BODY IN MOTION

Skeletal System

• It SUPPORTS the organs and tissues of the body. Without this support they would collapse under their own weight

• It provides PROTECTION for internal organs. For example, the cranium protects the brain; the thorax protects the heart and lungs.

• It provides a base for the attachment of muscles and so allows MOVEMENT with the bones acting as levers

• Bones are a source of BLOOD CELLS and a store for minerals required for the body to function. For example, red and white blood cells are produced in the bone marrow, which is found in the middle of bones.

Main types of bones

• LONG BONES are longer than they are wide, they function as levers.

• SHORT BONES have a short axis and are found in small spaces such as the wrist. They serve to transfer forces

• FLAT BONES have a broad surface and serve as places for attachment for muscles and to protect vital organs

• IRREGULAR BONES do not fall into any category due to their non-uniform shape. Primarily consist of cancellous bone, with a thin outer layer of compact bone

• SESAMOID BONES usually short and irregular bones, imbedded in a tendon where it passes over a joint which serves to protect the tendon

Anatomical Position - a reference to position where the subject is standing erect, facing front on and with palms forward

• Superior - towards the head;

• Inferior - towards the feet

• Anterior - towards the front

• Posterior - towards the back

• Medial towards the midline of the body

• Lateral - towards the side of the body

• Proximal - towards the body’s mass

• Distal - away from the body’s mass

TYPES OF JOINTS

Joints are where one or more bones meet. Some are fixed like a rib-cage, or they can move like an elbow. Joints are classified accoreding to their degree or movement. Joints may be classified as

• Fibrous or Immovable

• Cartilagnious or slightly moveable

• Synovial or freely moveable

FIBROUS joints occur where bone ends are joined by strong, short bands or fibrous tissue such as in the skull. This type of joint DOES NOT ALLOW ANY MOVEMENT TO OCCUR

CARTILAGNIOUS joints is where the bones are seperated by a disc or plate made up of tough fibrous cartilage. For example the joints of the vertebrae or spine are seoerated by this tissue thus causing limited movement

SYNOVIAL joints allow for a RANGE OF MOVEMENT. These include hinge joinnts (knee and elbow) and ball and socket joints (hip & shoulders). Synovial joints are made possible with the use of tendons, ligaments, cartilage, and synovial fluid.

What Connects These Joints?

• LIGAMENTS are fibrous bands that connect bones to bones. These maintain stability in the joint.

• TENDONS are though inelastic cords that attach muscles to bones. These further strengthened the joint and allow the joint to move

• CARTILAGE is a smooth shiny surface in the bones which allow them to glide across each other freely

• SYNOVIAL FLUID is a lubricant that keeps the joints moist and nourishes the cartilage to enable easy movement

• HYALINE CARTILAGE while synovial fluid acts as a cushion between articulating surfaces of the bones, they are also covered with a layer of smooth, shiny cartilage that allows bones to move freely over each other. Thicker in the leg joints, where there is greater weight bearing.

MUSCLE RELATIONSHIPS

• AGONIST - an agonist or prime mover is the muscle causing the major action. there are agonists for all moveable joints and usually more than one is involved in a particular joint movement.

• ANTAGONIST - An antagonist is a muscle tat must relax and lengthen to allow the agonist to contract, thus helping to control an action. The agonist works as a pair with the antagosist muscle. The two roles are interchangeable depending on the direction of movement.

• STABILISER - Stabiliser or fixator muscles act at a joint to stabilise it, giving the muscles a fixed base. the muscle shortens very little during its contraction, causing minimal movement. This permits the action to ne carried out correctlu and allows other joints to work more effectivley. For example in a dynamic movement such as throwing, while some shoulder muscles serve to propel the object, others act as stabilisers to allow the efficient working of the elbow joint and to reduce the possibility of damage to the joints

TYPES OF MUSCLE CONTRACTIONS

When a muscle is stimulated, it contracts. This may happen in a number of ways. There are three principal types of muscle contraction - concentric, eccentric and isometric,.

A CONCENTRIC contraction is the most common type of muscular contraction. During this contraction, the muscle shortens, causing movement at the joint. Examples of concentric contractions are the contraction of the rectus abdominis to raise the trunk during a sit-up, or the biceps contracting to lift a weight.

An ECCENTRIC contraction occurs when the muscle lengthens while under tension. The action often happens with the assistance of gravity. Examples of eccentric contractions are the rectus abdominis extending to gradually lower the trunk during the downward action of a sit-up, or the biceps muscle fibres lengthening as the weight is returned to its original position.

An ISOMETRIC contraction occurs when the muscle fibres are activated and develop force, but the muscle length does not change; that is, the movement does not occur. Isometric contractions are commonly seen in attempted movements where a resistance cannot be overcome. Examples are a weight-lifter trying to lift a weight that cannot be moved, or a person pushing against a wall. In each case, the effort is being made, but the muscle length does not change because the resistance is too great.

