core 2 - study notes.pdf

Core 2 study notes How do the musculoskeletal and cardiorespiratory systems of the body influence and respond to movement? ➔ SKELETAL SYSTEM - In the human body, there are 206 bones, over 650 muscles and over 200 joints or articulations (where two or more bo...

Core 2 study notes How do the musculoskeletal and cardiorespiratory systems of the body influence and respond to movement? ➔ SKELETAL SYSTEM - In the human body, there are 206 bones, over 650 muscles and over 200 joints or articulations (where two or more bones meet). FUNCTIONS OF THE SKELETAL SYSTEM SUPPORT - Provides a framework for attachment of soft connective tissue (muscles) PROTECTION - Protects internal organs (ribs protect the heart). MOVEMENT - When muscles contract, they pull on bones causing movement. MINERAL STORAGE - They store calcium and phosphorous which are released when needed. BLOOD CELL PRODUCTION - Blood cell formation occurs in the red bone marrow. STORAGE OF ENERGY - Yellow bone marrow is a stored source of lipids (fats), in the bones. DIRECTIONAL TERMS - Used to identify the location of bones. SUPERIOR - Towards the head INFERIOR - To the ground POSTERIOR - Back MEDIAL - Middle LATERAL - Towards the outside PROXIMAL - Top end of bones DISTAL - Bottom end of bones ANTERIOR - Front The anatomical position is palms outwards, thumbs pointing away from the body. MAJOR BONES INVOLVED IN MOVEMENT The 5 types of bones; - Long bones - Short bones - Flat bones - Irregular bones - Sesamoid bones LONG BONES - Used for movement - Muscles pull on long bones to cause them to move. - Examples of long bones include femur, humerus, ulna and radius. - Long bones consist of compact bone which allows the bone to lengthen, spongy bone which makes the bone strong and light and yellow marrow which stores red blood cells and fat. - Cartilage allows bones to rub smoothly. - Spongy or cancellous bone provides strength to the bone. It holds red bone marrow, where red blood cells come from. - Bone marrow contains red bone marrow (in the spongy bone), contains yellow bone marrow where blood vessels and fat tissue is stored. - Examples of long bones include phalanges and metacarpals. SHORT BONES - The bones are as long as they are wide (cube). - They act as shock absorbers and provide limited gliding motion. - Examples of short bones include tarsals and carpals.  FLAT BONES - These bones are thin. - Their function is to protect the tissues and organs. - Flat bones provide a large area for muscles and tendons to attach to. - Examples include the skull, the ribs and the sternum. IRREGULAR BONES - These bones are irregular in shape. - There are many protrusions (parts that stick out) on the bones. - Their function is to provide a site for muscles to attach to. - An example of this is the vertebrae. SESAMOID BONES - These bones are small and are embedded within tendons. - Their function is to protect the tendon from friction as it rubs against bony surfaces. - An example is the patella, in the knee. VERTEBRAL COLUMN - The vertebral column is made of 5 sections. - The cervical vertebrae - The thoracic curvature - The lumbar curvature - The sacrum convex - The coccyx - AXIAL SKELETON - forms the long axis of the body. This includes the skull, vertebra, ribs etc. APPENDICULAR SKELETON - includes the bones of the pectoral (shoulder) girdle and the upper body and the bones of the pelvic girdle and lower limbs. VERY IMPORTANT:  STRUCTURE AND FUNCTION OF SYNOVIAL JOINTS - Joints occur when one or more bones meet. Joints are classified into three categories; - Fibrous or immovable - Cartilaginous or slightly moveable - Synovial or freely moveable. FIBROUS JOINTS - FIXED - These joints occur where bone ends are joined by strong, short bands of fibrous tissue. - These joints don’t allow movement to occur. - An example of this is the skull. CARTILAGINOUS JOINTS - SLIGHTLY MOVEABLE - The bone ends are separated by a disc or plate made up of very tough, fibrous cartilage. - An example of this is the joints of your vertebrae or spine. SYNOVIAL JOINTS - MOVEABLE - The range of movement from synovial joints is determined by the type of synovial joint. - Synovial joints are characterised by the following features; - A synovial membrane - Ligaments - Hyaline cartilage - A joint capsule - Synovial fluid There are SIX MAJOR TYPES of synovial joints; THE BALL AND SOCKET movement in all directions Hip JOINT HINGE JOINT movement in one direction Knee SADDLE JOINT movement in two directions Thumb PIVOT JOINT movement in one direction Neck GLIDING JOINT movement in all directions Intercarpal CONDYLOID movement in two directions Wrist STRUCTURE AND FUNCTION OF SYNOVIAL JOINTS STRUCTURAL ELEMENT FUNCTION CARTILAGE Covers the ends of two meeting bones - Articular so that they slide smoothly over each other. SYNOVIAL MEMBRANE The tissue that lines the non-contact parts of the joint capsule, secretes synovial fluid. SYNOVIAL FLUID Provides nourishment for the cartilage and lubricates the joint. LIGAMENT A strong, fibrous cord that attaches one bone to another. They provide stability to a joint. TENDON Tough bands of connective tissue that join muscle to a bone. JOINT ACTIONS FLEXION - The bending movement that causes a decrease in the angle between the bones at the joint. - An example is bending the leg at the knee. EXTENSION - The straightening movement that causes an increase in the angle between the bones at a joint. - An example is straightening the leg at the knee. ABDUCTION - Moving the body part AWAY from the midline of the body. - An example is performing a star jump moving your hands up towards the sky. ADDUCTION - Moving the body part BACK TOWARDS the midline of the body. - An example is performing a star jump moving your hands down towards the legs. CIRCUMDUCTION - A combination of other movements that result in a circular or cone-like pattern. - An example is a softball pitch. PRONATION - When the radius rotates around the ulna. - So that the hand is facing with the palm downwards. SUPERNATION - When the radius rotates around the ulna. - So that the hand is facing with the palm upwards. INVERSION - The rotation of the foot so that the sole turns INWARDS. EVERSION - The rotation of the foot so that the sole turns OUTWARDS. ROTATION - The movement of a bone turning on a central axis. - An example is the neck-turning from one side to another. DORSIFLEXION - The flexion of the ankle. - Pulling the toes back towards the shin. - An example is stretching the hamstring muscles.  PLANTARFLEXION - The extension of the foot at the ankle joint. - An example is planting the foot into the ground. ➔ MUSCULAR SYSTEM MAJOR MUSCLES INVOLVED IN MOVEMENT - Movement is controlled by the muscles. - Movement can occur when muscles contract or shorten, pulling the bones they are attached to, closer together. - Movement can also occur when muscles lengthen or relax, allowing the bones they are attached to, to move apart. Skeletal muscles are made up of densely packed muscle fibres along with capillaries. - The blood in the capillaries provides the muscle with oxygen and nutrients they require. * to remember the names of muscles, they are often named after the action they perform, their shape (trapezius), their origin or insertion points (sacrospinalis), their having multiple points of origin (triceps), their location, their size (gluteus maximus) and the direction of their fibres (external obliques). MUSCLE RELATIONSHIP (AGONIST & ANTAGONIST) A skeletal muscle attaches to one bone, extends across a joint and attaches to another bone. - An example of this is the biceps brachii attaching itself to the end of the humerus, extending down across the elbow joint where it attaches itself to the radius. The muscles producing movement can play three different roles; - The agonist - The antagonist - The stabiliser Muscles work in pairs to produce movement. As one muscle contracts (agonist), its opposite muscles relaxes (antagonist). This is called RECIPROCAL INHIBITION. AGONIST (prime mover) - The contracting muscle that is primarily involved in producing the movement. - The muscle doing the work. - An example is the flexion of the leg at the knee joint, the agonist is the hamstring (leg curl). ANTAGONIST (muscles that react) - The opposite muscle that relaxes during a movement. - The muscle relaxes and lets the movement take place. - An example of this is the tricep in the flexion of the biceps (bicep curl). STABILISER (fixators) - Acts to stabilise a bone or body segment so that the agonist can work more efficiently. - An example of this is in the running action, where the torso muscles help keep the body in a stable position. The origin and insertion are the points at which the tendons attach to the bone. The origin is where the tendon of the muscle, joins the stationary bone. The insertion is where the tendon of the muscle, joins the moving bone. - When the arm is being flexed, the radius and ulna are moving bones (insertion), and the humerus and scapula are stationary bones (origin).  TYPES OF MUSCLE CONTRACTION (CONCENTRIC, ECCENTRIC & ISOMETRIC) - How the muscles in a specific action actually produce movement. This can occur in three ways; Isotonic contractions - Isotonic concentric contraction - the muscle SHORTENS to bring bones closer together (moving faster than gravity - against gravity). - Isotonic eccentric contraction - muscle LENGTHENS (moving slower than gravity - against gravity). Isometric contraction - STAY THE SAME LENGTH (stays the same through full range of motions). ➔ RESPIRATORY SYSTEM The process by which the body takes in oxygen and removes carbon dioxide. - STRUCTURE AND FUNCTION The nose - The nose has a sticky surface. - It is covered in tiny hairs called cilia that trap dust particles. The mouth - The mouth warms, filters and humifies air. The Pharynx - The throat - It carries food as well as air. - This follows into the oesophagus (food) and the trachea (air). - The epiglottis is a flap that stops any food from entering the trachea. The Larynx - The voice box. - It produces human speech. - As air from the lungs moves past, it causes the vocal cords to vibrate, producing sound.  