Chapter 4 ERQ
Using a sporting example, predict how a change in radius affects speed of rotation.
Angular momentum=moment of inertia x angular velocity, angular momentum is conserved after push off/take off OR the magnitude of angular momentum remains constant, with decrease in radius the body has lower moment of inertia, the speed of rotation/rotational velocity increases with decreased radius/body being in a compact shape OR eg moving arms/legs closer in will increase the speed of rotation, when an athlete wants to stop the spin, they increase the radius to decrease the rotational velocity
Using examples, outline the function of the axial and appendicular skeleton during physical activity.
Axial skeleton: provides protection of vital organs eg, skull protects the brain «during a tackle in rugby». Supports the weight of the upper body eg, vertebral column supports the weight of the upper body «while balancing on a beam in gymnastics». Appendicular skeleton: provides attachment for muscles eg, scapula provides attachment for rotator cuff muscles «which support the shoulders during the rings and vaulting». Provides levers to allow movement eg, humerus and ulna articulate to form a lever «that allows for a more effective release of a javelin»
Evaluate two fitness tests used to assess body composition.
BMI (body mass index): Body mass index is a measure of an adult's weight in relation to height/weight in kg divided by their height in metres squared. Strengths: more accurate than standard height and weight tables, easy to administer, non invasive. Limitations: BMI is not a direct measure of body fat, not suitable for certain populations eg, children, pregnant women, elderly or athletes, despite its inaccuracy it is still used as a medical standard to assess obesity. Anthropometry: most common field technique is skinfold calipers where skin fat thickness is measured at a number of sites and the sum of these sites used in an equation estimates percentage body fat. Strengths: accuracy is greater than BMI, more detailed protocol and equations are used to focus on gender specific differences, widely used due to its accessibility, limited cost implications, non-invasive. Limitations: reliability of the data is affected by the experience and consistency of the tester, accuracy is affected by the number of sites and the calculation being used to determine density, equations are based mostly on cadaver studies. Underwater weighing/Hydrostatic weighing: the athlete is weighed totally immersed in water OR where the difference between their scale weight and underwater weight is measured. Strengths: considered one of the most accurate measures of body composition, perhaps considered the most reliable and valid. Limitations: major weakness is in the conversion of body density to estimate relative body fat, equation assumes that fat mass and fat-free mass is constant in all people, specialized equipment, high cost.
Explain the mechanics of pulmonary ventilation in the human lungs at rest.
Breathing in: diaphragm flattens/contracts, external intercostal muscles contract OR rib cage moves upwards and outwards, thoracic cavity volume increases, thoracic cavity pressure decreases «therefore air rushes in», air rushes in from high pressure to low pressure OR inhalation continues as long as the pressure difference exists. Breathing out: diaphragm relaxes, external intercostal muscles relax OR rib cage moves down and inwards, thoracic cavity volume decreases, thoracic cavity pressure increases «therefore air rushes out».
Outline the process of the sliding filament theory after calcium has been released and until it is pumped back into the sarcoplasmic recticulum.
Ca binds with troponin. Tropomyosin are lifted from the actin filament binding sites. Myosin heads attach to actin to form a cross bridge. Heads of myosin tilt and drag the actin filaments, referred to as the power stroke. Cross bridge breaks as ATP splits. Z lines move closer together OR H zone disappears. Ratchet mechanism continues until the ends of the myosin filaments reach the ends of the Z lines
Describe how cardiovascular drift takes place.
Cardiovascular drift is an increase in heart rate during prolonged exercise <despite effort remaining the same>, during prolonged exercise there is an increase in core temperature, the rise in core temperature causes redistribution of blood to the periphery in order to cool, the blood volume redistribution causes the heart to work harder in order to maintain muscle blood flow / energy demands, blood flow to skin increases and water is lost via sweating, prolonged cooling/sweating causes a decrease in blood volume / increase in Viscosity, reduction in venous return/stroke volume causes the heart rate to increase to maintain cardiac output
Outline two types of connective tissue of joints.
Cartilage: joins bone to bone ‹as in cartilaginous joints›, allows limited movement ‹in cartilaginous joints›. Ligament: attaches bone to bone ‹in synovial joints›, helps provide stability for synovial joints. Tendon: attaches ‹skeletal› muscle to bone, helps provide stability for synovial joints
Describe how coding, chunking and association can be used to improve memory when learning a new skill.
Coding: changing the information into a word/number/movement code, ‹which is shorter and easier to remember›, eg, in many sports key moves are coded to help team members recall information quickly ‹as well as hide information from opposition›. Chunking: information is grouped together, instead of being presented/taught as individual items, eg, in the breaststroke the three actions of "reach, glide and pull" are better grouped together/ practised as one movement, allows more information to be memorized in a single glance/situation. Association: new learning is linked to what players already know/ movement patterns are matched to something already known to the performer, eg, throwing a javelin is like throwing a water polo ball
Outline how the general characteristics of skeletal muscle tissue function during a 200 m sprint.
Contractility: the ability of muscle cells to actively generate force/to undergo shortening for movements to bring about dynamic movements. Elasticity: the ability of muscle tissue to return to its original shape after contraction/extension OR helps store energy for movement. Extensibility: ability of muscle to stretch without damage ‹within the permitted range of movement› OR allows quick changes in range of movement (ROM). Controlled by nerve stimuli: the ability of the muscle tissue to be stimulated by electrical impulses/excitability/conductivity, muscles work in pairs through reciprocal inhibition fed by capillaries:capillaries supply muscles with oxygen and nutrients/remove waste products there may be a small amount of hypertrophy ‹due to blood moving into muscle›
Explain DOMS in relation to muscle contraction.
DOMS occurs after exercise / up to 48 hrs post exercise <and can last three or four days>, eccentric and isometric actions tend to produce the greatest post exercise discomfort, concentric contraction does not cause DOMS to the degree that it is produced by eccentric contractions, due to greater microscopic tears in eccentric contractions, with DOMS comes a reduction in the force generating capacity of the affected muscles / negatively affects performance. DOMS can be produced by: microscopic tears, osmotic pressure causing fluid retention in the surrounding tissues, muscle spasms, overstretching and tearing of muscle connective tissue, acute inflammation, alteration in the cells' mechanism for calcium regulation
Describe the functions of erythrocytes, platelets and leucocytes.
