Injury Process - Body Response to Exercise Stress

Introduction

The body will respond to an exercise stress in one of three ways and there may be primary and secondary damage to the tissues as a result of exercise stress. The three responses the body will take to an exercise stress are, the tissues may adapt to the stress and no damage occurs, the tissues may become injured, or the tissues will die. In athletics, athletes often stress their bodies to the point of tissue injury and tissue death. In this case the tissues in the body cannot over come the stress placed on them and they become injured.

The body’s primary reaction to an injury is tissue destruction. The degree of tissue destruction will greatly depend on the injurious force. Secondary damage may occur from cell death. Cell death occurs because of the hypoxia associated with the injured area. The damage done in the primary stage is irreversible; however with a sound rehabilitation program the secondary damage can be contained and limited.

Inflammation

Inflammation is a mobilization of the body’s defense mechanisms. It is mediated through hemodynamics and an altered cell metabolism. The inflammatory response is a natural physiological reaction of the body to tissue damage and tissue death. The tissue trauma may be triggered by heat, cold, chemicals, mechanical forces or bacterial invasion. The resulting inflammation serves to protect the injured tissues; thus protecting the area from further insult. This inflammation is required for the healing processes.2

Signs of Inflammation:

• Heat and Redness will be present at the injury site during inflammation due to increased blood flow and increased cell metabolism.

• Swelling will occur around the injured area because of inflammatory agents and a high concentration of proteins, fibrinogen, and gamma globulins. In addition, water follows blood proteins out of the cell via osmosis, resulting in edema.

• Pain is caused by chemical irritants that are released at the injury site. Pain will also result from an increase in tissue pressure. The onset of edema increases tissue pressure and applies pressure to surrounding nerve receptors which causes pain.

• Loss of Function may be due to mechanical blockage of a joint resulting from swelling, pain, and other problems that may come about.

Hemorrhage

Hemorrhage is the severe internal or external discharge of blood. Hemorrhage takes place when arteries, veins, or capillaries are ruptured. When the vessel is ruptured, there is an increase in blood’s permeability. Therefore, cells and fluids can escape. An important pressure gradient is also present. For hemorrhaging to take place, the pressure inside the vessel must be greater than that outside the vessel. For a vessel to stop hemorrhaging, it must be repaired and the pressure gradient altered.2

Edema

Edema is a build up of fluid in the intracellular space. Edema results from an imbalance in pressures inside and outside the cell. Edema can also result from a blockage of venous and lymphatic return. The fluids that move across the capillary membrane, do so depending on three forces, the capillary filtration pressure (forces contents into tissues), the tissue hydrostatic pressure (moves fluid from tissues into capillaries), and the hydrostatic blood pressure within the capillary. The hydrostatic pressure can be altered by changing the position of the limb. Formation and removal of edema is based on these pressure issues.2

Treatment options will include reducing the amount of edema that is formed and removing it from the injury site. There are three main mechanisms for reducing edema, increase lymphatic flow, increase blood flow, and increase venous return.

Muscle Spasm

When the body is injured it has a natural ability to splint the injured area. The body can splint and guard an area such as a joint from further harm. It does this by inducing muscle spasms. Muscle spasms can be painful as they will induce mechanical and chemically mediated pain. In some cases, if muscle spasms are not relieved, they can irritate tendons and ligaments. Muscle spasm is a natural form of splinting but modalities should be incorporated in order to alleviate the spasm.2

Disuse Muscle Atrophy

When a muscle is immobilized most if not all physical stresses are taken off the muscle. Therefore, the muscle does not have to do work. In other cases, denervation or psychological trauma will cause one not to use the muscles. After approximately 24 hours post immobilization, physiological changes occur in the muscle. The physiological changes that occur are in the form of deterioration. Synthesis of protein, energy system components, and contractility of the tissue begin to degenerate. In athletics, rest must be considered to be a fine line. Too much rest and atrophy will become your enemy, not enough rest and the forces placed on the tissues will result in further injury.

By: Craig Angle - ME.d, ME.d, ATC, CSCS

Author of the book: How to Raise a successful Athlete

Former CEO: The Athlete Project

References

1. Prentice , William. Rehabilitation Techniques in Sports Medicine. Mosby:

2nd Ed. Missouri; 1995.

2. Starkey, Chad. Therapeutic Modalities for Athletic Trainers. F.A. Davis

Company; 1993

3. Merrick, M. A., Jutte, L.S., Smith, M. E. Cold modalities with different

thermodynamic properties produce different surface and intramuscular temperatures.

J of Athletic Training Research. 2003, 38: 28-33

4. Knight, K.L. Cryrotherapy in Sport Injury Management. Champaign, IL: Human