PRELIMINARY HSC PDHPE

CQ1 – How do the musculoskeletal and cardiorespiratory systems of the body influence and respond to movement?

How do the musculoskeletal and cardiorespiratory systems of the body influence and respond to movement?

Students learn about: skeletal system − major bones involved in movement

structure and function of synovial joints joint actions, eg extension and flexion

Students learn to: • identify the location and type of major bones involved in

movement, eg long bones articulate at hinge joints for flexion and extension

muscular system − major muscles involved in movement − muscle relationship (agonist, antagonist) − types of muscle contraction (concentric,

eccentric, isometric)

• identify the location of the major muscles involved in movement and related joint actions

• perform and analyse movements, eg overarm throw, by examining:

− bones involved and the joint action − muscles involved and the type of contraction

respiratory system − structure and function − lung function (inspiration, expiration) − exchange of gases (internal, external)

• analyse the various aspects of lung function through participation in a range of physical activities

circulatory system − components of blood − structure and function of the heart, arteries, veins,

capillaries − pulmonary and systemic circulation − blood pressure.

• analyse the movement of blood through the body and the influence of the circulatory and respiratory systems on movement efficiency and performance.

MUSCULAR SYSTEM - watch video 1

The basis of all human movement is muscle action. Muscle consists of cells with contractile filaments that move past each other to change the size of the cell. There are three types of muscle in the human body: skeletal, smooth and cardiac. Smooth and cardiac muscles are voluntary muscles that determine movement over which the human body has no control, for example, a heart beat, or the movement of food through the digestive system. Skeletal muscle is responsible for producing human movement, and groups of muscles in the human body work together to control movement patterns. Muscles enable us to move, breathe and communicate; provide stability so we can stand upright; and serve many internal bodily functions. Muscles come in various shapes and sizes and make up approximately 40% of our body weight. There are approximately 640 muscles in the body, so their ability to convert energy and enable us to function is crucial to our everyday lives.

Types of muscles (3 types)

Cardiac — these are only found in the heart. The muscle is striated in texture but works involuntarily, so we have little control over the number of times our heart beats. At times, our body may need to increase the intensity of the heart’s pumping action—usually when undertaking cardiovascular activity. Our heart accommodates these periods of time to ensure adequate oxygen is provided to the body.

Types of muscles (3 types)

Smooth — These are found in the walls of organs such as the stomach and bladder, and in arteries and veins. They are non-striated, involuntary and have long, slim muscle fibres. Contractions are slow and sustained.

Types of muscles (3 types) - watch video 2

Skeletal — These are the most common types of muscles in the body. They are named because of their location; they are attached to the bones of the skeletal system. Skeletal muscles are voluntary and can therefore be controlled to contract and relax. They are striated in texture, contract easily and require rest after exercise. These muscles have tremendous power and strength.

Functions of muscles

Muscles can: produce movement to walk, run, jump, breathe,

digest and excrete provide stabilisation of posture and internal organs generate heat to maintain body temperature. If you examine a muscle you will find that it is

constructed of many smaller bundles of muscle fibres.

Correctly label the following diagram of a muscle fibres composition.

Explain why skeletal muscle is classified as a voluntary muscle

Correctly label the muscular system diagram using the list provided.

muscle relationship (agonist, antagonist) - watch video 3

Muscles work by generating tension that causes change within the cell. The tension created causes a muscle to shorten, lengthen or remain the same length. This is known as muscle contraction.

Muscles usually work in paired groups known as the agonist and antagonist. The muscle that is responsible for the shortening action is called the agonist. As the agonist contracts, the other muscle in a pair relaxes and lengthens. This muscle is called the antagonist.

Stabilisers are muscles that assist agonist and antagonists in producing particular movements at a joint. For movement to be effective there must be stability in the joint. Stabilising muscles will often contract statically to hold other parts of the body around the joint still.

Complete the following table for muscles, their origin, insertion and the actions the cause.

Muscle Origin Insertion Actions Deltoid Clavicle and scapula Humerus Abducts, flexes, extends, medially and laterally rotates

arm Biceps brachii Scapula Radius Flexes and supinates forearm; flexes arm Triceps Scapula and humerus Ulna Extends forearm and arm Latissimus dorsi Lower 6 thoracic vertebrae, all lumbar

vertebrae, lower 4 ribs, iliac and sacral crests

Humerus Extends, adducts and medially rotates arm; draws arm downward and backward; depresses scapula

Trapezius Occipital bone, spines of C7 and all thoracic vertebra

Clavicle and scapula Elevates clavicle; extends head; adducts, rotates upward, elevates and depresses scapula

Pectorals • Major • Minor

Ribs 2–6, clavicle and sternum Ribs 3–5

Humerus Scapula

Flexes, adducts and medially rotates arm; pulls rib cage upwards

With ribs fixed: draws scapula forward and downward

With scapula fixed: draws rib cage superiorly Erector spinae Vary along vertebral spines and

transverse processes, ribs and iliac crest Vary along vertebral spines and transverse processes, ribs and jaw

