Unit 1: Factors Affecting Performance

Ningbo International School IGCSE Physical Education

3. Skeleton and Joints

Functions of the Skeleton

There are four major functions of the skeleton:

• Shape and support • Movement• Protection

• Blood cell production

The bones of the skeleton also have storage capabilities for vital minerals such as calcium and phosphorus, which can be distributed to other parts of the body when required.

Shape and support

• The skeleton provides a rigid framework to the body to give it shape. The muscles and other vital organs are kept in place by the skeleton. The skeleton supports the soft tissues of the body as it forms a rigid framework to which our muscles, tendons, ligaments etc attach.

Functions of the Skeleton

Functions of the Skeleton

Movement

• Movement happens where bones meet at joints. The long bones in particular provide a system of levers against which the muscles can pull, causing movement.

Protection

• Our bones are very strong and provide protection for the internal organs. For example: the vertebral column protects the spinal cord, the skull protects the brain, the ribs protect the heart and lungs.

Functions of the Skeleton

Functions of the Skeleton

Blood Production

• Inside long bones is a substance called bone marrow, which makes new blood cells. Bone marrow produces both red and white blood cells. Red blood cells are generally produced at the ends of long bones such as the humerus and femur. White blood cells are usually produced in the shafts of long bones.

Bones

• You should know the major bones in the body and be able to give examples of them to highlight the four major functions.

• You should be able to discuss the relevance of this to performance and participation in physical activity.

HINT: Use the spaces in your handouts to record notes as you go ------>

Types of Bones

Long Bones – Cylindrical in shape and are found in the limbs of the body.

i. Femurii. Tibiaiii. Humerus

The function of the ‘Long bones’ are:• Act as levers – essential in movement• Production of blood cells which occurs

deep inside the bone.

Types of Bones

Short Bones – are small and compact, often equal in length and width.

i. The bones of the wrist (carpals)ii. The ankle (tarsals) and calcaneum

The function of the ‘Short bones’ are:• To support as they are designed for strength

and weight bearing.

Types of BonesFlat Bones – offer protection to the internal organs.i. The sternumii. The bones of the craniumiii. The bones of the pelvisiv. Scapulav. Upon close inspection the ribs would come under this

category

The function of the ‘Flat bones’ are:• To provide suitable sites for muscle attachment, with

origins of muscles often attaching to them• The pelvis, sternum and cranium also produce blood

cells.

Flat Bones

Types of Bones

Irregular Bones – Complex and individuality in their shape and have a variety of functions which include protection.

i. The vertebra (protect the spinal cord and help to absorb

shock when running and jumping)

ii. The bones of the face

Irregular BonesBones of the Spine

(Vertebrae)

TEST YOURSELF…-Name each bone

TEST YOURSELF…-Give the type of each bone

Classification of Joints

There are 3 main classifications of joints:

• Fibrous Joints – fixed or immovable• Cartilaginous Joints – Slightly movable• Synovial Joints – Freely movable.

Fibrous Joints

• Where bones are connected by fibrous tissue so that they are fixed or immovable.

• An example of this is between the bones in the skull.

Cartilaginous Joints

• Where bones are connected by cartilage so that there is very little movement.

• Examples of this are between the vertebrae or connecting the ribs to the sternum.

• Ligaments also restrict movement at these joints.

Synovial Joints

• Where bones require a movable point of connection.

• These form the majority of joints in our limbs and are essential for our body to move freely.

• There are 6 main types.

Characteristics of a Synovial Joint

Characteristics of a Synovial Joint

This is the outside layer of a Synovial

Joint & surrounds the

entire joint area.

Characteristics of a Synovial Joint

The Synovial Capsule is lined

on the inside with a

“Membrane” which produces Synovial Fluid.

Characteristics of a Synovial Joint

Synovial Fluid is a super-slippery

lubricant which eases the movement

of a joint to stop bones & cartilage

wearing away due to the friction of movement.

Types of Synovial Joints

There are six main types of synovial joints:

• Ball and Socket• Saddle• Condyloid• Pivot• Hinge• Gliding

Ball and Socket Joint

• Movements:– Allows flexion, extension, adduction, abduction

and rotation.

• Example:– hip/shoulder

Saddle Joint

• Movements:– Flexion, extension, abduction, adduction.– No rotation.

• Example:– thumb

Condyloid Joint

• Movements:– Flexion, extension, abduction, adduction.– No rotation.

• Example:– Wrist, ankle,Fingers.

Pivot Joint

• Movements:– This type of joint only allows rotation.

• Example:– Between the atlas and axis vertebrae, between the radius ulna at the elbow.

Hinge Joint

• Movements:– Flexion and extension only.