RESPIRATORY SYSTEM

Respiration is the process by which the body takes oxygen in and removes carbon dioxide.

Every cell in our body needs a constant supply of oxygen and food to maintain life and keep the body operating effectively.

Respiration is a process that occurs in practically all living cells. It uses oxygen as a vital ingredient to free energy from food and can be characterised by the following equation

This process is made possible through the respiratory system that facilitates the exchange of gases between the air we breathe and our blood. The respiratory system acts to bring about this essential exchange of gases through breathing; the movement of air in and out of the lungs.

1) Oxygen enters the body through the mouth or nose. Through the nasal cavities the air is warmed, moistened and filtered for any foreign material

2) The pharynx serves as a common passage for air to the trachea. It leads from the nasal cavity to the larynx, located at the beginning of the trachea

3) Trachea is a hollow tube, strengthened by rings of cartilage. After entering the chest cavity or thorax, the trachea divides into a right and left bronchus, which lead to the right and left lung.

4) The inner lining of the air passages, produces mucus that catches and holds dirt and germs

Lung Function

1) Lungs consist of two bag-like organs, situated on either side of the heart and enclosed in the thoracic cavity by the ribs at the side and sternum at the front, vertebral column at back.

The light soft lung tissue is compressed and folded like a sponge and is composed of tiny air pockets

2) The right and left bronchi that deliver air to the lungs divide into a number of branches or bronchioles within each lung. These bronchioles branch many times, eventually terminating in clusters of tiny air sacs called alveoli. The walls of the alveoli are extremely thin, with a network of capillaries (tiny vessels carrying blood) surrounding each like a string bag. This is where oxygen from the air we breathe is exchanged for carbon dioxide from our bloodstream

Inspiration = breathing on

Expiration = breathing out

During Inspiration

Diaphragm contracts and flattens, external intercostal muscles (between ribs) lift ribs outwards and upwards. This movement increases volume in chest cavity and pulls the walls of lungs outwards, which in turn decreases the air pressure within lungs. In response to this, air from outside the body rushes into lungs through air passages.

Diaphragm Expiration

Diaphragm relaxes and moves upwards, intercostal muscles allow ribs to return to their resting position. Volume of chest cavity has decreased, which increases the air pressure inside lungs. Air is consequently forced out to make pressure inside and outside the lungs about equal.

Exchange of Gases

During Insoiration, alveoli are supplied with air high in oxygen and low in carbon dioxide. However, blood in capillaries arriving at the aveoli is low in oxygen and high in carbon dioxide. Different concentrations of oxygen and carbon dioxide result between the blood and air result in a pressure difference.

Gases such as oxygen and carbon dioxide move from areas of high concentration or pressure to areas of low concentration or pressure. Oxygen, therefore, moves from the air in the aveoli across the alvedolar-capillary wall into the blood, where it attaches itself to haemoglobin in the red blood cells at the same time, carbonn dioxide is unloaded from the blood into the alveoli across the alveolar-capillary wall to be breathed out. This two-way diffusion is known as the exchange of gases.

Exchange of gases, using the same principle, occurs between blood in the capilparies of the aterial system and the cells of the body; for example, the muscle cells. Here, oxygen is unloaded to the cells while carbon dioxide resulting from cell metabolism is given up to the lungs where it unloads carbon dioxide.

Effect of physical activity on Respiration

1) Rate and Depth of breathing increase moderetly even before exercise begins, as body’s nervous activity is increased in anticipation of exercise

2) Once exercise starts, the rate and depth of breathing increase rapidly. This is thought to be related to stimulation of the sensory receptors in the body’s joints as a result of movement. Further increases during exercise result mainly from increased concentration of carbon dioxide in the blood, which triggers greater respiratory activity

3) Increase in rate (frequency) and depth (tidal volume) of breathing provide greater ventilation and occur, generally in proportion to increases in exercise effort

Breathing

Before Exercise

• Breathing is Regular

• Breaths have less volume

• Enough oxegyn is being provided to the muscles

After Intense Exercise

• Breathing is frantic

• Breaths have more volume

• Not enough oxygen is provided to the muscles after exercising because the muscles have used it up. This leaves the body in oxygen debt.

• Breathing is heavy (gulping in large amounts of air) to repay the oxygen debt.