Maintains erect posture; extends vertebral column Acts on one side to: bend vertebral column laterally; extend head and rotate face to side

Gluteus maximus Iliac crest, sacrum and coccyx Femur Extends and laterally rotates thigh Hamstrings: group of 3 muscles

Ischium and femur (biceps femoris) Femur (semitendinosus and semimembranosus)

Tibia and fibula (biceps femoris) Tibia (semitendinosus and semimembranosus)

Flexes leg and extends thigh

Quadriceps: group of 4 muscles

Iliac spine (rectus femoris) Femur (vastus group)

Common insertion to patella and tibia through the patella ligament

Extends leg and flexes hip (rectus femoris) Extends leg (vastus group)

Gastrocnemius Lateral and medial sides of femur Calcaneous via Achilles tendon Plantar flexes foot; flexes leg Soleus Fibula and tibia Calcaneous via Achilles tendon Plantar flexes foot Tibialis anterior Tibia First metatarsal Dorsiflexes and inverts foot Rectus abdominus Pubic crest Xiphoid process and ribs 5–7 Flexes and rotates lumbar vertebra; fixes and

depresses ribs; stabilises pelvis External obliques Lower 8 ribs Iliac crest and linea alba As pair—flexes vertebral column, compresses

abdominal wall

Singular—trunk rotation and lateral flexion

Muscles - watch video 3

Muscles can be classified functionally into three groups: agonists (prime movers)—the agonist muscle provides

the main force that causes the desired movement antagonists (muscles that react)—the muscle that

opposes or reverses a particular movement stabilisers (synergists and fixators)—the muscle that aids

agonists by promoting the same movement or by reducing unnecessary movement or undesired action. When a synergist immobilises the head of a muscle or a bone, it is called a fixator.

Activity/task - Participate in the following exercises (if possible) and complete the table Exercise Muscles Location Point of origin Point of insertion Bicep curl Biceps, triceps, wrist

flexors scapula radius

Deep squat Quadriceps, hamstrings, glutes, tibialis anterior, gastrocnemius

Bench press Pectorals, deltoids, triceps, biceps

Lateral pull down Lattisimus dorsi, deltoids, triceps, biceps

Lunge walk Quadriceps, hamstrings, glutes, tibialis anterior, gastrocnemius

Sit-up Rectus abdominus, transverse abdomin

Upright row Trapezius, tric, bi, delt, serrate

Prone alternating reverse fly Trap, delt, pect, bi, tric

Leg press calf raise

Gastrocnemius, tib anter, hams

Types of muscle contraction (concentric, eccentric, isometric)

Isotonic contractions Body movement occurs when there is a shortening of

a muscle with the agonist lengthening at the same time. In this case both the agonist and antagonist will be contracting or creating tension. Where the muscle is shortening the contraction is classified as a concentric contraction. The antagonist will be lengthening but will still be creating tension to control the movement. This contraction while extending is known as an eccentric contraction.

Isotonic Contraction

Types of muscle contraction (concentric, eccentric, isometric)

- watch video 4

Isometric contractions These occur where the muscle generates force

against a fixed resistance that does not move. There is no significant change in the muscle length. An example of this would be doing a calf stretch against a wall. Other sporting examples include an athlete performing a crouch start before a sprint, with muscles tensed waiting for the starter’s gun. Rock climbers will often perform isometric muscle contractions as they keep parts of their bodies still while searching for a new hand or foothold.

Isometric Contraction

Revision/Homework task Answer/complete the following statements/questions:

Analyse the following movements, eg overarm throw, by examining: bones involved and the joint action, and the muscles involved

and the type of contraction Identify the agonist and antagonist in the following

actions: A. extension of the elbow B. rotation of the shoulder C. flexion of the hip D. hyperextension of the hip E. rotation of the neck

Explain the different types of contraction that muscles are able to perform.

Identify some sport-based movements where isometric contractions are required.

Describe how skeletal muscles produce movement by pulling on bones.

Define the role of the agonist, antagonist and stabiliser in the production of movement.

Describe the movements that are possible at the shoulder joint and the muscles involved in producing these movements. Movements: abduction, adduction, rotation, circumduction

Identify the agonists, antagonists and stabilisers.

Revision/Homework task Answer/complete the following statements/questions:

Identify which of the following is the muscle of the arm that both flexes the elbow and supinates the forearm: triceps brachii biceps brachii deltoid brachialis

Explain the difference between an isotonic contraction and an isometric contraction.

Suggest three exercises and three sporting activities that produce both types of contraction.

Discuss the reasons why AFL players may be prone to injuries such as shoulder dislocations and hamstring tears.

Revision/Homework task Answer/complete the following statements/questions:

- watch video 5