They say “Rome wasn’t built in a day,” meaning great things are not completed quickly. In our give-it-to-me-now world, we get in the habit of wanting results quickly with as little complication as possible. Unfortunately, our bodies just don't work that way. Most of us really don't have a clear idea of how the tissues in our bodies respond to changes, especially in the realm of exercise and physical stress. It's my hope that by the time you are finished reading this, you will understand how your body will respond to your exercise efforts.
In order for any changes to be made in our body’s tissues, a stress must be applied. The good news is that increased physical demand will make the body stronger. However, decreased stress allows the body to decline in strength. This truth is applied to all tissues, including muscles, bones, blood vessels, the heart, ligaments and cartilage. Use them or lose them, literally.
People often wonder how much stress is enough without being too much? This is not a question that is easily answered. The real answer lies in determining, or at least estimating, where you are at the time. The key to improving the strength and function of any tissue is gradually increasing the stress that is applied, and then giving the tissue some rest so the body can adapt to be slightly stronger the next time. Then, repeat as needed. However, if too much stress is applied all at once or over a prolonged time, the tissue can be damaged. For example, in tendons a slight stress added a little at a time followed by some rest stimulates an improvement in strength. In contrast, a big stress (lifting too much weight) can injure the tendon. Likewise, a slightly too high stress level applied too often over a long period of time results in gradual injury, like tendonitis. The biggest difference between various tissues is the speed the individual tissues adapt. In general the more vascular, or the more blood supply, a tissue has the faster it adapts. This means that muscles, ligaments and blood vessels all adapt faster than bones, tendons and cartilage because they have a denser array of blood supply.
After the body (or a particular tissue) adapts, it is able to allow more physical stress before injury or failure occurs. As tissues become more resilient to stress, more stress can be applied through workouts, daily activities or occupational activities without getting injured. Likewise, if the stress is lowered for a prolonged period of time, the body will lose its tolerance to normal activities and loads.
The bottom line for this concept of gradual adaptation is that the stress needs to be tolerable, moderate and applied repeatedly over a long period of time. Just like Rome, strength must be built brick by brick over time. Getting the advice of an exercise specialist, like a physical therapist, can be a good starting point to determine what your current level is and how fast you can expect to make changes without the increased risk of injury.