The Trachea - The windpipe - Major airway to the lungs and is strengthened by cartilage rings. - It divides into two bronchi in the chest. The lungs - Two lungs - Made of elastic tissue - They are protected by the sternum, ribs and spine. - They play a large role in gas exchange and the transport system. The Bronchus - One bronchus goes into each lung. The Bronchiole - The bronchus, once in the lungs, divides into smaller branches. - These are called bronchioles. The Alveoli - The bronchioles divide until they reach tiny sacs. - These sacs are elastic and thin-walled. - They are densely covered in capillaries containing blood. - They play a large role in gas exchange. When humans inhale, oxygen enters the respiratory system through the mouth and nose. The breath then passes through the larynx and the trachea (entering the chest cavity). The trachea then splits into two smaller tubes (bronchi), which then divides, forming bronchioles. These connect to the alveolus (where gas exchange takes place). Oxygen passes through the thin wall of the alveoli and into the bloodstream. At the same time, carbon dioxide diffuses the other way through the thin wall, into the lung. LUNG FUNCTION (INSPIRATION & EXPIRATION) To breathe in air, the diaphragm moves down, increasing the lung capacity ro reduce the concentration INSPIRATION Breathing in. - The diaphragm contracts, the ribs move up, enlarging the chest cavity. Because the chest is bigger, the pressure within the lungs decreases. - The pressure inside the lungs needs to be less, than the pressure outside.  The air moves from an area of high pressure to low pressure so the air is drawn into the lungs. EXPIRATION Breathing out. - The diaphragm and ribs return to at-rest state, which decreases the size of the chest cavity. This makes the pressure inside the lungs higher, so air is forced out of the lungs. - The pressure outside the lungs is higher than the pressure inside the lungs. EXCHANGE OF GASES (INTERNAL & EXTERNAL) Gas exchange occurs between the alveoli of the lungs and the blood in the capillaries The substance moves from an area of high concentration to an area of low concentration. EXTERNAL RESPIRATION The alveoli in the lungs have a high level of oxygen whilst the blood in the capillaries have a low level of oxygen. - The oxygen diffuses from the alveoli into the blood in the capillaries. The blood in the capillaries has a high level of carbon dioxide whilst there is a low level of carbon dioxide in the alveoli. - The carbon dioxide in the blood diffuses into the alveoli. This uses the DALTON LAW - gases move from areas of high pressure to areas of low pressure. This uses the concentration gradient. INTERNAL RESPIRATION Internal respiration is the exchange of gases across the membranes of the capillary and the muscles using diffusion. - For example, the oxygenated blood is brought to the muscle, where oxygen is taken out of the blood and transferred to the muscle tissue, while at the same time, carbon dioxide is taken out of the muscle cell and brought into the blood. Oxygen is transported through the blood attached to haemoglobin. In order to have good cardiorespiratory endurance you must have an efficient cardiorespiratory system delivering oxygen to the working muscles - meaning technique won’t be altered and will be maintained, limiting injuries and maximising efficiency. A spirometer can be used to measure lung volumes. VITAL CAPACITY - the volume of air inspired in a breath after forcibly exhaling the air remaining in the lungs. RESIDUAL VOLUME - the air that is trapped in the lungs after forcibly exhaling (air that remains so the lungs don’t collapse). - ➔ CIRCULATORY SYSTEM The circulatory system consists of the heart, blood vessels and blood. Its major function is to transport nutrients, oxygen and water to the bodies cells and remove waste products. This is provided by the blood. - When blood flows to the cells and returns to the heart, it is called circulation. COMPONENTS OF BLOOD The purpose of blood is; - Transport oxygen, nutrients, hormones and enzymes around the body. - Transports carbon dioxide and waste products FROM the cells TO the body organs, to eliminate them. - Regulates the acid-alkali balance. - Maintains body temperature. - Regulates the water content of cells. - Protects the body from infection. The blood vessels; - Arteries (away from the heart) - Capillaries - Veins (to the heart) PLASMA - The liquid component of blood. - Make up 55% of blood volume whilst red and white blood cells make up 45% of blood volume. Substances such as proteins, nutrients, hormones and wastes (carbon dioxide) are dissolved in the plasma. RED BLOOD CELLS Formed in bone marrow. Their function is to carry oxygen and carbon dioxide around the body. - They contain iron and a protein called haemoglobin. - Haemoglobin combines with oxygen and carries it from the lungs to the cells. They have a flat disk shape that provides a large surface area, to collect oxygen. There are more red blood cells than white blood cells. WHITE BLOOD CELLS Formed in the bone marrow and the lmyph nodes (filtering system). Their function is to provide the body with a mobile protection system against disease. The most common white blood cells; - Phagocytes (engulf foreign material and harmful bacteria). - Lymphocytes (produce antibodies and fight disease). PLATELETS - thrombocytes - Tiny structures made from bone marrow cells. Their function is to produce clotting substances that prevent blood loss. - They create a grid to stop blood getting through.  