Erythrocytes: transports oxygen, transports carbon dioxide. Leucocytes: fight disease and infection. Platelets: responsible for clotting the blood
Using an example, discuss the effect of experience and memory on selective attention.
Experience: more experienced athletes can better use their long-term memory to improve their selective attention, experienced athletes selectively attend to stimuli quicker than less experienced athletes, selective attention can be improved through over-learning, more experienced athletes better filter stimuli into relevant and irrelevant «noise». Memory: the apparent limited capacity of the short-term memory indicates that there is some form of selective attention to prioritise stimuli, more long-term memories provide a greater source to draw from for selective attention, selective attention operates in the short-term sensory store, only relevant information is passed to the short-term memory, Long-term memory will enable a person to attend quickly to the correct stimuli in future situations
Distinguish between the movement permitted in different types of joints.
Fibrous/synarthrosis: no movement, cartilaginous/amphiarthrosis: slight movement, synovial/diarthrosis: freely movable.
Describe the endurance element of a general training programme.
Frequency: frequency of training can be from 2-7 sessions per week. Intensity: often working at an intensity of 60-80 % MHR to improve aerobic capacity. Interval training can be used working at a higher intensity with medium to long intervals, eg, 75-90 % MHR, 2-1/3-1 work-relief ratio. Time: training over 20 minutes in a continuous manner. Type: activities such as running/swimming/cycling/rowing/HIIT. HIIT circuit, including endurance activities in bouts of 30-60s, eg. burpees/spotty dogs/jumping jacks. Fartlek training can be used to replicate the change intensities within a team game
Outline six different types of feedback used in sport.
Intrinsic: information received from inside the performer/is received via proprioceptors/it is the "feel" associated with movement, could be positive or negative. Extrinsic: received from outside the performer/received via senses/such as sight and sound through exteroceptors from coaches. Knowledge of performance: information about the execution of the performance, usually from external sources but can be internally obtained if the performer is experienced enough. Knowledge of results: information about the outcome of performance/it is obtained externally from your senses. Positive: used to encourage and reinforce good behaviour such as praise, rewards, could be the feeling or sound created from a good contact. Negative: received if performance is not correct ‹the aim is to discourage performance›. Concurrent: received during the activity, could be intrinsic or extrinsic. Terminal: received after the activity has occurred
Outline two characteristics common to muscle tissue.
Muscle contractility: the ability of a muscle to contract forcefully. Extensibility: a muscle can be stretched beyond its normal resting length. Elasticity: the ability of a muscle to recoil back to its original resting length after stretching. Excitability: control by nerve stimuli. Atrophy: a decrease in size due to a lack of exercising a muscle group this change in size is primarily due to a decrease in the number of myofibrils and sarcomeres inside the muscle fiber. Hypertrophy: an increase in muscle size. Fed by capillaries: which supply oxygen/ remove CO2
Explain the application of Newton's three laws of motion to a swimmer as they start a race from the blocks.
Newton's first law/law of inertia: swimmer is at rest as no external force is acting upon them, after the starting signal they apply a force to overcome their inertia to start moving. Newton's second law/law of acceleration: the greater the force they apply as the push off from the blocks the faster they accelerate, the swimmer's movement is made in the direction of the force applied, acceleration is dependent on swimmer's mass. Newton's third law/law of reaction: swimmer applies action force down and back on the blocks, the blocks apply an upwards and forwards reaction force
Outline the functions of two components of blood.
Platelets/ thrombocytes: assist in the process of repair following injury, allow the blood to clot. White blood cells / leukocytes: involved in immune function / produce antibodies, protect the body from infection / foreign substances. Red blood cells / erythrocytes: contain hemoglobin and transport oxygen, hemoglobin binds with oxygen forming oxyhemoglobin, hemoglobin increases the blood's oxygen carrying capacity 65-75 times that above that normally dissolved in plasma, hemoglobin <contains a central iron ion which> can hold up to four oxygen atoms <per heme>. Plasma: is the fluid component of the blood assists in transport of substances such as food / waste products/ gases / hormones / antibodies
Describe the types of movement of the ball and socket joint at the shoulder.
Rotation: movement of bone/limb around a central/longitudinal axis. Flexion: bending or decreasing the angle between 2 bones. Extension: increasing the angle between 2 bones. Abduction: movement of the bone/ limb away from the midline of the body. Adduction: movement of the bone toward the midline of the body. Circumduction: when the end of the bone makes a circle and the bone makes the shape of a cone. Depression: movement at the shoulder downwards towards the feet. Elevation: movement of lifting the shoulders towards the head
Distinguish between the skill profile of a javelin throw and a forehand shot in table tennis.
Skill Profile Continuum: Javelin Throw vs Table Tennis Forehand. Gross-fine: Gross <body movement>, fine <body movement>. Open-closed: Closed skill <as there is limited external influence>, open skill <influenced by the return of the ball from the opponent and the opponent's permission>. Discrete-serial continuous: Serial skill <javelin is more of a serial skill compared to the table tennis forehand as there are stages to the action which are run up, side step and release>. Discrete skill <the forehand is a discrete skill as there is a distinct start and finish, but once the action starts it does not have specific elements to the skill>. Interaction continuum: Individual skill<a javelin throw is an individual skill as they perform on their own at one time>, interactive skill <forehand is an interactive skill where the performance is directly against an opponent and influenced by their performance>. Pacing Continuum: self-paced<although there is a limited time for the throw to be completed, the execution of the skill is self paced>, externally paced <forehand is externally paced as is it is influenced by the speed of return from the opponent>
Compare and contrast slow and fast twitch muscle fibre types.
Slow vs fast. Force production: low/high. Contraction speed: slow/fast. Fatigue resistance/aerobic capacity: high/low. Glycogen content: low/high. Mitochondrial density: high/low. Capillary density: high/low. Myoglobin: high/low. Oxidative enzyme capacity: high/low. Color: red/white. Fibre diameter: small/large. Primary function: endurance activities/high intensity & rapid activities
Evaluate the Harvard Step Test.
