Heading How do Biomechanical principles influence movement The

Heading: How do Biomechanical principles  influence movement? The study of biomechanics originates from combining two separate disciplines: bio refers to the study of living organisms; mechanics refers to the study of motion and forces. Biomechanical study involves identifying ways of improving  performance through 3 main ways: Refining an athlete’s technique Modifying and developing equipment Decreased risk of injury by improving movement efficiency

Heading: Motion is the movement of the body from one position to another   Some bodies are inanimate (non-living) such as basketballs,  shot puts; whilst other bodies are animate (living) such as  golfers, footballers. Motion itself can be divided into 3 categories: Linear Angular General

Sub: Linear Motion Linear motion takes place when a body and all parts connected to it travel the same distance in the same direction  and at the same speed. Examples: 100 m sprint, skii jumper, glide of the wall in swimming.

Sub: Angular Motion Also called Rotary motion. Occurs when the body, limb or object moves along a circular (curved) path about a Fixed point. It moves at same  time, direction & angle. The fixed point is the axis of rotation Examples sports such as gymnastics, skateboarding, basketball, diving, figure skating, and  ballet

Sub: General Motion As in everyday life, the majority of sporting skills have an  element of both linear motion and angular motion. This is  known as general motion. The swimmers’ arms represent  angular motion, while their hips display linear motion as they  glide through the water.

Sub: Velocity is equal to displacement divided by time. Displacement is the movement of a body from one location to another in  a particular direction, or an ‘as the crow flies’ measurement. Velocity is used for calculations where the object or person does not  move in a straight line. An example is a Javelin throw.

Sub: Speed is equal to the distance covered divided by the time taken to  cover distance So, if a runner runs 100 m in 12 secs   Although the terms speed and velocity are used interchangeably, the two are the same  only when the movement is in a straight line.

Sub: Acceleration is the rate at which velocity/speed Acceleration is the rate at which velocity changes in a given  amount of time When a person or object is  stationary, the velocity is zero. An  increase in velocity is referred to as  positive acceleration. A decrease is  negative acceleration The ability to accelerate depends  largely on the speed of muscle  contraction, but use of certain  biomechanical techniques, such as  forward body lean, can improve  performance.

Sub: Momentum https: //www. youtube. com/watch? v=h. TZI-kpppuw Momentum refers to the quantity of motion that a body possess. It is a product of mass and velocity. Momentum is expressed as: Momentum = mass x velocity (M = mv) Momentum is an advantage in many sports, especially in contact  sports, balance and throwing sports (Don't copy) Example 1 - When two rugby players collide, the athlete  with the greater momentum is more likely to be able to get into an  advantageous. However, momentum is only one of many factors that  will determine success, including: the angle of collision weight of players tackling technique and timing the amount of contact with the ground that affects stability.

More examples Choose one copy Example 2 - A discus with a mass of 2 kg and a velocity of 20 m/s will have a momentum of 40 kg m/s. The faster the object moves or the more mass of the  object, the greater the momentum. Example 3 - Catching a tennis ball vs a cricket ball travelling at the same velocity. A cricket ball is more difficult to catch because it has greater mass and therefore momentum.

Momemtum Cont. . Summarise: There are numerous instances in sport where bodies generate momentum but they do not travel in a straight line; for example, a diver  performing a somersault with a full twist, football kick, discus throw and golf  swing. In each of these cases, the body, part of it, or an attachment to it such as  a golf club or tennis rac is rotating. We call this angular momentum. Angular momentum is the quantity of angular motion in a body or part of a body Angular momentum is affected by: • angular velocity For example, the distance we can hit a golf ball is determined by the speed at which we can move the club head. • the mass of the object. The greater the mass of the object, the more effort we need to make to increase the angular velocity.