STRUCTURE AND FUNCTION OF THE HEART - Uytrxtzxcyvubi = arteries going away from the heart. —---------------- = going to the heart FLOW OF BLOOD - SUMMARY  - VERY IMPORTANT Left atrium holds the oxygenated blood. The left ventircle is stronger as it has to pump blood to the brain against gravity. ARTERIES Carry the blood away from the heart. Thick muscular walls. - The major artery of the body is the aorta. CAPILLARIES Blood vessels where nutrients are exchanged. Very thin walls. VEINS Blood vessels that return blood back to the heart. - In veins, the blood is under low pressure, meaning the veins have valves that stop the blood from running backwards. Muscles contract to get blood back to the heart after exercise. This is to ensure the blood doesn’t pool (meaning it doesn’t move through the veins), this is the reason for cool downs after exercise. - PULMONARY AND SYSTEMIC CIRCULATION Both sides of the heart work together is the pulmonary and systemic circulation. - PULMONARY The flow of blood from the heart to the lungs and back to the heart. Deoxygenated blood from the body enters the right atrium via the vena cava. The blood then flows into the right ventricle, which pumps it to the lungs via the pulmonary arteries. In the lungs, the carbon dioxide is dropped and the oxygen is picked up. The oxygenated blood then enters the left atrium via four pulmonary veins. HEART TO HEART —> BACK TO HEART. SYSTEMIC The flow of blood from the heart to body tissue and back to the heart. The oxygenated blood then flows into the left ventricle. From here, the blood is pumped up through the aorta and out to the upper and lower extremities (arms,  hands and legs) via arteries. The deoxygenated blood returns to the heart via veins and the vena cava to the right atrium. HEART TO MUSCLES —-> MUSCLES TO HEART. - BLOOD PRESSURE The circulation of blood is controlled by the regular contractions of the heart muscle. - An efficient resting heart rate is 60-65 beats per minute. - Each time the heart beats, the pressure of the blood against the walls of the arteries and veins increases. Blood pressure represents the amount of blood being pushed out (pumped) of the heart (cardiac output). Blood pressure is measured in two forms; - Systolic pressure - Diastolic pressure SYSTOLIC The highest pressure recorded when blood is forced into the arteries during contraction of the left ventricle. - (what you feel when you take your pulse). DIASTOLIC The lowest pressure recorded when the heart is relaxing and filling with blood.  MEASURING BLOOD PRESSURE - Measured with a sphygmomanometer. Measured in millimetres of mercury (mm.Hg) It is expressed as systolic pressure over diastolic pressure (a fraction). - FACTORS THAT CAN AFFECT BLOOD PRESSURE - Hypertension or high blood pressure occurs when readings are over 160/90 mmHg. - High readings mean the heart is under a lot of pressure, causing heart disease and stroke. Factors that contribute to hypertension; - Being overweight - High consumption of alcohol - High salt diet - Smoking Excitement, stress, posture, pain and sleep can also affect blood pressure. EFFECT OF EXERCISE ON BLOOD PRESSURE Exercise causes an immediate increase in systolic pressure, in direct proportion to the intensity of the exercise (as the exercise gets harder, the blood pressure gets higher). - facilitating blood delivery to accommodate the greater demands of the body. - - Exercise should be stopped if systolic blood pressure goes above 250mmHg. - Diastolic blood pressure changes very little during exercise (if it increases by 15mmHg or more, exercise should be stopped). - This is because the body goes into oxygen debt. A long-term effect of training, is a decrease in blood pressure at rest. What is the relationship between physical fitness, training and movement efficiency? ➔ HEALTH-RELATED COMPONENTS OF PHYSICAL FITNESS The aspects of fitness that enable us to maintain our health, perform daily tasks, perform well in sporting activities and protect us from sickness. - The following components are listed below; CARDIORESPIRATORY ENDURANCE (CRE) - The body's ability to maintain movement for an extended period of time. - The heart, lungs, blood and muscles have to work together to absorb, deliver and utilise oxygen. - Having a higher CRE allows an athlete to sustain technique, and intensity levels and reduce potential injury. - CRE predicts performance with distance-based events. - CRE can be tested by the step test or the beep test. MUSCULAR STRENGTH - The greatest maximal force or tension that a muscle group can exert against a resistance in one maximal contraction. - Muscular strength predicts performance in strength-based events. - Muscular strength can be tested by the grip tests and 1 repetition maximum test. MUSCULAR ENDURANCE - The ability for muscles to contract repeatedly without fatigue. - Muscular endurance allows movements to be repeated correctly. - Muscular endurance predicts performance in endurance-based events. - Muscular endurance can be tested by the 1min push-up test and the 1min sit-up