Some genetic differences are obvious and provide clear physical advantages in different sports.
Others differences are less obvious. These make it unclear why different people have different physical capabilities.
It's some of these less obvious genetic differences that cause you to habitually move in ways that can contribute to your low back pain, both when you're in the gym and when you're going about your everyday activities.
So, can you blame your back pain on your parents or is there anything you can do about it?
Even if you don't immediately recognise either of the athletes pictured above, you could probably guess which is the gymnast and which is the basketball player.
Shaquille O'Neal could have trained 8 hours a day, 7 days a week, with the world's best gymnastics coach, and he would still never have been able to do backflips on a balance beam the way Simone Biles can, no matter how much glitter he put on his leotard.
His seven feet (2.13m) tall frame is clearly more suited to other athletic pursuits, specifically slam-dunking a basketball one-handed into a ten feet high basketball net.
Biles’ compact 4 feet, 8 inch (1.42m) physique, on the other hand, is exactly what you would want if you had ambitions of becoming the world’s best gymnast.
They've both no doubt had to put in an immense amount of hard work to reach the pinnacle of their respective professions, but as David Epstein details in his book, The Sports Gene, certain genetic traits are required for success at the elite level of sports.
So, it's fair to say that Shaq could definitely blame his parents for not being able to represent the USA at gymnastics. But, he may have to give them at least some credit for his accomplishments in basketball.
It's not always so easy to identify innate capabilities. Take two other elite level athletes: masters weightlifting world champion, Jerzy Gregorek and Irish rugby international, Rob Henshaw.
At first glance, the obvious age and size differences between them would make you think that Henshaw (28 years old, 99 kgs) would be a significantly stronger athlete than Gregorek (64 years old, 61 kgs).
But, stronger at what?
Bench press? Probably, yes.
Overhead squat? Definitely not.
If you look at their ability to control a weight overhead, it's clear that Gregorek is significantly stronger and more comfortable handling a heavier weight (looks to me like 110 kgs, or almost twice his body weight) above his head. I couldn't find a video of him doing this but his facial expression is a clear indication of how much he's at ease in this position, with his hips clearly below his knees.
By contrast, in the video below you can see that in spite of his size and age advantage, Henshaw is visibly struggling to maintain good form while managing a much lighter weight (looks to me like 60 kgs, or under 2/3 his body weight). He's also unable to get his hips below the height of his knees (despite what it says in the text on the video!).
Their ability to perform a deep squat is easier to appreciate when you see them from the side. Not only are Gregorek's hips well below his knees while he's calmly holding a weight above his head, but he also has his feet together. This is simply impossible for most people.
Henshaw, on the other hand looks like he would either fall over backwards or round his back like a prawn if he tried to squat any deeper.
So, how is it that Gregorek, at more than double the age of Henshaw, and just two thirds of his weight, is able to hold significantly more weight over head while in a deep squat position?
Despite what most people would assume, it has very little to do with flexibility.
It’s because the bony structure of his skeleton (specifically his hips and shoulders, but for the sake of simplicity, we'll stick to talking about hips in this article) allows his body to get into a more bio-mechanically efficient position.
Gregorek has no doubt had to work extremely hard to achieve the athletic feats that he has, but it would have been impossible for him to become a weightlifting world champion if he'd had Rob Henshaw's parents.
That's because hip structure is genetic. No amount of soft tissue mobility work and stretching can alter the shape of your skeleton.
And as Stuart McGill explained in this interview with Bret Contreras, the most important determinant of the ability to perform a deep squat is the depth of the hip socket.
'The center of the world for hip dysplasia is Poland. They have very shallow anterior hip sockets and they can squat very deeply. The femur comes right up because there is no bone on bone contact there.
It’s actually called the Dalmatian Hip, which originates on the Dalmatian coast of Croatia up through Bulgaria into Poland and into Western Russia, which is the Ukraine. Now I think I just named the countries that produce year after year, unbelievable Olympic lifters. They also have the highest rate of hip dysplasia. So again, it’s form and function – and form and function determine athletic ability.'
