IB Sports, exercise and health science B.3.1.1 Internal and External Risk Factors That Predispose Individuals to Injury Notes

Injury and Risk Factors

1. Injury risk refers to the probability or likelihood of sustaining an injury during sports or physical activity.
2. It depends on multiple factors, including the athlete's physical condition, environment, and sport-specific demands.

Magnitude of Risk

1. The risk of injury is not just about how likely it is to happen.
2. It also depends on how severe the injury could be.
3. The magnitude of injury risk depends on two key factors:
   1. Likelihood of risk: How often an injury is expected to occur
   2. Severity of risk: The level of damage or impact an injury may cause

The magnitude of risk is determined using the following equation:

$$\text{Magnitude of risk} = \text{Likelihood of risk} \times \text{Severity of risk}$$

Likelihood categories

1. Almost certain: the event will happen most times the activity is performed.
2. Likely: the event will probably happen at some point.
3. Possible: the event could happen but is not expected.
4. Unlikely: the event is not expected to happen.
5. Rare: the event happens only in exceptional circumstances.

Severity categories

1. Negligible: no real impact, minor discomfort or first-aid only.
2. Minor: short-term symptoms, return within days.
3. Moderate: time off training and structured rehabilitation needed.
4. Major: significant time loss, may end the season.
5. Extreme: career-ending or life-changing.

Internal Factors Affecting Injury Risk (Internal Risk Factors)

Each person brings their own unique set of internal risk factors that can influence their likelihood of injury.

1. Age: affects tissue strength, healing capacity, and recovery time.
2. Sex differences: impact biomechanics, hormone levels, and injury patterns.
3. Pregnancy: changes body mechanics and joint laxity.
4. Training effects: influences muscle strength, flexibility, and technique.
5. Congenital factors: natural variations in anatomy and physiology.
6. Previous injury history: creates potential weak points and compensation patterns.

1. Age

As individuals age, several physiological changes occur that increase their susceptibility to injury.

Muscles

1. Loss of muscle mass: with age, there is a gradual loss of muscle mass (sarcopenia), resulting in weaker muscles that are less capable of protecting joints and absorbing force.
2. Reduced muscle elasticity: muscles become less elastic, leading to a higher likelihood of strains, sprains, and tears.
3. Decreased strength and endurance: aging muscles may not generate the same force or sustain activity as effectively, contributing to fatigue-related injury.

Bones

1. Decreased bone density: as individuals age, bones become less dense and more brittle due to reduced bone mineral density, increasing the risk of fractures.
2. Osteoporosis: a common condition in older adults, osteoporosis causes bones to become fragile, further increasing the risk of fractures, especially from falls.

Joints and Cartilage

1. Loss of joint flexibility: cartilage gradually degenerates with age, reducing joint mobility and flexibility, which can result in chronic pain or acute injury.
2. Arthritis: joint conditions like osteoarthritis are more common in older athletes, making movements painful and leading to more severe injuries over time.

Injury Susceptibility in Children vs. Adults vs. Elderly Athletes

Children:

1. Growth plate vulnerability: children's bones are still growing, and their growth plates (epiphyseal plates) are more vulnerable to injury.
2. Growth plate fractures: injuries like growth plate fractures are common in children and require careful management.
3. Coordination and strength gaps: children may lack the coordination and strength of adults, increasing their risk of muscle strains and sprains.

Adults:

1. Peak physical condition: in adulthood, the body is typically at its peak with strong muscles, bones, and ligaments.
2. Overuse injuries: can occur due to intense training and competition schedules.
3. Musculoskeletal injuries: adults are more prone to muscle strains, ligament sprains, and joint dislocations, especially as they age into their 30s and 40s.

Elderly Athletes:

1. Diminished physical capacity: as athletes age, they may have diminished strength, flexibility, and bone density, making them more vulnerable to fractures and joint injuries.
2. Slower recovery rate: older athletes take longer to heal, and they may be more susceptible to chronic conditions like arthritis.

2. Sex Differences

1. Sex: biological sex influences injury patterns through differences in biomechanics, hormonal profiles, and anatomical structure.
2. Understanding these differences helps coaches and athletes tailor training and injury prevention strategies effectively.

Male Athletes

1. Greater muscle mass: males generally have greater muscle mass and strength, which can offer more protection to joints and reduce some injury risks.
2. Contact injury risk: however, males may be more prone to contact injuries such as concussions, fractures, and dislocations due to higher-impact sports participation.
3. Testosterone levels: males tend to have higher testosterone, which helps in muscle growth and recovery, but may also promote risk-taking behaviour.

