The Impacts of Running

A few years ago I was training for a marathon, and I was feeling great throughout my training. I had just run my best half marathon time while training a couple weeks prior, and I was excited to get outside to do a 12 mile training run. The run felt great, the weather was beautiful, and I was in the zone. Then at mile 10, without changing anything in my stride, a sharp pain went straight through my ankle and I could barely walk. As a runner, I still tried to power through and managed to jog about another half mile, until finally I gave up and limped the rest of the way home.

So what happened? The short answer is I stress fractured my ankle from overuse. The longer answer dives into the anatomy of the human body, the stresses that are exerted on it, and the limitations of what we can endure without injury. After my injury (and a second stress fracture a couple months later), I began to wonder what kind of forces act of the human body while running, and whether or not it’s good for us to run for longer distances.

Any time you take a step, your body experiences a force that is greater than what it experiences while standing. A typical jog/run will exert between 2 and 4 times your standing force on your body. This means if you weigh 100 pounds, a single impact during a run will cause enough force to make you feel like 400 pounds. Your body does its best to absorb this shock to your body. The muscles in your legs act as a shock absorber, and the stronger your muscles, the less impact you will have loaded straight to your skeletal structure. This is why it’s important to weight train your lower body. Having weak or tight ankles or calves could lead to stress fractures in the foot and lower legs, which is what happened to me.

Shock absorbing shoes and insoles can help reduce the impact on your body, and has been scientifically proven that it helps reduce injury, but there could be some downsides to this. When you put on supportive shoes, the support and shock absorption that your muscles are adapted to provide are no longer needed. This triggers your body to weaken those muscles, and if you’re not careful, if you lose support in your shoes your muscles may not be ready to support the impacts of jogging the next time you go.

Another common technique runners use is they will run on softer surfaces to reduce the impact on their bodies. Scientists from the University of Calgary wanted to test this and see if impacts on harder surfaces such as concrete caused more injuries than softer surfaces, such as running on grass. The results were fairly surprising. They discovered that there wasn’t a noticeable difference in injury frequency when running on a softer surface rather than a harder surface. This could be because the cause of injury is more centered around an individual’s muscular and skeletal structure, rather than the force of the impact.

If you’re a walker or a runner it’s impossible to avoid the impact forces of the exercise, but you can reduce them by wearing supportive shoes or insoles. Also, impact activities such as basketball, running, or dancing typically produce an increase in skeletal mass, and are good ways to increase bone density to decrease your chance of stress fractures. Perhaps the best way to keep yourself from a running injury is to keep your lower body muscles strong and loose. The smaller muscles such as the ones in your ankles and calves are perhaps the most forgotten and important when it comes to preventing impact injuries. So for my runners and walkers out there, make sure you are staying ahead of any potential injuries by training your lower body muscles. If not you may end up like me, doing every cardio session on a stationary bike for months while my ankles healed.

Thank you for reading! If you want to learn more about the science behind walking and running impacts, check out these two peer-reviewed articles that I referenced when writing this article:

https://www.ncbi.nlm.nih.gov/pubmed/2782094

https://www.researchgate.net/publication/12154692_The_Role_of_Impact_Forces_and_Foot_Pronation_A_New_Paradigm

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What Type of Shoes Should You Wear When Trying to Lose Weight?

The human body is structured to be able to efficiently hold up a certain weight. If you start exceeding that weight, your body will begin compensating or breaking down, causing pain or discomfort in certain areas. One of the most common areas that become painful when you are carrying a couple extra pounds are your feet and lower legs, and your shoes could be either helping or hurting this pain.

The arch of your foot can be thought of as a spring that absorbs the shock caused by the weight of your body when you walk or run. This spring is rated to a certain weight, let’s use 150 pounds as an example. As you start to weight more than the spring is rated for, the spring will overcompress. If you weigh 180 pounds and the spring is rated for 150, the spring will collapse under the weight, just like you see the back of a truck dip down when there is a bunch of stuff loaded in the back. This collapse of the arch of your foot then causes the rest of your ankle to roll inward with every step, a process called overpronation.

Overpronation can cause a lot of discomfort in the feet and lower legs, but this pain can be mitigated by wearing the right shoes. While there is no replacement to weight loss when trying to cure this pain, wearing a stable shoe that adds support under the arch can keep your foot in a neutral position while walking and running. While lower leg pain when you are a bit overweight is usually caused by overpronation, you can verify this by looking at the wear and tear of an old pair of shoes. If you notice that more of the tread is worn down on the inside of your shoes than on the outside, this is an indication that you are an overpronator. Also, running shoe stores such as Body N’ Sole will video tape you walking and tell you if you are an overpronator for free.

A common mistake I see people making is that when you buy shoes, they choose them based on style rather than functionality. While the Nike Free series look great, they offer zero support for your collapsing foot. You want to look for a shoe that is supportive and rigid in design. Usually, shoe companies will make these types of shoes fairly easy to identify on their websites by allowing you to search for shoes based on if they are “support” shoes. Some companies, such as ASICS, even allow you to filter shoes by whether or not they are made specifically for overpronation. Some shoes commonly worn by overpronators are the ASICS GT-2000s, Nike LunarGlides, Mizuno Wave Inspires, Brooks Adrenalines, and Saucony Hurricanes. I’ve personally run with each of the following brands, and you can’t really go wrong with any of them.

When you are buying your new pair of shoes to combat your overpronation, make sure you try them on with athletic socks on, preferably at the end of the day when your feet are a bit swollen, and that you have about a half inch of extra room in the toe box. If you decide to use insoles for a bit of extra support, purchase them before you buy the shoes so you can make sure the shoe will still feel great once you add the insoles. Spend a week or two breaking them in, and hopefully your new shoes will help alleviate any pain you may have been having.

Finally, remember to replace your shoes about every 6 months if you are active. The support will begin to break down after awhile, and you will want to replace your shoes to ensure your feet are getting the support they deserve. I hope you found this article helpful. Feel free to email me with any comments, questions, or concerns at 2weekstohealth@gmail.com.

Author: Scott Van Hoy – Click Here to view the author’s profile