Ouch: Injury, Inflammation and Pain

When pain and inflammation arise, they are generally the result of a predictable cycle of occurrences. For example, a runner who runs 7 miles a day for weeks decides to run one more mile than usual. This extra effort requires additional recovery time, but the runner doesn’t allow for the added rest needed. Even though the run was only 1 mile longer, and not much tougher than usual, the reaction to the body is extreme; like foot, ankle and or knee pain.

When the heart or lungs work too hard, the body hyperventilates, and gasps for air. But when muscles, tendons, ligaments, joints and bones are worked too hard the warning signs are more subtle. In fact, musculoskeletal pain often disappears during activity and exercise, even though the damage is being compounded. Musculoskeletal pain normally doesn’t become evident until the body begins to cool down after exercise and exertion has ceased. During exercise, there is an increase in blood flow to joints and muscles, which temporarily forces inflammation to subside. However, once exercise and activity has ceased blood flow slows down, excess fluid begins collecting in the injured area again and eventually pain will return, becoming more pronounced.

Early signs of overuse injuries tend to be subtle, enough so that one must pay careful attention in an effort to notice subtle indicators. For example, morning stiffness and pain can be an indication of weakness or joint inflammation. At night, the body’s blood flow slows down, especially flow to inactive muscles and joints. During this time, it is easy for inflammation to build up. Once the body wakes from its slumber, trouble spots will feel particularly stiff. While most morning stiffness is transient, it’s a good time to make note of trouble spots that might be susceptible to injury.

Approximately 40 million Americans experience activity limitations per year, with 75% classified as disorders and injuries. Among the most prevalent are musculoskeletal disorders which represent 20% of all limiting conditions. Back problems, arthritis and lower extremity disorders of the foot and ankle affect 17 million people annually.

The incidence of non-life threatening, emergency room treated, injuries among popular sports in the United States accounts for approximately 5 million Americans per year; with basketball, cycling, football and skiing ranking among the highest.

Every force, whether intrinsic or extrinsic stresses the body. These stresses include traction or tensile stress, compressive force and twisting or shear force. When tissue is too weak or the stress too great athletic movement can cause the ends of muscles and bones to be pulled in ways that create a similar stress which can lead to injury. The Achilles tendon, which stretches every time during activities like; walking, running and jumping is particularly prone to tensile stress. Walking, running and jumping causes bones in the body collide with each other. Similarly, when feet are buckled into a ski boot, skiing downhill places compressive forces against the tibia or shin bone. These compressive forces can lead to fractures if the muscles protecting the bones are fatigued or if the pressure is simply too great for the bone to bear. Rotating any part of the body in opposition to another part or to the ground is called twisting force. For example, running across a field and stopping suddenly to pivot and turn twists the body in the opposite direction from where the feet have been planted; this shear force can damage ligaments in the knee. 50% of all sports injuries are the result of repetitive micro-trauma or overuse. Most other injuries are due to a traumatic event. Pain, inflammation, swelling and other related injury symptoms develop over time slowly.

Signs of an overuse injury include; mild pain after a workout, stiffness in a particular joint or muscle upon waking up in the morning as with plantar fasciitis, pain during a workout or when performing a particular movement, tenderness or pressing down on an area causing localized pain, swelling, instability, snapping, cracking or crunching feelings and sounds emanating from within a joint like the ankle or knee.

Pain accompanies most, but not all, injuries. It’s transmitted by specialized nerve endings known as pain receptors, which trigger an alarm warning in the brain that damage has been incurred.

Most pain is caused by inflammation. Inflammation is the body’s natural response to trauma or injury. Inflammation is a buildup of fluid and cells around an injury site and is synonymous with swelling. When an injury occurs, fluid from the bloodstream leaks into the spaces between the cells of the damaged tissue; muscle, tendon, cartilage, and more. This inflammation is visible with certain injuries, for example, an acute ankle sprain, which causes rapid pain and swelling. Sometimes, however, pain and inflammation can have a gradual onset and will not be obvious to the eye. A good example of this is, patellofemoral pain or pain under the kneecap, which is often referred to as runner’s knee.

Whether the injury is acute and inflammation immediate or gradual in onset, reasons for the conditions are identical. The brain treats inflammation like an infection. In doing so, the body attempts to quarantine the injured area by sending in platelets, small blood cells. Platelets function to clot and slow down blood flow. The brain sends in additional substances to the injured area, like white blood cells to fight an infection. It also sends in histamine, which causes cells in the area to leak fluid into spaces between the damaged cells, creating even more excess fluid in the area. This excess fluid and cellular matter impedes normal blood flow which results in pain. In the initial stages of an injury, the body’s inflammatory process helps stops bleeding of injured tissue. But when inflammation persists, the body’s reaction will interfere with movement and healing.