Strengths: can do many subjects at once, minimal equipment needed, it has subjects working to their sub-max - not too stressful, easy to score/administer. Limitations: equipment is specific - bench of a set height, metronome set to a beat, specific to leg muscle and action/ not specific to a sport, set bench height favours taller participants, heart rate measure can be of varying accuracy
Explain the reason for elevated breathing in the first minutes after a swimming sprint.
The greater the intensity of the exercise, the greater the EPOC, initial stages of exercise, oxygen demand cannot be met by the aerobic system <oxygen deficit> OR initial stages are met by anaerobic processes, oxygen deficit is paid back after exercise/oxygen debt, alactic/fast component is replenished with <3-4 litres of> oxygen, ATP and CP/PC stores are replenished, myoglobin oxygen levels are replenished, aerobically metabolize lactic acid, resynthesize lactate to glycogen, replacement of muscle / liver glycogen stores
Compare and contrast the structure of fast-twitch (type IIa and IIb) muscle fibres.
Type IIa fast oxidative glycolytic vs Type IIb fast glycolytic. Myoglobin content: medium, low. Capillary density: medium, low. Fibre diameter: medium, large. Mitochondria: high, low. Sample activity: 400 m sprint, 100 m sprint.
Using an example from sport, apply the concept of psychological refractory period.
When a stimulus is closely followed by a second stimulus, the first stimulus must be cleared before the second can be processed OR S2 only becomes relevant when S1 is finished with, the delay in reaction time to a second stimulus is called the psychological refractory period, a performer/defender has to sort out new and correct stimulus, but first they have to disregard the old and now useless stimuli, which causes the delay, any other action/response must wait until the first response has been completed, eg, in soccer an attacker may lean to the left/fake/dummy to move the defender; this is S1, the defender will begin to respond (R1) to S1/ to the initial stimulus first, the attacker immediately moves to their right to beat the defender; this is S2, the defender cannot respond to S2 until they have completed R1 <therefore they appear to be slow and beaten by the attacker>
Explain the concept of angular momentum during the flight phase of a front somersault.
a rotating object has angular momentum about its axis of rotation, angular momentum = moment of inertia × angular velocity ‹about the axis of rotation›, moment of inertia of a rotating object can be changed by redistributing the mass of the object about the axis of rotation, angular momentum will remain constant unless the object is acted upon by an unbalanced ‹eccentric› force ‹from Newton's First Law of Motion›, gymnast rotates in median plane about a transverse axis through centre of gravity <about TAG>, whilst in flight there are no unbalanced forces/ momentum remains constant/ there are no additional forces being applied, tucking the body reduces moment of inertia <about TAG>, tucking, simultaneously increases angular velocity <about TAG>, increased angular velocity enables gymnast to complete front somersault quickly gymnast opens out body to increase moment of inertia <about TAG>, simultaneous decrease in angular velocity ‹in preparation for landing›
Explain how acetylcholine contributes to skeletal muscle contraction.
acetylcholine is the neurotransmitter/initiates muscle contraction. Allows electrical impulse to pass from the nerve to the muscle OR converts electrical impulse into a chemical message. Acetylcholine is produced in the cytoplasm of the terminal end/ stored in vesicles. Acetylcholine diffuses across the synaptic cleft. Binds with postsynaptic receptors/receptors at motor end plates. Acetylcholine increases the permeability ‹of sarcolemma› to sodium/stimulates the release of calcium ions
Describe how a glucose molecule forms a polysaccharide molecule.
addition of monosaccharides/glucose «molecules» form disaccharide «if two molecules»/polysaccharide «if many molecules»/glycogen. A condensation reaction takes place to form a disaccharide/polysaccharides/glycogen. Condensation polymerization/condensation reaction releases/removes a water «molecule» from the reaction. Glycogenesis is the formation of glycogen from glucose
Analyse the long-term effect of training on maximal oxygen consumption.
aerobic training is likely to cause a higher VO max than those with no training, anaerobic non-interval training is likely to have little effect on VO max compared to those with no training OR high-intensity interval training produces improvements in maximum oxygen consumption, activities where individuals have trained a greater area of muscle mass are likely to have a higher VO max, due to an increase in stroke volume/maximal cardiac output, increased oxygen carrying capacity/hemoglobin content, increased capillary density in muscles, increased mitochondrial density / increased arteriovenous oxygen difference, increased maximal minute ventilation/increased muscular endurance of respiratory muscles
Explain the relative contributions of the three energy systems during a hockey or soccer match.
all energy systems work in a continuum during physical activity depending on the intensity / duration / fuel availability / oxygen availability. ATP-CP System/PC system/alactic system: resynthesise ATP during brief high intensity exercise «for more than 3 seconds to less than 10 seconds» eg, in hockey/soccer when performing a sprint/explosive movement for the ball at speed 20-60 m. The lactic acid system / anaerobic glycolysis: resynthesise ATP during short/medium high intensity exercise «between 10s−2 mins range» eg, in hockey/soccer during transition of play such as a counter attack from defense. Aerobic system: hockey/soccer requires moderate/high intensity movements but is ongoing «more than 2 minutes». Used during recovery between high intensity bouts or during lower intensity periods eg, returning to the halfway line after a goal is scored
Describe how breathing is controlled during exercise.
an increase in CO causes a decrease in pH, decrease in pH is detected by the chemoreceptors, movement is detected by the proprioceptors, this stimulates the ANS to increase the depth of breathing, baroreceptors inform the ANS to increase the rate of breathing, the increase in rate of breathing causes the lungs to stretch further
Outline the concept of angular momentum occurring in the legs of an athlete sprinting on a track.
angular momentum = rotational / angular velocity x moment of inertia, angular momentum is conserved / stays «relatively» constant, the moment of inertia is larger when the body / leg has an increased radius, moment of inertia is reduced when the leg is bent, large moment of inertia = more difficult to move, smaller moment of inertia = easier to move, angular velocity is increased by bending the knee, therefore the recovery time is shorter <allowing the runner to take their next stride quickly>, angular velocity is reduced as the runner extends the knee
Compare the distribution of blood in a runner at rest and during a 10 000 m race.
at rest muscles receive approximately 20% of blood flow, organs receive approximately 80%. During exercise this increases to more than 80% of blood flow at the muscles and a drop of approximately 20% at the organs. At rest the blood will be more evenly distributed to regions such as brain, stomach, kidneys, muscles. Regions such as the stomach, kidneys will require relatively less during the race; Regions such as the heart, lungs and skin will require greater flow during the race. Vasodilation increases at regions requiring greater blood flow/vasoconstriction increases at regions not requiring blood flow. As the athlete is finishing the race the working muscles will be demanding the greatest percentage of their total body flow.
