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PHYSICAL EDUCATION. ACHIEVEMENT STANDARD 3.2. DUATHLON TIMES. 2.5KM RUN…8KM BIKE…2.5KM RUN. WHAT THIS STANDARD INVOLVES. Task Preparation
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PHYSICAL EDUCATION ACHIEVEMENT STANDARD 3.2
WHAT THIS STANDARD INVOLVES • Task • Preparation • This assessment activity requires students to choose a discrete physical skill performed by self or others for analysis. Students may wish to work with and observe another student’s chosen skill in order to collect information for this analysis. The student should collect digital media evidence of the performance at the start of the unit of work to ensure they have accurate documentation on which to base appraisal and feedback/feed forward, with the aim of improving their own or partner’s performance. • The student will have to investigate and devise a detailed checklist of the parts/movements of the chosen skill against which they can assess their own or partner’s performance. (An ideal performance) This checklist should include information on the: • Preparation phase • Action phase • Recovery phase.
Analysis and presentation • Prepare and present your analysis of your own or partner’s performance of the chosen discrete skill • Your presentation should include: • A breakdown of the skill into its component parts and a comparison with the ideal. This should be broken down into phases (such as preparation, action, recovery) and could consider where parts of the body start and finish, joint position, anatomical movement and the muscles involved, the path of the body/projectile/object, speed in relation to accuracy, and so on • A biomechanical analysis (deconstruction) of the skill. Consider the strengths and weaknesses of the performance as identified above, explaining them in depth using appropriate biomechanical principles. • Feedback and feed forward that would enable you or your partner to improve the execution of the skill. There should be a clear relationship between your biomechanical analysis and your feedback/feed forward. An understanding of how biomechanical principles interrelate to improve performance should also be evident. • A conclusion, in which you consider which parts of the skill have the greatest impact on performance and which principles (if applied) potentially have the greatest influence on performance. You may even wish to question/challenge the worth of a biomechanical analysis in improving performance as well as considering other factors that might influence improvement.
Your presentation should be supported with evidence, which could include: • a range of qualitative information (explanations based on theoretical knowledge from observations) and/or quantitative information (numerical data from observations) • digital/visual media (for example, video clips, diagrams, photos) • notes taken when observing your partner (for example, biomechanical principle(s) applied, feedback/feelings from partner). • Everything in your presentation must be in your own words.
The shoulders are curved, they are facing the opposite direction to the target Ideal Preparation The wrist is in a neutral position that is comfortable with one or two fingers under the lip of the disk with the thumb on top not over-cocking the wrist with a firm grip The arm is cocked and is close to the torso The other arm is bent to increase stability The back is straight, not curved The disk is in line with the pectorals The trunk is slightly flexed, to a 30 degree angle The torso is facing the complete opposite direction to the target The weight is almost completely on the back foot Back foot Front foot The knees are flexed, the back one is only flexed to about 100 degrees but the front knee is only flexed to about 170 degrees The feet are pointing 45 degrees away from the target The stance is quite wide, wider than shoulder width Target
WORKING IN GROUPS-BRAINSTORMING ON THE BOARD-GENERALISED WORDING OR PHRASES • TYPES OF MOTION • FORCE AND BODY LEVERS • TORQUE • FORCE SUMMATION • STABILITY • NEWTONS LAWS OF MOTION
Front view of the over head hit Ideal performance technique of the over head hit My initial performance of the over head hit
Initial Performance (Front On) Ideal Performance (Front On)
Initial Performance (Side On) Ideal Performance (Side On)
This student is comparing the ideal performers knee movement in the preparation phase….(because his performer fails to do so…) ……therefore bending of the knees is required. The knee joint is a synovial hinge joint that allows movement of the entire leg. Movement in the knee joint occurs when the proximal end of the tibia articulates with the distal end of the femur. These two bones are attached by ligaments however it is the muscles that allow the bones to articulate. The origin is the place at which the muscle is attached to the stationary bone and the insertion is the place where the muscle is attached to the moving bone. Flexion of the knee joint will result in greater stability, for this to occur the angle of the knee joint must decrease. It does this by antagonist muscle action. When flexion takes place, the hamstring (biceps femoris) is the agonist as it is contracting during the movement while the quadriceps (combined from the rectus femoris, vastuslateralis, vastusmedialis and the vastusintermedius) is the antagonist as it is relaxing……… This is just an example of the depth we are looking for.