Female Athletes

1. ACL tear susceptibility: females are more prone to ACL (anterior cruciate ligament) tears and other ligament injuries.
2. Biomechanical factors: studies show that females have a greater risk of ACL injuries due to biomechanical differences including wider hips and increased valgus knee angle.
3. Stress fracture risk: women are more likely to suffer from stress fractures, especially in sports that demand high impact or low energy availability.

Hormonal Influence (e.g., Estrogen and ACL Injuries in Females)

1. Estrogen and ligament laxity: estrogen's effect on ligament laxity in females is an important factor in understanding their elevated ACL injury risk.
2. Ligament relaxation: the hormone relaxes ligaments, making them more flexible and prone to injury under high-load conditions.
3. Follicular phase: during the follicular phase (the first half of the menstrual cycle), estrogen levels are elevated, increasing laxity and injury risk.
4. Luteal phase: during the luteal phase (second half), progesterone is dominant, and some studies suggest this may reduce ligament laxity.

3. Previous Injury

Why previous injuries matter:

1. Weak spots: previous injuries create potential weak spots in the affected tissue that are more susceptible to re-injury.
2. Compensatory movements: previous injuries may lead to compensatory movement patterns that increase load on other structures.
3. Confidence and performance: previous injuries can affect an athlete's confidence and performance, leading to hesitation and altered mechanics.
4. Scar tissue: scar tissue that replaces injured fibres is stiffer and weaker than the original, making the area more vulnerable to repeated injury.
5. Persistent compensation patterns: compensatory movement patterns developed during recovery often persist after pain disappears, redirecting stress onto previously unloaded tissues.
6. Neuromuscular control gaps: neuromuscular control gaps linger after injury, so reflexes that protected the joint are slower or less precise even after clinical recovery.

Other internal factors: pregnancy, congenital anatomy, training status, psychology

1. Pregnancy: hormonal changes (relaxin) loosen ligaments and shift the centre of gravity, raising the risk of falls and joint instability.
2. Congenital anatomy: structural variations such as leg length differences, scoliosis, or hyper-mobile joints alter load distribution and increase injury risk.
3. Training status: under-prepared athletes who progress too quickly accumulate microtrauma faster than their tissues can repair, leading to overuse injuries.
4. Psychology: anxiety, low confidence, and inattention can disrupt motor control and decision-making in ways that directly increase injury exposure.

External factors such as protective equipment and environment affect injury risk

1. Environmental factors play a crucial role in injury risk and can often be modified to reduce the chance of injury.
2. The interaction between internal and external factors creates a unique risk profile for each individual in each situation.
3. Risk factors do not act in isolation.
4. Internal and external factors interact to create an individual risk profile.

The factors include:

1. Protective equipment: helmets, pads, and braces reduce the severity of impact forces on the body.
2. Training environment: surface type, temperature, and humidity all affect how forces are transmitted to the athlete's body.
3. Competition level: higher intensity and contact exposure in elite sport increases the probability and severity of injury.
4. Equipment condition: equipment must be properly maintained and appropriate for the athlete's size and skill level.
5. Rule enforcement: safety regulations and guidelines must be consistently applied to minimise preventable injuries.

Protective Equipment

1. Protective equipment is designed to reduce the severity of forces transmitted to the body during sport and physical activity.
2. Wearing the correct equipment for your sport, fitted and maintained properly, is one of the most effective external risk reduction strategies available.

Key considerations

1. Sport-specificity: equipment must be designed for the demands of the specific sport.
2. Fit: equipment must fit the athlete correctly to provide protection and avoid restricting movement.
3. Maintenance: equipment must be regularly inspected and maintained to ensure it functions as intended.
4. Skill level: equipment must match the athlete's age and skill level to provide appropriate protection without impeding development.

Playing Environment

1. The playing environment encompasses all the physical conditions surrounding training and competition that are external to the athlete.
2. Many environmental risk factors can be modified or controlled, making them an important target for injury prevention.

Critical factors

1. Surface type and condition: hard, uneven, or slippery surfaces increase the risk of falls, sprains, and impact injuries.
2. Weather impacts: extreme heat, cold, or wet conditions affect muscle function, joint mobility, and athlete alertness.
3. Equipment maintenance: poorly maintained equipment such as worn-out footwear or damaged playing surfaces directly elevates injury risk.
4. Rule enforcement: consistent application of safety rules limits dangerous play and reduces contact injury exposure.

Internal and external factors interact to create each athlete's risk profile

1. Combined risk: an athlete's injury risk is shaped by both internal and external factors acting at the same time.
2. Stacked risk example: a young female footballer with a previous ACL injury (internal) plus a wet pitch and worn studs (external) carries far higher risk than either factor alone.
3. Holistic prevention: effective injury prevention addresses internal factors (strength, mobility, technique) and external factors (equipment, surface, rule enforcement) together.