test. FLEXIBILITY - The range of movement that can be performed in and around a joint. - It is joint-specific. - Flexibility allows for greater balance and reduced injury risk. - Flexibility can be tested by the sit and reach test. BODY COMPOSITION - The proportion of fat to lean muscle tissue. ➔ SKILL-RELATED COMPONENTS OF PHYSICAL FITNESS POWER - The ability to transform physical energy into force at a fast rate. - Power allows energy to be put into movement efficiency and at a faster rate. - The ability of the muscles to exert maximum force in the shortest amount of time. - Power can be tested through the vertical jump. SPEED - The ability to move all or parts of the body from one point to another as quickly as possible. - It affects movement efficiency by how fast you move, affects the overall efficiency of the movement. - Speed can be tested through the 35m sprint. AGILITY - Ability to change direction or position (velocity or direction) of the body with speed and control. - These increase movement efficiency by increasing speed. - Agility can be tested the Illionis run. COORDINATION - Ability to move 2+ body parts at the same time efficiently and accurately. - Ability to move the body smoothly. - It increases movement efficiency by allowing the movement to move more smoothly. - Coordination can be tested the toss and catch. BALANCE - Ability to keep body’s centre of mass over base of support. - Ability to stay in control of their bodies position. - This increases movement efficiency by allowing the body to be balanced, making the movement easier. - It can be tested by the stork stand (balancing on one leg). REACTION TIME - The speed at which an athlete responds to an external stimulus. - The faster you react, the faster the movement occurs. - This can be tested by the ruler test. The difference between health-related and skill-related components of fitness is that the skill-related components of fitness are specific to sports and the health-related components of fitness are overall needed in daily life. The development of health and skill-related components of fitness allows movements and participation to be effective and efficient. The fitness test will PREDICT PERFORMANCE if it is relative to the sport and depends on the sport as to which fitness testing needs to be performed. - For example, you do not need reaction time as much in a 5km race, rather than a 100m race. There are many PURPOSES and BENEFITS for measuring physical fitness; - Make comparisons with others - Develop accurate training programs - Set realistic fitness goals. - Assess strengths and weaknesses - Identify medical problems - shoulder issues. - Motivate to improve results. - Monitors progress - Provides incentive for the athlete (they can see the progress of the training). ➔ AEROBIC AND ANAEROBIC TRAINING AEROBIC TRAINING - Sustained continuous activity with a longer duration. - Usually performed at low to moderate intensity and at a steady pace for an extended period of time. - Focuses on developing cardiorespiratory endurance (minimum 20 minutes). - Uses 60%- 85% maximum heart rate. - This shows how well you can consume, transport and use oxygen. - It uses oxygen to break down and metabolise energy sources to create movement. - This can be used for a long time. - Examples of aerobic events includes walking, swimming and cycling.  ANAEROBIC TRAINING - Powerful and explosive (intense) movement over a short duration. - Focuses more on strength and power of an athlete. - If the heart rate is between 85% - 100% of maximum heart rate. - It relies on stored energy in the body that doesn’t require oxygen and produces lactic acid (this slows or impairs muscular contractions). - This can NOT be used for a long time. - Training anaerobically allows an athlete to develop a higher tolerance to lactic acid, this increases endurance and reduces fatigue. - Examples of anaerobic training include sprinting and long jump. Anaerobic training: 1:2 (1 minute high intensity, 2 minute rest - work period is less than rest period). Aerobic training: 2:1 (2 minutes working, 1 minute rest - working period is less intense, but longer than rest period). To calculate maximum heart rate (MHR) Once the number is calculated (131.95), divide that by the maximum heart rate (203), and then multiply by 100, to find the percentage. This finds whether you are training in an aerobic or anaerobic threshold. FITT PRINCIPLE FREQUENCY - relates to how frequently a sportsperson should work out. - 3-5 days per week is optimal. - Active recovery can be done during rest days (light exercise). INTENSITY - explains how intensely a sportsperson trains. - Exercise can range in intensity from mild to strenuous. - Exercise should be completed between 60-85% of the individuals maximum heart rate. TIME - is the amount of that a competitor should train for. - Maintained for a period of not less than 20 minutes. - The best results are from sessions 30-60 minutes over a 6-8 week period.  