Preparation My trapezium is not engaged and causing flexion in my shoulder meaning I am not ready to react and move the racquet behind me to get it into a position so that I can extend/abduct my shoulder and hit the shuttle and also it moves my line of gravity away from my B.O.S. leaving me unstable My torso is bent forward putting pressure on my back which can damage it if I over exert and also it is harder for me to suddenly move back as my body is naturally tending to move forward in this position because of my line of gravity is in front of my B.O.S. The angle of the racquet is to low meaning I will have to flex my elbow so that I can quickly extend it to get the power I need out of my clear where if it was already flexed then I would be ready to straight away extend and hit the shuttle As my knees are extended then also my centre of gravity is high and unstable not giving me the right support or engaging the right muscles to suddenly react and move quickly to get into position to perform and overhead clear as I am not as stable and balanced Compared to Mr Hose my knees are too extended and are not allowing much more extension which means I will not be able to react as much or put as much force through my quadriceps to move myself around the court
My racquet and hand is still too low meaning my elbow is not fully flexed and ready to engage the tricep brachii to extend and power my radius and ulna to hit the shuttle. My torso is still bent forward which shows I have not had time to react and move backwards as standing in this position does not allow me to suddenly move backwards as I would be moving against my centre of gravity My hand is to low which effects the other side of my body and hinders its power/performance of rotation where it should be pointing towards the shuttle to gain better aiming and power My torso is parallel to the net therefore it will not be able to produce rotation of the trunk to allow for more power to clear the shuttle further My feet are flat on the ground where they should be bent allow the ankles to be in dorsiflexion ready to create the opposite movement (plantar flexion) and spring myself into position wherever I need to be My knees are not flexed enough which as well as hindering the flexion in my ankles also means that the hamstrings are not properly engaged so that I can then contract my qaudriceps to cause extension and jump up to hit the shuttle which provides more power and allows me to move more quickly around the court
My elbow is still not fully flexed which will not allow for maximum extension of the lower arm which means my shot will not be as powerful as possible as I can not move my radius and ulna towards the shuttle with the speed needed My shoulder is still not flexed therefore it is not ready to engage the pectoralis major and anterior deltoid to create enough speed through extension/abduction of the upper arm (humerus) toward s the shuttle so that I can perform a powerful clear My knees are not flexed properly which means my hamstrings are not engaged therefore my quadriceps are not properly acting as my antagonist muscles and are not ready to contract and power my self up into the air to hit a more powerful clear My base of support is very small which means my line of gravity will not be inside of it making me unstable and unable to support myself as well as I could so not allowing me to hit a powerful and successful overhead clear Also my hip could be slightly hyper extended so that I could create a little bit of flexion from my hip while still travelling up to the shuttle with my torso which would mean the gluteal muscles would be the main agonist muscles in this extension phase allowing me to be ready to engage the iliopsoas muscle which when used in force summation with the rest of the muscles can create an even more powerful shot
Performance Stages - Action • Footwork and body/racquet position • During the action phase at first you need a low centre of gravity which is based over your base of support which will allow you to be composed and balanced. By having a wide base of support it will make it much easier to keep you line of gravity within it and because you have a good balance you will be able to drive up with your legs and jump high and where you want without losing balance which will allow you to use your velocity as extra speed to hit the shuttle with and clear it further towards the back of the court. • As well as this by being on your toes it allows you to be responsive and have a much more powerful jump as your ankles will be in dorsiflexion therefore able to suddenly engage the gastrocnemius muscle as the agonist to cause sudden plantar flexion of your ankles and push you further and faster into the air. You must make sure that your knees are bent allowing you to be on your toes while still being in dorsiflexion of the ankle otherwise if they were not bent you would have to be in plantar flexion to be on your toes which would not allow you to extend your ankle anymore to provide a better jump/thrust into the air. • Also just as you hit the shuttle your line of gravity should be just in front of your base of support so that when you drive up you also drive forwards to the ball which as well as producing extra speed of the racquet hitting the shuttle to power it further to the back of the court it also allows you to be already moving towards the centre of the court where you should always recover therefore it aids the speed and effectiveness of your recovery. Also the angle of your racquet to the ground is important. It is best to have the racquet head should be slightly under 90 degrees to the ground behind you to provide the best height on the shuttle so that it can clear your opponent’s head while still not being pushed too high that it gives him/her time to get back to hit the shuttle.
Performance Stages - Action • Joint and muscle movements • As I mentioned before the ankles must perform plantar flexion which uses the gastrocnemius as the agonist and the tibialis anterior as the antagonist muscle. This creates a driving force forcing the tibia and fibula bones up towards the sky with your ankles which provides the thrust you need towards the shuttle to allow it to be more powerful. At the same time as this your knees must also be extended which means they must go from flexion and contract the quadricep group of muscles using them as the agonist muscles to power the femur bone up as well which gives extra force and thrust towards the shuttle • By having the hip in slight hyper extension before you jump, you can engage the iliopsoas muscle to provide very slight flexion back to 180degrees to your legs or slightly less. By doing this while jumping towards the shuttle it provides slightly more velocity for you to use as speed and strength so to clear the shuttle further. When flexing the hip the antagonist muscles will be the gluteal muscles which will be relaxing so that you can contract the iliopsoas . As well as your hip it is good to have your trunk slightly rotated away from the shuttle at first so that as you strike the shuttle you can rotate the trunk back around using your external obliques to create torque and therefore extra force and power. • During this action phase the elbow must start extending, using the tricep brachii as the agonist muscle , toward the shuttle at a rate as fast as possible to provide as much force and power to perform a successful overhead clear. While this is happening the shoulder joint must perform extension using the trapezius and anterior deltoid as the main agonist muscles powering your humerus towards the shuttle at a rate that will provide strength and force the clear the shuttle to the back of the court. As well as these actions just as you are about to hit the shuttle the wrist joint should perform quick pronation which engages the pronator teres and relaxes the supinator. This allows for you to, while providing extra speed and force toward the shuttle, move the face of the racquet to a 90degree angle to the shuttle when you hit it which allows you to get maximum power and accuracy from the shot as all the force is transferred directly through the string to the shuttle. • By performing all of these actions in co ordination with one another you are able to create a summation of forces which means all the power and force from each separate action benefits each other in such a way that the shot has so many different forces through it as a whole it as massively powerful and allows you to clear the shuttle all the way to the back of the court therefore being even more successful.
