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 tissue 1. 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

TRAPEZIUS DELTOID PECTORALS TRICEPS BICEPS LATISSIMUS DORSI ABDOMINALS GLUTEALS QUADRICEPS HAMSTRINGS GASTROCNEMIUS

Function of different muscle groups upper body and limbs 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 TRAPEZIUS LATISSIMUS DORSI PECTORALS

Function of different muscle groups upper 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 groups lower 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 For the following actions work out Antagonistic pair Contracting muscle Relaxing muscle Fixator point Insertion point Flexion of arm at elbow 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 There are two types of muscle fibres i) fast twitch fibres ii) slow twitch fibres 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.

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