Running is an exercise, sport, or activity that can be done by simply lacing up one’s sneakers and walking outside. The right footwear is fundamental to running because of the high incidence of lower extremity injuries. During the action of running the muscles in the lower extremities function as shock absorbers, protecting the joints with every movement and action. From a biochemical perspective the act of running is a repeated series of controlled falls as your feet land on the ground.
Unfortunately, many injury prone athletes are dedicated runners, where running is their main form of exercise. Each year, runners have a 40% to 60% chance of sustaining an injury with the chances for reoccurrence as high as 70%.
Running injuries can be minimized by selecting proper footwear and by determining the best surface to run on. Both factors play a significant role in the amount of impact transmitted to the joints with each stride.
Certain running surfaces can drastically affect susceptibility to injury. Asphalt and concrete are hard. These unyielding surfaces can add force that jar joints. While dirt, grass and cinder trails are much more forgiving, as are rubberized tracks and indoor treadmills. Tarred roads are good for running in spring and summer when warm weather has softened them, but during cold months the injury rate on these surfaces increases.
Banked or sloped roads, like most public roadways are slanted, allowing for drainage during rains. Even if the incline is subtle it can have marked effects on biomechanics which lead to chronic ankle and knee injuries. A banked road simulates a scenario in which one leg is longer than the other. Running on a track and banking at turns will produce similar effects. Beach running can produce significant injury and be problematic. When running on the beach, the heel lands below the surface of the sand contributing to Achilles tendinitis and pain at the back of the ankle.
Even with advent of significant technology and innovation there are no perfect running shoes. Many shoes do one thing right, but not everything, providing good stability, but poor conditioning, or good cushioning and poor stability.
Most runners are heel strikers; therefore, normal foot mechanics start by landing on the heel just slightly toward the outside of the foot. The foot then pronates, this motion will collapse the arch toward the ground tilting the foot inward. As the foot lands, pronation plays an intricate role in shock absorption. Pronation functions to unlock the bones of the foot, thereby dampening force that is transmitted from the ground up through the body. In a motion called supination, body weight moves forward over the foot, the weight is then transferred back to the outside of the foot. Supination functions to lock up the bones of the foot into a rigid structure, preparing the foot and body to push off for the next stride.
Pronation and supination is normal in running. However, over-pronates or under-pronates increases exposure and incidence to certain types of injuries. Over-pronates indicates the foot is too flexible; the muscles of the leg and foot will be constantly fighting to hold up an arch that wants to collapse. This leads to soft tissue overuse injuries in the leg and foot and sets the stage for chronic hip, back, and knee problems. Over-pronation requires footwear that has a good, firm midsole imparting stability to the shoe. These shoes have good motion control, the heel counter is high and rigid, the cup of the shoe in which the heel is seated extends from the base of the heel to just below the Achilles tendon.
Individuals suffering from high arches tend to under-pronate; whereby, the arch on the inner part of the foot doesn’t have enough spring. As a result, there’s no give in the foot, so the force of the impact isn’t absorbed efficiently. If the shock of landing is not absorbed by the foot, it will be absorbed further up the leg, causing potential stress fractures and Achilles tendinitis. Those under-pronating require more dampening or cushioning in their footwear.
Shoes that cushion must have integrated construction in the sole. Some fully integrated cushioning options include; air pockets, gel and high-tech forms of shock absorbent foam. Running shoes typically provide shock-absorption material in the rear of the shoe only, but there are some that extend that material into the middle portion of the shoe too. An added bonus for any runner is forefoot cushioning because of the great amounts of shock imparted to that area of the foot. The ball of the foot is where the highest forces are transmitted, not the heel as initially thought.
Many running injuries are linked to overuse and are associated with the challenge of absorbing shock up to 4 times the body’s weight when landing. Common injuries affecting runners include; patellofemoral pain syndrome or runner’s knee, iliotibial band syndrome, shin splints, Achilles tendinitis, plantar fasciitis and stress fractures of the bones of the foot and lower leg.
Once an injury from running has been sustained, depending on its severity, a reduced regimen or complete rest is required. Determining the cause of injury; bad mechanics, a banked road and improper footwear may all be factors. Checking shoes for signs of wear is important in avoiding injury, replace when necessary to ensure proper foot mechanics are maintained. When an injury is healing slowly work back up toward usual mileage. 10% is the maximize recommended rate of increase to one’s daily running regimen following an injury.
If injury persists modify your running technique and evaluate orthotics. Insoles and orthotics can be helpful with certain types of biomechanical problems, like over-pronation, but are unlikely to treat and or resolve serious foot conditions.