imagery
HAVE YOU DOWNLOADED OUR NEW PROTECTOMETER APP YET?
Just search the App Store from your iPad for ‘Protectometer’
WE’RE PACKING UP EP3 AND TAKING IN ON THE ROAD IN THE USA
EP3 events have sold out three years running in Australia, and we are super excited to be bringing this unique format to the United States in late 2016 with Lorimer Moseley, Mark Jensen, David Butler, and few NOI surprises.
EP3 EAST Philadelphia, December 2, 3, 4 2016
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To register your interest, contact NOI USA:
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Hi Tim, thanks for sharing this. As someone who has a background in anthropology and now has a keen interest in pain science and physiotherapy, I have some thoughts on this. I don’t doubt that our ancestors got rotator cuff tears, as that sort of stuff can happen to tissue with high load. Perhaps not with the frequency as seen in modern day throwing/overhead athletes, as they were not apt to repeat the motion as much, just to get good enough to capture prey as a group.
Because our ancestors lived in fairly large groups, I can imagine that an individual with an acute rotator cuff tear/injury would merely be asked by his tribesmen to do other tasks until he felt better. Perhaps he would still join in on the hunts and be involved with tasks such as tracking, ambushing, and corralling the prey animals. Tasks such as hunting were distributed across many skilled hunters, so the group as a whole would still be able to capture prey, although the probability of capturing prey may have decreased with one skilled projectile thrower out of commission. Isn’t it interesting to imagine that the survivability or quality of life of the entire group may have been threatened due to some tissue damage in a rotator cuff tendon of one of the individuals? Talk about social dimensions of pain!
As for modern humans, I would tend to agree that as with LBP, there is a focus on doing less to “preserve the integrity of what bit of tendon or disc is there and not blow out the rest” attitude that is still quite prevalent. Tying this back to Pietrzak’s review, the shoulder is a very complex joint that is clearly designed to move through large ranges of motion. I don’t doubt that lack of such motion can lead to the development of frozen shoulder in certain susceptible individuals, as outlined by Pietrzak.
Hi Tim, David & Co,
Really interesting piece, as always, thank you.
I recently read Dan Lieberman’s book, “The Story of the Human Body” and would strongly recommend physiotherapists and anyone with an interest in human evolution and evolutionary medicine to read this amazing book, if they haven’t already done so.
Consistent with the present articles Lieberman argues that Australopiths (early homminins 4 to1mya) selected for bipedalism thorough becoming more reliant on digging for tubers, bulbs and roots rather than fruit in the forest canopy. Apparently pointed spears were not commonly utilised until about 500 000 years ago, so the data on the rocks herein is quite interesting, particularly how various weapons may have related to hunting practices, for example, ‘persistence’ versus stealth hunting and survival!
My current understanding of studies comparing modern day hunter-gatherer to modern humans, is that hunter gatherers have relatively very little cardiovascular disease, cancer and mental health dysfunction. So if one accepts that relative modern trends of inactivity, obesity, metabolic syndrome and psychosocial stress have a major role in the aforementioned diseases, as well as chronic shoulder pain secondary to rotator cuff tear, then one may reasonably argue that even if the incidence of rotator cuff tear in hunter-gatherers was the same or higher than what it is now due to high demands/forces, the prevalence of shoulder pain chronicity or developing secondary AC in those above 40 or 50 would be much lower?
Max
Hi Tim,
We just don’t seem to get away from “Motion is lotion” do we !?……..I only know, from personal experience that I went through a phase, a few years ago of being less physically active in the sporting arena and, boy how I felt I was “Rusting up”. It took a while to get back into shape and oil up the rust, but I got there. Interestingly it was my shoulder joints that caused most concern at the time. From this experience I learnt two things:-
“Hunter gatherer” type life style kept me physically more comfortable and emotionally more stable…..
Age is not an excuse as I have learnt that the body and mind have a life long positive and negative plasticity capacity……