Action One good thing is that my wrist is nicely supinated meaning that my pronator teres is the antagonist muscle and is about to contract to provide pronation and that extra power in performing the overhead clear Neither my shoulder nor my elbow were flexed enough so that they were engaging their agonist muscles enough during the preparation phase and therefore now that the deltoid and tricep brachii are the agonist muscles they are not able to contact as much as wanted and are not able to provide the power that I needed for a successful overhead clear My base of support has become slightly wider but is still not wide enough to create that strong balance and composure that is needed and also my line of gravity should be slightly more in front of my B.O.S. so to push me forward in this driving stage and allow for extra horizontal power to hit the shuttle and also to set me up better for my recovery phase My knees have not extended enough to provide the force necessary towards the shuttle which means I have not gained any extra racquet speed of power on the shuttle which causes my stroke to be weak and unable to force the shuttle right to the back of the court My ankles have extended reasonably well which means they are providing another force to make my ascent to the shuttle quicker and therefore allow extra speed towards the ball which also mean extra racquet speed hitting the shuttle and making it a more effective clear
My striking arm has not followed through down past the opposite side of my body which has meant that I could not perform full rotation of the trunk and this also means that I have hindered the strength of my shot by stopping it to early which usually means I have slowed my racquet head speed before I actually hit the shuttle which is not wanted As well, because of my striking arm not following through, my torso has not fully rotated meaning I have not caused as much torque as possible. This means that my shot could have been more powerful than I made it and I could of performed a more successful overhead clear My line of gravity should be slightly more forward of my base of support as I strike the shuttle as to allow me to travel forwards to the shuttle causing for a more powerful hit and to allow me to be already moving back towards the centre of the court ready to recover
Performance Stages - Recovery • Footwork and body/racquet position • As I launched myself into the air using plantar flexion of the ankle and extension of the knees I made sure that my body position was forward so that my line of gravity was slightly in front of my base of support. This allowed me to move forward back to the centre of the court more quickly improving my recovery time. Also, when I land I still need to have my line of gravity forward of my base of support until I have reached the centre of the court. This will mean that gravity is aiding my transition from where I hit the shuttle back to the centre and therefore decrease the time it takes for me to do this. • Upon landing I need to absorb the shock by bending my knees and ankles and lowering my centre of gravity. As soon as I have done this I need to push myself forward as quickly as possible to move back towards the centre of the court and recover. As long as my line of gravity is in front of my base of support as I push, like I mentioned before, then gravity will naturally move me forward and towards the middle. • During these actions my racquet head should be high with my hands being above my elbows to allow for quick reactions this also means that the racquet has the shortest distance to travel to reach the shuttle. By having the racquet in this position it means that if the shuttle should come back at me while I am still recovering, both the racquet and I are in position to suddenly reach out and hit it without having to take a huge backswing or move the racquet a large distance. This increases the chance of me returning a shot like this and allows me to do it quicker and more efficiently.
Performance Stages - Recovery • Joint and muscle movement • A good follow through is important when striking the shuttle to perform an overhead clear. It allows you to maximise the power and torque generated by the rotation of your trunk and flexion of your hip. It also helps to prevent you from holding back from your stroke as you are trying to hit past and through the ball rather than at it. Therefore by following though you generate a much more powerful and smooth shot as you create large torque from the follow through of rotation of your trunk which activates your obliques. As well as this more flexion should occur in your hip which as well as allowing for extra power it shifts you line of gravity further in front of your base of support which helps you move forward back to the middle of the court • Once you have fully extended your elbow and abducted your shoulder using your tricep brachii and deltoid as agonist muscles, by following through with your arm and finishing on the opposite side of your body down low you have created both adduction and horizontal flexion which both allows for a stronger hot and it creates forward linear motion to help you travel back to the centre of the court to recover. • On your travel to the centre of the court you need to get back into position of the start of the preparation phase. Your knees must be flexed with the hamstrings acting as your agonist muscles and to allow for you to be on your toes while still being in dorsiflexion which is using your tibialis anterior as your agonist muscle. Also by moving your elbow back to its flexion position you contract your bicep and you use your latissimus dorsi and pectoralis major to abduct and horizontally extend your shoulder back to the position it was in to begin with in the preparation stage. By being in this position you are now ready to begin the preparation stage and begin this cycle again.
