88% of the world's population suffers from foot problems, but podiatry in Japan lags behind that of Europe and the United States, so there are few opportunities to receive education about feet. As a result, neck stiffness and back pain that would normally improve with foot adjustments remain unresolved for many years.
It is recommended to focus on strengthening the buttocks to improve the condition of your legs. In this article, we will look at the relationship between legs and lower back pain and stiff neck, which may seem like a minor issue.
Overpronation: A common problem affecting three out of five people worldwide
One of the causes of lower back pain is overpronation of the feet. Overpronation is known to be related to bunions and lower back pain .
Between 2002 and 2005, Menz et al. conducted a large-scale study of 1,930 people (men and women aged 36–92 years) *1 . They investigated whether flat feet, high arches, pronation, supination, and asymmetry were associated with low back pain.
the result,
- No association was found between flat feet and high arches and lower back pain in either men or women.
-In women, there is an association between pronated feet and lower back pain.
・Insoles (sole plates) are effective in preventing and treating lower back pain
It has become clear that...
Rheumatology (Oxford). 2013 Dec; 52(12): 2275–2282.
Women, in particular, are 1.48 times more likely to suffer from lower back pain than women without any abnormalities. Overpronation is a common symptom that affects three out of five people worldwide. Armed with knowledge based on the paper, let's take a look at what measures can be taken.
What is ankle overpronation?
What is overpronation? Pronation is a movement that occurs even in healthy feet, but when it becomes excessive it is considered overpronation. First, to understand pronation in more depth, let's deepen our understanding of the two foot mechanisms.
Feature 1: Flexible switching
When you walk, your feet bear twice your body weight. This is why your feet need shock-absorbing capabilities. Soft materials like sponges are ideal for absorbing shock. However, when you push off with your feet next time, it seems like a harder material would be better than a soft one.
In fact, the body switches between soft and hard feet . When landing, the foot instantly softens, and when the final foot leaves the ground, the foot firmly pushes off with the hard foot.
How do you switch between soft and hard feet?
How do you switch between soft and hard feet? See the illustration below.
There is a movement called pronation, which rotates (tilts) the foot inward. When you pronate, the bonds in your foot loosen and the arch lowers . You can imagine your foot being bent to absorb shock. This creates a flexible foot.
Supination is the opposite. When you turn your foot outward, it strengthens the bond between your foot and raises the arch . Imagine it tensing like a bow, ready to spring forward with force. This completes the process of creating a stiff foot.
How does pronation and supination occur?
Next, let's look at how pronation and supination occur. When you internally rotate your shin (turning inward) while your weight is on it, your foot also pronates . Conversely, when you externally rotate your shin (turning outward), your foot supinates.
How does internal and external rotation of the shin occur?
How does internal and external rotation of the shin occur? The driving force is the twisting movement of the hips.
For example, when the right foot hits the ground, it internally rotates, creating a flexible leg. Eventually, the left leg is swung forward. At this time, the left leg is swung forward while twisting the hips. This twisting movement of the hips is transmitted in turn to the thighs and shins, causing the shins to externally rotate . An externally rotated shin creates a stiff leg.
The diagram below shows how internal and external rotations are switched from the pelvis to the feet. The rotation is transmitted in order from the hips, skillfully switching between flexible and stiff feet.
If the switch function does not work, you will walk with your arches collapsed, which will eventually lead to problems such as bunions.
Function 2: Move more efficiently! Rolling foot function
The foot is equipped with a mechanism that allows the body to move efficiently, just like a round ball rolling endlessly. When the heel touches the ground, the round shape of the heel rolls forward without using muscles. This is called heel rocker movement . (Rock: rocking) It can be likened to the rocking motion of a rocking chair. 
This forward rolling movement is then carried over to the next movement, the ankle rocker . The heel has a bone called the talus, which has a part called the talus trochlea. The talus is the only bone without muscles attached, and it allows the weight to be smoothly transferred forward.
The final step is the forefoot rocker . This is when the MP joint bends and throws your weight forward. Working in coordination with the small sesamoid bones, it relays the energy that propels you forward efficiently.
However, this forefoot rocker movement only works if certain conditions are met, and you end up walking while putting a brake on your propulsion (abductive twist). This causes the forefoot to repeatedly twist against the ground, resulting in excessive calluses on the soles of your feet. I first noticed this symptom when I had a hole in the big toe area of my sneakers.
