Your Hip Joint Suspension System
Why it's important, and learning to activate it at will
When we stand upright the entire weight of our upper body (the torso, the head, the arms, their muscles, and organs) all rests on our hip joints. As a result the top of the hip socket (the hip socket is called the acetabulum) can potentially rest on the ball of the hip joint.
Standing with our weight on one leg, the hip joint of the supporting leg bears all of that weight. It’s also bearing the weight of the other leg (unless it is supported externally).
Now, imagine what happens while walking or running. During heel strike, not only is the hip joint subject to the weight of the upper body and opposite leg, it’s also got the force of impact to deal with.
How does the hip joint withstand this wide range in forces?
The idea I’ll put forward here is that the hip joint has a suspension system.
Vehicle suspension system analogies for the hip joint
In a car or motorbike, the suspension system for each wheel generally consists of a spring and a damper. The suspension is set up in such a way that relative to the body of the vehicle when at rest, the wheel can move up or down without bottoming (or topping) out.
- Going over a bump, the wheel moves up relative to the vehicle body. The spring stores this energy, then pushes the wheel back down after the bump has passed. The damper prevents the car body from continuing to bounce up and down.
- Going over a hole, the wheel moves away from the body, then back in towards it. The spring again stores this energy and uses it to return the wheel to center while the damper quietens the rebounding as quickly as possible.
Tires are also part of the suspension system. They take care of the smaller bumps and divots and they also provide cushioning, as well as grip, so that the wheel rims never impact the hard surface of the road.
Our hip joint suspension system may have similarities to both elements of a vehicles suspension system.
A Spoked Bicycle Wheel as a Hip Joint Analogy
Another analogy for hip suspension is a spoked bicycle wheel. The spokes keep the rim centered relative to the hub even as the wheel rotates.
This analogy is relevant because it allows us to integrate a mechanism for joint movement. If we replace the spokes with variable tension elements we have a mechanism not only for absorbing shock, but for measuring effort and tension.
For more on this read about using a controllable bicycle wheel tensegrity as an analogy for ideal hip joint proprioception and control
Back to the hip joint proper.
Primary Muscles of the Hip Joint Suspension System
While standing upright, the muscles that can act to slightly lift the top of the hip socket away from the ball of the hip joint without going too far in the opposite direction include the obturator internus, obturator externus, gemellus superior and gemellus inferior.
In most western anatomy texts, if you look at these muscles from behind they seem to angle down from the hip bone to the femur making it seem unlikely that they can pull the hip bone up relative to the femur.
This is mainly because western anatomy texts tend to depict rear views of the pelvis with a particular angle of forward tilt so that certain anatomical landmarks end up aligned.
If you view the hip joint from the side or if you change the front-back angle of the pelvis when viewing it from behind, you can see that the aforementioned muscles angle up from the hip bone to the femur.
When active while standing, these muscles can create a slight amount of lift, sufficient to prevent the top of the hip socket from bottoming out on the ball of the hip joint.
More importantly this activation is relatively easy to do yourself.
It’s something you can practice.
Why Activate Your Hip Joint Suspension System
Why might you want to practice it? Whether young or old, your hip suspension system may be one of the key systems for preventing the need for a hip replacement surgery.
Preventing the need for Hip Joint Replacement Surgery
If the ball of the hip joint is kept centered relative to the hip socket, then the hip joint is lubricated at all points and this means that there are no rubbing parts. This in turn means that the capsule of the hip joint and its associated tendons and ligaments can redistribute tension freely.
As an example of what this might look like, you can press a finger into an inflated balloon. The resulting change in tension will redistribute throughout the entire surface of the balloon. However, if you pinch a portion of the balloon without rupturing it, and then subsequently press a finger into another part of the balloon, the change in tension is transmitted to a large portion of the balloon but not the portion that you are pinching.
With the hip joint, if the hip socket contacts the ball of the hip joint at any point, and if boundary layer lubrication fails i.e. if the contacting surfaces rub together and friction results, then the joint capsule can no longer freely distribute tension.
