Shin splints (Medial tibial stress syndrome or MTSS) is a common problem with runners and there are many different products on the market as well as a lot of poor information about how to reduce the pain. Shin splints are inflammation of the part of the tibia where the muscles on the front of the lower leg attach. This is caused by overuse and stress being incorrectly transferred through the anterior leg musculature.
So why is stress being incorrectly transferred to the tibia? While this is a complex answer the most common cause is running style. Modern shoes have allowed runners to do what is known as heel striking. Shoes are heavily cushioned on the rear aspect of the shoe and the shoes are taller in the rear foot then in the toe box. This is a great shoe design and technology, however we are not designed to run with a heel strike and this overloads the anterior musculature.
I make the claim that we are not designed to run with a heel strike. Simply looking at anatomy of the lower leg and the entire kinetic chain backs this. The most important thing to look at is the size of muscle mass in the lower leg. The posterior aspect of the leg is larger then the anterior by a significant amount. So why does this matter? Well muscles are the main source of shock absorption as well as propulsion. When we land on the heel with a heel strike while running the knee is straight and the toes are up with the foot out ahead of the body, the calf is in a fully stretched position and the anterior aspect of the leg is contracted. As the foot comes down the smaller muscles in the anterior of the leg now have to eccentrically contract (contract while lengthening) to slow the foot down and absorb the impact of the landing. Also important to note in this landing position the knee is fully extended and locked out. This means that the knee is unable to absorb any stress through bending and stress is transferred through the joint and up the kinetic chain into the hip and lower back. Also, while landing on the heel the leg has a pivot point through the heel where the leg can easily twist and with the knee extended the only way to control this rotation is in the hip. Since we are talking about shin splints I won’t go into what problems that causes in the hip. So with heel strike we have an impact in which we have the anterior leg essentially controlling all of the impact and deceleration of the foot, then we have the knee eliminated from the equation because it is fully extended, and we have rotational stress up into the hip.
Now here is another reason why you aren’t designed to heel strike. First, take your shoes off and run across the room or across your yard. Pay attention to how you land. You land on the ball of your foot or mid foot. Now go try and run on concrete barefoot but heel strike. Sounds painful doesn’t it? It would be and I bet you could only make it a few strides. Now there is no pain with running on the mid foot is there? Well unless you step on a rock. The reason there is no pain with running on the mid foot is because you have multiple structures that are able to absorb the stress when landing. When you land on your forefoot the bones and ligaments in the foot shift and absorb some stress, next the heel lowers causing eccentric contraction of the calf muscle which again is the larger muscle group, also the knee is not locked out and can flex allowing the quadriceps to absorb some stress. All of these things allow the stress to be distributed through large muscles, ligaments and tendons. Some of these tissues actually store energy and then it is used for propulsion. Fox example the ligaments of the foot and the Achilles’ tendon both can store energy like a spring. Now back to the relevance of this to shin splints. In this running style because the stress is distributed through multiple muscles you don’t get the focused stress on a single bone and therefore the much less opportunity for shin splints. I’m not saying that every person that runs with a heel strike will get shin splints, but I am saying that you are likely to not get shin splints with a mid foot running style.
Here is what I suggest when it comes to running style. If you are a heel striker and you don’t have any problems then I wouldn’t change a thing unless you develop issues. If you are constantly battling shin splints, IT band issues or other injuries then you need to consider a few things. First maybe heel striking isn’t good with your anatomy. Second, you could try some simple fixes such as strengthening the anterior leg muscles and strengthening the gluteus muscles. Third, consider changing to a mid foot strike running style. Finally, you may have some biomechanical restrictions or problems that should be addressed by a biomechanics expert such as a qualified sports chiropractor. I would strongly suggest the 3rd and 4th options if you plan to continue running for a long time.