MUSCULAR SYSTEM

MUSCULAR SYSTEM Works in conjunction with the skeleton:

to produce movement of the limbs & body.

It has to work with nervous system because: it produces a nervous impulse to initiate movement.

3 types of muscles: Smooth muscles.

Cardiac muscles.

Skeletal muscles.

1. Smooth muscles: Involuntary muscles – out or our conscious control.

Found in the digestive system, circulatory system & urinary system.

Contract with peristaltic action – fibres contract consecutively rather than at the same time.

Produce a wave-like effect.

Cardiac muscles Involuntary muscle.

Makes up the heart muscle or myocardium.

Has it’s own nerve supply via the sino-atrial node

works by sending nervous impulse through consecutive cells.

Heart always contracts fully.

+/- 60 – 80 times a minute.

Function:

to pump blood around body.

Skeletal muscles Voluntary muscles

we decide when to contract muscles & produce movement.

Muscle attached to skeleton across joints.

Arranged in rows of fibres.

Called striated or stripy.

Coordinated contractions of skeletal muscle allow us to move smoothly & produce sports skills.

Over 700 skeletal muscles in the human body & make up +/- 40% of our body weight (slightly less in females).

Skeletal muscles Skeletal muscle is responsible for the following

functions:

Producing movement

Maintaining body posture

Generating heat to keep us warm

Storage of glycogen for energy

FIBRE TYPES OF SKELETAL MUSCLE

2 types of muscle fibres:

Fast twitch

Slow twitch

due to speed they contract.

Slow twitch fibres Type 1. Red in colour – have good blood supply. Dense network of blood vessels. Suited to endurance work. Slow to fatigue. Contain many mitochondria to make them more efficient at producing energy using oxygen.

Mitochondria – energy-producing organelles withincells.

Fast twitch fibres Type 2.

Contract twice as fast and

are thicker in size.

Poor blood supply.

Whiter in appearance, due to

lack of oxygen.

Fatigue fairly quickly.

Suitable for producing fast, powerful actions such as sprinting & lifting heavy weights.

Fast twitch fibres Within the group of fast twitch fibres there are 2 types:

2A & 2B.

Type 2B work when a person is working very close to their

maximum intensity, eg. 100 m sprint.

Type 2A

work at a slightly lower intensities but higher intensities than slow twitch

eg. 400 m sprint.

Training Effect on Muscle Fibres Type 1 & type 2B fibres don’t change.

Type 2A can take on characteristics of Type 1 & 2B.

More endurance training = 2A would develop more endurance.

More speed training = 2A would develop more speed.

They don’t change their fibre type.

Training Effect on Muscle Fibres Postural muscles predominantly slow twitch.

Arms tend to be more fast twitch.

Legs depends on endurance running or sprinting.

GROUP ACTION OF MUSCLES When muscles contract they work as a group.

The muscle contracting is dependent on other muscles to

enable it to do its job.

A muscle can play 1 of 4 roles, as outlined below:

Agonist

Antagonist

Synergist

Fixator

GROUP ACTION OF MUSCLES 1. Agonist ( or prime mover):

This muscle contracts to produce the desired movement.

2. Antagonist: This muscle relaxes to allow the agonist to contract.

3. Synergist: This muscle assists the agonist in producing the

desired movement.

4. Fixator: These muscles fix joints and the body in position to

enable the desired movement to occur.

TYPES OF MOVEMENT Muscles can contract or develop tension in 3 different

ways:

Concentric Contraction

Eccentric Contraction

Isometric Contraction

Concentric Contraction Involves the muscle shortening & developing tension.

The origin and insertion of the muscle move closer together and muscle becomes ‘fatter’.

To produce a concentric contraction a movement must occur against gravity.

Eccentric Contraction Involves the muscle lengthening to develop tension.

The origin and insertion move further away from each other.

It provides the control of a movement on the downward phase and it works to resist the force of gravity.

Isometric Contraction If a muscle produces tension but stays the same

length:

When we are standing up our postural muscles produce isometric contractions.

ASSIGNMENT 1 – Major Muscles: Please provide the each of the following for all of the muscles listed below: Position Origin Insertion Action Exercise

Muscles: Trapezius Lattissimus Dorsi Pectoralis Major Deltoid Biceps Brachii Triceps Brachii Teres Major Rectus Abdominis & Obliques Erector Spinae Gluteus Maximus Quadricep Group Hamstring Group Gastrocnemius & Soleus Tibialis Anterior

Please Note: You must work in pairs for this assignment. All assignments are to be typed, and should include a cover page, as well as a contents page, pictures of each muscle, and

reference page. Due date: 26 April 2014 (late assignments will not be marked) Please ensure you have both your names and student numbers on the cover page.

Correct technique chest and back Back Pull-ups Seated Row Deadlifts Lat Pull downs Back Extensions

Chest Bench Press Incline Bench Press Flyes Push-ups