TYPE - is used to describe the type of workout activity being performed. - This area relates to specificity (what is the goal for training? Leg muscle growth?) - For example, aerobic interval training has intervals of exercise followed by shorter periods of rest. This can be done through jogging or swimming. (example response). ➔ IMMEDIATE PHYSIOLOGICAL RESPONSES TO TRAINING - The effects of physiological responses can been be observed and measured through; HEART RATE The number of times your heart beats per minute. - The average working heart rate is between 60-100 beats per minute, trained athletes have a heart rate of 40-60 BPM. As intensity increases, the rate the heart beats increases (LINEAR) - A fitter persons heart rate will level off whereas an unfit persons heart rate will continue to rise. - When exercise stops, the heart rate quickly decreases. This happens faster with fitter people. The heart rate increases with exercise and decreases once exercise is stopped as the muscles are in high demand for oxygen and once exercises ceases, the demand for oxygen decreases. The less fit the person, the more unstable the increase of their heart rate is and has more spikes as it rises rapidly. VENTILATION RATE At the beginning of exercise there is an immediate increase in ventilation (breathing in and out), followed by a rise in the depth and rate of breathing. Once exercise stops, heart rate decreases but ventilation rate remains at a high rate for longer. This is because the body is in oxygen debt. This is because it borrows oxygen from systems not being used so has to payback those areas. STROKE VOLUME The amount of blood pumped by the heart with each contraction (beat). - It is measured in millimetres. This amount increases with exercise. The more fit the person is, the HIGHER stroke volume they have - the more blood their body has access too. - Stroke volume increases during exercise becasuse of an increased strength on contractions of the heart - meaning more blood is ejected from the ventricles each contraction. - - The trained athlete has a larger access to blood and a larger difference between amount of blood available at rest and when training. CARDIAC OUTPUT The volume of blood that is pumped OUT of the heart per minute, increases during exercise. - It is measured in litres per minute. CARDIAC OUTPUT = STROKE VOLUME X HEART RATE - At rest, cardiac output is 5-6 litres per minute. - A trained athlete during exercise, can have a cardiac output as high as 30 litres per minute. - This means there is a larger difference between resting and training cardiac output (similar to the photo above). The higher the maximal VO2, the higher the maximal cardiac output. - This is because the body needs to meet the oxygen demands. LACTATE LEVELS - A solution of lactate ions and hydrogen ions in water. Blood lactate levels increase as exercise intensity increases. During exercise, the body can not remove lactate quick enough so the levels increase. - The athlete either has to decrease intensity or rest until the lactate levels reduce. An untrained athlete will reach lactate threshold much faster than a trained athlete.  Cardiac output and ventilation increase to ensure that working tissues are supplied with oxygen and nutrients and to remove waste. - To assist this process, the body directs blood away from non-working areas such as the digestive system. How do biomechanical principles influence movement? ➔ MOTION - The internal and external forces that act on the body and the movements that these forces produce. LINEAR MOTION Occurs when the human body propelled by a human moves in the same direction at the same speed over the same distance. Three types of linear motion; - Rectilinear - a movement that takes place in a straight line. (running) - Curvilinear - a movement that takes place in a curved path. (gymnastics tumble) - Angular/rotary - movement is circular, around some fixed point. (bowling in cricket) Most sports are referred to as general motion, a combination of both. VELOCITY The displacement (distance between point A and point B) of the body. - SPEED The magnitude of the speed of the body. How quickly the body is moving.  - EXAMPLES Shows how to calculate velocity, different to speed. ACCELERATION How quickly velocity changes (a softballer sprinting to steal a base). - MOMENTUM The product of measuring a bodies mass and velocity. Momentum = mass x velocity - Once a body is in motion, it will tend to stay in motion, unless acted upon by a force.  Momentum can be transferred between bodies. (if two bodies collide, the total momentum is equal to the total momentum of two bodies before the collision). - For example, a softballer will have to swing the bat faster with a higher velocity to hit the ball further and reduce bat velocity to bunt the ball. The differences in momentum are the variations in mass and velocity - mass is usually constant in sports, making velocity the main influencing factor on momentum. - An example of this is when an ice skater brings their arms closer to their body during a spin. This is done to move the moment of inertia. By tucking their arms to their chest, it decreases inertia because their body comes closer to the axis. (If the moment of inertia gets smaller, the objects angular velocity is going to be faster). ➔ BALANCE AND STABILITY Stability is the resistance a body has to change in its equilibrium. (wanting the body to