Mechanics of Breathing

Inspiration - Breathing In

• Intercostal muscles contract

• Ribs move up & out

• Diaphragm contracts and flattens

• Chest expands increasing space

• Air pressure decreases

• Air is drawn in to lungs

Expiration - Breathing Out

• Intercostal muscles relax

• Diaphragm relaxes becoming domed

• Chest becomes smaller

• Air pressure increases

• Air is expelled from lungs

Obtaining Energy

• Carbohydrates in the form of starch from foods such as bread, pasta and potatoes form most of our energy supply

• The starch is digested into glucose molecules and passed into the blood

• As well as in the liver and muscles glucose is diffused easily into the body cells and is used to meet the energy demand via respiration

Relative composition or inhaled and exhaled air

Inhaled Air has the same composition as normal air, it contains:

• 78% nitrogen

• 21& oxygen

• 15% inert gas such as argon

• 0.04% carbon dioxide

• little water vapour

Exhaled Air contains less oxygen and more carbon dioxide, it is also saturated with water vapour. Exhaled air contains;

• 78% nitrogen

• 17% oxygen

• 1% inert gas such as argon

• 4% carbon dioxide

• saturated with water vapour

The difference between the amount of oxygen in inhaled and exhaled air is equal to the difference in the amount of carbon dioxide in exhaled and inhaled air

The special adaptations of the alveoli for gas exchange are;

• Thin walls

• Huge surface area

• Covered in capillaries to provide blood

• A wet lining to dissolve gasses

USEFUL TERMS

Oxygen Debt - The amount of extra oxygen required by muscle tissue following vigorous exercies

Vital Capacity - The amount of air that can be forcibly expelled from the lungs after breathing in as deeply as possible

Tidal Volume - The volume of air inhaled and exhaled with each breath

CIRCULATORY SYSTEM

Cardiovascular System

4-6 Litres of blood

Red Blood Cells

• responsible for blood colour

• 40 - 45% of blood

• Carry 02 from lungs to cells/C02 from cells back to lungs

• Made by bones

White Blood Cells

• Body defense system (fights disease)

• Recognise, surround & eat germs

Platelets

• Small

• Form Clots

• Stick to the walls of the blood vessel and to each other to block blood from escaping

Structure and function of the heart, arteries, veins and capillaries

Atria: the upper thin-walled chambers that receive blood coming back from the heart

Ventricles: The lower, thick-walled chamber that pump blood from the heart to the body

Pulmonary and Systemic Circulation

Pulmonary Circulation: is the flow of blood from the heart to the lungs and back to the heart. The right side receives venous blood that is low in oxygen content (deoxygenated) from all parts of the body and pumps it to the lungs.

Systemic Circulation: Is the flow of blood from the heart to the body tissue and back to the heart. The left side of the heart revives blood high in oxygen content (oxygenated) from the lungs and pumps it around the body.

What is Blood Pressure?

Blood pressure is the force exerted by the blood on the walls of the arteries. It is measured at two points during the beating of the heart.

Systolic Pressure: is the highest (peak) pressure recorded when blood is forced into the arteries during contraction of the left ventricle (systole)

Diastolic Pressure: is the minimum or lowest pressure recorded when the heart is relacing and filling. (diastole)

Blood pressure is measured in milimetres or mercury by an inflatable cuff wrapped around your upper arm. This is called a sphygmomanometer.

The “normal” blood pressure range is 120/180. 120 is the systolic pressure (contraction) and the 80 is the diastolic pressure (relaxing & filling)

Blood pressure generally reflects the quality of blood being pushed out of the heart (cardiac output) and the ease of difficulty that blood enounters passing through arteries (resistance to flow). It can be affected by:

• Cardiac Output: increase in cardiac output = increase in blood pressure

• Volume of blood in circulation: water retention (salt intake is high) increases BP, blood loss decreases blood pressure

• Resistance to blood flow: viscosity (stickiness) of blood increases BP as resistance increases, such as during dehydration. Narrowing of blood vessels due to fatty deposits affect blood flow

Measure Blood Pressure

COMPONENTS OF PHYSICAL FITNESS

Physical fitness is important in establishing and maintaining total body health. Physical fitness has a number of components which contribute to total body fitness. These components can be grouped into health related components and skill related components.

Health Related Components are related to our personal health and can reduce the event lifestyles diseases occurring such as heart disease, obesity, and diabetes. The health related components are -

• Cardiorespiratory Endurance

• Muscular Strength

• Muscular Endurance

• Flexibility

• Body Composition

Health-Related fitness components respond positively to physical exercise. For example, exercise can help us lose weight, improve muscle tone and assist in prevention of lower back pain. However, exercise should not be considered in isolation. Other factors such as heredity, environment, nutrition and lifestyle practices all contribute to total body health.

Skill Related Components are related to sports performance and the ability to execute activities. The skill related components are

• Power

• Agility

• Coordination

• Balance

• Reaction Time

• Speed

An improvement in health-related fitness components improves personal health and lifestyle including lowering the risk of hypokenetic disease.

