L8 Muscle-Tendon Interactions Flashcards
define flexibility
a measure of the range of motion available at a joint
what is your flexibility determined by?
shape of your bones and cartilage in the joint.
List the factors that can affect the degree of an individuals flexibility/ ROM
- shape of bone + cartilage
- Age - ROM decreases in adulthood
- Gender - women generally have better ROM
- Heredity - Sets limit
- Posture - tissues adapt to posture
- Disease - arthritis, osteoporosis
What is osteoporosis?
loss of bone mineral density
common in post-menopausal women but can affect males too
- hip, wrist, vertebrae
what is Lordosis
forward concave curve of the spine when viewed from the side
What is scoliosis ?
abnormal lateral curvature of the spine
How does flexibility relate to efficiency of movement?
How does this then relate to a sprinters and an endurance runners performance?
efficiency of running is negatively related to sit + reach test in long distance runners
Musculoskeletal looseness can increase oxygen cost of jogging, decreasing efficiency.
Musculoskeletal tightness can decrease O2 cost (less movement = less ATP used) increasing efficiency = better for sprinters
Explain how muscles adapt to fixation in a shortened or lengthened position
Muscles adapt when fixed in a shortened position. You lose sarcomeres an your fibres become shorter = slower and less powerful
how does muscle fibre length influence velocity and power output?
A fibre half the length that contract at the same velocity as the other will contract with half the power
Explain how a countermovement can increase the height of a vertical jump?
countermovement gives the muscles more tie to switch on, thus storing energy in elastic tissues
Describe the changes in length of the muscle and tendon during an isometric contraction if a muscle-tendon complex
When starting at the optimal length, in an isometric contraction, the muscle fibres shorten almost in proportion with increased tension.
@ the end of the stimulus, tension drops with little lengthening in fibres but slow stretch as the tendons recoiled during the drop in tension.
How do you calculate strain of a tendon?
change in length divided by length
How do you calculate the stress of a tendon?
load divided by cross sectional area
describe a static stretch?
lower sustained force required to stay at the same length
Describe a ballistic stretch
rapid application of force results in increased stiffness requiring more force fort eh same elongation
