Mechanisms and Types of Sports Injuries
Sports injury mechanism is a mechanical description of the cause of a sports injury. The cause of sport injury is force. The mechanism of sports injury will help you to learn the types of force that cause sport injury.
We have identified three mechanisms of sports injuries as
1. Compression
2. Tension or stretching
3. Shearing
1. Compression: This is an impact injury to a specific part of the body that causes bleeding, superficial or deep tissue bruising, broken bones or joint injuries. It occurs as a result of compressive force. Examples of compression include:
a. Colliding with another player or with sports equipment;
b. Falling on a hard surface, like courts.
2. Tension: This occurs as a result of tensile forces. It is an injury that occurs when a tissue is stretched beyond its normal limits. You can experience this when landing from a jump, over stretching of hamstrings or quadriceps when running or landing on an outstretched hand. All these are stretching which can tear the muscle or ligament.
3. Shearing: This occurs as a result of shear forces. It is a friction injury that develops when two surfaces rub together. Contacts between two bodies such as skin and the ground can result in a shearing injury to your skin. This is common when sliding.
It is important you note that although shearing usually causes skin injuries, other tissues such as tendons or cartilages can also be affected. Tendons are designed to resist tensile forces.
However, they are less effective when subjected to shear forces and are poorly designed to deal with compression. Conversely, bones are designed to absorb compression but are less effective against tension and shearing. On the other hand, ligament is best suited to resist tension but is more vulnerable to shearing compression.
Types sports injuries
Regardless of the mechanism of the injury, sports injuries are commonly classified using medical classification system, into two major types:
a. acute
b. chronic injuries.
This classification is based on the injury’s length of time to develop.
Acute injuries: These are injuries that occur suddenly as a result of specific injury mechanism. American Academy of Orthopaedic Surgeons (AAOS) (1991) defined acute injuries as those characterized by a rapid onset, resulting from a traumatic event. Examples include broken bone, cuts and bruises.
Chronic injuries: These are those that develop slowly over a period of time, may be weeks or more. Unlike acute sports injuries, they do not develop with a single traumatic event. A chronic injury is something that has been going for weeks. You cannot even say a particular thing you did that caused the injury or when you did it, with a chronic injury.
Chronic sports injuries are often a result of overuse or repetitive motions in sports. Examples include:
(i) A runner’s constant wear and tear on knees
(ii) A swimmers stroke causing pain in the shoulder.
These injuries worsen during activity. These activities cause a progressive breakdown of the tissues, leading eventually to failure or sports injury. This is usually common in repetitive continuous movements like running. Common sites for chronic or overuse injuries are the achilles tendon, the patellar tendon and the rotator cuff tendon in the shoulder.
1. Acute Sports Injuries
After learning how acute injuries occur, let us now look at some specific acute sports injuries. Most common are – Abrasions, contusions, punctures, cuts, dislocations, fractures, sprains and strains.
Hardly will any athlete or player finish a career without having most of, if not, all these injuries.
2. Abrasions
There are commonly known as scraped skin. These are common and occur when the skin is scraped against a rough surface (friction). This removes the top layer of the skin, thereby exposing many blood vessels to dirt and other materials that may penetrate the skin and increase the chances of having skin infection, if the wound is not handled. The cornea of the eye, which is a clear tissue in front of the eye, can also suffer abrasion by dust.
3. Contusions
These are common bruises and are the most frequent sports injuries regardless of activity. They result from a direct below where tissues and capillaries are damaged. Contusions are characterized by pain, swelling, stiffness, discoloration, (ecchymosis) and pooling of blood (hematoma).
We have two common types of contusions
1. Superficial contusions also called skin contusions: They are minor and not life threatening.
2. Deep contusions: These contusions are life threatening. They go beyond the skin and touch the muscles and bones making them suffer loss of function. They can also affect the heart, lung, kidney or brain. Can you see the object that pierced the knee?
Punctures, as the name implies, are penetrations of the skin by sharp objects. They are narrow stab wounds to the skin and internal organs, which are often caused by pointed objects, like, javelins and spike shoes. These pointed objects can introduce infectious agents like tetanus bacillus into the blood stream. If punctures are superficial, they wound will not bleed much, but if deep, they can be life threatening. Superficial punctures should not be ignored as they are breeding grounds for infection.
5. Cuts
Cuts are tears on the skin and occur in the following three common ways:
1. Laceration: These occur when a sharp or pointed object tears the tissue, giving the wound the appearance of a jagged edged cavity. The wound is not smooth and may also be caused by a blow from a blunt object. They cause steady bleeding. You can see examples when a soccer or basketball player catches an elbow to the face, resulting in laceration above the eye.
2. Incisions: Unlike lacerations that are jagged, incisions are smooth cuts caused by very sharp objects like knife or pieces of glass. Remember that part of the preventive roles of each is to inspect the playing areas and equipment to see if there are sharp objects that can cause injury and remove them. If the coach does his job well, these injuries (incisions) are minimized, if not completely prevented. Incisions can also occur as a result of a blow delivered over a sharp bone or over a bone that is poorly padded. However, the coach has little or nothing to do to prevent this cause. Nevertheless, he should encourage wearing protective equipment over such surfaces.