As I have not followed through with my striking arm it means that I was not able to create the torque needed to propel the shuttle to the back of the oppositions court and also by following through it brings my centre of gravity forward helping me to recover to the centre of the court so that I am more ready for the next shot My hands are to low which does not allow them to be as ready as possible to suddenly hit the shuttle. By being low they are increasing the distance they have to move to hit the shuttle which does not give me much time to set up My centre of gravity is to far back meaning I will not be able to use gravity to aide my move forward to the middle of the court therefore I will not be able to recover well My knees have not flexed to absorb body weight and therefore are not as able to transfer my body weight and push it back towards the centre of the court to recover
By not moving back to the centre of the court quickly I am not getting ready and in my preparation position for the next shot which means my reaction time is slower and also my whole body has to be displaced more to get to hit the shuttle therefore making it less effective As my knees are still not flexed they are not engaging the hamstrings or using the quadriceps as the antagonist muscle . This means I am not ready to engage my quadricep to cause flexion in the knee and spring to where I need to be to hit the shuttle My line of gravity is being held to far behind my base of support which means gravity creates momentum backwards towards the floor which hinders my forward motion and the speed in which I can recover to the centre of the badminton court My base of support is very small meaning I am not as balanced as possible and therefore am not as able to suddenly change my direction and speed as I can not apply as much force to my legs without losing balance than that of which I could If I had a larger base of support
As my ankles are not in dorsiflexion, and my knees are not in flexion they are not ready to contract the antagonist muscles, the gastrocnemius and the quads so that plantar flexion in the ankles can occur to propel me towards where I need to be to hit the shuttle. My hands have still not moved back to a high enough position for them to be ready to hit the next shot. As they have bot done this they will have to displace more distance to hit the shuttle taking more time and allowing less time for me to prepare properly and hit a successful overhead clear My body is facing diagonally towards the right of the court. This means if my opponent hits the shuttle to the left hand side of the court I will have to rotate my body more to be able to reach it which takes more effort and time than necessary.
Side view of the over head hit Ideal performance technique of the over head hit Harry Llewellyn Mr Hose, Physical education 3.3 My initial performance of the over head hit
Preparation phase 1 (Ideal performer) In this task I will be breaking down my overhead clear in to three key areas; the preparation stage, action stage and recovery stage. I will analysis each area using video footage broken down in to a series of photos to expose my strengths and weaknesses. The first area I will breakdown is the preparation stage- this is the initial stage of the overhead clear. This shot begins from a strong base, the feet should be a shoulder width apart with the left leg slightly in front of the right (very similar to a boxers stance). The weight is primarily on the front foot to begin with, standing on the ball of the foot with the back foot. This will allow the transfer of weight during the shot to achieve maximum power. The left arm is up at a 90degree angle to the shoulder and is directed to the incoming shuttle cock. The right arm holding the racket uses the forehand grip with the V shape in between the thumb and index finger, the arm is also at 90degrees in preparation for the shot. The knees are bent in order to create a low centre of gravity in which to perform the shot. This first step is shown by the ideal performer in ‘Fig 1.1, 1.2 and 2.1’ From here the body begins to track the path of the shuttle cock anticipating where its going to land, this shown by the weight transferring to the back leg and the first steps of the grape vine movement being applied. Both arms begin to rise with the left arm leading, directing the power towards the incoming shuttle. The face of the racket opens up and becomes vertical with the ground. The body turns side on to the net and another transfer of weight is implemented from the back foot to the front foot. This is shown in ‘Fig 1.3 and 2.3’ by the ideal performer. Fig 1.1 Fig 1.2 Fig1.3 Harry Llewellyn Mr Hose, Physical education 3.3 Fig 2.1 Fig 2.2 Fig 2.3
Preparation phase 2 (Ideal performer) The final part of the preparation phase is shown by the ideal performer in ‘Fig 1.4-1.6 and 2.4-2.5’ To begin the final stage of preparation the feet and the body are both side on to the net and the incoming shuttle cock. The weight from the front leg transfers to the back in preparation to hit the shuttle, this occurs as the knees bend and lower centre of gravity is created. Both feet are on the toes with the heals lifted in anticipation to spring upwards. Towards the very end of this stage the leading arm is perfectly straight pointing directly to the incoming shuttle cock with the racket extended far behind the head. The bodies centre of mass is located further back in ‘Fig 1.5’ but as the racket arm extends in ‘Fig 1.6’ the mass becomes centred again with the body parallel to the net. This achieved through accurate and carefully considered footwork as the back foot is well behind the body. The preparation stage of the ‘overhead clear’ is arguably the most important part of the shot. I will therefore need to analysis my preparation phase with that of the ideal performer and find errors in my shot in which I can improve from. Harry Llewellyn Mr Hose, Physical education 3.3 Fig 1.4 Fig 1.5 Fig 1.6 Fig 2.4 Fig 2.5