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Heading: Balance and Stability All sports require athletes to maintain a steady balance and  equilibrium. Archery, require a stationary and balanced. Gymnastics judged on the degree of balance and stability  demonstrated, such as the beam in gymnastics. Rugby Wrestling require opponents to disrupt each other’s  balance There are two main types of balances that are evident in  sport: Static balance: headstands and handstands. Dynamic balance: skiing and surfing

Video Dynamic Balance Aj Bear Swiss Ball #1 - https: //www. youtube. com/watch? v=8 dk 4 r. Eoz. Qp. Y Aj Bear Swiss Ball #2 - https: //www. youtube. com/watch? v=z. AXXVhl. C 3 g https: //www. youtube. com/watch? v=-IIl. YCV 0 f 3 o

Sub: Centre of Gravity (COG): The centre of gravity of an object is the point at  which all the weight is evenly distributed and about which  the object is balance. All Athletes are highly skilled in manipulating body  position or equipment. Generally an unconscious and automatic response, refined  over years of practice. centre of gravity can  actually move outside  of the physical mass of  the body into space.

Centre of Gravity High Jump 1: 09 – 3: 22 - https: // www. youtube. com/watch?  v=Ra. GUW 1 d 0 w 8 g&list=PLY 25 n. QRy. T 8 x. CBEu 36 z. Ryr q 4 R 2 deeq. A 2 r  8

Where an object has a uniform and consistent shape, such  as a tennis ball, the centre of gravity lies directly in the  centre of the sphere. Irregular shapes are more difficult to identify; however, an athlete quickly learns to feel.

Sub: Line of Gravity

Sub: Base of Support The base of support refers to an imaginary area that  surrounds the outside edge of the body when it is in  contact with a surface. It affects our stability or our ability to control equilibrium. A wide base of  support is essential for stability because the centre of gravity is located well  within the boundaries.

Write some examples of how an athlete  could use the base of support to their  advantage? There are many examples where athletes use the base of support to  their advantage. • The gymnast performing a pirouette has a very narrow base of support  and must work hard to ensure that their centre of gravity remains within  the base. • Wrestlers widen their base of support to prevent their opponents from  moving them into a disadvantageous position. • Tennis players lower the centre of gravity and widen the base of  support in preparation to receive a fast serve. This enhances balance  and enables the centre of gravity to be moved in th desired direction  more readily. • Swimmers on the blocks widen their feet and move the centre of  gravity forward to improve their acceleration. • Golfers spread their feet to at least the width of their shoulders to  enhance balance when they rotate their body during the swing.

Heading: Fluid Mechanics Fluid can be either a liquid or gas, predominantly this is  either done through water or air. Any sport that includes movement, whether of an  object or the human body, is subject to the impact of  the fluid it moves through. Generally, sports require this movement through the  fluid to be as fas and efficient as possible.

Video Down Hill Skiing 0: 40 – 1: 25 - https: //www. youtube. com/watch? v=MFl. EUP 8 b. GPQ

Sub: Floatation Immersed in water, there are two opposing forces acting on our bodies Gravity is a force pulling the body down Buoyant force is a force pushing up against a body Archimedes' Principle - When a body is in water, the body experiences an upward force equal to the weight of water displaced by  the body. For an object to float, it needs to displace an amount of water that  weighs more than itself Conversely, if the object displaces a quantity of water that weighs less  than itself, it sin Hence, wearing a personal flotation device (PFD) increases buoyancy  because its size displaces a lot of water with only a minimal increase  in weight.

Homework Question (Do in you notes book) Outline using examples some Factors that can influence the flotation and buoyant properties of  a body in water?

Possible Answers Bone = most dense. Muscle = next, similar to water. Fat = least dense People with a greater amount of body fat float better Legs sink first as they are denser and are mainly muscle and bone The lungs when full of air, act like a balloon. Give your body a bigger  volume. Flotation devices e. g. life jacket Wetsuit - The thicker the more buoyant

Sub: Centre of Buoyancy Every floating object has a centre of gravity and centre of  buoyancy. Centre of buoyancy: is the centre of gravity/weight of a volume of water displaced by an object when it is  immersed in that water. A persons centre of weight/gravity can be altered by a  change in body type or body position A persons centre of buoyancy can only be altered by a  change in body type

Sub: Fluid Resistance Forces act on us when we attempt to propel ourselves through a fluid environment. (Air or water) These forces include drag force and lift force. Elite athletes understand use these forces in a way that will benefit the efficiency of their performance. Swimming Video

Sub: Drag: is the force that opposes the forward motion of a  body or object, reducing its speed or velocity. Drag forces run parallel to flow direction (airflow, water),  exerting a force on the body in the direction of the stream. Example: The swimmer’s forward motion gradually decreases  due to resisting forces applied by the water.

