The goal of these next blog posts is to remove some of the mystery of how to find the right running shoe for your specific foot. For the average consumer, shopping for a good pair of running shoes can be daunting. There are thousands of different models and styles of shoes to pick from. It doesn’t help that most costumers are influenced more by TV commercials about the shoe and how the shoe looks esthetically, than how it actually functions on their foot. I like to use the analogy that shopping for running shoes is like buying a $100 lotto ticket. It’s exciting when you are purchasing the ticket, but there is often buyer remorse when you get home and you realize the ticket was not a winner. Even more frustrating if you do find a winning ticket, you can never play the same numbers again because the shoe companies are always changing their shoe designs. Hopefully, after reading this blog, you stop feeling like you’re always playing the lotto at the shoe store, and your shoes always feel like a million dollars!
This blog will be 3 parts long. It will start by discussing what goes into a shoe first, that being your foot. The shoe must match your foot, not the other way around. Then in the second part, it will breakdown shoe anatomy and the different types of shoes and how they can help improve function and decreases injuries in runners. There will be a brief discussion in this part on running style/technique and the type of shoe that suits the runner (I will post more specific blogs on running form and technique in the future). Finally in the third part, I’ll post about several injuries that occur while running and how to prevent and aid in healing specific injuries with specific shoes.
Getting to know your own Foot:
Humans started to walk bipedal (on two feet) anywhere from 5 million to 10 million years ago, depending on which archeologist you ask. The transition from ambulating on all fours to bipedalism may actually have been one of the most important evolutionary developments in mankind. There are two theories on why we started to walk up right. The first is that by walking only on our feet, we freed up our hands to use tools. The second idea, and most accepted theory is that by walking on two feet, human beings became more efficient. Ancient humans were able to walk/run for greater distances; which improved their ability to hunt. Bipedal man could literally chase his pray to death because of the improved efficiency. Maybe this why modern man still has the deep desire and love for running long distances?
To make the physiological change to bipedal locomotion, some major adaptions had to take place in the human body. First our posture changed to a more vertically erect posture, we developed a lumbar lordosis/mobile lumbar spine. The shape of our pelvis changed and many of the muscle of our pelvis had to change their function compared to other primates. I believe this is why so many injuries can be related back todysfunctional hips in modern man. Finally, our feet had to change in shape and function. We ask more out of our feet than any other animal on this planet. Our feet act as a stable platform for when we need to stand for hours, they act as the first line of shock absorption and they also transform into ridged levers when we need to push off in running.
The human foot is composed or 33 different joints and 26 bones. The structure of the foot articulations give the foot the ability to be very mobile and then stiffen depending on the position and contraction of muscles. Speaking of muscles, there are two types of muscles that attach to the foot, a short group called the “intrinsics”that are found within the foot, and then there are longer muscles that start at the leg bones (tibia/fibula) and then attach to the bones in the foot. The muscles and ligaments hold together the arches of the foot. Yes, I wrote arches, with an “s”. There are actually three different arches in the foot, the medial arch that most people think of when they think of a foot arch runs between the base of the big toe to the inner heel. The longitudinal arch runs along the outside of the foot, and the transverse arch runs across the forefoot. Together, these arches create a triangle or tripod within the foot. It doesn’t matter if you have really high arches or a “flat” foot; everyone needs to support themselves on the three points of the foot tripod. The most common deformity that occurs when there is a dysfunctional foot tripod is a bunion. When the tripod point at the base of the big toe becomes dysfunctional, the angle of progression changes when you walk (over pronation), forces are distributed unevenly, and muscles that usually anchored from that tripods point become weak. If this occurs over several years, the forefoot will widen and the joint of the big toe with start to deform.
As I mentioned previously, the foot needs to be a mobile shock absorber, for 5 million years humans walked barefoot on uneven terrain (it was not until the last few hundred years that humankind made everything flat with cement and concrete). This ability to keep the joints of the foot loose and adaptable is termed “pronation”. Pronation gets a bad rap; really, it is one of the most important motions in your foot. As a runner I would take a foot that slightly over pronates any day over a foot that doesn’t pronate enough. The motion of pronation is complicated when you breakdown the motion of every bone in the foot, but for the sake of simplicity, think of pronation as the foot “collapsing or rolling in”. Supination is the exact opposite of pronation, it is the mechanism of making the foot a “ridged lever”. As we walk or run, after we have adapted to the ground, absorbed the shock of impact through pronation, we transfer our body weight over and past our foot by pushing off through supination. It would not be very efficient to push off if the foot was still a “loose bag of bones” as it is in pronation. During supination, the muscles and tendons of the foot and leg bring the foot downward and inward, causing the bones of the foot to lock (windlass effect).Some rights reserved by sportEX journals
Bio-mechanically, there are differences between running and walking. Walking can be described as a pendulum motion, where the rotation of the different parts of the body preserves momentum. In walking, the foot is in contact with the ground 60% of the time, and both feet are touching the ground simultaneously at different parts of the walking gait cycle to preserve the momentum used to propel walkers. Running uses principles more related to a spring. Running relies on the elasticity of the muscles and tendons to propel the runner forward. In contrast to walking, most of running is done in the air (40% foot ground contact time) and only one foot is ever in contact with the ground at one time. During running, pronation occurs during 70% of the ground contact period, and supination comprises the rest of the time the foot touches the ground.