Preparation phase 1 (Initial performer) The action phase describes the point at which the action occurs and finishes, the action phase is a very important part of the overhead clear, however the preparation stage is equally important as it controls what position your in ready for the action stage. Continuing from the ideal performance of the preparation stage the ideal performer demonstrates the action stage of the overhead clear. He begins with leading left arm directing the swing of the racket towards the incoming shuttle cock, the weight is primarily on the back foot so that the power can be brought forward on the swing. The stance begins slightly wider than shoulder width apart, this creates a solid base in which to perform a shot with maximum power. This stance widens through the sequence of photos in ‘Fig 1.1-1.3’ with the front foot almost elevating completely off the ground during the initial part of the action phase. The weight from the back foot begins to move further forward as the swinging arm of the racket becomes closer to hitting the shuttle. As this weight is moved further forward the leading left arm becomes straighter and drops down to become parallel with the ground shown in ‘Fig 1.3’. As well as this happening towards the middle of the hit both feet almost become completely lifted off the ground with only the tips of the toes taking the full body weight. The racket face remains open the entire time in order to take the shot much faster as no time is wasted having to turn the racket mid flight. The head of the ideal performer remains lifted but in a fixed position tracking the path of the shuttle cock in till impact is made, the head acts as a balancing counter lever therefore by keeping the head steady the body remains in the correct position. Harry Llewellyn Mr Hose, Physical education 3.3 Fig 1.1 Fig 1.2 Fig1.3 Fig 2.1 Fig 2.2 Fig 2.3 Fig 2.4
Preparation phase 2 (Initial performer) The action phase describes the point at which the action occurs and finishes, the action phase is a very important part of the overhead clear, however the preparation stage is equally important as it controls what position your in ready for the action stage. Continuing from the ideal performance of the preparation stage the ideal performer demonstrates the action stage of the overhead clear. He begins with leading left arm directing the swing of the racket towards the incoming shuttle cock, the weight is primarily on the back foot so that the power can be brought forward on the swing. The stance begins slightly wider than shoulder width apart, this creates a solid base in which to perform a shot with maximum power. This stance widens through the sequence of photos in ‘Fig 1.1-1.3’ with the front foot almost elevating completely off the ground during the initial part of the action phase. The weight from the back foot begins to move further forward as the swinging arm of the racket becomes closer to hitting the shuttle. As this weight is moved further forward the leading left arm becomes straighter and drops down to become parallel with the ground shown in ‘Fig 1.3’. As well as this happening towards the middle of the hit both feet almost become completely lifted off the ground with only the tips of the toes taking the full body weight. The racket face remains open the entire time in order to take the shot much faster as no time is wasted having to turn the racket mid flight. The head of the ideal performer remains lifted but in a fixed position tracking the path of the shuttle cock in till impact is made, the head acts as a balancing counter lever therefore by keeping the head steady the body remains in the correct position. Fig 1.4 Fig 1.5 Fig 1.6 Harry Llewellyn Mr Hose, Physical education 3.3 Fig 2.5 Fig 2.6 Fig 2.7
I TAKE IT YOU HAVE COMPLETED THE FOLLOWING • AN EFFECTIVE INTRODUCTION • BREAKDOWN OF PHOTOGRAPHS FROM SIDE ON AND FRONT ON • SAME FOR THE IDEAL PERFORMANCE • A CHECKLIST TO SEE WHAT SHOULD BE HAPPENING. • NOW-LETS GET TO THE REAL NITTY-GRITTY
THE ANALYSIS-THREE STAGES • A BREAKDOWN OF THE SKILL INTO ITS COMPONENT PARTS AND A COMPARISON WITH THE IDEAL. THIS SHOULD BE BROKEN DOWN INTO PHASES (SUCH AS PREPARATION, ACTION, RECOVERY) AND COULD CONSIDER WHERE PARTS OF THE BODY START AND FINISH, JOINT POSITION, ANATOMICAL MOVEMENT AND THE MUSCLES INVOLVED, THE PATH OF THE BODY/PROJECTILE/OBJECT, SPEED IN RELATION TO ACCURACY, AND SO ON • A BIOMECHANICAL ANALYSIS (DECONSTRUCTION) OF THE SKILL. CONSIDER THE STRENGTHS AND WEAKNESSES OF THE PERFORMANCE AS IDENTIFIED ABOVE, EXPLAINING THEM IN DEPTH USING APPROPRIATE BIOMECHANICAL PRINCIPLES. • FEEDBACK AND FEED FORWARD THAT WOULD ENABLE YOU OR YOUR PARTNER TO IMPROVE THE EXECUTION OF THE SKILL. THERE SHOULD BE A CLEAR RELATIONSHIP BETWEEN YOUR BIOMECHANICAL ANALYSIS AND YOUR FEEDBACK/FEED FORWARD. AN UNDERSTANDING OF HOW BIOMECHANICAL PRINCIPLES INTERRELATE TO IMPROVE PERFORMANCE SHOULD ALSO BE EVIDENT.