Hypokinetic Diseases is a term given to modern lifestyle diseases asssociated with inactivity. These include condition such as: heart disease, obesity, high blood pressure, insomnia, diabetes and depression.

4.5.2 Questions

Question 2 -

• LIGAMENTS are fibrous bands that connect bones to bones. These maintain stability in the joint.

• TENDONS are though inelastic cords that attach muscles to bones. These further strengthened the joint and allow the joint to move

• CARTILAGE is a smooth shiny surface in the bones which allow them to glide across each other freely

• SYNOVIAL FLUID is a lubricant that keeps the joints moist and nourishes the cartilage to enable easy movement

The ligaments connect the knee bones together, the tendons hold everthing together and allow us to move our knee.

Question 3 - Difference between each of these Joint Actions

Flexion - Decrease in the Angle of a Joint (Bending an elbow or knee)

Extension - Increase in the Angle of the Joint (straightening a knee)

Abduction - Movement of a body part away from the midline of the body (Lifting arm out to side)

Adduction - Movement of a body part back towards the midline of the body (Returning arm into body)

Circumduction - Movement of the end of the bone in a circular motion (Drawing a circle in the air

Rotation - Movement of a body part around a central axis (Turning head from side to side)

Pronation - Rotation of the hand so that the thumb moves in towards the body (Palm facing down)

Supination - Rotation of the hand so that the thumb moves away from the body (palm facing up)

Eversion - Movement of the sole of the foot away from the midline (twisting ankle out)

Inversion - Movement of the sole of the foot towards the midline (twisting ankle in)

Dorsi flexion Decrease in the angle of the joint between the foot and the lower leg (Raising toes upwards)

Plantar flexion - Increase in the angle of the joint between the foot and the lower leg (Pointing toes to the ground)

Elevation - Movement of the shoulders towards the head

Depression - Movement of the shoulders away from the head

Question 4 - Sports that Relate to these Movement Descriptions

Flexion of the Knee - Basketball

Flexion of the Elbow - Javelin Throw

Abduction of the Leg - Hockey

Dorsiflexion of the Ankle - Running

Wrist Flexion - Water Polo

Question 6 - Role of Agonists and Antagonists in Movement

• AGONIST - an agonist or prime mover is the muscle causing the major action. there are agonists for all moveable joints and usually more than one is involved in a particular joint movement.

• ANTAGONIST - An antagonist is a muscle tat must relax and lengthen to allow the agonist to contract, thus helping to control an action.

  The agonist works as a pair with the antagosist muscle. The two roles are interchangeable depending on the direction of movement.

Question 9 - Describe the Process of Inspiration and Expiration

Inspiration - Breathing In

• Intercostal muscles contract

• Ribs move up & out

• Diaphragm contracts and flattens

• Chest expands increasing space

• Air pressure decreases

• Air is drawn in to lungs

Expiration - Breathing Out

• Intercostal muscles relax

• Diaphragm relaxes becoming domed

• Chest becomes smaller

• Air pressure increases

• Air is expelled from lungs

Question 11 a) - The functions of the various components of Blood

Red Blood Cells

• responsible for blood colour

• 40 - 45% of blood

• Carry 02 from lungs to cells/C02 from cells back to lungs

• Made by bones

White Blood Cells

• Body defense system (fights disease)

• Recognise, surround & eat germs

AEROBIC AND ANAEROBIC TRAINING

Training programs aim to develop a range of fitness and skill components. To develop an effective training program it is necessary to identify the correct energy pathway.

An energy pathway is a system that converts nutrients to energy or exercise

If we perform short sharp movements as in jumping and lifting, the body uses the anaerobic pathway to supply energy. Anaerobic means ‘in the absence of oxygen’

If movements are sustained and of moderate intensity, the aerobic pathway supplies the bulk of the energy needs.; Aerobic means ‘with oxygen’

Aerobic exercise refers to exercise that is dependent on oxygen utilisation by the body to enable muscular work

Walking , marathon running and the 1500 meters in swimming are examples of activities that require a high degree of aerobic fitness.

To improve aerobic fitness we need to:

Engage in activities that are continuous and of long duration. Cross-country running, sand-hill running, cycling and jogging are activities that develop our aerobic energy system.

The FITT principle is used to develop an aerobic program. The principle provides guidleines for individuals who aim to improve cardiorespiratory fitness and some forms of resistance training. It ensures a program has the quantity and quality of movement necessary to produce the desired physical improvement.

This refers to how many times per week we train

For improvement to occur, individuals must train on at least 3 occasions per week. This can be increased to five, but the benifit to be gained from sessions in excess of this is minimal.

The aim is for a training session to sufficiently stress body systems, causing a response called adaptation.