3. Avulsions: These are cuts that occur when skin is torn completely from the body. See figure 2.7. Pain is most noticeable when the skin is said to have been ripped or chopped off, such as tearing off the end of the ear lobe. Rings and other jewelries can cause avulsions. Avulsions are often associated with major bleeding. When skin is torn off, don’t throw the avulsed skin away, instead, and place it on moist gauze that is preferably saturated with saline solution. Place this skin and gauze in a plastic bag immersed in cold water, take them along with the athlete to the hospital for possible reattachment.
When the coach prevents his athletes from wearing jewelries during sports practice and competition, how will you describe his action?
6. Sprains
These are injuries to ligaments. They surround all synovial joints in the body. These stretching or tearing injuries to the ligaments are caused by compression, or a twisting or tension.
They are classified from minor to severe as: First, Second and Third grades of sprains.
1. First Grade or Degree Sprains: This is minor, less severe and mildest form of sprain. In this grade, some of the ligament fibers are stretched with only a few forms. They are characterized by only mild pain with little or no swelling. There may be no disability.
2. Second Grade or Degree Sprains: These are moderate sprains that are more severe than first grade sprains, implying more actual damage to the ligament involved in stretching. More ligaments tear when compared to first degree sprains. This increases the amount of pain and loss of function in the joint.
3. Third Grade or Degree Sprains: This is the most severe form of sprain, hence it is called severe sprain. In this form of sprain, the ligament involved tears completely. This damage brings extreme pain with any movement of the joint involved; swelling, hemorrhage – (discharge of blood or bleeding), and considerable loss of function.
We have discussed that the ligaments play an important supportive role to joint stability by holding bones together. Therefore, any injury to the ligaments should be prevented to maintain joint stability. Appropriate and adequate warm-up is very necessary in the prevention of sprains. Coaches and athletes should always see warm-up as an important part of their training programmes.
7. Dislocations
This is a very common sports injury. It is a separation of the bone from its joint. In this condition, the bone is displaced.
This displacement comes in two forms
– Sub-luxation
– Luxation.
They are most common at the shoulder and fingers.
Sub-luxation: Is a condition where the bone of a joint is not completely displaced or separated from the joint surface. It is a brief, transient occurrence in which the bone quickly returns, on its own, to its normal position in the joint after displacement.
Luxation: Is the second form of dislocations, which is a condition where the bone is completely separated or displaced at the joint and does not, on its own, return to its normal position at the joint.
All forms of dislocation mimic severe sprain. Do you remember what a severe sprain is? A complete tear of a joint ligament. All dislocations involve damage to the tissue surrounding a joint and ligament is one of the major tissues. There are pain, loss of function and deformity associated with dislocations. Do not try to set the joint instead immobilize and support the affected part. Its first aid management follows that for sprain and fracture which we will consider in later.
7. Fractures
When bones are compressed, twisted or hit too hard, they can break or fractures. So, fractures are a break of a bone. Fractures can occur in any sport but are most common in collision sports where high amount of forces are involved.
There are two major categories of fractures based on the orientation of the break.
They are:
a. Closed or simple
b. open or compound fractures.
This is when the broken or cracked bone does not push or protrude though the skin surface. However, the tissues beneath the skin may be damaged. They are the most common types of fractures in sports. There are many types of fracture in this category but the following three types are prevalent in sports – avulsion, epiphyseal and green stick fractures.
• Avulsion fractures occur when sprained ligaments pull off a piece of bone from its cortex. They occur usually as a result of a sudden, powerful twist or stretch of a body part. They are common at the ankle and finger.
• Epiphyseal fractures – These are growth plate injuries which result when the growth plates at the ends of bones are injured. This is a category of fractures unique to adolescent athletes. They are also called Salter-Haris fractures and are classified into five types (I, II, III, IV & V) as follows:
• Type I involves complete or total separation of the epiphysis from the metaphysis without breaking the bone.
• Type II involves a separation of the epiphysis (growth plate) from the metaphysis (bone) with a small portion of the bone broken.
• Type III describes a fracture of the epiphysis.
• Type IV involves a fracture of a portion of the epiphysis and metaphysis.
• Type V describes a crushing injury of the epiphysis without displacement. The crushing force that caused this injury can cause a growth deformity.
These fractures most often occur to athletes before age 18 years and can affect the growth of bone affected. So, when it occurs, it should be taken very seriously. They typically occur in the elbow.
Greenstick fractures: These are incomplete breaks in bones that have not completely ossified, as seen in the bones of children and adolescents. The injury occurs most in the convex surface of the bone while the concave surface remains intact. These fracture derived their name from the green twig of a tree. So to understand this fracture, get a green twig from a tree and beak it, then, discuss what you observed.
Open or Compound Fractures: Open fractures occur when a broken or fractured bone penetrates or pierces the skin. The broken bone tears and breaks the blood vessels and exposes the skin to infections.
However, these fractures are not common in most sports, but where they occur; the wound must be carefully covered with sterilized gauze to help prevent infection in the exposed bone and muscle tissues.
In a nut shell, the following are signs and symptoms of fractures:
• Deformity which can easily be observed by comparing the injured part to the uninjured opposite part of the body.
• Swelling which is as a result of bleeding;
• Cracking sound at the time of the injury though not in all cases;
• Crepitation or grating sound or sensation but do not look for this sign.
Loss of movement or use, so always guard the athletes injury.
One of the ways an active body responds to stress in sports in through injury. It is important you understand these injuries as a factor that can hinder participation and joy in sports. The acute injuries are serious on the-field emergencies that you must fully understand. Poor background in this area might result in your inability to identify sports injury types that occur during sports. Without proper identification of injury, care may be misplaced.
