This achievement standard requires demonstration of understanding of

This achievement standard requires demonstration of understanding of functional anatomy and biomechanical principles and how they relate to physical activity, through participation and/or observation

Learning Intention n n To understand what Biomechanics is and how it can be applied to Badminton. To develop an understanding of the key aspects of Biomechanics as part of the learning process.

Defining Biomechanics Bio = body Mechanics = forces and motion “Biomechanics is the science concerned with how forces (internal & external) act on the human body and the effects these forces have on the motion of the body”.

WHAT IS BIOMECHANICS? n n It involves the study of Forces and Motion involved in human movement, particularly sport performance. In other words, biomechanics looks at what is the best technique for generating forces and producing the most efficient motion, in order to maximise sport performance (technique).

QUESTION? ? n What is the best way to kick a rugby ball? , hit a golf ball? , throw a softball? , shoot a basketball? , hit a tennis ball?

FORCES n n Force = “is a push or pull that changes a body's state of rest or motion”. n Internal Forces – generated within the body e. g. . forces due to muscle contraction External Forces – acting outside from the body e. g. . gravity

FORCES n In sport athletes primarily produce force within the body by contracting the muscles. Types of Forces Muscular Gravitational Frictional Aerodynamic Contact (ground or another body), Inertial Elastic Centripetal Centrifugal

TYPES OF FORCES n n Muscular Force = due to the contraction of muscle. Friction Force = due to two surfaces in contact with each other and the tendency of the two surfaces to oppose each others motion e. g. . mountain bike vs. racing bike tyres, sports shoe soles for various sports,

n n Gravity = is the downward acting force which attracts bodies to the centre of the earth. Aerodynamic Force = (is a type of frictional force) due to air resistance, where particles of air resist the motion of a body through it. e. g. . use of aero bars for cycling, spin in a tennis serve, swing in bowling a cricket ball

n n Contact = the force involved in a collision of bodies or the ground. e. g. . Scrum or Tackling collisions in rugby, hitting or catching a cricket ball, running Inertia = the force of an object due to its mass (whether moving or stationary) e. g. . catching a medicine ball vs. catching a volleyball, catching a cricket vs. tennis ball

n n Centripetal = force which is directed in toward the central axis of a rotating body. Centrifugal = force directed outward away from the central axis of a rotating body.

Task n For each of the following, identify the forces acting and what or who they are acting on. n n n n Kicking a soccer ball Tennis serve Throwing a javelin A rugby tackle Hitting a ball in cricket Catching a medicine ball Somersault in gymnastics

Newton's 3 Laws You Tube - Three Laws of Motion

Newton’s First Law The Law of Inertia (The 1 st Law of Motion)

Newton's First Law of Motion The Law of Inertia A body will remain in a state of rest or in uniform straight line motion, unless acted upon by a force to change that state of rest or motion”. e. g. . Steven Adams free shot; the ball will remain at rest until Steven applies a force with his hand. The ball would travel in a straight line into the sky, but is acted upon by gravity and air resistance (wind) to change its motion. n

Newton's First Law of Motion The Law of Inertia n n Moving Inertia An object in motion tends to remain in motion and to travel in a straight line with uniform velocity unless acted upon by some external force. Stationary Inertia An object at rest tends to remain at rest unless acted upon by some external force.

Newton's First Law of Motion The Law of Inertia n Inertia In order to set in motion a body presently at rest, you need to overcome the tendency of the body to remain at rest. This tendency of the body to remain at rest is called it's stationary inertia. The applied force must overcome the body's stationary inertia for motion to occur. If the force is not great enough to overcome the body's stationary inertia the body will remain at rest.

Inertia n A very heavy Barbell has stationary inertia, A large force overcomes this and action occurs. The heavier barbell has greater stationary inertia, force cannot overcome this, motion does not occur and barbell remains at rest.

Inertia An object in motion tends to remain in motion and this tendency is called the body's moving inertia. A force must overcome the body's moving inertia in order to alter the body's motion. The motion of the basketball is altered, i. e. the ball is deflected when a force is applied by the hand.

NEWTONS 3 LAWS OF MOTION The Law of Acceleration (The 2 nd Law of Motion)

Newton's Second Law of Motion = The Law of Acceleration n n The acceleration (change in motion) of a body is proportional to the force causing it, and the change takes place in the direction that the force acts. Newton's Second Law of Motion, the law of acceleration can be expressed as: Acceleration = force / mass

Newton's Second Law of Motion = The Law of Acceleration When a body is acted upon by a force. . . n The greater the force, the greater the acceleration. n The smaller the mass, the greater the acceleration. n The change in motion takes place in the direction in which the force is applied.

