Term
Speed and Velocity Units
Acceleration Units
Angle Units 

Definition
m/s or ms1
m/s2 or ms2
rad



Term
Significant figures rule 1 

Definition
When multiplying or dividing the final answer has the same number of sinificant figures as the number with the least significant figures 


Term
Significant figures rule 2 

Definition
When adding or subtracting the final answer has the same number of decimal places as the smallets number of decimal places in any term 


Term

Definition
Power = Force x Velocity
Peak power occurs at approx one third of maximum isometric force and an intermediate velocity of contraction 


Term
ACL injury risk factors  Gender 

Definition
 Females  6 to 8 times higher injury rate
 Landing with knees less flexed
 Poor Hamstrings Quadriceps balance
 Hamstrings protection of ACL reduced
 Hamstring coactivation defacit
 Slow activation of Hamstrings



Term
ACL injury risk factors  Poor landing technique 

Definition
 Reduced knee and hip flexion angles
 Increased knee valgues
 Internal rotation of the femur on tibia
Landing/Pivoting with knee extended:
 Patella tendon shear load higher
 Hamstring coactivation less effecive in protecting ACL



Term

Definition
Joint moment (Nm) = Muscle Force (N) x Moment arm (m)
M=Fxd
F=M/d 


Term
Mobility Problems in Older People 

Definition
 Falls
 Balance
 Acciedents
 OA and Chronic Conditions
 Osteoporosis/Fractures
 Ergonomic Problems



Term

Definition
Application of mechanical principles in the study of living organisms 


Term

Definition
The centre of Mass is the point around which the body's mass is equally distributed 


Term

Definition
Upper body (head and trunk)  50%
Arms  5% each  10%
Legs  20% each  40% 


Term
Calculating centre of mass 

Definition
Laying down on board with scales:
Measure and record the length of the board = Board length (D)
Record the mass measured on both scales in kg = M1 & M2
Calculate ratio of the two masses (R) = M1/M2
Divide the length of the board into two segments:
d1=D/R+1
d2=Dd1 


Term
Location of COM in human body 

Definition
Under static conditions, the vertical projection of the COM has to fall within the base of support
The COM can be outside the human body, which has important impliations for sporting performance (eg high jumping) 


Term

Definition
Measured along a path of motion (sum of all movements) 


Term

Definition
Result of movement (straight line between start and finish) 


Term

Definition
Specified by magnitude (number) only. May be positive or negative
Examples: Temperature (T) Volume (V) Mass (m) Time (t) Energy (E) 


Term

Definition
Specified by magnitude and direction
Examples: Displacement, Velocity, Acceleration, Force, Momentum
Can be graphically represented as an arrow 


Term

Definition
Distance 400m
Displacement 0m 


Term

Definition
Distance 200m
Displacement: 100m along straight 62 metres vertically across track.
O = 62
A = 100m
Pythagoras. Square root of 62squared plus 100squared
=118
Calculate angle = O A = TOA = TAN = 62/100 = 0.62
Angle therefore = Inverse Tan (0.62) = 32 degrees 


Term

Definition


Term

Definition
Displacement/Change in time 


Term

Definition
Change in Velocity
Change in Time
Therefore
V2V1
Change in Time



Term
A sprinter's velocity is 3m/s on leaving the blocks and 7m/s two seconds later
What is the acceleration? 

Definition


Term

Definition
Multiply by Pi and divide by 180 


Term

Definition
Multiply by 180 and divide by Pi 


Term

Definition


Term

Definition


Term

Definition
Angle of a body segment in relation to a fixed reference line eg vertical or horizontal 


Term

Definition
Angle at a joint formed between two body segments eg knee, hip or elbow angle 


Term

Definition
A projectile is a body in free fall that is only subject only to the forces of gravity and air resistance 


Term
Factors influencing the trajectory of a projectile 

Definition
Projection height
Projection Angle
Projection Speed 


Term

Definition
For a given projection speed and a given projection height, the optimal angle for max horizonal distance is 45 degrees and max vertical distance is 90 degrees
However in sporting movements the optimum angle is not always 45 degrees  The reasons lie in the anatomical structure of the human body, humans are not machines
Eg optimum shot angle is around 32 degrees
optimum long jump angle is around 22 degrees 


Term

Definition
Is the difference in height from which the body is initially projected and the height at which it lands
The greater the projection height, the greater the horizonal distance 


