Kinesiology Chapter 3&4

isometric contraction

(static)muscle contraction against an external force has no visible change in muscle length greater external load is greater than the force generated by the internal force no external movements no work is performed but a high amount of tension is developed

In women theres

30-35 percent of muscle

how many muscles are in your body

324

In men theres

42-47 percent of muscle

each myosin has

6 actin filaments

Define what a motor unit is. What factors affect the number and strength of motor units?

A motor unit is a group of fibers activated via the same nerve. Precise and less precise movements affect the number and strength of motor units. Precise movements have a large number of motor units and few muscle and less precise movements is the opposite.

If muscle can only contract to produce force, explain how agonists and antagonists work.

Agonists are the prime movers and produce a desired effect. Antagonists are the opposite of agonists and it is a muscle or group of muscles opposing the action. Ex when you flex your bicep the triceps "rests" and vise versa

Describe how athletes can increase functional strength without increasing muscle mass.

Athletes can increase functional strength without increasing muscle mass by high weight low reps. If you lift heavy and stick with low reps, you'll train your brain and nervous system to lift more without activating growth factors that increase muscle size. You'll become stronger without becoming bigger. Your muscles need a certain amount of time under tension to activate the sequence of events that causes them to grow larger.

Identify three factors that influence muscle contraction and how they affect force and power output.

Athletes physique, Athletes leverage, speed of movement. Athletes physique is a factor because it determines how much they can lift. Athletes leverage is also a factor because it helps bring the bar/weight up better and the same goes for the speed of movement. Speed of movement increases, the force on the muscle decreases.

Describe the differences between concentric and eccentric contractions and how each can affect training.

Concentric involves the muscle shortening as it goes through a range of motion, usually termed flexion. An example of this would be in a resting position. Eccentric involves lengthening during movement and usually termed extension. An example of this would be lowering the weight back down during a bicep curl.

slow twitch vs fast twitch

Every human is born with a different range of fast twitch and slow twitch muscle fibers. An example is that sprinters can run short distances extremely fast but will have trouble with long distance. This is because they have a larger range of fast twitch muscle than slow twitch muscles in their legs.

Describe the two changes that occur inside a muscle as high resistance training occurs.

In resistance training fast twitch muscle fibers increase in diameter and also increase in number. Also, switch twitch muscle fibers decrease in number but do increase in diameter.

Describe the differences between intramuscular and intermuscular coordination.

Intramuscular coordination is the capacity to apply motor units simultaneously. Trained athletes have not only a larger muscle mass than untrained individuals, but can exploit a larger number of muscle fibers. intermuscle coordination is the interplay between muscles that generate movement through contraction and muscles responsible for opposing movement. High level intermuscle coordination improves strength performance and enhances the flow, rhythm, and precision of movement.

Describe the difference between isokinetic and isotonic contractions. Give an example of each.

Isokinetic contraction involves a constant contraction against a present high resistance. An example is using a specialized strength machine that maintains a constant speed of movement. Isotonic contractions are a person using free weights in a gym. During dynamic work, continual changes in joint angle and speed result in changes in strength needs. Adaptive to changing tension requirements.

Describe how small sarcomeres produce large strength results.

It has to be optimal level for adequate overlap of actin and myosin. Muscle fully stretched not going to generate a lot of force bc not enough over lap and when muscle is fully contracted can't generate a lot of movement/ force because too much overlap.

Explain the relationship between maximal strength and muscular endurance and the issues related to both.

Maximal strength is the ability to perform maximal voluntary muscular contractions in order to overcome powerful resistances. Muscle endurance is the ability to resist fatigue in strength performance of longer duration; also known as 'strength endurance'. Vigorous cardiovascular training can lead to an associated decrease in the diameter of fast-twitch muscle fibers. Increased endurance can be associated with decreased muscle strength as a result of a corresponding decrease in muscle volume.

Define relative strength and write the formula for calculating relative strength. What sports rely on high relative strength?

Relative strength= maximal strength over body mass. Gymnastics, especially still rings, rely on high relative strength.

List the four levels of structure in a skeletal muscle and define how each related to the other.

The Muscle Belly (the bulk of muscle), muscle fiber bundle, muscle fiber, myofibril. The muscle belly is the whole muscle then it is made up of lots of muscle fiber bundles. Muscle fiber bundles are then made of singular muscle fibers which is made up of myofibril.