Hip socket depth
Jerzy Gregorek is originally from Poland. He has the right hip structure for squatting deeply or catching a weight in the bottom of a snatch in Olympic weightlifting, as pictured below.
If Rob Henshaw tried to squat that low, his deeper hip sockets would make contact with his femurs (thigh bones) before he could get his hips below his knees. The bone on bone contact would force his pelvis to rotate underneath him, which in turn, would cause 'butt wink' where his lumbar spine flexes into a weaker, more vulnerable position. This is what robs him of his strength at the bottom of a deep squat.
As McGill explains:
'Now you take the archetypical deep hip socket and that’s a Celtic hip, prevalent in the Normandy area of France, Ireland, and Scotland.
Now how many Olympic lifters come from those countries. Not very many. The reason is they have very deep hip sockets and when you measure the power production out of that hip architecture, you’ll find that they don’t have much power at the bottom of the squat. But the top half of this squat is really powerful.'
Here's a list of all the men's weightlifting world championship medallists from 1891 to the present day.
There are 115 Poles on the list, yet not a single Irishman.
Differences in hip structure are are even more evident when revealed in a hip exam, conducted here by Stuart McGill, first on someone with a typical 'Celtic' hip, then on Jerzy Gregorek's 'Dalmatian hip':
While it's not the case that everyone with Irish ancestry has the Celtic hips that McGill describes, it would seem that Rob Henshaw does. This type of hip architecture may not be great for Olympic lifting (where a large range of motion is required), but it's ideal for rugby, where more stability is required and the force production occurs throughout a shorter range of motion of the hip joint, for example, while running, tackling and rucking.
Not only is it unnecessary for his sport to develop maximum strength at the bottom of a deep squat, but for him it would be physically impossible due to the limitations of his skeleton.
Expecting Rob Henshaw to be able to do an 'ass to grass' squat if he 'just worked on his mobility' is a bit like expecting Shaquille O'Neal to be able to do a double-twisting double-tucked salto backwards dismount off the balance beam if he 'just worked on his plyometrics'.
Good luck with that Shaq
If you've got hips like Rob Henshaw and you try squat like the guy in the gym who has hips like Jerzy Gregorek, then you're asking your body to do something that it's not built for.
Adding load to repeated 'butt wink' squats is a great way to injure your back because you're forcing it to deal with stress that should be transferred via the much more appropriately equipped ball and socket joints of your hips.
You may get away with it on occasion but if you frequently perform multiple sets of multiple reps, whilst progressively increasing the load (as is normal with any strength training program), you will actively provoke a well-documented disc-injury mechanism.
Repeated spinal flexion under compressive load has been shown to cause the outer wall of the intervertebral discs of your lumbar spine (usually L4/L5 or L5/S1, which are subjected to the most load) to gradually delaminate and weaken which can result in a herniated disc.
It's not that strength training, or even squatting, is bad for you. You just need to adapt your technique to the body that you've got. In the case of squatting, this means taking into account the structure of your hip sockets before deciding how deep you can squat. For the guy pictured above, it would mean squatting no deeper than he is in the picture on the left.
It's not only the depth of your hip socket that matters
It's not only the depth of your hip socket that affects how you squat. A number of other factors determine how you should squat without over-stressing your spine:
The orientation of the hip socket
Your average pelvis has hip sockets facing out to the sides, and slightly forwards. However, some hip sockets are more anteverted (forward-facing), like those belonging to the pelvis on the left in the picture above, and others are more retroverted (rear-facing), pointing completely to the side or even towards the rear, like those belonging to the pelvis on the right. In this example, the acetabulums aren't even visible due to their relatively extreme retroversion.
If your hip sockets are more retroverted you'll probably be more comfortable squatting with a wider foot position, with toes pointing out more (although other anatomical features will affect ideal foot position too — see below).
However, if your hip sockets are more anteverted you're more likely to be able to squat with your feet parallel in a narrower stance because there aren't any bony protrusions at the front of your hips that block your femurs.
The degree of torsion of the femur
I've been told by numerous trainers that I should squat with my feet more parallel to each other instead of out at an angle of at least 45º which is my preferred position to squat in. The circular reasoning usually given is: 'because that's how you should squat'.