So what’s the big deal about “over pronation”? As stated previously, pronation is essential to human movement and actually helps prevent injuries then it causes. But, when pronation occurs at a speed or rate that your body can’t control, you can have complications that lead to injuries and decreased performance. I use a slingshot analogy to explain the concept of over pronation. I can pick up a pebble and toss it to someone; they will be able to catch it without difficulty because of the predicable slow speed of the toss. However, if I take that pebble and load it into a slingshot and fire it at someone, they will not be able to control and stop the pebble without some type of shield, or they will become injured. The shield in this analogy is a shoe or an orthotic that slows down the pronation. The worse type of over pronation is one that only happens in one foot, and not the other. In this case there is an asymmetry in the body that travels up the kinetic chain. (over pronation causes the lower leg to rotate in, the knee to twist down and in, the thigh rotate causing the pelvis to tip down and forward, leading to a curve in the lower back and a compensation in the middle back, dropping and rounding one of a shoulders).
Some rights reserved by whiteafrican(flicker)
So what’s the big deal about “over pronation”? As stated previously, pronation is essential to human movement and actually helps prevent injuries then it causes. But, when pronation occurs at a speed or rate that your body can’t control, you can have complications that lead to injuries and decreased performance. I use a slingshot analogy to explain the concept of over pronation. I can pick up a pebble and toss it to someone; they will be able to catch it without difficulty because of the predicable slow speed of the toss. However, if I take that pebble and load it into a slingshot and fire it at someone, they will not be able to control and stop the pebble without some type of shield, or they will become injured. The shield in this analogy is a shoe or an orthotic that slows down the pronation. The worse type of over pronation is one that only happens in one foot, and not the other. In this case there is an asymmetry in the body that travels up the kinetic chain.
The best story of this relationship between the foot and rest of the body comes from baseball. In 1937, Dizzy Dean was pitching in an All-Star game. The batter hit a comebacker that hit Dean’s foot, fracturing his toe. While still nursing a sore foot, Dean resumed pitching. The soreness caused him to change his foot position and his pitching mechanics, leading to shoulder and arm problems. Dean was never able to overcome his shoulder injury, leading to his early retirement. His quote ““Fractured. Hell, the damn thing’s broken!”.
Is There an Ideal Foot?Image from www.dukehealth.org
Many people make the mistake of only looking at their foot when are trying to determine if they under or over pronate. The assumption is that if your foot is “flat” you must over pronate. This is a myth, if a person with a flat foot uses their foot tripod effectively, they may not have a pronation problem at all. Actually, a person with a flat foot can have a very stiff and ridged foot and may need a completely different type of shoe compared to what it looks like they should wear. The best example of this is the fastest man in world, Usain Bolt. Did you know he has flat feet? I don’t think I remember watching him run at the Olympics in heavy motion control shoes. Sadly many people with flat feet with normal foot mechanics are improperly fit into a motion control shoe or an orthotic. This causes them to complain the shoes are uncomfortable due to the artificial arch that presses into their underfoot. Actually, people with high arches that have very mobile and loose feet are more likely to become injured because their body can’t control the rate in which their foot collapses at a greater distance because of their high arch starting point.
Much like the stereotyping of flat feet, there is an assumption that people with high arches need a cushion shoe because it is assumed that their foot is very stiff and they supinate more than they should. And the person with a “normal” looking arched feet (what ever normal is?) should be ok in a stability/neutral shoe. The moral of the story here is that looks can be deceiving. I can look at a door and assume I know how it moves, but until I physically open it, I never know if the door moves easily or is locked/jammed. The best way to tell how a foot moves is to have a professional palpate the motion of a foot and then analysis the foot when walking/running. Palpating your own foot or trying to self-analysis your gait can be tricky. The easiest way to tell about your foot tendencies during your gait cycle is to look at the wear pattern of an old pair of shoes. I call this “arch”eology (sorry it’s a lame pun).
The two other variables in foot function that become very important when fitting shoes are:
1. Where and how much your big toe bends in relation to the shoe. You may have never realized the ramifications that people have different sized toes, and the joints of the toes don’t always match where the shoe bends (can you say turftoe?). Typically in an athlete the big toe should bend up in the air 65 degrees when standing flat. There is also specific group of people that have a Morton’s foot, this is easy to distinguish because in a Morton’s foot the 2nd and maybe 3rd toes are longer then the first toe. This causes an alteration in toe off when they run and special attention needs to be paid in fitting them into a shoe that bends in the forefoot at the proper location.
2. How well your ankle flexes (dorisflexs) is also really, really, really important in runners and all other athletes. The number one reason we lose our ability to flex our feet are ankle sprains. If you severely sprain your ankle and never properly rehab after, the ligaments on the side and back of the foot scar down and you end up losing the ability to flex the ankle. In a runner ankle dorsiflexion should be between 20 and 30 degrees. Anything less will shorten the stride length and put excess stress on the soft tissues of the plantar fascia, Achilles tendon and the calf musculature.
The last point I’ll make before we start to break down shoes in the next blog, is that there are these things called legs that attach to your feet. In an ideal world there would never be anything wrong with the legs above the feet that could cause concern about shoe fit and function. But, we live in the real world, not an ideal world. For example, if people have knees that are bowed out or knocked in, special consideration needs to be made in shoe choice. Sometimes function may call for one type of shoe, but that shoe will not work with the individual because the shoe makes a condition in the knees or hip/back worse. This is when compensation needs to be made in shoe choice and professional help should be sought out.
Dr. Chris Feil