Term

Definition
The greater the projection speed the greater the horizontal and vertical distances
The horizontal distance increases in proportion to the square of the increase in projection speed



Term
Long Jump example
Take of speed v is 9.81m/s and take of angle is 22.1 calculate the horizontal components of v  vx and vy 

Definition
9.81 = h
to find vx which is a  we have h and need to find a = COS
?/H=COS(0)
?/9.81=COS(22.1)
?=COS(22.1)x9.81 = 9.09 m/s
to find vy which is o  we have h and need to find o = SIN
?/H=SIN(0)
?/9.81=SIN(22.1)
?=SIN(22.1)x9.81 = 3.69 m/s



Term

Definition
Position  m
Distance  m
Displacement  m
Velocity  m/s
Acceleration m/s2 


Term

Definition
Angular position  rad
Angluar distance  rad
Angular displacement  rad
Angular velocity  rad/s
Angular acceleration  rad/s2 


Term
Angular distance and displacement 

Definition
Angular distance  The sum of all angular changes that have occured
Angular displacement  The distance between the initial and the final position of the pendulum:
Final angle  Initial angle 


Term

Definition
Linear:
change in displacement
change in time
Angular (w):
change in displacement (0201)
change in time (t2t1)



Term
Relationship between linear and angular velociy 

Definition
For any given anguar velocity, the linear velocity increases with an increase in the radius of rotation:
Linear velocity = radius of rotation x angular velocity
v=rw
The unit for angular velocity HAS to be rad/s 


Term
Example of relationship between linear and angular velocity
Known: r1 = 0.2m
r2 = 0.4m
w = 30 rad/s 

Definition
0.40.2 = 0.2m
0.2 x 30 = 6 m/s 


Term

Definition
Linear:
Change in velocity
Change in time
Angular:
Change in angular velocity (w2w1)
Change in time (t2t1)



Term

Definition
Step: Right heel contact to Left heel contact
Stride: Right heel contact to Right heel contact 


Term
Swing phase and Stance phase 

Definition
Swing Phase: toe off to heel contact
Single support phase: one foot on the ground
Double support phase: both feet on the ground
Stance phase approx 60%
(20% contact 30% midstance 50% propulsion)
Swing phase approx 40%
In running there is no double support phase, rather a flight phase: both feet off the ground 


Term
Gait calculation exmple:
1.57s
Swing
Stance (contact, midstance, propulsive)
Double support 

Definition
Swing = 0.628
Stance = 0.942
Contact = 0.1884
Midstance = 0.2826
Propulsion = 0.471
Double support is 20% in stride therefore
= 0.314



Term
Cadence and stride frequency 

Definition
Cadence: Quantifies the number of steps per minute steps.min1
Number of steps x 60
Time (s)
Stride freequency: Quantifies the number of strides per second (steps.s1) or Hz
number of strides
time (s) 


Term
Stride and cadence example:
Usain bolt 41 steps in 9.63s
Calculate: Average speed, Number of strides, Average stride length, Cadence, Stride frequency 

Definition
Average speed = 10.38m/s
Number of strides = 20.5
Average stride length = 2.44m
Cadence = 255.45 steps.min1
Stride frequency = 2.13Hz



Term
Normalise stride length by height (stature)


Definition


Term
A more accurate way to calculate joint angles 

Definition
Use anatomical landmarks:
Greater Trochanter of Femur
Lateral Femoral Epicondyle
Lateral Malleolus
Head of fifth metatarsal
Use 2D angles to calculate joint angles properly 


Term
Calculating angles eg hip
Opposite  0.26cm
Adjacent  0.43cm 

Definition
O and A = TOA = TAN
= TAN (0.26/0.43)
= 31.16 degrees 


Term

Definition
Push or a pull
Tends to cause a body to accelerate or change shape
Vector (has magnitude and direction) 


Term

Definition
Kicking or throwing a projectile
pushing feet against the floor
Lifting a weight
Friction
Gravity
Force is a vector
Unit: Newtons (N) 


Term

Definition
A meaaure of a bodys inertia
Depends on quantity of matter of which a body is composed
Units: Kg
Scalar: Magnitude, but no direction 