ANOTHER EXAMPLE • FROM THE VIDEO EVIDENCE, YOU CAN SEE THAT MY PARTNER DIDN’T HAVE ENOUGH WEIGHT ON HER BACK FOOT AT THE BEGINNING OF THE SERVE. THE DIGITAL PHOTOS CLEARLY SHOW THAT HER RIGHT LEG IS RELATIVELY STRAIGHT AS SHE IS DOING THE BALL TOSS. THIS COMPARES TO THE BENT LEG OF THE ‘IDEAL’ PERFORMER. MY PARTNER’S STRAIGHT LEG MEANT THAT SHE WASN’T CREATING A LARGE ACTION FORCE ON THE GROUND TO PUSH UP AND TRANSFER MOMENTUM INTO THE SERVE. • TO HAVE A LARGE AMOUNT OF MOMENTUM, YOU NEED TO CREATE A LARGE ACTION FORCE ON THE GROUND SO IT WILL CREATE A LARGE REACTION FORCE TO YOUR LEGS TO ALLOW YOU TO PUSH FORWARD INTO THE SERVE. WITHOUT A GREAT ACTION FORCE, MY PARTNER WASN’T ABLE TO GET A LARGE REACTION FORCE FROM THE GROUND, SO THE BALL DIDN’T HAVE A FAST VELOCITY. • MOMENTUM (P) = MASS (M) X VELOCITY (V). • TO CREATE THIS LARGE FORCE, SHE MUST GET HER WHOLE BODY (MASS) MOVING FAST (VELOCITY) INTO THE SERVE. THIS INCREASES MOMENTUM AND ALLOWS THE TRANSFER OF MOMENTUM CREATED INTO THE RACQUET AND, AFTER CONTACT, INTO THE BALL AS THE TOTAL MOMENTUM IN THE EQUATION IS CONSERVED. • TO PERFORM A FASTER SERVE, SHE COULD BENEFIT FROM PUTTING MORE WEIGHT ONTO HER BACK FOOT AS SHE IS PERFORMING THE BALL TOSS. TO DO THIS SHE WOULD NEED TO FLEX AT THE HIP, WITH HIP FLEXORS BEING THE AGONIST AND GLUTEALS THE ANTAGONIST, AND ALSO FLEX THE KNEE JOINT, WITH THE HAMSTRINGS BEING THE AGONIST AND QUADRICEPS BEING THE ANTAGONIST. • SHE COULD DO THIS BY INCREASING THE SIZE OF THE SUPPORT BASE BY PLACING HER RACQUET FOOT BEHIND HER NON-RACQUET FOOT AT APPROXIMATELY SHOULDER WIDTH APART. • BY CREATING THIS WIDER STABLE BASE, SHE WILL NOT ONLY BE FLEXING HER KNEE TO ALLOW FOR EFFICIENT TRANSFER OF MOMENTUM AS EXPLAINED ABOVE, BUT SHE WILL ALSO PROVIDE A STABLE BASE THROUGH WHICH FORCE CAN BE GENERATED. THIS WILL ULTIMATELY ENSURE THAT THE MAXIMAL NUMBER OF BODY PARTS, STARTING IN THE LOWER LEG, CONTRIBUTE TO THE MOVEMENT. BY HAVING A STRAIGHT LEG INTIALLY, THE MUSCLES IN HER LOWER BODY HAD MINIMAL CONTRIBUTION TO THE FORCE OF THE MOVEMENT.
CONTINUED • THIS ASPECT OF MY PARTNER’S PERFORMANCE IS VITAL IN THE PERFORMANCE OF A QUALITY TENNIS SERVE. THE FORCES THAT ARE GENERATED FROM THE LEGS FOR THE BASE OF THE TENNIS SERVE ARE THE FORCES THAT ARE TO BE TRANSFERRED TO THE REST OF THE BODY. THE LARGER MUSCLES OF THE BODY, IN PARTICULAR THE LEGS’ QUADRICEPS, HAMSTRINGS, AND GLUTEAL GROUPS, CAN GENERATE A GREAT PERCENTAGE OF THE TOTAL FORCE IN A SERVE. • AS THE DIGITAL PHOTOS AND THE CHECKLIST SHOW, MY PARTNER FAILS TO USE THESE MUSCLE GROUPS, AND AS A RESULT SHE IS AT A CLEAR DISADVANTAGE IN RELATION TO GENERATING A HIGHLY SUCCESSFUL SERVE. • MY PARTNER INDICATED THAT WHILE IT IS ALL WELL AND GOOD TO UNDERSTAND THESE PRINCIPLES THAT SHOULD IMPROVE HER PERFORMANCE, IT WILL BE THE LACK OF ABILITY TO APPLY THEM THAT WILL INFLUENCE THE ABILITY TO IMPROVE. FROM OBSERVATIONS I MADE AND COMMENTS SHE MADE, SHE FOUND IT QUITE ‘STAGED’ TRYING TO CONCENTRATE ON ONE ASPECT TO IMPROVE, SUCH AS FLEXING HER KNEES AND DRIVING UP. ON ISOLATING THIS ASPECT OF THE MOVEMENT, THE REST OF THE SKILL SUFFERED AND HER PERFORMANCE SUFFERED. AFTER A COUPLE OF SESSIONS SHE SAID THAT CONCENTRATING ON THE MAIN BIOMECHANICAL WEAKNESSES I IDENTIFIED MEANT THAT THE BEST APPROACH WOULD BE TO PRACTICE USING THE WHOLE-PART-WHOLE METHOD IN A REPETITIVE DRILL SITUATION ... • SHE FEELS THAT THIS APPROACH IS ONE OF THE FACTORS THAT WILL INHIBIT HER IMPROVEMENT IN THE GAME. WHILE IT MIGHT ULTIMATELY IMPROVE THE DISCRETE SKILL OF THE SERVE, SHE WOULD PREFER TO EMPLOY A MORE GAME SENSE APPROACH WHERE SHE WOULD IMPROVE THE SKILLS AND STRATEGIES OF THE GAME AS A WHOLE. ALTHOUGH SHE SAID SHE HAD IMPROVED AFTER OBSERVING THE TECHNIQUE IN COMPARISON TO THE IDEAL AND RECEIVING FEEDBACK ABOUT, FOR EXAMPLE, SERVING INTO THE GRID, SHE FELT HER SERVE WAS STILL LACKING IN SPEED. ALTHOUGH HER SERVE NOW SEEMED MORE ACCURATE, IT WOULD NOT BEAT AN OPPONENT DUE TO LACK OF POWER/SPEED … • THE EXAMPLES ABOVE RELATE TO ONLY PART OF WHAT IS REQUIRED, AND ARE JUST INDICATIVE.