Describe how joint angle affects muscular strength.

The distance between sacromeres is dependent on the stretch of the muscle and the position of the joint. Maximal muscle force occurs at optimal muscle length and optimal joint angle. Optimal joint angle occurs at optimal muscle length.

Describe how a single sarcomere contracts.

The outflow of calcium allows the myosin heads access to the actin cross-bridge binding sites, permitting muscle contraction

List and define the main factors that influence muscle contraction in humans.

There are 3 main factors that influence muscle contractions in humans. 1 of them is Concentric and it is when the muscle shortens in length as it overcomes resistance. The second is Eccentric and it is when the muscle increases in length to accommodate resistance. The third is isometric and it is when the muscle resists outside stress without exhibiting motion.

what are the two types of protein myofilaments

actin myosin

myosin bridges connect

actin to myosin

what is voluntary control

activated through signals carried to the muscles

less precise movements

are composed of fewer motor units with many fiber per unit

how is maximal strength beneficial to power development

because the higher the external resistance the more maximal strength is need to power through the performance. making your fast twitch muscles grow in diameter q

ligaments connect

bone (joint) to bone

as speed increased the force of a muscle

can have a decrease

Skeletal muscle

connects different parts of the skeleton through on or more connective tissue

when sarcomeres are too close together

cross bridges affect each other and less force is produced

isokinetic contraction

dynamic involve onset speed contraction against a preset high resistance external load changes during movement muscle tension muscle strengthens occurs at all joint angles

when sarcomeres are stretched farther apart

fewer cross bridges which means less force

bigger the cross section the more

force it can generate

Other than athletic training, what major factor influences muscle fiber composition

gender and genetics

precise movements

have a large number of motor units and few muscle fibers

smaller and lighter physique people can have

high strength potential when intramuscular, intermusclar, anatomical structure and muscle elasticity is considered

plyocentric contractions

hybrid contraction muscle does an isotonic concentric prestretching of the golgi tendon organ reflex jumping ability include leaping and bounding use this kind of contraction

all or none principle

if the motor unit activates upon arrival of an impulse

isotonic contraction

in dynamic work continually changes in joint angle and speed results in changes in strength needs. requires tension to move external load more or less units allow the muscle to adapt to changing tension requirements

concentric contraction

involves muscle shortening as it goes through a range of motion usually termed flexion

eccentric contraction

involves muscles lengthen during movement usually termed extension

static has

isometric, concentric and eccentric

dynamic has

isotonic, isokinetic and plyocentric

when a muscle is relaxed it

lengthens

three main components of strength related to speed

maximal strength, power, and muscular endurance. Maximal strength is the ability to perform maximal voluntary muscular contractions to overcome powerful external resistances. Power is the ability to overcome external resistance by developing a high rate of muscular contraction. Muscular endurance is the ability to resist fatigue in strength performance of longer duration; also known as "speed endurance".

dynamic contraction

muscle tension or force exerted against an external load internal force is entered greater than the external load visible movement

tendons connect

muscle to bone

fixators

muscles or group of muscles that steady joint closer to the body axis so the desired action can occur

certain magnitude

requires the fiber that are inverted to contract

when a muscle contracts it gets

shorter

what are the types of muscle are they

skeletal muscle(conscious control), smooth muscle(no conscious control) and cardiac muscle(no conscious control) (60-200 times a minute it contracts)

muscle fiber

smaller structure with the muscle fiber bundle almost like tape making it harder to break

what are the types of muscle contractions

static and dynamic

What are the differences between static and dynamic contractions, what roles do each have in training?

static is no visible movement wall sits or planks and dymanic contractions is isotonic, isokinetic and plyocentric. lifting weights stronger than the weight the external load is less than the weight.your external force is greater than the weight

body mass is connected with

strength

what is power

the ability to overcome external resistance by developing a high rate of muscle contraction

muscle belly is

the bulk of the musle lots of individual bundles sheet of connective tissue white part tendons blood vessels

what happens during muscle contractions

the skeletal muscle shortens and moves parts of the skeleton

myosin is

thick filament

actin is

thin filament

how are muscle fibers activated

through impluse of motor end plate

myofibil

tiny little proteins does the work of the muscle

what are sarcomeres

unit of contraction

muscle fiber bundle

within the muscle belly individual bundles with connective tissue has lots of individual bundles