Term

Definition
Gravitational force exerted on a body by the Earth
Weight = mass x gravitational acceleration (W=mg)
g is the acceleration due to gravity (9.81m/s2 on Earth)
On the moon it is only abut 1.62
Vector (magnitude and direction)
Mass is a measure of a bodys inertia whereas weight is a force due to gravity 


Term

Definition
The acceleration of a body is zero if the sum of all forces acting upon this body is zero 


Term

Definition
Force = Mass x Acceleration
Units: N
1N = 1kg.m/s2
A force applied to a body causes an acceleration of that body which is proportional to the force and inversely proportional to the bodys mass 


Term
Example for F=ma
Sprinter has horizontal velocity of 15m/s2 she has a mass of 58kg
How much force is the sprinter applying to the blocks?


Definition


Term

Definition
Keeps us from falling down by working in opposition to gravity 


Term

Definition
For every action there is an equal and opposite reaction
When a body exerts a force on a second, the second body exerts a reaction force that is equal in magnitude and opposite in direction on the first body 


Term
Ground reaction force example
calculate the reaction force that the ground is exerting on a person of a mass of 80kg 

Definition


Term
peak vertical ground reaction forces 

Definition
walking 1.2 x BW
jogging 2.1 x BW
sprinting 4.8 x BW
Landing after countermovement jump 10 x BW 


Term

Definition
If a force is applied over a period of time, an impulse is applied
An impulse is the product of force and time:
Implse = Force x Time
Vector (magnitude and direction)
Unit: Ns 


Term
Calculating impulse
F = 100N
t = 10s 

Definition
100 x 10 = 1000Ns
An impluse can be though of as the area under a force curve 


Term

Definition
Momentum, M, is a measure of the 'quantity of motion' of a body:
M = mv
m = mass of the body (m)
velocity of the body (v)
Vector
Units: kg.m/s or N.s 


Term

Definition
If the resulatant external force acting on a system is zero, the total momentum of a system remains constant
M1=M2
Total momentum of system at time t1 (M1)
Total momentum of system at time t2 (M2) 


Term
Example problem for momentum
Ice hockey players collide:
A 90kg ice hockey player travelling at 6.0m/s
A 80kg ice hockey player travelling at 7.0m/s
They entangle and continue to move, but at what velocity?


Definition
90 x 6 = 540 kg.m/s
80 x 7 = 560 kg.m/s
540  560 = 170kg (combined mass) (v)
20 = 170 (v)
20/170 = (v)
= 0.12 m/s is the velocity 


Term
Conservation of linear momentum 

Definition
The total momentum of an isolated system is conserved
If the resultant external force acting on the system is zero the total momentum of a system remains constant 


Term

Definition
The change in momentum is equal to the impulse applied to the body
Impulse = change in momentum
Impulse = m2m1
Ft=(Delta) M
We call this the impulse momentun relationship 


Term

Definition
A torque is a force that causes rotation
Torque = Force x Distance (T=Fd)
Vector
Counterclockwise is positive
Units: Nm 


Term
Torque and muscle strength 

Definition
Torque = Muscle force x Moment arm
Muscule strength depends on both muscular force and moment arm
The moment arm of a muscle with respect to a joint axis of rotation depends on the joint angle 


Term
Example: Biecps and tricps cocontraction
F biceps = 2000N
MA biceps = 0.05m
F triceps = 2500N
MA triceps = 0.04m
What movement will occur 

Definition
2000 x 0.05 = 100Nm
2500 x 0.04 = 100Nm
100100 = 0Nm
Isomeric contraction



Term
Why is it difficult for a cyclist to accelerate? 

Definition
The moment of inertia is the property of a body to resist rotation
It is the angular equivalent for mass
Mass is the property of a body to resist linear acceleration 


Term

Definition
Depends on:
 The mass of the body
 How the mass is distributed about the axis of rotation
I=mk2
I = moment of inertia
m = mass of the body
k = radius of gyration
Units: Kg.m2
Scalar (magnitude, no direction) 


Term
Application of newtons 2nd law 

Definition
Force = Mass x Acceleration
Torque = Moment of inertia x Angular acceleration 


Term
Torque and force example
knee extensors 3cm from axis of rotation at knee
How much force must the knee extensors exert to produce an angular acceleration at the knee of 1rad/s2 at a given moment of inertia of 0.24kg.m2 

Definition
Moment of inertia = 0.24
Acceleration = 1 rad/s2
Torque = 0.24 x 1 = 0.24 Nm
Required force therefore is:
Force = Torque/Distance
0.24/0.3 = 8.0 N



Term

Definition
Angular momentum is a measure of angular motion possesed by a body
Angular momentum = Moment of inertia x Angular velocity
H = Iw
Units: Kg.m2/s
Vector 


Term
Angular momentum example
Moment of inertia of diver = 6 kg.m2
Angular velocity of diver = 9.2 rad/s
What is the angular momentum? 

