Wheel Analogy

Ever heard the expression “It looks like the wheels have come off.” used by sports commentators once the form of a runner deteriorated? It couldn’t be more perfect of an analogy.

The wheel has several properties that make it such a good horizontal mover. First, it always has its general center of mass (GCM) above its support. Second, it constantly changes its support when moving. And lastly, its support is always at exactly the same distance from its general center of mass. Let’s look more closely at each one of these.

The general center of mass is the point where one can balance an object. For a circle this is its center point. In a concrete case like the wheel, this is where the axle goes.

The change of support can easily be observed by the spokes of a wheel. When the wheel is moving, there is a constant shift from one spoke to the next. There is also a constant feed of new material that is contacting the ground, namely the tire. This constant switching is reducing wear. This in contrast with a fixed support that you have to drag to move.

A circle by definition, and by extension a wheel, has all the points of its edge at the same distance from the center. This offers a smooth horizontal movement. There is no up and down bouncing, or vertical oscillation. No energy is wasted in counteracting gravity. The movement is both smooth and efficient.

Let’s apply these concepts to running. Of course, humans are bipeds and don’t have wheels. We won’t be as efficient as with wheels but we can be as efficient as possible. We’ll use the three factors as mentioned above: GCM above support, constant change of support, and no vertical oscillation. A human’s general center of mass is located a bit below the navel. Every time we are supported, we want our body’s weight over this support as perfectly as possible. The supports we use during running are our two legs and feet. With every stride we use one to balance our body against the surface. As with the wheel, no matter the speed with which we move forward, a new support is constantly available. The faster we go, the faster a new support should come. Bounce should be minimal. Bouncing is observable by someone watching our head move next to a fence or any other horizontal edge. Or from the runner’s perspective, if you keep an eye on the horizon or a fixed object, it shouldn’t move up and down a lot. A fine example of this is Alberto Salazar, a top marathoner in his time. During the 1981 New York City Marathon there is a shot of the leading runners crossing the Queensborough Bridge. Here we see them behind the railing with their head and shoulders sticking out above. An excellent reference frame to observe vertical movement. Salazar is hardly moving up and down. There is no energy wasted in lifting the body. The “Salazar Shuffle” is indeed an efficient way of moving forward. Here Channel 6 provides the full broadcast. Around the 1h10:50 mark the broadcast switches to the bridge crossing.

Fueling Your Runs

There is a concept out there called ‘carbo-loading’. We are told to eat extra carbohydrates in the day, or even the days, leading up to a long run. This can be achieved by either having more meals in the day or increasing your portion sizes per meal of eating bread, pasta, rice and the likes. These extras will be stored by your body and will be used during your run. On top of that, you won’t even get fat.

Let’s step back for a moment and examine this claim. It is likely, though not necessarily true, that these extra carbohydrates (carbs) will be stored somewhere on your body in one way or another as an energy source your body can use. However, there is also the possibility that it will go straight through you without being absorbed. This can happen when your gut is damaged (e.g. inflamed).

Now consider the type of carbs that are suggested: bread, pasta, rice, etc. All of these are mostly sugar. When you eat these, your blood will be flooded with sugar. Your body doesn’t like this spike. Mechanisms will work to get the level of sugar in your blood back to an acceptable level. The sugar will be transformed to a storage form. It can be stored in muscle or the liver as a readily accessible sugar, or becomes fat and is stored in fat cells. There is little storage space in the liver and muscles, so most will wind up as fat.

Unless you eat these carbs relatively close to your run, they are stored as fat well before you get to your run. Using these fat stores for energy is an option. There is however a problem. As long as you keep eating these carbs or any other sugary source like the abundant ‘gu’ or ‘gel’ then you won’t be able to access your fat stores and convert these to energy for your muscles.

Once you go down the path of eating carbs to fuel your run, you will be eating carbs constantly to meet your energy needs. As long as you can absorb these, it can work out and supply you with energy. Though, as the run gets longer and longer, your gut will start protesting this constant carb eating. This has now become an absorption issue. You are using energy while running. Your gut has difficulty in absorbing all that energy. You can’t access your fat stores for energy. Continuing will deplete you of energy, and that isn’t pretty. What starts lightheaded, can lead to medical intervention.

We don’t advocate any particular diet. We want you to be healthy and able to perform. What you do before your run matters as much as what you do during your run (maybe even more). Consider using your own fat stores to supply your energy needs. For one thing, you won’t have to lug around all those gels. That is quite freeing. Or think of all the money you save by not having to buy these overpriced goodies. Think about your diet as an ongoing experiment. Find out what works best for you.

Choosing Running Shoes

Whenever people pick up a new sport, whether it be cycling or running or anything else, they quickly ask themselves what type of gear they need. For cycling you need a bike. For running you need running shoes. Choosing the right shoe should not be complicated. Shoe recommendations based on arch height and pronation has been tested in research studies. It has not shown much clinical success.

Let’s look at arch height first. Feet are traditionally divided into a low or a high arch and normal feet. This is simply a distinction between how high the curve of your foot is in relation to the ground. The low arched feet were prescribed motion control shoes. The normal feet were prescribed stability shoes. High arched feet were prescribed a neutral shoe. Studies concluded that this method of shoe selection did not reduce injury risk, or could even increase risk, as compared to people who were assigned shoes randomly.

Pronation is an inward rolling of the foot and ankle. This is a natural movement of the foot that enables movement like walking. There is no standard that tells you when you are overpronating (too much inward rolling) and are risking injury. It is also difficult to measure this when you are wearing a shoe. The foot can move inside the shoe. This can not be readily observed from the outside. It becomes difficult to tell how far you are pronating. Wrongly attributing overpronation as the cause for injury can lead to more injury. In other words, you weren’t overpronating but you got a corrective device anyway and it is now hindering the natural movement of your feet. Studies are conflicting and there is little evidence that links overpronation to injury. Some even suggest that overpronation is protecting you from injury.

So what can be done? First of all, start from proper running technique and strong feet. Strengthen your feet so they can do the job of supporting your body. Practice running technique so that you are moving in a way that is in line with the way the human body is built. This alone will reduce your chance of injury a lot. But what about shoes? Their primary function should be to protect the feet from harm, like cuts, and not try to assist you in running. Stronger feet can get away with less. Less shoe will allow for better technique. Build your way up to a minimal, zero-drop (there is no incline from toes to heel) shoe. These are flexible and thin enough to allow your feet to do all the things they should be doing: flexing and sensing the surface to create a strong base to support your body.