Explain the mechanics of pulmonary ventilation in the human lungs during high intensity exercise.
breathing in: external intercostal muscles contract OR rib cage moves upwards and outwards. Diaphragm flattens/contracts. Additional muscles can also be involved such as the trapezius, sternocleidomastoid/scalene/pectoralis minor/back muscles. Thoracic cavity volume increases/lungs increase in size/capacity. Thoracic cavity pressure decreases (therefore air rushes in). Air rushes in from high pressure to low pressure/inhalation continues as long as the pressure difference exists. Breathing out: external intercostal muscles relax. Internal intercostal muscles contract OR rib cage moves down and inwards actively. Diaphragm relaxes. Additional muscles required when working during high intensity exercise would include abdominals/rectus abdominis/external obliques (which act to force air out faster). Thoracic cavity volume decreases. Thoracic cavity pressure increases (therefore air is forced out). Depth and rate of breathing increase during high intensity exercise due to chemoreceptors/proprioceptors/stretch receptor stimulation
Analyse the contraction of skeletal muscle after the release of calcium ions from the sarcoplasmic reticulum.
calcium binds to troponin, changing its shape to expose the active site OR exposes active sites on actin, cross-bridges are formed with myosin binding with actin, ATP binds to myosin heads causing them to detach from binding sites, ATP is broken down so that the myosin head can recock to new position <storing potential energy from ATP>, myosin then reattaches to a new active site further along the actin filament, ADP+Pi are released and the myosin head drags actin along myosin filaments (known as the power stroke), sarcomere shortens (Z line shortens and H zone disappears / shortens), repeated attachments and power strokes cause the filaments to slide as long as calcium ions are present
Describe the recommended relative contribution of macronutrients in a healthy balanced diet.
carbohydrates are primary energy source «40-70%», carbohydrates provide 4 calories per gram / 1760 kJ per 100 grams, proteins contribute a smaller amount «10-30%», proteins provide 4 calories per gram / 1720 kJ per 100 grams, lipids make up a relatively small amount of intake «10-30%», fats provide 9 calories per gram / 4000 kJ per 100 grams, recommendations vary by country / age / gender / height / weight / RMR /activity level, calorie intake should be 2000-3000 for males and 1600-2400 females, there is much contention about recommended ranges
Outline the re-synthesis of ATP by the ATP-CP system.
creatine phosphate/CP/PCr is a high-energy molecule/fuel, speed of breakdown is increased by creatine kinase, CP is broken down to provide a phosphate molecule for the re-synthesis of ATP/ energy released is used to add Pi to ADP «endothermic reaction», reaction is a coupled reaction where one reaction is linked to another reaction, releases energy «exothermic reaction» and phosphate molecule/Pi, 1 PC = 1ATP, does not require oxygen, is the first system to provide ATP / occurs in the first 10-15sec of exercise
Describe the phenomenon of oxygen deficit.
deficit is calculated as the difference between the oxygen required for a given rate of work and the oxygen actually consumed, deficit takes place during the initial stages of exercise, muscles generate ATP through anaerobic pathways, oxygen transport system is not immediately able to supply the needed quantity of oxygen to the active muscles OR oxygen consumption requires several minutes/time before a homeostatic levels is reached, homeostatic level is reached when the aerobic system meets the demands, is repaid after exercise is finished
Outline the process of glycogenolysis.
defined as the removal of glucose units from glycogen, producing glucose-1-phosphate OR defined as the breakdown of glycogen to glucose, glycogen is stored in the liver, glucagon acts on the liver to stimulate glycogenolysis, insulin inhibits glycogenolysis, requires enzymes for optimal function OR phosphorylase is the main enzyme, it provides a rapid rate of production of glucose-6-phosphate, adrenaline is released during the fight or flight system, which also stimulates glycogenolysis to raise glucose levels, glucose is taken up by the muscle cells, where glycolysis takes place, involves a hydrolysis reaction
Explain how characteristics of type IIb muscle fibres could enhance the performance of a sprinter.
greater fibres per motor neuron therefore more fibre recruitment per contraction. Fast motor neuron conduction transports action potential quickly. A highly developed sarcoplasmic reticulum helps spread the action potential across the muscle fibre quickly. «therefore» delivery of calcium is increased to the muscle cell. «therefore» the contractile speed is fast. High PC and ATP stores provide an immediate source of energy for fast muscle contraction. High glycogen stores provide energy for high intensity movements. Have a high anaerobic capacity «which is important for sprinters». Can produce an explosive performance «which is required at the start of the event»
Outline two named methods of memory improvement.
rehearsal, information is processed mentally or physically, Coding, labelling sets of information to make it easier to access, Brevity, giving a learner a small amount of information at a time to avoid overload, Clarity, keeping learning / teaching simple at the beginning, avoiding to teach / learn similar but distinct items in the same session «to avoid interference with the memory of the other», Chunking, learners retain more if the information is chunked «instead of being presented as individual items», Organization, we remember more easily if we organize the way in which we are to learn and ensure that the information is meaningful, Association, ensuring that new learning is linked to what players already know, Practice, establishes memory trace/pathway
Outline three types of transfer that a sports coach needs to take into account when planning a practice, with reference to sporting examples.
skill to skill/between two skills eg rugby union to rugby league OR basketball to netball OR tennis to badminton. Practice to performance/positive transfer likely only to occur if environmental conditions are similar in both situations/authentic/realistic practice. Eg attack versus defence at set plays in soccer. Abilities to skills. Eg balance to balance on the beam in gymnastics. Bilateral/limb to limb/positive transfer of learning and training occurs between limbs «hand to hand, leg to leg». Eg striking a football with the right/left foot OR reverse sweep in cricket. Principles to skill. Eg principles of defensive play in invasion games such as soccer and field hockey. Stages of learning/stage to stage. Eg skills that are learned in the cognitive phase of named activity will develop until the associative stage of named activity
Explain sliding filament theory after acetylcholine (ACh) increases muscle membrane permeability.