Definition
H = Iw
H = 6 x 9.2
H = 55 Kg.m2/s (clockwise) 


Term
Conservation of linear and angular momentum 

Definition
The total (linear) momentum of an isoalted system is conserved
If the resultant external force acting on the system is zero the total momentum of a system remains constant
The total angular momentum of an isolated system is conserved
If the resultant external torque acting on the system the total angular momentum of a system reamains constant 


Term
Conservation of angular momentum in a dive example
Moment of inertia at take of is 14 kg.m2
Angular velocity at take of is 2.6 rad/s
Moment of inertia in pike is 5.8 kg.m2
Angular velocity as take of is what? 

Definition
H = Iw
14.0 x 2.6 = 36.4
Angular momentum must be conserved therefore angular momentum must remain as 36.4
rearrange equation to H/I = w
36.4/5.8 = 6.3 rad/s 


Term
Angular analogues/equivalents 

Definition
Linear  Angular
Force  Torque
Force = mass x acceleration  Torque = Moment inertia x agular acceleration
Linear momentum (M=mv)  Angular momentum (H=Iw)
Work = Fd  Work = T0
Power = Fv  Power = Tw
Linear Impulse Ft  Angular Impulse Tt 


Term
Models and types of models 

Definition
A model can be defined as an artificial representation of reality
Types of biomechanical models are as follows:
 Conceptual
 Statistial or regression
 Mathmatical (computer)
Models can be used to increase knowledge and insight about reality and estimate or predict variables of interest 


Term
Information used to construct a model 

Definition
1. Knowledge of the system being modelled
2. Experimental data that constitute system inputs and/or outputs
In general simple is better, need to decide what should be neglected and included 


Term

Definition
Direct or indirect
In direct use, the model proceeds from cause to effect, nd typically yields a unique solution
In inverse use, a model attempts to move from the effect to the cause and typically yields several possible solutions (not unique) 


Term
Types of mathmatical models for sports motions 

Definition
 Point mass (Athlete or implament)
 Rigid body
 Musculoskeletal
Simulation nvolves the performance of a series of controlled experiments using the model



Term
Blocks to sprinting power 

Definition
First step: 54% hip 31% knee and 15% ankle
Stecond stance: knee only accounts for 9% total power and ankle up to 38%
Maximal velocity: 39% hip 17% knee and 44% ankle 


Term

Definition
The end of the chain is not freely moveable
Characterised by:
 High force production
 Low or moderate movement velocity
 Push like movement pattern (all joint angles change simultaneously)



Term

Definition
The end of the chain is freely moveable
Characterised by:
 Can operate push like
 High force or high accuracy
 All joint angles move simultaneously
 Can operate throw like
 Joint angles occur in a sequential order
 This maximises movement velocity



Term
How do we maximise throwing distance? 

Definition
By maximising projection speed
By rotating segments sequentially
Kinetic chain is all about angular momentum being transerred through segments
Eg trunk moves and angular momentum is transferred to arm, moment of inertia of the arm is smaller and so angular velocity must increase to conserve angular momentum 


Term
Baseball pitcher example
Trunk rotation of 0.43 rad/s
moment inertia of trunk 2.4 kg.m2
Trunk stops rotating and momentum transferred to arm with a moment of inertia of 0.023 kg.m2


Definition
Angular momentum generated = 0.43 x 2.4 = 1.032 kg.m2/s
Angular velocity of arm after momentum transerref = 1.032/0.023 = 45 rad/s 


Term
Mono and Biarticular muscles 

Definition
The function of monoarticular muscles is predominantly the generation of momentum
The function of biarticular muscles includes both the generation and transfer of momentum (also contribute to more than one motion) 


Term

Definition
If a force is applied over a distance mechanical work is performed
Work is the product of force and displacement
Work = Force x Displacement
Scalar
Units: J 