Boundary layer lubrication is the type of lubrication that occurs when two parts rub against each other. It generally results in a wear of the two surfaces involved.
What that means is that parts of joint capsule may be subjected to excessive tension. Over time this can result in the joint capsule failing, i.e. rupturing so that it can no longer contain synovial fluid and no longer pressurizes it.
Further hip joint capsule damage then occurs with the result that the hip joint eventually fails completely.
What this means is that the hip joint can no longer redistribute loads so that some muscles work excessively while others don’t work at all. This in turn can affect the knee and the lower back.
Note that this can take some time to happen. The idea of learning to activate your hip suspension system is that you can possibly prevent it from ever happening.
Reducing Low Back Pain
As well as allowing the hip joint to function optimally, and possibly without pain and discomfort, activating the hip suspension system, when appropriate, may help in reducing or eliminating low back pain, particularly if that low back pain is the result of hip joint imbalances (imbalanced function between the left and right hip joints).
Failing that, it may be an important or necessary part of the solution.
Helping Prevent Knee Pain
Activating your hip suspension system may also play a role in dealing with knee pain. One reason is that the same muscles that act to suspend the hip while standing can also help in stabilizing hip rotation. Another way to look at it is that these same muscles can help to stabilize the hip bone relative to the femur. With the hip bone stabilized, the muscles that originate from the corner points of the hip bone and insert on the inside and outside edges of the lower leg bone can then act effectively to help control shin rotation and knee rotation.
Again, learning to activate your hip suspension system isn’t a guaranteed fix for knee pain, but it may be a necessary part of working towards a pain free knee.
(This is assuming that the knee pain in question is the result of improperly controlled knee, hip and foot muscles versus some other problem.)
Why you can feel your hip joint suspension system when it is active
As mentioned, the primary muscles of the hip suspension system are the obturators and the gemelli. The pectineus may also be a component.
When activated, you can think of these muscles as working to either lift the hip bone off of the femur or of reaching the femur away from the hip bone. In either case, the amount of movement is small. However, since muscles are being used to generate this movement, that muscle activation also makes the movement (or “action”) perceivable. In other words, you can feel it.
This is important because it means you can recognize when your hip suspension activation intentions are successful or not. It’s like throwing a dart at a dart board and noticing where your dart hits so that you can see how accurately you’ve thrown it.
Learning how to activate your hip joint suspension system.
To get a taste of activating your hip suspension system, sit upright in a chair. Focus on one knee. Push your knee forwards away from your hip joint. You should notice some muscular activity or tension around your hip joint as you do this. Relax and repeat a few times.
Then repeat with the other knee and hip.
To vary the sensation you can try moving your knee slightly inwards and outwards while pressing your knee away from your hip joint.
Note that when doing this exercise while sitting it is possible to over use this action. To minimize that possibility, after pushing your knee away from your hip, then add a pull in the opposite direction, pull your knee towards your hip. You should notice some thigh muscle activation.
Here again, you can adjust by moving your knee (or knees) slightly inwards or outwards. I’d suggest when doing both knees, adjust one knee at a time.
Activating your hip suspension system while standing
You can then try the same exercise while standing. Here too you can imagine pushing your knee away from your hip.
While standing, your hip suspension muscles are working against the weight of your body. You may find that you are less likely to overuse the muscles in this instance. However, if you do find you get excessive muscle soreness, experiment with the opposing action to see if it helps.
If you are learning to activate your hip suspension system to help deal with knee pain, you may find that using the opposing action even while standing can help.
Once you get a general feel for activating your hip suspension, experiment with various amounts of leg rotation. If experimenting with it while walking, notice where your landing foot lands with respect to the other foot.
Contextualizing Activation of your Hip Joint Suspension system
For any muscle activation, it's generally a good idea not to over do it or over use it. That being said, part of the process of learning it is to practice it in a range of poses or actions so that you can activate it at will. From there the next step is to integrate it with other actions.
Published: 2022 04 26