Ask the Expert – Part 2 of the Barefoot Running Series by Dr. Christopher Moran
In Part 1 of this series, we touched upon heel-strike running vs. mid-foot/forefoot running techniques. In this article, we will continue this thought and explore the bio-mechanics of running strides which may lead to injury in the runner, and how to minimize these common injuries while at the same time learning how to become a more efficient runner and faster while expending the same energy.
Ouch! The idea from the ‘padded shoe folks’ in favor of landing on the heel upon each stride is based on the thought or assumption that running should be the same as walking, only faster. In walking, the leg and foot is extended out in front of the body with toes pulled up, striking the heel first then rolling onto the outer edge of the foot, onto the ball of the foot and finally pushing off with the big toe. This is often referred to as ‘heel-to-toe rolling technique.’
The forces generated by running, and the human anatomy however, do not favor this ‘speedy walk-running technique.’ In running, when you strike the ground with your heel first, your body weight is coming down onto a bone. The calcaneus or heel bone where there is no ‘give.’ No cushioning effect. The force of landing on the heel bone is transferred up the leg through the tibia, or shin bone, to the knee, hip joint, sacroiliac joint(s) and into the low back, or lumbar spine.
This heel-first strike with the foot out in front of the body and the leg straight (extended knee) causes the body’s forward momentum to be momentarily halted by acting as a ‘brake.’ The body then passively glides forward until finally gaining leverage for the foot to push off the ground and propel the body forward with the next stride. The problem comes when, in order to run at the same speed as before the braking, the calf muscles (gastrocnemius and soleus primarily, along with the posterior tibialis and flexor hallicus longus) must contract harder than normal to push against the ground with the foot to make up this lost speed…with every stride! This greater-than-normal contraction creates excessive tension within the Achilles tendon which may lead to Achilles tendonitis or strain of this tendon and/or muscles attached to the tendon.
Another consequence of striking the heel bone against the ground and the resulting breaking that follows is that these forces must be absorbed somewhere, and that ‘somewhere’ is the quadriceps muscles in the front of the thigh. Think of walking down a steep hill. The quads must contract and ‘break’ your forward momentum in order to keep you from falling on your face. This is true while running and striking the heel against the ground with your foot out in front of your body. The quads contract forcefully, slowing the body down and leads to fatigue in the quadriceps, muscle cramps and ‘pulls’ or strains of the muscle.
“The front of my shin bone really, really hurts!” Every runner’s worst nightmare! “Shin splints.” Anterior Tibial Tendonitis. Tibial stress fracture. These injuries are common consequences of the ‘heel strike’ in the run and can range from annoying, nagging pangs keeping you from enjoying the run, decreasing training intensity and ultimately, slowing you down. This may be understood by looking at the excessive strain produced on the muscles in the front of the lower leg.
When the heel is first to contact the ground in front of the body, the toes need to be pulled upward. This is done by flexing at the ankle bringing the foot ‘up’ and accomplished by contraction of the shin muscles, or anterior tibialis. With the anterior tibialis contracted and thereby shortened, the heel hits the ground and the foot falls, slaps or ‘rolls’ (depending on your point of view), onto the ground resulting in the anterior tibialis muscle being stretched while it is still in contraction and under tension. This forced stretching while the muscle is still contracted and generating tension results in excessive strain where the muscle fibers attach to the shin bone possibly causing some of the fibers embedded in the tibial shaft to be pulled away (shin splints), excessive chronic inflammation of the tendon (tendonitis) or even a stress fracture of the tibia.
These are just a few of the possible and more common injuries sustained in distance running because of landing on the heel bone with the foot out in front of the body during each stride. In the next article, we will discuss the biomechanics of ideal running form in order to avoid these and other potential injuries (hint: review Part 1 of this series previously published, ‘Barefoot Basics’).
Dr. Chris Moran is in private practice at Traverse City Knee and Shoulder Solutions in Traverse City, Michigan and may be reached by calling (231) 943-2100 or by e-mail at email@example.com.