BM - Muscles

Functions of Muscle

Movement, posture, joint stabilization, heat generation

Muscles aid the skeleton by…

Distributing load, absorbing shock, bone mobility (at joint)

Two types of skeletal muscle activity

Dynamic, static

Static activity

Maintain posture

Dynamic activity

Body movement

Smallest bit of a muscle that can contract

Motor unit

(Less/More) muscle fibers making up a motor movement increases the degree of contractility.

More

Slow Oxidative Fibers

• Aerobic

  • Quick bu

Pennate Fiber Arrangement

• Run obliquely

• Angled & shorter fibers

• Smaller range of shortening

• More powerful

Parallel Fiber Arrangement

• Fibers parallel to muscle

• Greater range of shortening

• Longer fibers

Force transmission of this arrangement is dependant on the angle.

Pennate

Force transmission of this arrangement is always 100%

Parallel

___________ arranged fibers shorten more and have greater range of motion, but the ________ arrangement is more powerful.

Parallel; penate

Concentric

Contracting involving muscle shortening

Isometric

Contraction involving no change in muscle length

Eccentric

Contraction with muscle lengthening

Lowering a weight during a bicep curl.

• Concentric

• Isometric

• Eccentric

Eccentric

Raising a weight during a bicep curl.

• Concentric

• Isometric

• Eccentric

Concentric

Agonist

muscle primarily responsible to cause a movement

Antagonist

opposes prime agonist’s action and cause movement in the opposite direction; act to control or stop a contraction of a primary mover

Agonists and antagonists are typically paired an __________ sides of a joint.

Opposite

Stabilizer

role played by a muscle acting to stabilize a body part/segment against another force (holds a body part immobile while another body part is moving)

Neutralizer

role played by a muscle acting to eliminate an unwanted action produced by an agonist (acts to prevent undesired motion)

Origin

the less moveable attachment of a muscle

Insertion

more moveable attachment of a muscle

The (insertion/origin) is pulled toward the (insertion/origin).

Insertion, origin

The origin is ________ (direction) to the insertion.

Proximal