Chapter 1 - Biomechanics of Musculoskeletal Injury

KNES 463

Why study the biomechanics of injuries? National Safety Council: Annual cost >

$435 million and 40% of hospital admissions

Unintentional injuries are the 5th leading cause of death in the U.S.

Potential life span for injures related deaths 36 years

What is the difference between an accident and injury? Accident: unexpected,

unavoidable and unintentional event

Some accidents involve injuries

What is an injury?

Damage caused by physical trauma sustained by tissues of the body

What is Biomechanics?

The applications of mechanical principles to biological problems.

Mechanism: Physical process responsible for a given action, reaction, or result.

Interdisciplinary approach (anatomy, physiology, mechanics, medicine, engineering, psychology)

Historical Perspective

Origins of mankind (prehistoric)

Treatment of injuries also as old as injuries

Surgical Instruments by Indian, Egyptians, Incas, and other cultures

Famous Contributors to the study of Injuries Hippocrates: Establish

foundations for the study of injury and medicine. Father of medicine.

Described many Orthopaedic conditions

Famous Contributors to the study of Injuries Galen: Roman

Physician (Gladiators) Basic anatomy,

treatment of spinal deformities, use of pressure bandages

Dark Ages after Roman Empire

Famous Contributors to the study of Injuries Andreas Vesalius:

Belgian Physician, provided detailed anatomical drawings of human dissections

Famous Contributors to the study of Injuries Leonardo DaVinci:

Role of joints, body senses (pain), trauma (impact), scientific drawings, similarities between man and machine.

Industrial Age and Technology

Technological advances Laser surgery Arthroscopy Artificial joints Microsurgery

Epidemiology

Study of incidence, distribution, and control of disease (can predispose a person to injury) and injury in a given population

Epidemiological Studies Descriptive: Analysis

of the frequency and distribution of an injury in a population

Categorization items:– Severity– Location (site)– Type of disability– Population subset– Activity

Analytical: Finds the cause and effect relationships in an injury

– More difficult, time consuming

– Must rule out all possible factors such as coincidence or mere correlation

Terminology

Incidence: Number of new injuries in fixed period of time by a group of people at risk.

Prevalence: Number of people with an injury/number of people at risk

Injury rate: Number of injury in population/reference measure (practice episodes, hours of exposure, innings played)

Relative risk: Likelihood of an injury happening to a group

Psychological Perspective

A person’s likelihood to injury depends on the task, environment, and the person’s psychological state

Psychological States

Psychological states predispose people to injuries– Stress

– Distraction

– Fatigue

Human Error

Inappropriate or undesirable human decision or behavior that has the potential for reducing effectiveness safety or performance

How can we reduce human error?

Selection of people with appropriate skills

Training Effective equipment,

procedures, and environment

Why do people suffer accidents?

Accident-proneness Accident-liability (situations) Capability-demand (increase demands) Adjustment-stress (increase stress levels) Arousal-alertness (boredom/anxiety) Goals-freedom-alertness (workers set own

goals injuries) CFAC (comprehensive multi-factor model)

Risk for Injury or death

Perception of risks– overestimation of

expertise or abilities

– overemphasizing situations

– It can’t happen to me! philosophy

Psychological factors in InjuryPreceeding factors Associated factors Factor after

Medical/Psychologicalhistory

Emotional distress Culpability

Somatotype Injury site Rehabilatationcompliance/effectiveness

Life Stress/or change Pain Pain/medication

Sports stress Timeliness Psychological status

Overtraining Unexpectedness Social Support

Sport related risk factors Personality conflicts

Fans & media

Litigation

How can we prevent injuries?

Injury Control programs– educate those at risk

– Legislation (seat belts)

– Automatic protection (airbags)

Automatic protection is the most effective

How can we prevent injuries?

Health & safety Education Programs– Least effective program– Greater the effort to adopt a safer behavior the

less likely the adoption of that behavior

Fitness Programs– Fit individual a less likely to be injured and

recover faster

Can injuries be eliminated?

No, but the severity and the incidence can be reduced