An adaptation refers to an adjustment made by the body as a result of exposure to progressive increases in the intensity of training

This is an adjustment made by the body as a result of exposure to progressive increases in intensity of training. For resistance training, 3 sessions are sufficient, 4 is maximal, allowing rest days in between for muscle fibres to regenerate.

This refers to how hard we work during each training session or the amount of effort required be an individual to accrue a fitness benefit.

The most accurate way of measuring intensity during aerobic exercise is by calculating your target heart rate and using this as a guide. The target heart rate together with the area above and below is called the target heart rate zone. When exercising, the level of intensity needs to be sufficient to keep the heart rate within the target heart rate zone for the required period of time.

LOOK UP HOW TO DETERMINE HEART RATE

Time

This refers to the period of time that you exercise for continuously. A minikuk 20 minutes is needed to secure an aerobic training effect

There is little sense in exercising for periods longer that 60 minutes or to exhaustion as this carries the risk of overtraining and the possible development of overuse injuries (elite athletes excepted)

For those beginning a program or those with lower levels of fitness 15. This does not include warm up and cool down.

In terms of duration, six weeks is the minimal period for the realisation of a training effect; that is, for adaptations to have taken place

Type

The best type of exercise is continuous exercise that uses the large muscle groups. Running, cycling, swimming and aerobics are examples of exercises that utilise large muscle groups. These draw heavily on our oxygen supply, necessitating an increased breathing rate, heart rate and blood flow to the working muscles. Our aerobic fitness improves as the cardiorespiratory system adapts in response to the demands being made on it.

For resistance training, low resistance with high repetitions is preferable and this can be provided using many activities such as circut training and resistance bands.

Anaerobic means “in the absence of oxygen”. In anareobic activity, the intesnsity level is uch higher and the effort period much shorter than required in aerobic activity.

In general, activity that lasts for two minutes or less and is of high intensity is called anaerobic because muscular work takes place without oxygen being present. Anaerobic exertion requires specialised training to generate the adaptations necessary for muscular work wothout oxygen. Training enhances the ability of muscle cells to improve their use of fuel reservers and be more efficient in coverting blood sugar to energy during intense exercise.

It should be noted that anaroeboic training generally requires an aerobic foundation, particularly in activities like sprinting and swimming. Other more spontaneous activities such as driving, vaulting and archery require minimal aerobic base.

To improve anaerobic fitness, we need to;

Work had at performing and enduring specific anaerobic movements such as lifting weights, throwing or jumping

practise the required movements at or close to competition speed to encourage the correct adaptations to occur

use activities such as interval training where periods of intense work are interspersed with short rests to train the anaerobic system to supply sufficient fuel to utilise resistance (weight) training exercises to further develop the muscles required fir the movement

train to improve the body’s ability to recharge itself; that is, to decrease recovery time after short periods of intense exercise

train to improve the body’s ability to tolerate higher levels of lactic acid, a performance use crippling substance that builds up in the muscles following intense exercise

gradually develop the body’s ability to utilise and/or dispose of waste that is created by intense exercise

Training programs are all about meeting the specific needs of the indivdual , their chose activity and goals

Some sports require a high level of aerobic fitness and a general level of anaerobic fitness while the reverse is true of others. games such as touch football, soccer and netball are characterised by periods of moderate intensity interspersed with periods of high intensity

While the amount of aerobic/anaerobic fitness varies according to the game, it is also affected by the position of the player, each individuals effort and their base fitness level. The spront on ruby, rally in tennis and man-to-man defense in basketball are all highly demanding, causeing muscles to use avaliable fuel and then requiring cells to find other sources for energy supply

The change between aerobic and anaerobic energy supply is gradual rather than abrupt. When engaged in activity, the body switches between systems according to the intensity of exercise, with one system being predominant and the other always working but not being the major supplier of energy. A sprint during a touch football game requires anaerobic energy due to the instant and heavy demands made on the muscles involved in the movement. During this period, the aerobic system is still functioning, but is not the major energy supplier.

Netball - running, defence, moving defence

PHYSIOLOGICAL RESPONSES

The immediate physiological responses to training are:

• heart rate

• ventilation rate

• stroke volume

• cardiac output

• lactate levels

The immediate physiological responses to training are proportional to the intensity of the training

Physical activity demands oxygen delivery along with the removal of carbon dioxide and lactic acid. The immediate changes help to achieve a higher delivery of oxygen, faster removal of carbon dioxide and conversion of pyruvic acid to lactate

the reason for many of the immediate physiological responses to training is the increased amount of carbon dioxide preoduced by the working muscles, stimulating an increase in heart rate, ventilation, stroke volume and cardiac output. Lactate levels increase in response to an increased use of the lactic acid energy system, and the muscle’s need to remove lactate to delay fatigue.

