Factors affecting strength Flashcards
what is muscle strength in the MSK system?
- the ability of skeletal muscle** to develop force** for the purpose of providing stability and mobility within the MSK system, so functional movement can take place
why is muscle strength so important in sport, daily life activitiea and also throughout our life span?
- higher levels of muscular strength lead to better performance in sport
- we require an adequate level of muscle strength to **perform activities of daily living **
- higher muscular strength is associated with a **reduced risk of premature mortality **
define muscle tension
- force developed in a contracting muscle when the muscle acts on an object
- (internal force)
define load
the** force exerted on the muscle by an object** is called the load
compare active vs passive tension of muscle
- active tension - tension developed by the contractile elements of the muscle
- passive tension - tension developed by **stretching the non contractile elements **of the muscle - ie elasticity
what is the epimysium?
the membrane that surrounds the entire muscle, binding all of the muscle fibres together
what is the perimysium?
- a sheath of connective tissue which binds muscle fibres together into bundles called fasciculi
what is the endomysium?
- fibrous connective tissue that surrounds each individual muscle fibre
what is a torque?
- the capability of a force to **produce rotation **is known as a torque
what is a fulcrum in relation to muscle?
the joint around which the movement occurs
what 4 things is muscle force inhibited by?
- inflammation
- injury
- disease
- pain
of the connective tissue or the bone upon which the muscle acts
if muscle shortening (concentric contraction) is followed by an eccentric contraction, resulting concentric action is capable of generating greater force … why?
- because a stretch in a muscle increases its tension (force produced) by storing potential elastic energy in the elastic component of the muscle
- the shortening contraction must occur within a short time frame to use that stored elastic energy
how does muscle length affect muscle strength?
- as the muscle shortens -** the actin and myosin filaments start to overlap** and the** sarcomere** is then at an** optimal length** - where most force can be produced
- a sarcomere that is too short or that has been stretched will not be as efficient
Describe the length tension relationship in muscle
- **short length **- when a muscle has shortened to half its length, **the filaments have exceeded their overlapping capability **- fewer cross bridges forming
- long lengths - when the muscle is lengthened, cross bridges slip past one another and fewer cross bridges can be formed
3.** optimal length is slightly longer than resting length** because the contractile components are optimally producing tension and the** passive components are optimally storing elastic energy **
how does the velocity of a contraction affect the force in a concentric contraction?
*** as velocity increases, force decreases **
* as the velocity of muscle shortening increases, the cycling rate of cross bridges increases, leaving fewer cross bridges attached at one time
Describe the force-velocity relationship of skeletal muscle
- force and velocity have different relationships with e/o in skeletal muscle depending on whether the contraction is concentric or eccentric
- concentric - the higher the force, the lower the velocity of skeletal muscle contraction.. and the lower the force the faster - INVERSE relationship
- eccentric - as the force increases, the velocity of the contraction also increases