sodium ions/Na enter the muscle and change the polarization in the myofibril the sarcoplasmic reticulum releases calcium ions, calcium ions bind to troponin, Tropomyosin/troponin complex exposes the binding site «on actin», myosin «head» creates a cross-bridge with the actin, power stroke takes place, z lines come closer together / H zone gets smaller, myosin releases actin if new ATP appears, myosin head reattached further down the actin filament repeating the cycle <called the ratchet mechanism>, process goes on until acetylcholine-esterase breaks the acetylcholine down
Explain how the mechanics of exhalation change from rest to exercise.
stretch receptors initiate exhalation, the diaphragm and/or <internal> intercostal muscles contract more forcefully, accessory muscles are required to pull the rib cage in during exercise, the rib cage moves downwards and inwards further when exercising, increasing the depth of breathing, the rate of breathing is increased, the thoracic volume decreases further, the thoracic cavity pressure raises higher than at rest, air rushes out faster due to a greater difference between the lungs and the atmosphere
Describe the role of stretching in a general training programme.
stretching is a useful component of a warm up before an exercise session/cool down after exercise, stretching may be used as part of a general flexibility training programme, to improve the range of motion at a joint/improve performance, reduce injury risk ‹in long-term›, static stretching is when the limb is moved slightly beyond the terminal position slowly and then maintained in that position ‹eg for 10-30 seconds›. Dynamic stretching involves movement based activities within a comfortable range of motion / these are active and simulate exercise in the muscle. Ballistic stretching involves bouncing movements to achieve the terminal range of motion ‹not recommended›. PNF stretching involves combination sequences using relaxation and contraction of the muscles being stretched. Recent research questions the effectiveness of static stretching as a necessary component of the warm-up. There is little, if any, evidence that stretching pre- or post-participation prevents injury or subsequent muscle soreness. Research indicates that lengthening a muscle may inhibit its ability to transfer force in power events. Static stretching has also been shown to lead to a decrease in force production, power performance, running speed, reaction and movement time, and strength endurance. Warm up to include dynamic exercises/stretching to increase muscle temperature/loosen-up muscles and stimulate blood flow. Dynamic stretching does not seem to elicit the performance reduction effects of static and PNF stretching/ based on current evidence, dynamic stretching would be the preferred option for stretching during a warm-up
Describe five features of a synovial joint.
synovial membrane: lines the inside of the capsule / produces synovial fluid, bursae: sacs of synovial fluid / located in areas where there is a lot of friction, meniscus: crescent-shaped pad of cartilage prevents wear / rubbing / provides Cushioning, ligaments: connect the bones of a joint / provide stability, articular capsule: strong tissue enveloping the joint / blends into the periosteum / gives the joint stability / stops unwanted material getting into the joint area, articular cartilage: smooth cartilage that reduces friction / that is on the end of the bones <of the joint>, synovial fluid: fluid that lubricates the articular surfaces / forms a cushion / provides nutrients for the cartilage / absorbs any debris / fluid inside the capsule
Outline how the Bernoulli principle affects a golf ball in flight.
the Bernoulli principle explains how relative air pressure «from backspin», around a golf ball means that it experiences a lift force and travels further through the air, as a golf ball travels with backspin, it experiences higher air pressure on the bottom of the ball and lower air pressure on the top of the ball, the ball/object is attracted to the area of lower air pressure, which is above the ball and therefore experiences lift, the lift force is perpendicular to the direction of the airflow, the faster the ball travels / spins, the greater the differences in relative air pressure and therefore the greater the lift force, the dimples on the golf ball encourage small turbulent air, which protects the ball against drag force, a ball struck off «laterally» centre will spin in the air, therefore creating lower relative air pressure on one side and generating curve
Apply Newton's second law of motion to the distance travelled by a golf ball after being struck.
the acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, and inversely proportional to the mass of the object OR F = ma, the ball will travel in the same direction as the direction of the net force applied to the ball, when the club contacts the ball, the change in momentum of the club is transferred to the ball/conservation of momentum, the greater the change in momentum of the ball, the longer distance the ball will travel OR the greater the impulse applied to the ball, the longer distance the ball will travel, larger clubs /club with greater mass will generate a greater force and therefore propel the ball further OR a lighter golf ball will accelerate faster when struck by the golf club
Outline how Bernoulli's principle acts on the discus whilst in flight.
the discus acts as an aerofoil, the angle of flight of the discus causes air to travel faster over the top, air pressure is lower above the discus, difference in air velocity creates a differential pressure above and below the discus, lift is generated as a result of the pressure gradient, flight of discus becomes horizontal at apex of flight, when the pressure is equal above and below the discus, unbalanced forces acting on the discus <eg, gravity> cause the angle of the discus to change, so, air travels slower on the top, causing a pressure gradient, discus accelerates towards ground, creates an asymmetrical flight path
Explain how the application of Newton's third law of motion enables an athlete to run uphill.
the player applies force by extending his/her legs against the ground/pushing back against the ground/earth, the force from the extension of the legs is the action OR the action force is caused by muscle contraction, the ground/earth exerts an equal and opposite force on the athlete, the push back from the ground/earth is the reaction because the ground/earth is a larger mass than the mass of the athlete, the effect on the athlete is greater than the effect on the ground/earth, the result of the reaction force is to displace the relatively small mass of the athlete/produces the uphill movement of the athlete, the faster/harder the athlete pushes «action» the greater the force will be
Distinguish between the Fosbury Flop and the scissors technique in terms of the position of the centre of mass of the jumper.
the position of the centre of mass ‹centre of gravity› of a body or object is the point at which the mass and weight of an object are balanced in all directions/if the object was suspended from that position it would be balanced; the centre of mass moves in an object if the shape of that object is altered. Fosbury Flop: the athlete bends their body like a banana around the bar and their centre of mass is below and outside the body/may be below the bar OWTTE. The jumper using the Fosbury technique will therefore not have to raise their centre of mass as high as an athlete performing the scissors when clearing the same height. Using the Fosbury technique the jumper will be able to clear a higher bar compared to using the scissors ‹all other things being equal›. Scissors: the upper body is upright and the legs are horizontal to the body - this puts the centre of mass above the legs/hips/bar. The distance between the centre of mass of the athlete and the greatest height cleared is generally 25-30cm.