HEART RATE

Heart rate is the number of times your heart beats in a minute

Heart rate responds to training by increasog from the resting value and is often used to set or determine the intensity of the training session

• For example, an athlete might train for 20 minutes an 80% maximal heart rate (MHR)

Before the body begins to move a trained athlete’s body will begin to response to the familiar stimulus by increasing the heart rate.

Heart rate then increases in response to exercise ebcause due to an increase in carbon dioxide in the blood

This indicates that the body requires more oxygen, which results in your body increasing its heart rate

Higher intensity training produces more carbon dioxide and therefore causes a greater increase in heart rate

• For example an athlete will have a higher heart rate running at 16km/h on a flat terrain than they will running at 10km/h on the same terrain

• HR can increase just prior to training in the trained athlete, and then increases quickly to around 120bpm

• The body then responds to the carbon dioxide levels in the blood to increase the HR as required, with the trained athlete having a lower HR than the untrained athlete

• Once training is finished the trained athletes HR will return to normal level faster than the trained athlete

• The body can take 1 to 3 minutes to complete this change in heart rate so that the new heart rate is moving blood around fast enough to deliver the oxegyn and remove the carbon dioxide at the rate required.

• As the intensity canges, the body will adjust the heart rate

• For example, if our athlete is doing hill runs, their heart rate might be at 174 beats per minute (BPM). If we then change the activity to jogging around a football field, their heart rate will drop, possibly to 130 bpm, but this could take 1 to 3 minutes to occur

• After the training sessionn, the heart rate returns to normal as the body is no longer producing carbon dioxide at the higher rate, causing the body to reduce the heart rate.

VENTILATION RATE

• Is a measure of how many breaths a person takes per minute, and is also known as the respiratory rate.

• Ventilation rate will have an immediate increase in response to training as the body is responding to the increasing concentration of C02 in the blood.

• Your body has to breathe out the Co2 to remove it. Increasing respiration rate increases the amount of C02 removed, while at the same time increasing the amount of oxygen inspired

• The more intense the training the higher the ventilation rate.

• For example, the athlete who was training at 85% MHR will have a higher ventilation rate than when they are training at 65% MHR. The is because there is less demand for oxygen and a smaller amount of carbon dioxide being produced.

• Ventilation rate (VR) increases slightly just before training in anticipation of movement

• VR then increases according to the intensity, with the untrained athlete requiring a higher VR than the trained athlete. After training, the trained athlete returns to normal faster than the untrained

• Change in the intensity means a change in ventilation rate

• Eg an athlete who was jogging at 60% will have an increase in ventilation rate when they complete a 60m sprint at 100%. This change in rate comes in response to the increases demand for oxygen delivery and carbon dioxide removal.

STROKE VOLUME

• Stroke volume is the amount of blood in mL pumped out of the left ventricle of the heart per contraction

• The stroke volume of each ventricle is often the same so that the right ventricle pumps the same amount of blood to the lungs as the left ventricle pumps to the body

• Stroke volumes immediate response to training is to increase. The average human has a stroke volume of around 70 mL, this volume can double during exercise at high intensities

• The continuing rise in stroke volume for some athletes and not others has been attributed to a variety of variables including sex, blood volume, and fitness levels of the athletes. It is thought that the elite athlete is able to continue to increase their stroke volume through to their V02 max, while others cannot, but more study is needed

• The reason for stroke volume increase during training or exercise is three fold

• Firstly there is an increase in blood returning to the heart due to muscular contractions, which naturally results in greater diastolic filling of the heart increasing the strome colume

• Secondly, the body has a higher demand for oxygen and therefore the heart contracts more forcefully during exercise

• Thirdly, there is less resistance to the blood moving out of the ventricle due to vasodilation (widening) of the blood vessels

CARDIAC OUTPUT

• Cardiac output is the amount of blood pumped out of the left ventricle in a minute

• It can be calculated by multiplying the stroke volume by the heart rate and is usually given in litres per minute

• Cardiac Output = Stroke Volume x Heart Rate

• Cardiac output immediatley increases in response to training and directly related to the intensity of the workout

• For example, an athlete who is cycling and producing 20— watts of energy will have a lower cardiac output than when they are cycling at 400 watts

• Reasons for increase in cardiac output in response to training include:

  • Greater blood flow back to the heart, creating a larger stroke volue

  • Less resistance to blood flow due to vasodilation

  • An increased demand for oxygen and nutrients by the working muscles

  • Larger production of carbon dioxide during exercise

• It is the increases in stroke volume and heart rate that produce the increase in cardiac output. Without these increases, the cardiac output would remain the same

LACTATE LEVELS

• Lactate levels refers to the amount of lactate and/or lactic acid in your blood

• Lactic acid is produced by the lactic acid energy system and is quickly converted to lactate before being transported to your liver where it is converted to glucose

• During exercise lactate levels rise in propotion to the intensity of the training (as shown in the graph)

• Lactate levels in the blood rise in response to the body using the lactic acid energy system, which is required for higher intensities of training

• During lower intensities, there is a slight rise in the lactate levels, but this level is maintained throughout the training, before returing to resting levels once training stops.