There are conditions under which locking and switching cannot be performed.
Now, we have seen how the foot functions to roll and transfer energy efficiently while switching to a flexible foot to protect the body. When I first learned about this, I was amazed at how well designed it was and it inspired me to learn more about the foot. However, even though this is such an amazing function, there are factors that can easily stop it.
This is called overpronation. Pronation, which occurs even in healthy feet, is a very natural movement, but if it becomes excessive, the two functions explained above will not work.
the result…
・Unable to switch between soft and hard feet, always walking with soft feet
→ This can lead to problems such as bunions and flat feet.
・When doing forefoot rocker exercise, you cannot roll the ball and have to brake while walking.
→ Develops into abductive twists, calluses, bleeding nails, etc.
Eventually, the injury to the foot can spread to the hip joint, which is located further away, and can even cause pain in the lower back, neck, head, etc.
What causes overpronation?
What causes overpronation? The pathomechanics are complex and the causes are not fully understood. Currently, it is believed to be caused by the interaction between the hip and knee joints and dysfunction of the subtalar joint .
Until now, treatment has been carried out using top-down, bottom-up control methods such as the use of insoles (sole plates). Currently, an approach that also includes top-down control methods that approach areas above the foot, such as the hip joint, is recommended. Methods of improvement include muscle training, insoles (sole plates), and modifying walking style .
Reason 1: Weak muscles
Reed et al. investigated 283 papers on running injuries. Their results revealed a relationship between weak gluteal muscles and running injuries . *2 If these muscles do not function properly, balance will be impaired when standing on one leg. If you look closely at walking movements, you will see that you are standing on one leg repeatedly, so weak gluteal muscles are a problem.
According to Kelli et al., 57% of participants actually saw an improvement in overpronation as a result of training their glutes . *3 Exercises such as deadlifts and back lunges are effective for training the gluteal muscles.
Cause 2: Muscle imbalance and bone alignment issues
For example, if the movement of the talus becomes poor due to lifestyle habits or an accident, it will also affect the posture of the knee and hip joint. As a result, you will start using your feet incorrectly. Eventually, the incorrect movement of the hip and knee will be reflected in the feet, creating a vicious cycle.
When this happens, no matter which side you stand up, one side will fall over. It may be possible to correct this manually, but it is difficult from a structural medicine perspective because the side will return to its original position due to gravity when you stand and walk.
From the moment you put the insoles on, they guide your feet to move in the natural way, so they are effective in restoring muscle balance and bone alignment that have become disrupted.
As Menz's study also recommended insoles, they have become an effective option for podiatrists in Europe and the United States, where research is progressing rapidly. *1 In addition, various companies are selling shoes designed to prevent overpronation for runners.
It is best to get fully custom-made insoles that are tailored to each individual. This is because if the way your feet land changes, it can cause so much pain that you can no longer wear them. In that case, if you get fully custom-made insoles, you may be able to readjust them by applying heat.
Cause 3: Problems with walking style
The walking style taught in schools and the media can sometimes lead to pronated feet. Some recommend landing with the knees fully extended, while others instruct to grip the ground with the big toes, but this leads to landing softly and pushing off by squashing the foot. Also, uniaxial walking, where you walk on a single line, puts strain on the body due to problems with shifting the center of gravity. We will discuss walking styles on another occasion.
summary
The cause of lower back pain may lie in the feet. Ignoring foot problems can eventually lead to problems in the upper body, from the hip joints to the lower back to the shoulders to the head. Proper walking techniques, proper strength training, and appropriate insoles can increase the chances of resolving neck and lower back pain that has persisted until now. Because the foot has a complex structure, we recommend combining these three methods to efficiently resolve the issue.
References
∗1 Menz HB et al.
Foot posture, foot function and low back pain: the Framingham Foot Study.
Rheumatology (Oxford). 2013 Dec;52(12):2275-82.
*2
Reed Ferber, PhD et al.
Suspected Mechanisms in the Cause of Overuse Running Injuries
Sports Health. 2009 May; 1(3): 242–246.
*3
Kelli R. Snyder et al.
Resistance training is accompanied by increases in hip strength and changes in lower extremity biomechanics during running
Clinical biomechanics (Bristol, Avon) 24(1):26-34 · November 2008