Analyse the distribution of blood during maximal exercise.
ANS/sympathetic nervous system shunts blood from an area of low demand to high demand. Redistribution increased to 80-85 % blood flow (Q) to the «working» muscles. Causes a reduced blood flow to kidneys/liver/stomach/pancreas/intestines OR 15-20 % blood flow / Q to non-essential organs. Blood flow to the brain remains constant/slightly lower. Vasodilation «of arterioles» in the «working» muscles OR local dilation substances prevent vasoconstriction of the muscle tissue. Vasoconstriction «of arterioles» in the organs. Constriction of pre-capillary sphincters to the organs. Dilation of pre-capillary sphincters to the «working» muscles. If the body starts to overheat as a result of exercise or high environmental temperatures more blood is redirected to the skin . The percentage blood flow to the heart remains the same at rest and during exercise OR in absolute values the heart receives greater volumes of oxygen as exercise intensity increases
Discuss the key principles of training programme design for resistance training.
Progression: A programme needs to gradually increase in its demands beyond the current load in order to gain improvement. Overload: To train harder/ place systems under greater load than normally encountered ‹can be achieved through adjusting frequency, intensity and duration›. Specificity: Involves training the muscles, energy system and skills that you will need and use in your sport. Reversibility: If you don't train or cannot train at all, you will gradually lose any gains you made from your training. Variety/Tedium: Having variation in your training programme can help an athlete keep motivated/can prevent the athlete plateauing in their fitness/prevents tedium. Periodization: The organisation of the training into distinct periods where specific components are done first before others in order to maximize the training effect. Frequency: The number of trainings per week. Intensity: How hard you are working/calculated a variety of ways such as from working heart rate and comparing to HR max, perceived exertion. Duration: Can refer to the length of a training session or the length of a training programme. For example: progression ‹eg when set number of reps is being surpassed›/increasing the load being used and not staying on the same level of resistance›, overload ‹frequency, intensity and duration› ‹eg increase sessions per week/split programme, increase weight/sets›, specificity ‹eg specific program to desired goal ie power/maximal strength/lean body mass/ training should be specific and planned for the individual performer/needs analysis›, reversibility ‹eg effects of training will be lost should cessation of programme occur›, variety/tedium ‹eg vary exercises targeting muscle groups›, Periodization ‹eg doing a general resistance training programme for the first few weeks of the programme to allow the body to adapt to the training›, intensity eg ‹use the weight lifted as a percentage of rep max as a way to monitor and increase intensity›, frequency eg ‹athletes should give muscle groups 24 to 48hr rest between bouts/athletes must train several times a week›, duration ‹eg will vary depending on the muscle groups being worked/no. Of exercises in a session/the programme needs to be maintained for a good length of time/months in order to see the benefits›
Analyse how rehearsal and organization improve memory in a sporting routine.
Rehearsal: by practising the sequence as much as possible they can become overlearned. This means that they become automatic and therefore effective in establishing a memory trace. However this requires time and may not be accessible to the performer. Therefore other methods such as mental rehearsal may be required. Organization: the sequence can be organized in meaningful ways to help learn and remember them more easily. For example ensuring that the movements are practised in sequence so the end of one movement is followed by the start of one movement. Verbalizing the routine as it is organized may also assist the learner to memorize the routine. Organization of the routine still requires rehearsal and therefore in isolation may not be the only method
Explain how skeletal muscle contracts once a muscle fibre has been stimulated by a neurotransmitter using the sliding filament theory.
depolarization of the motor end plate travels throughout the muscle via the transverse tubules/neural impulse action potential/muscle action potential, calcium ions are released from the sarcoplasmic reticulum, calcium binds to troponin, changing its shape/moving tropomyosin from the active site of the actin/exposes active sites on actin, actin and myosin bind together forming a cross-bridge, myosin head tilts toward the arm of the cross-bridge, the breakdown of ATP releases energy, myosin head drags actin and myosin filaments in opposite directions/performs a power stroke, pulling of the actin filament past the myosin results in muscle shortening/sarcomere shortening/Z line shortens, shortening of the sarcomere occurs along the entire length of every myofibril in the muscle cell, pulling of the myosin head results in the generation of force, immediately after the myosin head tilts, it breaks away from the active site, rotates back to its original position, and attaches to a new active site further along the actin filament, the myosin head detaches from the actin when an ATP molecule binds to the myosin head, the ATP is then broken down and the myosin head can again attach to an actin binding site further along the actin filament, repeated attachments and power strokes cause the filaments to slide/contract past one another, process continues until the ends of the myosin filaments reach the Z disks, H-zone disappears ‹and thus shortens›at rest, troponin holds the tropomyosin in position to block the myosin-binding sites on actin filaments
Describe the mechanics of inspiration in the final stages of a cycling race.
diaphragm contracts OR flattens. «external» intercostal muscles contract. Raising the rib cage upwards and outwards. This increases the thoracic volume. This decreases the thoracic pressure. Final stages of the race accessory muscles contract (eg, pectoralis minor, sternocleidomastoid and scalenes) increase (thoracic) volume further.
Outline the types of movements and muscle contraction at the knee joint when a soccer player kicks a soccer ball.
during the upward motion/preparation phase/hamstring curl the joint action is flexion, during the downward motion/action phase the joint action is extension, during the upward motion/preparation phase/hamstring curl the hamstring contracts concentrically/is the agonist/the quadriceps relaxes/is the antagonist/eccentrically OR during the upward motion/preparation phase/hamstring curl the quadriceps relaxes/is the antagonist/eccentrically during the downward motion/action phase quadriceps contracts concentrically/is the agonist while the hamstring relaxes/is the antagonist/eccentrically, motion occurs as a result of reciprocal inhibition of muscle pairs
Describe the role of acetylcholine in stimulating muscular contraction.