• Anaerobic training causes a much larger increase in lactate levels due to the use of higher intensities that specifically rely on the lactic acid energy system.

• A sample comparison can be seen in the table below, where the aeronic training is constant, while the anaerobic interval training continually rises in response to the repeated bouts of high intensity workloads

THE BIOMECHANICS OF MOVEMENT

Biomechanics is the science concerned with forces and the effect of these forces on and within the human body

A knowledge of biomechanics help us to:

• choose the best techniques to achieve our best performance with consideration to our body shape. For instance, an understanding of the biomechanical principles that affect athletic movements, such as the high jump, discuss throw, golf swing and netball shot, improve the efficiency with which these movements are made. This improves how well we perform the skill

• Reduce the risk of injury by improving the way we move

• Design and use equipment that contributes to improved performance

MOTION

Motion is the movement of the body from one position to another

Some bodies are inanimate (non-living) such as basketballs, shot puts; whilst other bodies are animate (living) such as golfers, footballers.

Motion itself can be divided into 3 categories;

• Linear

• Angular

• General

LINEAR MOTION

Linear motion takes place when a body and all parts connected to it travel the same distance in the same direction and at the same speed

The easiest way to determine if a body is experienceing linear motion is to draw a line connecting two parts of the body; for example, the neck and hips. If the line remains in the same position when the body moves from one position to another, the motion is linear.

ANGULAR MOTION

Angular motion the motion of a body about a fixed point or fixed axis. Angular movement plays the dominant role because most of an athlete’s movements result from swinging, turning action of teh athletes limbs as they rotate around the joints

Many terms are used to refer to angular motion. Movements include rotating, spinning, swimming, circling, turning, rolling, pirouetting, somersaulting and twisting. All of these terms indicate that an object or an athlete is turning through and angle, or number of degrees. In sports such as gymnastics, skateboarding, basketball, diving, figure skating, and ballet, the movements used by athletes include quarter turns (90 degrees); half turns (180 degrees); and full turns, or “revs” (revolutions), which are multiples of 360 degrees

GENERAL MOTION

General motion a mix of linear and angular, which we simply call general motion. In sport, a mix of linear and angular movement is most common.

Even those sport skills that require an athlete to hold a set position involve various amounts of linear and angular motion. For example, a gymnast balancing on a beam. In maintaining balance on the beam, the gymnast still moves, however slightly. This movement may contain some linear motion but will be made up primarily of angular motion occurring around the axes of gymnast’s joints and where the gymnast’s feet contact the beam. Perhaps the most visible combination of angular and linear motion occurs on a wheelchair race. The swinging, repetitive angular motion of the athlete’s arms rotates the wheels. The motion of the wheels carries both the athlete and the chair along the track. Down the straightway, the athlete and chair can be moving in a linear fashion. At the same time the wheels and the athlete’s arms exhibit angular motion.

ENHANCING MOTION

How motion is classified depends on the path followed by the moving object. We will focus on linear motion in a range of sporting activities and apply the principle to enhancing performance

VELOCITY

Velocity is equal to displacement divided by time

Displacement is the movement of a body from one location to another in a particular direction, or an ‘as the crow flies’ measurement.

Velocity is used for calculations where the object or person does not move in a straight line. An example is a runner in a cross-country race. Activities to improve speed may also relate to velocity. Improving the velocity of implements such as javelins or arrows requires specialised training, as does improving the performance of athletes in non-linear events such as marathons.

SPEED

Speed is equal to the distance covered, divided by the time taken to cover distance

So, if a runner runs 100m in 12 seconds

100/12 = 8.3 meters per second (m/s)

Speed is important in most sports and team games. The player who can move quickly has a distinct advantage in games such as touch football, rugby and soccer because not only is that player difficult to catch, but they can use their speed to gather opponents quickly in defense.

Much of our potential for speed is genetic and relates to the type of muscle fibre in our bodies. However, individuals can develop their speed as a result of training and technique improvements, the basis of which is the development of power and efficiency of movement.