NEWTONS 3 LAWS OF MOTION The Law of Action. Reaction (The 3 rd Law of Motion)

Newton's Third Law of Motion Law of Action Reaction n Newton's Third Law of Motion states that “ “For every action, there is an equal and opposite reaction. ”

n n n Newton's Third Law of Motion Law of Action Reaction For every action there is an equal and opposite reaction; A force acting anywhere always has a force equal to that acting in the opposite direction Forces work in pairs opposing one another The initial force (action force) is opposed by a second force (reaction force)

Force Summation n n Force generation by the body is explained in terms of force summation the sequential acceleration of body segments, timing of body parts, Range of Motion (impulse) and Stretching Out. The acceleration of body parts can be greatly improved through the process of FORCE SUMMATION. Force = mass x acceleration

Force Summation n In many sporting actions such as kicking a rugby ball, the desired movement is a combination of a number of body parts and the forces each body part generates. These forces are added together through a sequence of body movements to generate a far greater force. The correct sequence and timing of body parts permits the athlete to produce a greater force and therefore attain optimal velocity at release or contact.

Generating greater force n n The body parts that are large muscle groups can generate large forces. The large force causes a large acceleration in that body part. When that body part reaches peak force then the body part has reached peak acceleration, after which the body part would start decelerating (slow down). Peak force diagram (see teacher notes)

Force Summation & Timing n n The sequence and timing of the body movements are extremely important in order to obtain maximum force generated by each successive body part and therefore maximise the efficiency of the movement. Each successive body part should begin to accelerate when the previous limb has reached peak force, and therefore peak acceleration Look at these examples; Girl throw Man throw The fewer body parts used = less force

Force summation: ROM and stretching out n n Impulse: Applying a Force for a longer period of time Muscular force has to be produced when athletes want to get moving or they want to accelerate an object such as a soccer ball and give it momentum. The force that athletes apply always takes time. When athletes apply force to an object over a certain time , we say that the athlete has applied an IMPULSE to the object. IMPULSE = FORCE x TIME (force is applied for) The longer the time the force is applied for, the greater the impulse. Athletes can apply an impulse to their own bodies or to another athlete or to an object.

Example of ROM n Javelin n The combination of force and time depends on the needs of the skill and sport. Some skills, such as punches in boxing, require tremendous forces applied over a very short time frame. Other skills like throwing a javelin require forces applied over a longer timeframe. An expert javelin thrower accelerates the javelin by pulling it from way behind his body and releasing it far out in front. Long arms are beneficial as is a backward lean entering the throw position, why? The athlete applies the force for a long period and therefore more overall force is produced. To do this an athlete will increase the range of motion, which allows them to apply the force for a longer period of time. Javelin throw

Some working examples Use these clips to apply the principles of force summation we have just discussed Carter kick Tennis serve Tennis Serve 2 Hammer throw Caber toss

Motion Forces produce three types of motion: n Deformative Motion: changing the shape of the body n Linear Motion : moving a body from one place to another in a straight line. n Angular Motion: or rotation , this is where the body rotates or spins about an axis (either internal axis or external axis)

Linear Motion n Where movement occurs in a straight line. During translation, all parts of a body move through the same distance in the same direction in the same time.

Angular Motion During angular motion or rotation all parts of a body move in a circular path around a central axis moving through the same angle, in the same direction in the same time.

Angular Motion There are two types of axis of rotation: n Internal Axis this is when the axis passes through the body, usually at a joint, e. g. . the lower leg rotating a bending at knee joint occurs. n External Axis this is when the axis is outside the body, e. g. . a giant swing in gymnastics.

General Motion n n In physical activity the motion that occurs is quite often a combination of linear motion and rotation. General motion can be described as linear movement of the whole body that is achieved due to the angular motion of some of the body parts.

Projectile Motion n Projectile: Any body that is released into the air becomes projectile and the motion of the projectile is governed by a number of factors

Forces influencing projectile motion Propelling Force Gravity Air Resistance

Propelling force (force at impact or release) The most important force affects the projectile in how far and/or how high it travels.

Gravity n n Acts equally on all objects, accelerating the object towards the ground. Gravity acts on the vertical component of the objects motion

Air resistance n n Air particles through which the object travels, opposes its forward motion. Air resistance opposes the horizontal component of the projectiles motion. The lighter the object or the larger its surface area, the more it is affected by air resistance. Air resistance also increases with speed. e. g. a golf ball drive is more affected than a chip shot onto the green.