Sub: Types of Drag There are 3 types of drag forces — surface, form and  wave drag. Surface Drag : is a drag force that is determined by the surface material of and object. It is caused by friction  between object and the air or water around it. Rougher  surface = more drag. Smoother surface = less drag e. g swim  suits.

Form: (also called form or pressure drag)  refers to drag created by the shape and size of a  body or object. Objects cause the medium to separate, resulting in  pressure differences at their front and rear. The separation causes pockets of high and low  pressure to form, resulting in the development of a  wake or turbulent region behind the body or object.

https: //www. youtube. com/watch? v=Xka. Ls. VOr. Bk 0

Wave: This occurs between different  fluid types ie water and air.  Swimming along the surface of the  water creates waves. The larger the  waves the more drag.

Question What can be done to reduce drag? Shape- If a body or object is streamlined at the front and  tapered towards the tail, the fluid through which it is moving  experiences less turbulence and this results in less resistance.  Bend forward position in cycling Tactics- eg. Distance runners and cyclists follow one another closely where possible. Surface - A smooth surface causes less turbulence, resulting  in less drag. Swimming suits Size of frontal area. If the front of a person or object (area  making initial contact with the fluid) is large, resistance to  forward motion is increased.

Sub: The Magnus Effect The Magnus effect: explains why spinning objects such as  cricket and golf balls deviate from their normal flight path. Cricket ball or golf ball is bowled or hit into the air, its spinning  motion causes a whirlpool of fluid around it that attaches to  the object. The three types of spin. Top Back - Side - Describe what each type of spin does to a  ball?

Tennis Video (a) Topspin and (b) backspin. The direction of rotation of an object causes  pressure differences that affect ball flight.

Surface Drag and Swing Bowling (Cricket) Shine one side of a cricket ball while leaving the other  rougher. This allows ball to swing during flight as one side of the  ball is able to move through the air with less resistance  than the other side. The cricket ball experiences a force towards the side of  the low pressure causing it to move in that direction. In fact, where pressure differences occur, objects always  move from the area of high pressure to low pressure.

Cricket

Heading: Force FORCE - Is a push or pull applied by one object on another & tends to produce or change the motion of the objects. Force is measured in Newtons (N) Speed up, slow down, stop or change direction EXTERNAL FORCE – from outside the body. Eg gravity, wind, another person INTERNAL FORCE – produced by muscles

Sub: Newton's Laws of Motion Newton’s first law: An object remains at rest or will move at a constant velocity, unless acted upon by an external force. Newton’s second law: The acceleration of a body is directly proportional to, and in the same direction as, the force acting on the body. Newton’s third law: For every action, there is an equal and opposite reaction

Newton's 1 st Law - https: //www. youtube. com/watch? v=08 BFCZJDn 9 w Newton's 2 nd law - https: //www. youtube. com/watch? v=qu_P 4 lbm. V_I Newton's 3 rd Law - https: //www. youtube. com/watch? v=e 1 lz. B 36 a. HD 4 Padding - https: //www. youtube. com/watch? v=2 ORe. Lc. COCN 4

Sub: How the body applies force The body produces force through the coordinated contraction of skeletal muscle, resulting in movement of the skeleton; for example, jumping, throwing and running Maximising force is achieved through training in the development of power and strength. In addition, improving movement patterns through technique can increase the force possible.

Sub: How the body adsorbs force Forces exerted on the body are absorbed through the joints, which bend or flex in response to the impact. Examples: Activities such as rebounding in basketball, landing in high jump and stopping the bounce while on a trampoline.

Cont. . The body also absorbs forces while catching balls or similar objects. Catching a ball can sting if the force of the ball is not absorbed effectively. Force of the ball remains constant, only variable is the distance through which the hands move when catching the ball.

Sub: Applying force on an object There a number of considerations. First, the quantity of force applied to the object is important. The greater the force, the greater is the acceleration of the object.