…Torque is also known as the moment of force. Torque is defined as a turning force and is categorised by the amount of force applied and the length of the lever arm. Torque (T) = Force (F) x Distance (D) ref- pg.7 of Sport Biomechanics ppt. Torque is created when the force is applied. In THIS case ITis the magnitude of the force generated by the use of her muscles and the acceleration of the body parts during the swing (f=mxa). SHE HAS TO ensure THATshe has created long levers for herself by extended her elbow joint (Tricep being the antagonist and the bicep being the agonist) to ensure the lever is at its maximum length. We know that the longer the lever (arms and club) the greater the speed of the club head will be at the point of contact with the ball. You can see from (name removed) performance that she is using the principles of torque, Newton's laws, and levers to effectively influence her performance.
POINTS TO CONSIDER • I WOULD EXPECT YOU TO BE WORKING ON THE FOLLOWING….A BIOMECHANICAL ANALYSIS IN RELATION TO HOW THE PERFORMERS SET THEMSELVES UP IN THE PREPARATION PHASE OF THE SKILL. • ONCE THIS HAS BEEN COMPLETED…..YOU THEN MOVE ON TO THE ACTION PHASE OF THE SKILL ….IN THIS STAGE I WOULD LIKE YOU TO COMBINE ANATOMICAL AND BIOMECHANICAL ANALYSIS….STATE THIS AT THE START…..IT WILL BE DIFFERENT FROM HOW YOU HAVE PRESENTED YOUR PREPARATION ANALYSIS. • I BELIEVE THE ACTION PHASE IS THE BIGGEST AND MOST COMPLEX OF THE PHASES…THEREFORE I WOULD EXPECT MORE…THERE WILL BE AN INCREASE IN MUSCLE MOVEMENTS…EXPLAIN THEM ALL. • DO NOT UNDERESTIMATE THE RECOVERY STAGE…IF YOU ARE THROWING , STRIKING A BALL…THEN PRINCIPLES OF PROJECTILE MOTION MUST BE ANALYSED. • I WOULD ADVISE YOU TO HAVE COMPLETED THE ANATOMICAL AND BIOMECHANICAL BREAKDOWN BY THE END OF TERM. • DURING THE LAST WEEK WE WILL LOOK AT HOW WE CONSTRUCT THE LAST SECTION…THE FEEDFORWARD….IF YOU HAVE COMPLETED THE FIRST SECTION WELL…IT SHOULD BE EASY. • PLEASE GET ME TO READ IT…EVERY SO OFTEN….I CAN ONLY GUIDE YOU ON CONTENT!
And now….the last part • FEEDBACK AND FEED FORWARD THAT WOULD ENABLE YOU OR YOUR PARTNER TO IMPROVE THE EXECUTION OF THE SKILL. THERE SHOULD BE A CLEAR RELATIONSHIP BETWEEN YOUR BIOMECHANICAL ANALYSIS AND YOUR FEEDBACK/FEED FORWARD. AN UNDERSTANDING OF HOW BIOMECHANICAL PRINCIPLES INTERRELATE TO IMPROVE PERFORMANCE SHOULD ALSO BE EVIDENT. • A CONCLUSION, IN WHICH YOU CONSIDER WHICH PARTS OF THE SKILL HAVE THE GREATEST IMPACT ON PERFORMANCE AND WHICH PRINCIPLES (IF APPLIED) POTENTIALLY HAVE THE GREATEST INFLUENCE ON PERFORMANCE. YOU MAY EVEN WISH TO QUESTION/CHALLENGE THE WORTH OF A BIOMECHANICAL ANALYSIS IN IMPROVING PERFORMANCE AS WELL AS CONSIDERING OTHER FACTORS THAT MIGHT INFLUENCE IMPROVEMENT.