Air Resistance

Quantifying Motion n n Having identified the types of motion a body can have; biomechanists need to then quantify (measure) the motion (i. e. describe motion in terms of certain quantities) in order to calculate the forces acting. This information can be used to compare and analyse the efficiency of the motion and movements of the athlete. When we talk about the motion of a body or object we say it moves through a certain displacement (or distance) in a certain time interval. (i. e. it has a certain velocity). If that velocity is changing then the is undergoing acceleration or deceleration

Measuring your motion n See handout and do practical

Factors influencing the Flight Path or Trajectory of a projectile Velocity of release Angle of release Height of release Spin

Velocity of release n The speed at which the projectile leaves the propelling force (bat if hitting, hand if throwing, ground if jumping)

Height of release n Relative to the height at which the projectile lands, whether it is above or below the height at which the projectile was released.

Angle of release n The angle that the projectile is released on its flight path.

Spin n n Imparting spin on the projectile (e. g. . top spin or back spin in tennis or hooking or slicing as in golf), will alter the projectiles flight path, toward the direction of the spin. This is called the “magnus effect”.

Centre of Gravity, Balance and Stability n n n Centre of gravity in physical activity is explained as it relates to balance and stability. Balance implies co-ordination and control, so that the athlete can neutralise those forces that would otherwise disrupt their performance. External forces such as gravity, friction and contact forces applied by opponents can all unbalance there position and upset their performance. Stability relates to how much resistance an athlete “puts up” against having their balance disturbed. The more stable an athlete, the more resistance the athlete puts up against disruptive forces.

Centre of Gravity The point where an object mass is considered to be concentrated n Generally your centre of gravity may be found using the following calculation: MALES: 57% of height (height x 0. 57) FEMALES: 55% of height (height x 0. 55)

Principles of Equilibrium n n n The equilibrium of a body is said to be STABLE if, when being slightly displaced the body tends to return to its original position. The equilibrium is UNSTABLE if the body tends to move further from the original position. Equilibrium relies on: 1. The location of the centre of gravity in relation to the base of support 2. The direction of the forces acting

Principles of Equilibrium n Principle 1 An Athlete increases their stability when their Line of Gravity is centralised within their base of support. n Principle 2 An athlete increases their stability when they increase size of their Base of Support. n Principle 3 An athlete increases their stability when the lower the height of their Centre of Gravity n Principle 4 An athlete increases their stability when they extend their base , Line of Gravity in the direction of an oncoming force.

Principles of Equilibrium n n Principle 5 An athlete increase stability by increasing mass. Principle 6 An increase in Friction can improve an athlete’s Stability Principle 7 Stability Rotation can improve an athlete’s Principle 8 Shifting the line of gravity toward oncoming forces can improve stability

Principles of Equilibrium Stability of a body depends on : The height of the centre of gravity The centrality of the line of gravity The size of the base of support The direction of applied forces The mass of the body Friction Rotation

Momentum n To understand the concept of momentum, how it influences motion and the principle of TRANSFER of MOMENTUM. Momentum is the product of a MASS that has VELOCITY It is the amount of motion a moving object has, is calculated by multiplying the mass of the object by its velocity Momentum = MASS x VELOCITY

Transfer of Momentum Within a Body n n Momentum can also be redistributed from one part of the body to another part of your body. This transfer of momentum is common in jumping, diving and gymnastics.

Transfer of Momentum from one Body to Another Body n n Momentum can also be transferred from one body to another. The momentum that an object possesses due to its motion is an important consideration when there is a collision of objects. In such collisions MOMENTUM is TRANSFERRED from one body to another and vice versus (Newton's 3 rd Law of Motion).

Phases of Execution n A phase is a connected group of movements that appear to stand on their own and that the athlete joins together in the performance of the total skill preparation phase = the initial stance and preparatory movements n action phase, = the force producing movements n post action phase = the follow through or recovery n

Phases of Execution for a Javelin Throw n Preparation phase n n n Grip and Carry Run Up Shoulders rotated back Javelin Drawn Back Cross-over stepping into final throwing stance

Phases of Execution for a Javelin Throw n Execution /action phase = (force producing movements) n n n n Athlete takes are large step into the throwing stance Body Tilted backwards Centre of Gravity Lowered by flexed rear leg Rear Leg rotates forward in direction of throw Hips rotate forward in direction of throw Torso rotates and pulls shoulder and arm forward Lead arm swings back pulling chest and throwing arm forward Elbow flexes then extends as it comes forward to release

Phases of Execution for a Javelin Throw n Post action phase = Follow Through n Trailing leg steps forward n Shoulder and Torso rotate on Follow through n

Newton's 3 Laws of Motion and Movement Sequence Newton's 1 st Law n The javelin, soccer ball, rugby ball will remain at rest until acted on by a force applied by the player. n The Baseball will remain in straight line motion until acted on by a force Bat and Gravity , which act to change its motion