ends of axon terminals contain synaptic vesicles filled with chemical neurotransmitters, space between the axon terminal and sarcolemma is the synaptic cleft, synapse formed between axon terminals of a motor neuron and the motor end plate of a muscle fibre is known as the NMJ, arrival of nerve impulse at the synapse triggers release of acetylcholine, acetylcholine diffuses across the synaptic cleft ‹between motor neuron and motor end plate›/acetylcholine binds to receptors in the sarcolemma/motor end plate, binding of acetylcholine ‹to its receptors in motor end plate› opens ion channels, open ion channels allow sodium ‹Na › to flow across membrane, inflow of sodium ‹Na › generates muscle action potential, each nerve impulse generates one muscle action potential, if another nerve impulse releases more acetylcholine, then repeat, effect of acetycholine lasts only briefly, acetylcholine is rapidly broken down in the synaptic cleft, acetylcholine rapidly broken down by an enzyme called acetylcholinesterase, the action potential travels through the muscle and down the t-tubes, this causes the release of Ca ions, Ca ions opens the binding sites on actin/ exposes the binding sites as part of the troponin, tropomyosin complex, myosin cross bridges move towards these sites to cause the muscle to contract
Explain the mechanics of exhalation in the human lungs during the initial stages of submaximal exercise.
exhalation occurs when pressure in lungs is greater than pressure of atmosphere, exhalation results from elastic recoil of chest wall and lungs ‹passive process›, rib cage moves downwards and inwards, exhalation begins when diaphragm relaxes, ‹diaphragm relaxes›, decreasing volume of thoracic cavity, lung volume decreases and alveolar pressure increases to about 762 mmHg, air flows from area of higher pressure to lower atmospheric pressure, exhalation ends when pressure balances equal ‹alveolar to atmosphere›, exhalation only becomes active during moderate to high intensity exercise OR muscles of exhalation ‹abdominals an internal intercostals› contract during moderate to high intensity exercise
Distinguish between fibrous, cartilaginous and synovial joints.
fibrous: no synovial cavity, bones held together by fibrous connective tissue, connective tissue contains collagen fibres, no or very limited movement. Cartilaginous: no synovial cavity, bones held together by cartilage, limited movement ‹compared to fibrous›. Synovial: synovial cavity, bones forming the joint are united by a surrounding articular capsule, ‹bones forming the joint are united by a surrounding articular capsule› and often by accessory ligaments, a greater range of movement ‹compared to cartilaginous and fibrous›, presence of synovial fluid inside joint capsule
Using an example, analyse conditions for acceleration.
force is proportional to acceleration / F=ma OR more force yields greater acceleration, eg kicking harder/application of more force increases the acceleration of a ball, mass is proportional to the force / m = OR smaller mass yields greater acceleration with application of the same amount of force, eg decreasing the weight of gear in cycling allows for more acceleration when the same force in pedaling is applied, longer application of the same force causes greater acceleration, acceleration occurs in the direction of the force
Discuss the process of gaseous exchange at the alveoli during exercise.
gases diffuse across the alveoli membrane, the membrane is very thin / one cell thick to allow this movement, movement is from high to low partial pressure/concentration, oxygen partial pressure / concentration is higher in air breathed in compared to blood, carbon dioxide has higher partial pressure / concentration in blood compared to lungs, greater volumes of gases diffuse across the alveoli membrane when Exercising, the diffusion gradient in alveoli is maintained by ventilation
Describe the cardiovascular adaptations resulting from endurance training.
increased left ventricular volume / increased stroke volume so that it pumps more blood per beat, lower resting heart rate as the heart is stronger from training doesn't need to work so hard at the same level, lower exercising heart rate when working at the same load as when untrained increased arterio-venous oxygen difference so the muscles are able to extract a greater volume of oxygen from incoming blood, larger and more numerous mitochondria in trained skeletal muscle to produce more aerobic energy/ assist with recovery, increased level of aerobic system enzyme activity so it can create more ATP / energy, increased ability of the muscle to mobilize, deliver and oxidize lipid to prevent glycogen stores from running out, increased glycogen storage in the muscle due to increased muscle size / efficiency, increased capacity for glycogenolysis so you are able to turn more glycogen into glucose for ATP production, slight cardiac hypertrophy/increase in heart size due to training of the heart muscle, increase in blood ‹plasma› volume to support the bodies sweating needs and due to the increase in blood cells / maintain viscosity, increase in cardiac output as the heart is stronger/ larger so the heart can potentially pump more blood in a minute, increase in capillarization which will mean that greater volumes of blood /oxygen can be transported to muscle, increase in blood volume/RBC which means blood can carry more oxygen
Explain the role of insulin in the body.
insulin is released from the pancreas when blood glucose is high/when blood glucose levels increase after eating, insulin helps to maintain a stable/normal level of blood glucose, inhibits gluconeogenesis, insulin inhibits glucagon, inhibits lipolysis, promotes glycogenesis, insulin promotes the uptake of glucose into fat cells, it encourages an anabolic reaction
Describe how cardiovascular drift occurs during a marathon.
is an increase in HR during prolonged exercise. Blood volume is reduced through sweating OR increased blood viscosity therefore causing a reduction in venous return. Stroke volume is directly affected by venous return OR reduction in stroke volume/SV. HR × SV = Q/ cardiac output is the product of HR times SV. The compensation takes place to help maintain cardiac output during exercise. Exercise in a hot environment exaggerates cardiovascular drift OR dehydration contributes to cardiovascular drift. As blood is redirected to the skin to help temperature regulation
Outline the characteristics of muscle.
is controlled by nerve stimuli, is fed by capillaries. Contractility: ability to generate force / create tension. Extensibility: ability to be stretched beyond its normal resting length. Elasticity: ability to return to resting length after it has been stretched. Atrophy: a decrease in myofibrils / fibre diameter due to a lack of physical activity. Hypertrophy: an increase in myofibrils / fibre diameter due to an increase in activity/training
Analyse the movement taking place at the figure skater's shoulder when moving from Position A to Position B.
joint is a ball and socket joint, movement is adduction, agonist pectoralis major and/or latissimus dorsi, antagonist deltoid, concentric contraction of the agonist, third-class lever
Explain how the Bernoulli principle applies to a ball sport.