• Example:– knee/elbow

Gliding Joint

• Movements:– A small amount in all directions by gliding over

each other

• Example:– Between tarsals/carpals

Joint Movements

There are different types of movement available at different joints, for example the shoulder moves in far more ways than the knee.

The five kinds of joint movements that you need to know are:

• Flexion• Extension• Abduction• Adduction• Rotation

Check out the link joint movements for more information and video demonstrations.

Flexion

• Closing a joint or decreasing the angle of the joint.

Extension

• Opening a joint or increasing the angle of the joint.

Adduction

• Moving a limb towards the centre line of your body.

TIP: Remember – ADDuction is bringing two bits together, kind of like adding them.

Abduction

• Moving a limb away from the centre line of you body.

TIP: Remember – ABDuction is taking someone away, like being abducted by aliens.

Rotation

• Turning or twisting a body part, either clockwise (external or lateral) or anti-clockwise (internal or medial).

At the hipOf the neck (at the atlas and axis)

Connective Tissues and Joints

There are three types of connective tissue in and around joints:

• Cartilage - This sits on the ends of bones within a joint to stop the two ends from rubbing.

• Ligaments - These connect bones to bones and help keep the joint together.

• Tendons - These connect muscle to bone and usually cross a joint so that the associated muscle can cause movement at the joint.

Lateral View of Knee (from side)

Tendons join muscle to bone

Cartilage protects ends of bones

Ligaments join bone to bone

Joint Problems

• Many of these problems can be reduced by having a healthy and active lifestyle.

• If our joints are healthy and efficient, they add value to our physical performance.

There are a variety of problems that can be associated with the ligaments, tendons, cartilage and synovial fluid at our joints.

Joint Problems

These can include:• Soft tissue injuries that damage ligaments,

tendons, cartilage and muscles.– E.g. sprains, dislocations, torn cartilage

• Chronic injuries of joints• Deterioration of flexibility• Inflammation of joints (arthritis)• Osteoarthritis (deterioration of bone density)

Sprains

• These occur when ligaments at joints get stretched and torn. E.g. a sharp twist of the foot can give you a sprained ankle.

• Sprains can cause considerable pain and loss of function at the joint.

• Sprains should be treated with ice and rest and

• A physiotherapist should be consulted if possible.

Dislocation

• A dislocation occurs when a bone is twisted or pulled out of place at a joint.

• This damages the connective tissue around the joint.

• Dislocations are very painful and require hospital treatment to move the bone back into position.

• The ligaments, muscles, cartilage and tendons around the joint can take a long time to recover.

Torn Cartilage• Cartilage aids friction free movement at joints

and provides some shock absorption. • Cartilage can tear if the joint is twisted

excessively. • E.g. torn knee cartilage is a common injury for

footballers caused when they change direction quickly.

• A cartilage tear is a very painful injury. • Swelling may be reduced by using an ice pack

but surgery is sometimes needed to repair the damaged cartilage.

Chronic Injuries of Joints

• Chronic injuries are caused by continuous stress on a joint or body part over a long time.

• E.g. tennis elbow, runners knee. • Chronic injuries can be caused by training too

hard, not allowing time for recovery, poor footwear or bad technique.

• It is important to give your body time to adapt when increasing training demands and ensure enough recovery time between training sessions.

Deterioration of Flexibility

• Most people’s flexibility deteriorates as they get older. This is because the connective tissues around the joints become less elastic.

• Flexibility exercises and extended warm-ups before exercise can help, but ultimately, it becomes harder and harder to maintain the same levels of flexibility.

Joint Inflammation and Arthritis

• Joint inflammation occurs when the immune system is trying to fight off unwanted organisms or unhealthy cells in the area.

• It usually involves pain and swelling (from increased blood and synovial fluid in the joint).

• Some people, especially older individuals, may develop arthritis – a disease that causes pain, stiffness and inflammation around joints.

• It is usually hereditary, but injured joints that have not healed properly can be more prone to arthritis.

Bone Density and Osteoporosis

• After the age of 35, bone tissue begins to be broken down more quickly than it is replaced.

• This means that bone density and strength begin to deteriorate.

• Osteoporosis can occur where bones become very brittle and are more likely to break.

Exercise for Bone and Joint Health

• Exercise has been shown to increase bone density and strength.

• Stronger, denser bones are better at carrying weight and more resistant to injury.

• The increase in bone density is specific to the activity – walking will strengthen your leg bones but not your arm bones.

• Both anaerobic exercise and weight training are effective in increasing bone strength but the activity must be weight bearing.

Exercise for Bone and Joint Health

• Regular exercise including aerobic, anaerobic and strength training increases blood flow to connective tissues.

• This helps to regenerate synovial fluid and connective tissues.

• If joints are mobile they are more likely to maintain flexibility and continue to work effectively.

• This will help to reduce strain and injury at joints.

What happens when things go wrong...