Biomechanics: Force and Load Directions Quiz

Study Notes

Aetiology and Biomechanics

Aetiology is the study of causation or origination
Stress is the load or cross-sectional area of the tissue
Strain is the amount of deformation, which can be caused by different force directions:
- Compression: force along the axial plane (top to bottom)
- Tension: pulling forces along the axis
- Shear: force is applied parallel in the object, causing sliding and displacement
- Torsion: causes twisting, typically one end is fixed and the other is moving
- Bending: atypical loading pattern, load is different on one side to the other

Types of Tissue Injuries

Abrasion: skin tissue injury, usually the result of a shear force (e.g., scrap against concrete)
Contusion: injury to underlying tissue, usually a bruise on the muscle, typically resulting from a force from a blunt object
Laceration: cut or tear in the skin having rough edges, caused by forces from a sharp and/or hard object
Strain: an elongation of muscle or tendon beyond the elastic limit, where actual tearing or breaking of some fibers is present, caused by excessive tensile force
Puncture: small break in the skin from a pointed object, force that is perpendicular to the skin and focused on a small area
Sprain: stretching and tearing of ligaments or capsular tissue, caused by tensile, shear, or rotary force that pushes the tissue fibers beyond the elastic region
Inflammation: irritation or swelling causing pain and additional friction, usually a repeated micro-trauma due to tensile strain for muscles and tendons
Fracture: disruption to the normal matrix of bone tissue, caused by shear, compression, torsional, or tensile forces, or a combination of them
Subluxation: partial dislocation, injury to a joint which forces it to move beyond its normal limit of motion, usually due to a tensile or compressive force, with some shear to torsional force
Dislocation: more severe injury where articulating bones have lost their alignment, force may be tensile or compressive and usually involves some shear or torsional loading

Injury Grading

Hamstring Strain:
- Grade 1: simple pull/elongation of the muscle
- Grade 2: partial tear
- Grade 3: avulsion/complete tear
Lateral Ankle Sprain:
- Grade 1: stretching, small tears
- Grade 2: larger but incomplete tear
- Grade 3: complete tear

Fracture Types

Impact Force Fractures (Direct):
- Forces from outside the body
- Transverse fractures: these occur at a slight angle, caused by a tapping mechanism, small forces over a small area
- Crushing mechanism: large forces over a large area, results in an extensive comminuted fracture
Active Force Fractures (Indirect):
- Due to active forces originating within the body
- Traction mechanism: transverse or avulsion fracture as a result of tensile loading
- Bending mechanism: bending occurring of the bone causing either an oblique or butterfly fracture
- Rotational mechanism: occurs due to torsional loading causing a spiral fracture
- Transverse and oblique fracture: combo of loading patterns causing axial compression and angulation
- Angulation with torsion and axial loading causing a compound fracture

Injury Control Process

1. Establish the extent of the incidence and severity
1. Establish the aetiology and mechanisms of the injury
1. Introduce a preventative measure
1. Assess its effectiveness by repeating Step 1

Injury Reporting Scale

Level 1: niggles/pain
Level 2: modifications in class
Level 3: off class < 3 days
Level 4: off class > 3 days

Description

Test your knowledge on biomechanics by identifying different force and load directions such as compression, tension, shear, torsion, and bending. Understand the causes of deformation in tissues and the concepts of stress and strain.