the musculoskeletal structures.

Bones, ligaments, cartilage, tendons, muscles & nerves.

the types of external forces.

Gravity, friction, drag & contact.

force definition.

energy used to create movement, measured in newtons (N). Two types, internal & external forces.

Internal force types.

Compressive, tensile & shear forces.

leaver definition.

a rigid bar used with force to create movement.

1st class lever definition, example & function.

Load-fulcrum-effort. usually for balancing weight and/or changing direction e.g. a seesaw.

2nd class lever definition, example & function.

Fulcrum-Load-Flea. Used to move large loads but with loss of distance e.g. a wheelbarrow & calf and body weight.

3rd class lever definition, example & function.

Fulcrum-Effort-Load. Typically used to move small loads but at a large distance e.g. shovel & bicep, forearm.

mechanical advantage definition.

when the effort arm is longer, the lever operates at a mechanical advantage. if equal it is neutral.

functions of bone.

organ protection, rigid kinematic link, sites of muscles attachment & muscle action.

composition of bone.

inorganic portion of mineral salts (60%), organic matrix of collagen (30%) & water (10%).

Osteon (Haversian system) definition and function.

the fundamental functional & structural unit of compact bone, designed for strength & nutrient transport.

compact outer layer bone name.

cortical bone (high density).

sponge inner layer bone name.

cancellous bone (loose mesh).

how much force can a bone withstand.

190 megapascals in compression, 130 megapascals in tension & 70 megapascals in shear.

tendons definition and function.

connect muscle to bone. transmit tensile load & stabilise joints.

tendon composition.

(20%) tendocytes, (80%) extracellular matrix.

extracellular matrix composition.

Elastin (2%), collagen (33-50%), proteoglycan (2%) and water (55-75%).

collagen definition and function.

collagen is synthesised by tenocytes and functions to sustain large tensile loads. collagen molecules band together in parallel arrangement to form many tendinous layers.

paratendon

tendons and ligaments are surrounded by loose areolar connectivity tissue called a paratendon.

crimp

important for biome chancel loading as it allows for the straightening during tensile loading.

ligaments definition and function.

same general composition as tendons. instead of tendocytes they have ligamentous fibroblasts. collagen fibres are not parallel. multidirectional tensile forces.

toe region definition.

lag in tensile force.

factors affecting ligaments and tendons.

aging & maturing (collagen reaches a plateau after which tensile strength and stiffness begin to decline), pregnancy (during pregnancy there is a increased laxity of tendons & ligaments in the pubic area due to increase in the hormone relaxin), mobilisation (like bone, ligaments & tendons appear to remodel in response to mechanical demands), immobilisation (decreases collagen production and thus causes a decreased tensile capacity of ligaments & tendons), comorbidities (diabetes, mellitus/connective tissue disorder/renal disease) & pharmacological agents ( intake of medications have been shown to negatively impact ligaments & tendons. mostly due to inhibition of collagen synthesis. e.g. steroids & into-imflamatory drugs).

sprain vs strain.

A sprain is a ligament injury. A strain is a muscle/tendon injury.