stay still). When an individual achieves a stable position they are balanced. There are two types of balance - Static balance - not moving - Dynamic balance - body is moving To make your body more stable, lower your sense of gravity. CENTRE OF GRAVITY (CG) The greater the mass, the stronger the attraction. Centre of gravity is the balance point at which all mass is concentrated. Our centre of gravity is always changing as we move. - The lower your centre of gravity is, the more stable you are. LINE OF GRAVITY A straight line is drawn from the CG to the ground. - The object is most stable when the line of gravity, goes through the centre of the base of support. BASE OF SUPPORT The region bounded by the body parts in contact with a surface, applying a reactive force against the body parts. - Your feet are your base of support when you stand up. Increasing the area of base of support will increase stability. The greater the mass of an object, the greater its stability. - A block start is very unstable, due to centre base of support being minimal and line of gravity not falling in the centre of base of support. - ➔ FLUID MECHANICS - The forces that operate in water and air environments. Two important forces include; - Buoyant force - If the body weighs more than the water, it will float. - Drag force. FLOTATION The two forces that act on a body in a fluid environment include; forces that push the body up and the WEIGHT FORCE that pulls the body down (gravity). Archimedes principle: the body will experience buoyancy that is equal to the weight of the volume displaced by the body. - If someone was going to float, the amount of water displaced (spilt out of pool), must be equal or more weight for him to float. If the buoyant force is greater than the weight force - the body will float. If the buoyant force is less than the weight force - the body will sink. - CENTRE OF BUOYANCY (CB) The centre of buoyancy is at the centre of gravity of the water that the swimmer displaces. - When the body is fully submerged, the swimmer's CB will fall directly above the swimmer’s CG. The CG and CB change as a result of movement changes, particularly the legs. - FLUID RESISTANCE Forces that act on movement in fluid are drag and lift. DRAG - mainly friction The resistance that acts against a body as it moves through a fluid environment. - Friction is an opposing force. Friction occurs when one body (a hand), moves across the surface of another (water). A difference in pressure occurs on the opposing sides of the body. - When swimming, a low-pressure area is created in front of the hand and a corresponding high-pressure area forms behind the hand. The drag force as the hand is pulled through the water, is created. -  LIFT - Hydrodynamic lift force The force is greater than the lift created in the air, as water is denser. This force occurs perpendicular to the flow of the water over the body when swimming. - When performing an eggbeater kick in water polo, the hydrodynamic lift force is created as the legs alternately circle under the water. This creates pressure differences between the top and bottom of the foot and leg. - - FLUID MECHANICS INFLUENCING PERFORMANCE - The study of fluid mechanics influences clothing, equipment and the environments in which competition take place in. - Fast skin swimsuits were created by Speedo, by reducing drag on the swimmer and increasing buoyancy. - Racing environment has changed through olympic pools being 10 lanes wide, keeping two outside lanes free, stopping excess wave motion. - Plastic buoys that divide the lanes, are designed to direct water downwards and not outwards, stopping excess wave motion. THE MAGNUS EFFECT Occurs when a spinning object creates a whirlpool of rotating air or liquid around it. Velocity increases on one side of the object where the fluid travels in the same direction as the whirlpool. As the velocity of a fluid increases, the pressure exerted by the fluid will decrease. The opposite side of the object experiences decreased velocity as the motion of the whirlpool is reversed. This creates a spin. - Top spin, caused by the magnus effect, produces a downward swerve of a moving ball, greater than gravity, and - Back spin has the opposite effect - rising in the air. (seen in golf -driving from a tee) - Side spin causes swerve to either side (baseball pitch) - - ➔ FORCE A force causes or has the potential to cause, divert or slow the movement of an object upon which it acts. - Force could be a push, pull, blow, impact, friction or gravity. - Forces are always acting on a body. - They are measured in newtons (N). Force can be internal and external. - Internal forces act from inside the body (muscles contract to exert a force on bones to produce movement). - External forces exert a force outside the body (gravity, friction, contact with the ground or another body and air or fluid resistance). These forces act on the body. The properties of force; - Magnitude - how much force is applied. - Direction - the angle at which the force is applied - Point of application - the specific point at which the force is applied to a body. - Line of action - a straight line through the point of application in the