THE MUSCULAR SYSTEM

LEARNING GOALS

By the end of this unit you should be able to• identify and describe the composition of skeletal muscle• identify and describe different muscle fibre types• indentify the major muscle groups• describe the roles of muscles in movement including the role of antagonistic pairs, prime movers and synergists• describe the role and function of tendons• identify how improved muscle functioning can improve performance and participation in physical activities

TYPES OF MUSCLE

Approximately 45% of or body weight is muscle

There are 3 types of muscle tissue1. voluntary / skeletal muscle which are attached to the skeleton and which we control.2. involuntary muscle which are not under our control and contract / relax automatically

3. cardiac muscle found in the wall of the heart that will never tire as long as it has a good blood supply

SKELETAL MUSCLE

Muscle is made of protein Skeletal muscle is made up

of cylindrical fibres Skeletal muscle cells are

long and thin All these muscles are

attached to the skeleton These muscles pull on

bones to create movement

SKELETAL MUSCLE

Muscles are made of many fibres Each fibre contains many myofibrils

DELTOID

TRAPEZIUS

PECTORALS

BICEPSTRICEPS

LATISSIMUS DORSI

ABDOMINALS

GLUTEALS

QUADRICEPS

HAMSTRINGS

GASTROCNEMIUS

FUNCTION OF DIFFERENT MUSCLE GROUPSUPPER BODY AND LIMBS

TRAPEZIUS

LATISSIMUS DORSI

PECTORALS

holds back the shoulders is attached to head and neck Functions are to lift

shoulders, to brace back and rotate scapula

Adduction and rotation of arms

Adduction of the arms and draws arms forwards and rotates it

FUNCTION OF DIFFERENT MUSCLE GROUPSUPPER BODY AND LIMBS

DELTOID

ABDOMINALS

BICEPS AND TRICEPS

Abduction of the arm and lifts arm above the head

Holds your stomach in as well as flexion and rotation of trunk

Flex and extend arm

FUNCTION OF DIFFERENT MUSCLE GROUPSLOWER BODY

GLUTEUS MAXIMUS

QUADRICEPS

HAMSTRINGS

GASTROCNEMIUS

Pulls leg backwards

Extends the leg

Flexes the leg backwards

Ends in the Achilles tendon and points toes away

MUSCLES AND MOVEMENT The skeleton provides attachment for

the muscles Muscles contract against the skeleton

to move Most muscles are long and thin, when

they contract they get shorter and thicker

MUSCLE AND MOVEMENT

Muscles are attached to the bones by tendons.

Muscles are attached at both ends. At the origin to something rigid and at the insertion which is the bone it moves.

Muscles work in pairs. One muscle contracts whilst the other relaxes. This is called antagonistic action.

MUSCLE AND MOVEMENT

A prime mover is the main muscle that moves the joint in a particular direction.

A synergist will work with another muscle to create movement. Often it works in stabilising a joint for movement to occur.

QUESTIONS

1. For the following actions work outa) Antagonistic pairb) Contracting musclec) Relaxing muscled) Fixator pointe) Insertion pointi) Flexion of arm at elbowii) Flexion of leg at knee

QUESTIONS

For the muscles mentioned give an example how they are used specifically in a sport.

DIFFERENT MUSCLE FIBRES AND SPORT

Fast twitch fibres are used for short bursts of energy usually in explosive activities. They only have a limited oxygen supply so tire quickly. Best used for speed events, throwing and jumping

Slow twitch fibres are used for slow prolonged activities involving endurance. They can contract many times and stay efficient for long periods. They have a good oxygen supply. Best suited to long distance running, cycling, swimming.

There are two types of muscle fibresi) fast twitch fibresii) slow twitch fibres

FOR THE FOLLOWING DECIDE WHAT TYPE OF MUSCLE FIBRE IS BEING USED

ACTIVITY MUSCLE FIBRE

100m sprint

300m race

Throwing a javelin

Kicking a penalty in rugby

10k Cycle race

A handspring vault in gymnastics

1500m swim

TRAINING THE MUSCULAR SYSTEM

STRENGTH – the maximum force a muscle can contract. By repeating strength exercises the size of the muscle increases as well as becoming stronger. Increased muscle size is advantageous in several sports. Weight training can be used to increase strength and the athlete would lift heavy weights for a few repetitions.

TRAINING THE MUSCULAR SYSTEM MUSCULAR ENDURANCE – means

that the muscle can continue to work over a long period of time without tiring. Training the muscles this way will not increase muscle size only their ability to work for longer. If weight training is used then light weights with lots of repetitions would improve muscle endurance. Muscular endurance is needed in specific sports like long distance running but also in general in games.

TRAINING THE MUSCULAR SYSTEM

List 5 sports which you specifically need muscular strength for and explain why

List 5 sports you specifically need muscular endurance for and explain why.

MUSCULAR CONTRACTIONS

ISOTONIC MUSCULAR CONTRACTIONS – this is when there is movement of the body. The muscle will contract and relax – shortening and lengthening as it does. Working the muscles isotinically improves dynamic strength.

MUSCULAR CONTRACTIONS

ISOMETRIC MUSCULAR CONTRACTIONS - this is when the muscle length stays the same. Used for stabilising parts of the body and holding the body steady so movement can take place. Working the muscles isometrically improves static strength.

MUSCULAR CONTRACTIONS

ISOMETRIC CONTRACTION

ISOTONIC CONTRACTION

Fill in the table with specific examples from sport