Term
Work example
How much work is performed?
Mass of bar bells = 250kg
moved 0.75m 

Definition
First must convert mass into weight 250 x 9.81 = 2452.5 N
2452.5 x 0.75 = 1839.375 J 


Term

Definition
Power is the rate at which work is done
Power = work/change in time
Scalar
Units: Watts (W) 


Term
Alternative expression for power 

Definition
Power is the product of force and velocity
P = w/change in time = force x distance/time
= F x d/change in time = Force x Velocity
P = Force x Velocity 


Term
Power example
A power lifter lifts 236kg over a distance of 0.62m in a time of 0.42 seconds 

Definition
236 x 9.81 = 2315.16 N x 0.62 =
1435.3992 J
1435.3992/0.42 = 3417.6 W 


Term

Definition
Energy is a body's capacity to do work, forms of energy incule: kinetic, gravitational potential, elastic potential, chemical, thermal (heat)
Kinetic energy is the energy of motion
KE=1/2.m.v2
m = mass of body
v = speed of body
Scalar
Units: J 


Term
Kentic energy of pole vaulter example
Mass of pole vaulter = 80kg
Speed at end of run up = 9.5 m/s


Definition
0.5 x 80 x 9.5 sqaured = 3610 J



Term
Gravitational Potential energy 

Definition
Gravitational energy is the enrgy due to a body's height above a reference surface
Graviational potential energy is the product of a body's weight and height
PEgrav = mgh
m = mass of body
g = acceleration due to gravity (9.81m/s2)
h = vertical height above reference level 


Term
Gravitational potential energy example
mass of diver 78kg
height of centre of mass above water 3.83m


Definition
78 x 9.81 x 3.83 = 2930.6 J 


Term

Definition
Elastic potential energy is the energy stored in a spring
PEelastic = 0.5 . k . x2
k = stiffness of the spring
x = deformation of the spring
Scalar
Units: J
The total amount of enery is always consered, no energy is lost, simply transformed from one form to another 


Term
Pole vault example
Mass of vaulter 80kg
Height of vaulter = 5.50m
What is the vaulters velocity at touchdown? 

Definition
Use conervation of energy
Grav potential energy = KE at touch down
80 x 9.81 x 5.50 = 0.5 x 80 x v2
4316 = 40 x v2
4316/40 = v2
107.9 = v2
sqaure root 107.9 = v
10.39 m/s
because he's falling



Term
Coefficient of restitution 

Definition
Bounce height = Drop height x e2 


Term
Hockey problem advanced
90kg at 6m/s
80kg at 7m/s
Calculate energy loss as a result of the collision 

Definition
Before the impact = (0.5 x 90 x 6 squared) + (0.5 x 80 x 7 squared) = 3580 J
(90 x 6 = 540)  (80 x 7 = 560) = 20 = 170 (v)
0.12m/s
After the impact = 0.5 x 170 x 0.12 squared = 1.224 J
3580  1.224 = 3578.776 J



Term

Definition
The resistance force that acts at the interface
between two surfaces in contact
Arises due to applied force that produces relative motion (kinetic friction), or tends to produce relative motion (static friction)
Force therefore, units are: Newtons 


Term
Causes of surface friction 

Definition
Mechanical interaction between two bodies or surfaces (studs, cleats, spikes)
 Molecular interaction between two surfaces eg: sole of a sports shoe and the court such as basketball and netball
 Hand and a sports ball or implament eg: netball pass, discus throw, high bar or weight lifting
 Due to surface roughness, contact is only made at a few points
 This causes electrostatic force between atoms or moecules
 Leading to 'breaking off' of surface protrusions



Term

Definition
Magnitude of the friction force, F, is given by
F = uR
u = coefficient of friction
R = normal reaction force
Vector: Direction of friction force is opposite to the direction of motion (or opposite to the direction of aplied force)
Units: Newton (N) 


Term

Definition
Two surfaces are in relative motion (slding);
Fk = ukR
Fk = Kinetic friction force
Uk = coefficient of kinetic friction
R = Normal reaction force 


Term

Definition
Two surfaces are stationary;
Fs (less than or equal to) usR
Fm = usR
Fs = static friction force
Fm = maximum static friction force
us = coefficient of static friction
R = normal reaction force



Term
Coefficient of friction (u) 

Definition
 A dimensionless number (no units)
 An indicator of the ease of sliding of two surfaces (low value of u means easy sliding)
 Coefficent of static friction is greater than coefficient of kinetic friction (it is more difficult to get a body sliding than it is to keep sliding



Term
Example problem (friction)
The coefficient of static friction between a sled and
the snow is 0.18 with a coefficient of kinetic
friction of 0.15. A 250 N boy sits on the 200 N
sled.
a. How much force directed parallel to the
horizontal surface is required to start the sled in
motion?
b. How much force is required to keep the sled in
motion? 