direction that the force is acting. - Vector - the direction in which forces act. - HOW THE BODY APPLIES FORCE NEWTONS FIRST LAW OF MOTION Everything continues in its state of rest or motion unless compelled to change that state by an external force exerted upon it. NO FORCE, NO MOVEMENT. INERTIA - The tendency of an object to remain unchanged in its current state of motion or rest. To overcome inertia, a greater force needs to be applied. - An example is the block start; and how the CG is higher than the rest of their body, maximising instability - therefore it is easier to overcome inertia. NEWTONS SECOND LAW OF MOTION - not as important A body will experience a change in its motion in proportion to the force applied to it, and the direction of the force. FORCE = MASS X ACCELERATION The greater the force that acts upon the body, the greater its resultant force. - An example is a putt in gold will not travel as far as a drive. As the mass of the body increases, a greater force is required to produce the same acceleration. (a 4-kilogram discus needs more force than a 2-kilogram). When a force is applied to a moving body, the motion is adjusted according to the force. This law also relates to momentum. NEWTONS THIRD LAW OF MOTION For every actio, there is an equal and opposite reaction.  This illustrates that forces act in pairs and are equal and in opposite directions. - The result is not always the same. When you perform a long jump, the force of the ground when landing, is much greater than the force that you apply to the ground. This is because the earth is much heavier than you. This shows the relation between Newton’s Third and Second law. CONTACT FORCES Contact forces - (push or pull) exerted by one object in direct contact with another. (when a foot hits the ground). There are 6 types of contact forces; - Ground reaction force - athletes are in contact with the ground. (sprinting - reaction force to the tartan track, more rebound force). - Joint reaction force - the force that two bones apply to each other across a joint. - Friction - the force that resists the motion of one surface across another (the reason spikes are worn). - Fluid resistance - motion is affected by the fluid in which it is performed. - The law of inertia - the resistance of an object to move or an object to continue in motion can affect movement. (the crouch start is done to overcome inertia). - Elastic force - when a force is applied to a material and it changes length. (diving boards, trampolines). For movement to result, the force applied needs to be greater than the external forces acting on the body. (a footballer needs to step hard, in order to swerve around an opponent). Non-contact forces - acts from a distance and doesn’t involve contact between objects. (Gravity). SUMMATION OF FORCES The force produced during the movement of one body segment will be added to the force produced by the next body segment (the thigh) and so on until the movement is complete. It's a kinetic chain of movement. - Summation of force is influenced by; - Number of body parts used in the movement. - Order and timing of the movement. - Force and velocity generated - Way in which body parts are stabilised for other body parts to act upon. (adding more body parts to transfer force through the body). Athletes can achieve maximum velocity or force by transferring momentum through successful body part movements - this can be done through technique.  CENTRIPETAL AND CETRIFUGAL FORCES CENTRIPETAL FORCE - when an object moves along a curved path, a centre-seeking force acts towards the centre of the rotation. CENTRIFUGAL FORCE - an equal and opposite centre-fleeing force (Newton's third law). - An example is a gymnast swinging around a bar, which generates force both in and away from the bar. The gymnast must retain their grip to counter the effects of these forces. - HOW THE BODY ABSORBS FORCE - To prevent injury, the momentum of the speeding body must be gradually decresed by joint actions. PROPULSIVE FORCE - an external force that acts to cause motion in a body. RESISTIVE FORCE - a force that acts to resist the movement created by a propulsive force. - The controlling of a barbell requires the momentum to be reduced to zero, therefore providing a resistive force. Sporting safety equipment uses this principle, to spread the force over a greater area (cricket pads, hockey goalie pads). Athletes can take a number of precautions to ensure safer collisions; - Use a large surface area when landing or catching (land on two feet). - Keep as great a distance as possible between impacting objects (avoid running into players). - Regulate the position of one’s centre of gravity (staying low and stable). - Give with the impact by slowing the object gradually. - Use materials (gloves, headgear) - Protect projections of the body during contact (fingers, shoulders). APPLYING FORCE TO AN OBJECT - Top spin is an example of how force can be effectively applied to an object (tennis). - Spin bowlers alter their wrist and finger motion to use Magnus effect as this causes the ball to drift.  IMPORTANT 1. Joint movements 2. Flow of blood, (oxygenated and deoxygenated blood) 3. Diagram of the heart