lift force component acts perpendicular to drag OR lift force acts perpendicular to direction of motion, the lift only occurs if the object is spinning OR the lift only occurs if the object is perfectly symmetrical, lift force is produced by any break in the symmetry of the air flow about an object, when a body or object is rotating while moving through the air ‹eg a spinning ball› the air is dragged around the rotation of the ball, this causes an increased velocity on either the top or bottom of the ball and decreased velocity on the other, the relationship between air flow velocity and air pressure is an inverse one, and is expressed in Bernoulli's principle, a spinning ball creates areas of different pressure a ball will move towards the low pressure region of a rotating ball, for example, top spin ground stroke in tennis: because the rotation of spin is in the same direction as the movement of air particles at the bottom of the ball, this increases velocity at the bottom of the ball causing a low pressure area at the bottom, the top of the ball is subsequently a high pressure area the horizontal drag force caused by the movement from low to high pressure sees the ball drop. The aim of this form of spin is to hit the ball with pace but see it land within the boundary designated by the court. This is opposite to the lift force generated when a golf ball is struck
Explain the concept of reciprocal inhibition occurring at the knee when kicking a ball.
muscles work in opposing/antagonistic pairs/groups. A contracting muscle/prime mover is the agonist. The relaxing muscle/muscle that opposes the action is the antagonist. When an agonist is stimulated the antagonist neuron is inhibited. Example for knee: During the preparation phase/flexion at the knee: hamstring group is acting as the agonist, quadriceps is acting as the antagonist. As the leg extends at the knee/action/execution phase: quadriceps is the agonist, hamstring is the antagonist
Using examples, discuss two ways overload could be applied to an endurance training programme.
overload involves increasing intensity eg when running increasing target heart rate from 70% maximum HR to 75% maximum HR. Overload involves increasing duration eg when running increasing training time from 20 minutes to 30 minutes. Overload involves increasing frequency eg increasing training frequency from three times a week to five times a week
Using examples from team sports, evaluate the concept of the psychological refractory period (PRP).
psychological refractory period/PRP is the increase in reaction time to a second stimulus caused when the second stimulus has been delivered while the performer is responding to the first stimulus OR it is the time delay in reaction time caused by the arrival of a second stimulus before the first is processed, this is believed to take place due to brain processing information on a single track/using the single channel mechanism, in sports you can use PRP as an advantage by introducing a dummy stimulus before the real movement, Strengths: can be used to help a performer have greater chances of success eg pretending to pass / run one direction then quickly changing to pass / run the other way, provides a performer with a greater range of options in their play, external noise eg other players calling, or crowd noise can enhance the effectiveness of the PRP, the more options that a player has will increase the reaction time to the stimulus <Hick's law>, Limitations: if a performer uses it too often, they will become predictable and this limits Success, PRP may be reduced by anticipation / early cue detection / effective coach analysis / practicing «open» skills, anxiety might make the performer get the timing wrong and thus the PRP is not effective
Outline how the centre of mass can be used to enhance performance in a sport.
the terms centre of mass and centre of gravity are often used synonymously OR the centre of gravity refers only to the vertical direction ‹of the force of Gravity› the centre of mass is the mathematical point around which the mass of a body is evenly distributed OR the balancing point of the body the centre of mass depends on the distribution of the material in the body or object, the centre of mass is a theoretical point whose location may change from instant to instant during a movement OR the change in position of the centre of mass results from the rapidly changing positions of the body segments during movement, the centre of mass does not have to be inside the limits of the body, the centre of mass will be affected by the density of the body or object and also by its shape. For example, in weight lifting: the centre of mass is lowered the body is in a reverse "C" shape with the centre of mass essentially outside the body this position allows for maximal leg drive ‹summation of force›, and leverage to allow the elbows to be located below the bar for the final lift above the head. Fosbury Flop: the athlete bends their body like a banana around the bar and their centre of mass is below and outside the body/may be below the bar OWTTE, the jumper using the Fosbury technique will therefore not have to raise their centre of mass as high as an athlete performing the scissors when clearing the same height, using the Fosbury technique the jumper will be able to clear a higher bar/ athlete will more easily clear the bar
Apply Newton's third law of motion when a sprinter starts a race from the blocks.
the third law states: for every action, there is an equal and opposite reaction. Must push backwards and downwards with large forces on to the blocks (action force). According to Newton's third law, the blocks will push back with the same force, but in the opposite direction ‹forwards and upwards› (reaction force). As the blocks are connected to the ground ‹which has a much larger mass than the athlete› the ground will not move backwards, but the athlete will move forwards and upwards out of the blocks.
Define the term overload as a principle of training.
to train harder than you have previously
Outline the role of hemoglobin in the transportation of gases in the body of a trained athlete.
transports oxygen in the red blood cells, transports carbon dioxide in the red blood cells, carries oxygen from the lungs which has diffused across the tissue membranes (down a concentration gradient), carries carbon dioxide from the working tissues to the lungs to be expired, carries oxygen from the lungs to the working tissues to be used, hemoglobin has a high affinity for oxygen, higher amounts of hemoglobin will be found in a trained athlete.
Discuss how maximal oxygen consumption data can vary with different modes of exercise in the same individual.
variations in VO max during different modes of exercise reflect the quantity of activated muscle mass, there is more muscle mass activated during treadmill running compared to either cycling or arm ergometry OR there is more muscle tissue activated during cycling than arm ergometry, treadmill running produces the highest VO max values compared to either cycling or arm ergometry, cycling produces higher VO max values compared to arm ergometry, arm-crank exercise test achieves only approximately 70 % of treadmill VO max scores, competitive cyclists pedalling at their fastest rate achieve scores equal to their treadmill VO max scores OR trained status in an exercise mode can influence VO achieved ‹for example a sailor who grinds may actually have a very high VO2 max with arm ergometry›
Outline the chemical control of ventilation during exercise.
ventilation is «chemically» regulated by blood acidity levels/low pH, blood acidity levels increase/pH drops due to an increase in carbon dioxide Levels, blood acidity levels are detected by chemoreceptors, medulla oblongata/ANS/respiratory control centre receive information from Receptors, increased blood acidity «and information from the proprioceptors» increases the depth / rate of ventilation
Define Newton's second law of motion.
when a force acts upon a mass, the result is acceleration of that mass/force = mass × acceleration OR acceleration is proportional to the force acting upon the mass and inversely proportional to the mass of the object OWTTE. Do not accept f = m × a
