Looking out her front window, she saw something very unusual. It was a man wearing very short shorts, sneakers and a t-shirt. He was moving quickly. Not really walking and not running. “What is he doing?” she thought. She watched him disappear around the corner. A few minutes later, he was back. “This is really odd. I wonder if he is feeling ok?”
The man was doing something people do routinely today. Jogging. Drive through any neighborhood, stroll through local parks or visit a high school track and you will find people jogging. It’s what we do. But, in the early 1960’s, jogging for exercise was about as common as a flying pig. You only ran if you competed in track, were about to miss the bus or someone was after you. You did not jog in your neighborhood for exercise. You were considered an oddball if you did.
Today, running is a commonly used form of exercise and many people run very regularly. But, too much running can injure you. If you run often (5 hours per week), you will likely sustain 2 injuries per year; 1 injury each 100 hours of running*. These injuries are not from falling down or running into a tree. The injuries occur because your body can’t keep up with the workload of running.
Tendons, in your foot, lower leg, knee, hip, back, function much like tension cables that suspend a bridge. But unlike bridge cables, your tendons can increase or decrease their tensile strength. Their strength depends on a series of chemical links called cross-links. Imagine your tendon as a ladder with lots of rungs. The strength of the ladder depends on the strength of the connection of each rung. Cross-links are similar to the rungs in a ladder. Where the rungs connect in a tendon is called a covalent bond. Because the strength of the connection is chemical, you can change it.
Movement and inactivity alter the strength of your tendons. In response to inactivity, your body reduces the number of rungs thinking it doesn’t really need so many. Exercise breaks some of the rungs or cross-links. Adequate rest following exercise restores the bond strength and adds more rungs. Rest makes you stronger. This cycle of running-resting-running builds and maintains the integrity of your tissues.
Inadequate recovery time leads to weaker tissue. Your body needs time to add rungs and enhance the connections of each rung to the ladder. When you demand too much, too fast from your recovering tendons, it is like climbing a ladder with a few weak rungs. You are asking your body to do something it is not yet ready to do and the result is pain, weakness and deteriorating performance. But in almost every case before you begin to hurt, there is a signal of impending danger: stiffness.
Running too much, too fast or too often, creates small tears in the tendons. The disruption of tissue causes a mild swelling or fluid shift within the tendon. You feel this as stiffness. You may not hurt – yet. You are just stiff typically in the tendon after a period of inactivity like sleeping or sitting. The more damage you have in the tendon, the longer the stiffness lasts. If you ignore it, pain follows.
If you love to run, the hardest part of running is not running. To enjoy your running and avoid sidelining injuries, listen to your body’s quiet call for help. If you notice stiffness, slow down. Give yourself time between runs to recover. If you are just starting a running program, consider resting for 2-3 days between runs. If you are a seasoned runner, build in a recovery week every six weeks. During the recovery week, cycle, swim or walk instead of running. This will allow your body adequate time to fully repair, restore and recover which keeps you feeling good.
*Reference: Byrnes, W. C.; McCullagh, P.; Dickinson, A.; Noble, J.(1993) Incidence and Severity of Injury Following Aerobic Training Programs Emphasising Running, Racewalking, or Step Aerobics,’ Medicine and Science in Sports and Exercise, 25(5), pS81