Definition
To start the sled in motion, the applied force must exceed the force of maximum static friction:
Fm =usR
Fm = (0.18) (200+250)
=81N
Therefore the applied force must be greater than 81 Newtons
To maintain motion the applied force must equal the force of kinetic friction:
Fk =ukR
Fk = (0.15) (200+250)
=67.5N
Therefore the applied force must be at least 67.5 newtons 


Term
Example problem 2 (friction)
A sled including its passenger weighs 1200 N. It
takes a horizontal force of 250 N to start the sled
in motion. Once the sled is moving a force of 220
N is required to keep the sled in motion.
a. What is the coefficient of static friction?
b. What is the coefficient of kinetic friction?


Definition
a. Fm = usR
250 = (us)(1200)
250/1200 = us
= 0.21
b. Fk = ukR
220 = (uk)(1200)
220/1200 = uk
=0.18 


Term
Factors that do not affect friction 

Definition
Contact area eg size of shoe sole
Relative speed of two surfaces (the coefficient of kinetic friction is almost independent of the speed of the two surfaces 


Term
Practical ways to increase or decrease friction


Definition
Increase/decrease the weight of the body
(Increase/decrease the normal reaction force)
Pull up/push down on the body
(increase/decrease the normal reaction force)
Apply a lubricant to the surface(s)
 Water, oil, graphite powder, chalk
this reduces the coefficent of friction between the two surfaces
Change one or both of the surfaces
eg a rougher or smoother surface
(increases or decreases the coefficient of friction between the two surfaces)



Term
Applications of friction in sport 

Definition
– tests for playing surfaces in field sports
(hockey, American football)
– ice surface in winter sports (bobsled)
– ball surface texture (basketball, rugby)
– gloves (Football, American football)
– chalk and glue (gymnastics, weightlifting,
throwing, pole vaulting)
– body oil, sweat (wrestling) 


Term
Measuring the coefficient of friction 

Definition
Horizontal sliding of two surfaces
measure the applied force with a spring balance or load cell)
Inclined plane
applied force increases with increasing angle
measure the angle at which the body begins to slide 


Term
Aerodynamic and hydrodynamic drag force 

Definition
Form drag (also called pressure drag or profile drag)
Skin friction
Mechanism of form drag
 fluid separates from the surface of the body
 crates a turbulent wake
 energy is lost from the body in creating the eddy currents
 This creates regions of higher and lower pressure



Term

Definition
 Fluid density  Air = low density, low drag  Water = high density, high drag (form drag is important in water sports)
 The frontal area  size of the body, ball or implament
 Speed  Drag increases with speed (Flow separates earlier; greater turbulant wake = more drag
 Shape  more streamlined the body the later the flow separates leading to less turbulant wake = less drag



Term

Definition
Density of fluid (p)
air: 1.20 kg/m3; Water: 1000 kg/m3
Cross sectional (frontal) area (Ap)
Drag coefficient (Cd); depends on shape of the body
relative speed of the body and fluid (v)
The aerodynamic/hydrodynamic 'form drag' force FD, is given by
FD = ½ApCdv²
Vector: oppose the forward motion of the body in the fluid
Units: N



Term
Example drag problem
Usain Bolt (JAM) reached a
top speed of 12.2 m/s
Calculate the form drag force acting on Bolt at
this speed.
(Bolt has a frontal area of 0.50 m2 and a
drag coefficient of 0.60).
What forward propulsive power was Bolt
generating to overcome this drag force?
Remember, the air density is 1.20 kg/m3


Definition
½ x 1.2 x 0.5 x 0.6 x 12.2² = 26.8N 


Term

Definition
• Use ‘streamlined’ equipment (with a lower CD)
• use teardrop shapes
• Use ‘streamlined’ body position (with a lower AD)
– use teardrop shapes