Newton's 3 Laws of Motion and Movement Sequence Newton's 2 nd Law n The acceleration of the javelin, soccer ball, rugby ball or baseball is proportional to the force applied by the athlete (and bat) n The acceleration of the javelin, soccer ball, rugby ball or baseball occur in the direction that the athlete or bat apply the force

Newton's 3 Laws of Motion and Movement Sequence Newton's 3 rd Law of Motion n The bat applies an action force to the ball, but the ball also applies a equal and opposite reaction force back on the bat n The players foot applies an action force to the soccer or rugby ball, but the ball also applies a equal and opposite reaction force back on the players foot

Force Summation and Movement Sequence n n To generate the most force the athlete will use a number of body segments to generate force The force generated in each body segment will be added together as each body part accelerates in a sequential order. The following example describes the sequential acceleration of body parts, resulting in successive force summation: Throwing/Hitting = Legs→hips→torso→shoulder→arm or Kicking = Shoulder→Torso→Hips→ Leg

Force Summation and Movement Sequence n n In order to generate the greatest force most effectively, in any throwing, hitting or kicking activity. The timing of when each successive body part moves is important. Each body segment should accelerate or begin to generate force once the previous segment has reached its peak force stage. The following body part (e. g. . forearm) should begin to accelerate once the preceding body part (e. g. . upper arm) has reached peak acceleration, which would have accelerated once the previous body part (trunk) had reached its peak acceleration.

Force Summation and Movement Sequence n n n If the body parts move to early, before the previous limb reaches peak force or too late, after the previous limb has reached peak force. Then less force is produced. By increasing the Range of Motion the athlete can apply the force for a longer period of time (impulse = force x time) resulting in a larger force being applied increasing the range of motion allows for increase in force. In turn by increasing the range of motion muscles are Stretched Out and the muscles can then contract more forcefully

Projectile Motion and Movement Sequence Forces influencing projectile motion Propelling force The most important force affect the projectile in how far and/or how high it travels. Gravity Acts equally on all objects, accelerating the object towards the ground. Gravity acts on the vertical component of the objects motion. Air resistance Air particles through which the object travels, opposes its forward motion. Air resistance opposes the horizontal component of the projectiles motion

Factors influencing the Flight Path or Trajectory of a projectile. Velocity of release The speed at which the projectile leaves the propelling force (bat if hitting, hand if throwing, ground if jumping) Angle of release The angle that the projectile is released on its flight path. Height of release Relative to the height at which the projectile lands, whether it is above or below the height at which the projectile was released. Spin Imparting spin on the projectile (e. g. . top spin or back spin in tennis or hooking or slicing as in golf), will alter the projectiles flight path, toward the direction of the spin. This is called the “magnus effect”.

Centre of Gravity Balance and Equilibrium Stability in a headstand handstand can be improved by: Increasing the size of the base of support. Maintaining the centrality of the line of gravity inside the base of support. Lowering the height of the centre of gravity. The direction of applied forces. The mass of the body. Friction. Rotation.

Biomechanics Summary n n Forces and Motion involved in human movement (sport performance) Force - push, pull that change state of rest or motion of a body, n F = m x a Types of forces, effects of forces, impulse (range of motion) Newton's Three Laws of Motion Law of Inertia, Law Acceleration and Action/Reaction. Force Summation sequential acceleration of body segments, timing of body parts and range of motion and stretching out.

Biomechanics Summary n n n Motion Linear, Angular and General motion, Measuring Motion – equations. Projectile Motion Forces acting = propelling force, gravity, air-resistance, Influencing factors. = speed, height and angle of release, spin, gravity, air resistance. Centre of Gravity, Balance, Stability and Equilibrium Base of Support, Line of Gravity centralised, Height of C of G, Extend base & C of G into oncoming forces, increase Mass, Increase Friction and rotation.

Biomechanics Summary n n Momentum and Transfer of Momentum Amount of motion a moving object has, Force = mass x velocity In a collision, the momentum of one body can be transferred to another. A complex movement sequence is described in terms of the phases of execution. Javelin, Baseball Hit, Place Kicking a Ball (Soccer or Rugby), Phases of execution - preparation phase, execution/action (force producing) phase, post action phase.

Biomechanics Summary n Biomechanical principles are described as they apply to the sequence. Javelin, Baseball Hit, Place Kicking a Ball (Soccer or Rugby). Biomechanical principles-, Newton’s laws, momentum, projectile motion, force summation, timing of body parts. n Biomechanical principles are described as they apply to the sequence. Gymnastic Balance (Headstand-Handstand) Biomechanical principles – stability and equilibrium, centre of gravity, base of support, Line of Gravity centralised