HEAVY READING-BUT IT MAY HELP • …Going back to the point of biomechanics although, I do agree that this factor(excluding the actual lines of the swing), is extremely important and does have a major impact on both the executive, overall performance and the smaller more defined aspects of the swing...through research I have found that even some of the top Qualified sports science and health professors at Auckland University and also at the New Zealand Institute of Sport and Recreation, rate biomechanics and the principles within so highly. In one review on (http://www.ncbi.nlm.nih.gov/pubmed/15896091), “Biomechanics has a role in maximising the distance and accuracy of all golf shots(swing and putting) by providing both qualitative and quantitative evidence of body angles, joint forces and muscle activity patterns. The quantitative biomechanical data needs to be interpreted by the biomechanist and translated into coaching points for golf professionals and coaches.” I believe that this statement is fair, but much like the different lines in golf there cannot be only one Biomechanical principle seen as being the most important. This is because each principle interrelates... example of these principles inter-relating within (name removed)swing, is when his lever (the golf club) is in an effective position in relation to his body and this then positively effects his stability for the rest of his swing. This effective use of levers also benefits on his force summation later on in his swing when his lever in backswing and downswing creates maximum adaptable and influential aspects of biomechanics as a whole. Of course there could be the view that in order to improve we must only focus on our weak points of biomechanics, say for example (name removed)might only try and improve his sequencing and timing, a.k.a his force summation. But we must ask the question; would all that focus on only one principle allow for overall improvement of the executive movement? Or would it hinder progress of those biomechanical principles that are less focused on? This again comes down to that question of which has the most impact on the swing, and the answer is simple, they are all inter-related and equally important and influential. If you took one of these principles out of the swing, e.g. stability then I know for a fact that the rest of the principles incorporated into the swing would be hindered and affected greatly.
ideas • A quote from the website http://www.makingstridz.com/node/16 agrees with my statement; ‘Biomechanical analysis can benefit athletes of all ages and skill levels. Whether you are a weekend runner or a high performance sprinter, biomechanical analysis can be beneficial to you as it will allow you the opportunity to develop more efficient movement patterns. This can benefit the weekend runner by allowing them to increase their distance and run pain free, while the high performance sprinter can benefit from a more efficient running stride and allow them to shave milliseconds off their personal best time.’ • The inter-relationship of biomechanical principals within the performance was brought to light for me as I delved deeper into the depth of each biomechanical skill. Not a single principal stands alone to help improve the performance, they all inter-relate and work together to improve each skill. By applying all the biomechanical skills, you are creating the maximum efficiency in your performance. An example of this during the preparation stage is the use of force summation and the use of stability. It would be impossible for the ideal performer to start contracting their large muscle groups within their legs in preparation for the force summation if their base of support wasn’t wide enough, or if their centre of gravity wasn’t close enough to their base of support. From the other end of the spectrum, having a very controlled state of stability would be completely useless without the principal of force summation to give it a purpose for being applied.
ideas • The two biomechanical principals inter relate, they complement each other, make each other worthwhile and they wouldn’t be half as effective without the other. In the action stage of the drive, the torque, the force summation, the levers, the stability and the force all affect the projectile motion. If all of those biomechanical principals are applied correctly, the projectile motion on the disk will be extremely successful and the disk will have a long flight time, will gain maximum horizontal and vertical distance and it will be an accurate shot that will get much closer to the target than if none of the principals are applied. • For example, I realised that my lack of torque in the action stage is probably one of my biggest weaknesses because it doesn’t allow for any force summation to occur and it inhibits my use of the levers throughout my body. If I didn’t have biomechanical knowledge, I wouldn’t have been able to identify this weakness or know what is needed in order to correct it, instead I probably would have tried to increase the speed in which I bring my arm across my body which would have only resulted in a very minimal improvement, if any at all. A biomechanist will use their knowledge and skills to analyse an athlete to enhance performance.
ideas • The question I have tried to answer is; by having biomechanical knowledge, does my performance automatically improve? I personally think that the answer to the question would be a yes. If I went out after biomechanically analysing my backhand drive, I think my performance would improve, however I do not think that this means I would become an ideal performer. Although you may be able to critically analyse every single biomechanical skill you are applying, at the end of the day, factors such as body strength, natural athleticism, and natural ability come into play and they determine how far you can excel in every sport you play and the skills you utilize. • Factors that could influence the performers ability to improve could include; the method of practice used, the stage of learning that the performer is in, the type of skill it is, the type of practice used and the type of feedback the performer is receiving and how they react to that.
ideas • As I looked over my performance I was able to view the strengths and weaknesses throughout the progressive phases. My preparation phase was the phase out of the three which needed the most work. I had let myself get into the habit of leaning too far forwards which hindered my overall position throughout all of the phases. While my legs showed a stable position and my heels were stretched downwards, my upper body should have been altered to gain maximum stability through preparation and therefore prepare myself for the position in both the action and recovery phase which would encourage the horse to present with the perfect arc over the fence. In preparation, my strengths definitely lay in my stable leg position with my weakness being my forward weighted upper body. This imbalance caused a loss of opportunistic stability and set me and my horse with difficulties. • The relationship between biomechanical insight and performance improvement lies directly within the idea that without knowledge of biomechanics we can apply a basic form, but not understand and therefore regulate our ideal biomechanical position as a rider. Ideally, if our position was in the correct biomechanical structure then our horse would respond to the critical muscular formations and therefore follow our own ordinance to correct their own biomechanical form.