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?
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.
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).
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!”.
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.
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.