EXSS2029 Lecture Notes - Lecture 4: Bone Density, Hyaline Cartilage, Fracture Toughness

• School: University of Sydney
• Department: Exercise and Sport Science
• Course: EXSS2029
• Professor: Amanda Semaan

Document Summary

Stiffness: amount of deformation for a given load. Strength: amount of stress/force needed to damage the material. Types: cortical greater stress before failure, trabecular greater strain before failure, useful for shock absorption, cancellous decreasing compressive strength with age. Direction of force affects the strength of bone (eg. tensile, compressive, torsional force) Bending of bone: produces compression (push) and tensile (pulling) (fractures on side under tension) Fast load: bone is more stiff and can withstand greater stress, less deformation. Ability of material to withstand fracture once there is a flaw (repeated loads after crack) Bone material will adapt to an increase in appropriate loading, decreases with insufficient loading. Strain is essential for new bone development. Osteocytes sense larger strain in lacunae > activity from osteocytes will form new bone. Osteocytes sense strain smaller than target = osteocyte activity will absorb bone. Affected by exercise = eg. runners have high bmd compared to swimmers. Lecture 2 biomechanics of soft tissue and injuries.