WEEK 4 Flashcards
identify and give an example of the 5 muscle architecture structures
1) fusiform= muscles run in a line
eg bicep brachii
2) uni pennate= muscles run in one direction
eg: palamaris longus
3) bipennate= muscles run in two different directions
eg gastrocnemius muscle
4) strap like= run as a strap along the body
eg= sartorius
5) multipennate= multiple directions of muscle fibres
eg deltoid
what does ‘adding a sarcomere in series mean’
adding sarcomeres in the direction in which force is generated
- also means that the muscle doesn’t get stronger
what does adding sarcomeres in parallel mean
- sarcomeres re added horizontal way side by side,
- this means the muscle will get stronger
what does anatomical cross sectional area mean
creating the slice of 90 degrees half way through the muscle.
- calculate the area of the cut of the cross sectional area.
what does the physiological cross sectional area mean
is 90 degrees to muscle fibres
meaning the cross sectional cut follows the direction of the muscle fibre length
describe a pennate muscle performance (x4)
1- pennate muscles have a greater proportion of fibres in parallel and a lesser proportion in series.
2- force generated in the fibre gets transferred directly to the tendon
3- the greater angle you have the less fibre force is going to the tendon
4- pennate muscle structure= stronger than peanut muscle fibre arrangements
what is a trap muscles ( force, angle and force to tendon)
force= 100 newtons
angle= 0 degrees
force to tendon= 100%
what is a pennate muscles ( force and degree)
degree= 30 degrees
force= 100 x cos of 30 degree
87 newtons
describe muscle architecture and performance ( x3)
- fascicle length= proxy for how man sarcomeres you have
- faster shortening of the muscle
- the longer the fascicle length means this is less seen in elite sprinters etc
define a muscle strain injury and describe how it occurs
damage to muscle fibres
- typically occurs during high force, eccentric contractions
- usually affects the muscle tendon junction
adaptable architecture ( describe sarcomeres in parallel)
- more hypertrophy ( increase in muscle Size)
adaptable architecture ( sarcomeres in series)
certain exercises increase sarcomeres
- overloading eccentric part
- longtidunal in growth, immobilisation at long length , sprint training
describe the tendon composition
cells = 20%
extracellular matrix= 80%
- water is 60-75%
- solids (collagen) 25-40%
collagen composition= 95 % TYPE 1 AND 5% TYPE 3
describe tendon loading (x3)
- increase cross sectional area
- increase collagen concentration and cross linkage
- increase tensile strength and stiffness
describe tendon de loading (x3)
- decrease collagen content and cross linkage
- decrease tensile strength
- varies in size
describe tendon stiffness on a table with strain on the x axis and force on the y axis
strain stands for length change in the muscles
- line increasing= linear which means more force applied there is an increase in strain
- when the line starts to plataeu= partial failure, if you lengthen the tissue long enough and you damage it, the muscle will not return to its original length
- if line in graph is steep this means there is more stiffer tissue
describe muscle tendon decoupling
- the tendon is passive and elastic and therefore has the ability to deform.
- influenced by: contractile conditions, storage and release of mechanical energy, dissipation of energy
define tendinopathy
overuse tendon injury
- disruption to structural integrity and disorganised collagen
- not inflammatory
define a tendon rupture
a partial or complete disruption of the tendon
