Muscles - Actions & Factors Flashcards
Which muscle is responsible for plantar flexion?
The gastrocnemius
soleus
tibialis posterior
fibularis brevis and longus
flexor hallucis longus
flexor digitorum longus
plantaris are the primary muscles acting in plantar flexion
What are the factors that influence muscle strength (aka contractile force)?
- Size -The size of the muscle. If you develop a muscle to twice it’s size, then it will double in strength. It’s not the number of fibres that change, but the size of them.
- The proportion of difference muscle fibres in that particular muscle
- Neurological factors
- The structure of the muscle, i.e. whether it is fusiform or penniform 5. co-ordination
What are the three main characteristics of muscles? i.e. what does the layman think defines muscle
Strength
Speed
Endurance
What are the three factors that influence endurance? i.e. what is going to assist with muscles endurance?
- The strength of the muscle - the contractile force. Strong muscles are able to repeat a particular action more times than weaker ones before becoming tired.
- How efficient the body’s circulatory and respiratory system systems are. Muscles need a good supply of oxygen to be able to eliminate waste products efficiently. Blood carries the oxygen from the lungs to the muscles and then carries the carbon dioxide back to the lungs to repeat the process again.
- The nervous system’s capacity to continue to provide sufficiently strong stimuli. The nervous system may also become fatigued. Is the muscles receive weaker impulses, they are unable to respond effectively.
A muscle can adopt one of five roles, what are they? Think about working muscle and assisting muscles
Agonist - the one working
Antagonist - the one relaxing
Fixator - the one attached to the bone and stabalising the agonist
Neutralisers - Pull against the agaonist, to stop unwanted action, not anchoring to a bone to do it
Synergist - Assists the agonist
What are the two types of fixators?
Stabilisers - These will contract to prevent unwanted movement that may be casue by the active contraction of another muscle
Supporters - These will contract to prevent a movement that would occure due to an external force e.g. gravity
What is the name of a muscle or group of muscles that contract to prevent the unwanted action of another muscle, but permit the desired action of that muscle,and are not necessarily attached to bone?
.they’re called neutralisers. In many body movements, co-ordinated contractions of muscles are required, when this is done, one set of muscles is said to neutralise part of the function of another set.
Not sure I understand this…ok, now I do. For example in a sit-up. If only one side of the obliques contracted, then it would be a lateral squeeze, right? If they both work to neutralise each other you get a clean sit-up.
What are the four muscles of the rotator cuff?
Teres Minor
Infraspinatus - as in inferior……as in beneath, at the bottom and back of the scapula
Superspinatus….. as in supperior, they are on the front of the scapula
Subscapularus……as in, it’s at the bottom of the scapula
Whats the smallest fibre in a muscle?
Myofibril…made up of tiny filaments of protein