MOMENTUM

Momentum is the quantity of motion the body posseses

Mass refers to the amount of matter in a body

The application of the principle of momentum is most significant in impact or collision situations. The principle can be applied to certain sporting games such as rugby league and rugby union, where collisions in the form of tackles are part of the game. However, collisions between platers in sporting events tend to exhibit different characteristics to that fo objects due to a range of factors, including;

• the mass inferences of the players - in most sports, we do not see the huge variations in mass that e find between cars, bicycles and similar objects

• elasticity - the soft tissue of the body, which includes muscle, tendons and ligaments, absorbs much of the impact. It acts as a cushion

• evasive skills of players which often result in the collision not being ‘head on’. In some cases there may be some entanglement just prior to collision, such as a palm-off or fend. This lessens the force of impact.

The momentum described in the previous situation is called linear momentum because the object or person is moving in as straight line.

There are numerous instances in sport where bodies generate momentum but they do not travel in a straight line; for example a diver performing a somersault with a full twist, football kick, discus throw and golf swing. In each of these cases, the body, part of it or an attachment to it such as a golf club or tennis racquet, rotating. This is called angular momentum.

Angular momentum is the quality of angular momentum is the quantity of angular motion in a body or part of a body.

Angular momentum is affected by:

• Angular velocity, for example the distance we can hit a golf ball is determined by the speed at which we can move the club head.

• The mass of the object, the greater the mass of the object, the more effort we need to make to increase the angular velocity.

• The location of the mass in respect to the axis of rotations. With most sport equipment, the centre of mass is located at a point where the player is able to have control and impart considerable speed.

BALANCE & STABILITY: CENTRE OF GRAVITY

The centre of gravity of an object is the point at which all the weight is evenly distributed and about which the object is balanced.

If the object spherical, it’s centre of gravity is directly in the centre however, some objects used in sport are not perfectly spherical or do not have an evenly distributed mass ie. lawn bowl. When rolled on a flat surface, the object will have a slight ‘bias’ to where the mass has been redistributed.

In the human body, the position of the centre of gravity depends upon how the body parts are arranged; that is, the position of the arms and legs relative to the trunk. Because the human body is flexible and can assume a variety of positions, the location of the centre off gravity can vary. It can even move outside the body during certain movements.

Force (biomechanics) is the push or pull acting on a body

Internal forces are those that develop within the body: that is, by the contraction of a muscle group causing a joint angle to decrease (for example, the contraction of the quadriceps when kicking a football)

External forces come from outside the body and act on it in one way or another. For example, gravity is an external force that acts to prevent objects from leaving the ground.

There are TWO types of forces:

Applied Force are forces generated by muscles working on joints. Applied forces are forces applied to surfaces such as a running track or to equipment such as a barbell

When this happens, a similar force opposes it from outside the body. This is called a reaction force.

Reaction Forces are equal and opposite forces exerted in response to applied forces

The result is that the runner is able to propel his or her body along the track surface because the applied force generated by the legs is being matched equally by the reaction force coming from the track surface

This is explained by Newtons third law. In other words, both the runner and the track each exert a force equal to whatever force is being applied.

POWER

Power (biomechanics) is the ability of muscle groups to contract at speed

To propel the body higher as in high jumping, faster as in running, or further as in long jumping, we need to develop power. Power is expressed by the formula

Power (P) = Work (W) / Time (t)

An increase in strength (force) or an increase in the speed at which muscles shorten results in an increase in power. While an increase in both causes an increase in overall power, the athlete must decide which component (strength or speed of muscular contraction) is of greatest benefit.

Jumpers and runners need to focus on rapid muscular contraction while controlling the strength aspect. This is called speed-dominated power. In contrast, the weight-lifter needs power and must be able to lift the weight. He or she needs to develop strength-dominated power.

HOW THE BODY ABSORBS FORCE

Forces exerted on the body are absorbed through the joints, which bend or flex in response to the impact. Joint flexion helps prevent injury to surrounding tissue. With innantimate objects, techniques have been developed to absorb their impact.

APPLICATION OF FORCE ON AN OBJECT

There are principles to remember with the application of force on an object:

1) The quantity of force applied to the object is important. The greater the force, the greater is the acceleration. of the object

2) If the mass of an object is increased, more force is needed to moce the object the same distance. For example, if a football becomes heavier as a result of wet conditions, more force is required to pass or kick it.

3) Objects of greater mass require more focus to move them

APPLICATION OF FORCE ON AN OBJECT

Centripetal force is a force directed towards the centre of a rotating body

Centrifugal force is a force directed away form the centre of a rotating body

These forces commonly occur with skills that require rotation such as the golf swing or the hammer throw.

To manage centripetal and centrifugal forces in sporting situations it is important to:

• begin carefully so that you learn to feel the forces as they develop

• respond gradually, trying to match the force exactly

• work on your balance so that you become comfortable leaning beyond where you would normally be balanced

• ensure you have a firm handgrip if holding an object such as a bat or high bar

• bend your knees and ensure you have good traction if working on a track, field or circut.