However, this dogmatic approach doesn't take into account individual anatomy. Not only are my hips retroverted (revealed by my severe lack of hip internal rotation in the test below), but it's also possible that my femurs may be like one of the more twisted specimens seen above.
These differences in hip socket orientation and torsion of the femurs show that it's clearly absurd to expect everyone to be able to squat with their feet in the same position.
Other factors that affect individual mobility of the hip joint are:
Femur neck angle
Femur neck length
Not only is Jean-Claude van Damme undoubtedly very flexible but I would also speculate that he has relatively shallow hip sockets and long femur necks that are closer to a 45º angle than a 90º angle. This would allow the extreme range of motion required to do wide splits without the greater trochanters of his femurs colliding with his pelvis.
You most likely don't care if you can do the splits like Jean-Claude van Damme or a deep squat like Jerzy Gregorek. You may not even be interested in doing any kind of squats in the gym. However, it's not just when you're working out that you need to respect the structure of your hips. You also should also be mindful of it while you're carrying out repeated movements in your daily routine.
The way you tie your shoes, empty the dishwasher, clean your teeth, sit on a chair, pick up your kids, etc. all affect how much stress you transfer through your spine. And your hip structure can amplify this stress depending on how much it restricts your movement.
An example of a common flawed movement pattern that I see in people with low back pain is how they sit down into and stand up from a chair.
Someone who has been identified as flexion-intolerant during their assessment will habitually provoke their pain when they sit down in a low chair and when they stand up again. This often happens because they have their feet too close together as they sit which causes their femurs collide with their pelvis, causing their spine to flex which provokes their pain trigger.
If spinal flexion is a pain trigger for you, a simple way to avoid provoking your pain when sitting and standing is to move through your hips instead of your spine.
If you have deeper, more retroverted hip sockets, you may only be able to do this if you widen the position of your feet to a point where your femurs don't collide with your pelvis. Then you'll be able to avoid flexing your spine as you sit and stand by moving through your hips while maintaining a neutral spine position with your abs braced.
Given that most people sit and stand dozens of time every day, this can prevent you from repeatedly provoking your back pain unnecessarily and as a result, allow your back to heal. It can be the difference between having persistent back pain and being pain-free.
Fortunately, you don't need to wait for a coroner to carry out an autopsy on you to determine what type of hip structure you have. You don't even need to get an MRI.
You can either get a movement specialist to carry out a hip assessment on you or you can try the following tests yourself. Then you can apply what you've learned to your exercise program and daily activities.
These tests help you determine the depth, shape and orientation of your hip joints so that you can transfer more force through your hips without compromising your spine.
The Hip Scour
Prone internal / external rotation to check hip socket orientation
“Genetics loads the gun, but the environment pulls the trigger.” —Dr. Judith Stern
While it's true that you inherited your skeleton from your parents, you're not obliged to move it in the same way that they did. If you learn where the limits of your body lie and work around them, you'll have a better chance of avoiding the low back pain that previous generations in your family may have suffered.
You can apply your knowledge of the structure of your hips to exercises you do in the gym, especially while doing variations of squats and deadlifts. Finding the optimal width and angle of your feet will help you to maintain a neutral spine whilst driving force through your hips. This will allow you to maximally challenge the muscles of the hips, legs and back whilst sparing the joints of your spine.
Equally importantly, as you go about your everyday activities you can minimise the stress you transfer to your spine by learning how to move more through your hips.
The genes you inherited from your parents may determine whether you have the potential to be an elite athlete or not. They may also make you more susceptible to move in ways that cause low back pain. But genes aren't destiny.
In the same way that not every tall, naturally athletic person becomes a professional basketball player, or every person with a compact, explosive physique becomes a world-class gymnast, not everyone born with a certain hip structure is obliged to spend their life suffering from low back pain.
Learning about your body, respecting its unique structure and maintaining its condition can be the difference between living with chronic pain and living pain-free.
Bone images all courtesy of www.paulgrilley.com