Chapter 5 PowerPoint Flashcards
What is kinematics?
The study or description of the spatial (3D world) and Temporal (time) characteristics of motion without regard for causative forces.
Kinematics can be said to be: Form or technique used to describe ____ with respect to ____?
Form or technique used to describe movement with respect to time
What two general aspects of observation does kinematics involve?
Qualitative: Visual Observation
Quantitative: Measuring, Biomechanist’s researching factors limiting performance
What are five visually observable aspects of technique or form?
Patterns
Sequencing
Shapes
Angles
Lines
What is motion?
Motion – Change in position with respect to a reference point
What is distance?
Distance (l) - The directed distance from initial to final location; Length.
Measured in Meters or feet
units of cm, m, km or inches, feet, yards.
What is displacement?
Displacement (d)- Vector quantity for distance. Right Angles
Calculated (final position – initial position in that direction)
Horizontal and Vertical vectors.
Positive and Negative used for direction.
Why do biomechanists use displacement rather than distance?
Biomechanist’s often use displacement rather than distance because directional information is crucial to calculation of kinematic and kinetic variables.
Skaters distance traveled=?
Skater’s distance traveled = measured from the track left on the ice.
Skaters displacement=?
Skater’s displacement = measured in a straight line from start to finish.
What is speed?
Distance covered over the time interval
How fast an object is moving w/o regard to direction
A scalar quantity
m/s, ft/s, Km/hr, mph
distance
Speed = distance/time = Length/change in time
What is the equation for speed?
s = 𝑙/Δ𝑡
What is velocity?
Velocity (V) – The speed of an object, in a particular direction
V = change in position / change in time
Units are the same as speed but with + or –
Rate of change of displacement - How quickly position is changing in the specific direction.
+ m/s, - ft/s, + mph
What is the equation for velocity?
V = change in displacement/change in time
What is peak rate of motion?
Peak rate of motion: maximum rate of motion achieved
What is average speed/velocity?
Average speed/velocity: speed or velocity divided by the entire interval over which it is measured
What is instantaneous speed/instantaneous velocity?
Instantaneous speed/Instantaneous velocity: the rate of motion at one given instant in time
What is stride length primarily influenced by?
Stride length influenced Primarily by: Body Height
What 6 things is stride length influenced by secondarily?
Muscle fiber composition, Footwear, Level of fatigue, Injury history, Inclination(grade), Stiffness of running surface.
Running Velocity is the product of ____ ____ and ____ ____?
Running Velocity is the product of stride length and stride frequency.
Most regular runners tend to chose a combo of ____ ____ and ____ ____that minimizes the ____ cost of running. Naturally adjusting to their runner’s economy and Oxygen consumption for the given task?
Most regular runners tend to chose a combo of stride length and stride frequency that minimizes the physiological cost of running. Naturally adjusting to their runner’s economy and Oxygen consumption for the given task.
Over-striding puts ____ at risk for injury?
Over-striding puts hamstrings at risk for injury
Elite performers use ____ to manipulate ____ for increased results?
Elite performers use techniques to manipulate variables for increased results
What is acceleration?
change in magnitude and/or direction of the velocity vector with respect to time
The rate of change in linear velocity
What is the equation for acceleration?
change in velocity
Acceleration = change in velocity/time
a = V2-V1/t
In what instances will acceleration be 0, positive, or negative?
Acceleration can be 0:
Velocityfinal = velocityinitial
Acceleration can be positive:
Velocityfinal > velocityinitial
Acceleration can be negative:
Velocityfinal < velocityinitial
Acceleration may be ____, ____, or equal to ____, based on the direction of ____ and the direction of the ____ in velocity.
Acceleration may be positive, negative, or equal to zero, based on the direction of motion and the direction of the change in velocity.
What is average acceleration?
Average acceleration: the rate of change in velocity divided by the entire interval over which it changed
What is instantaneous acceleration?
Instantaneous acceleration: the rate of change in velocity at one specific instant in time
What is linear kinetics + 3 examples?
Kinetics: the study of the forces that inhibit, cause, facilitate, or modify the motion of a body
Forces such as gravity, air resistance and friction
Without forces (____), the spatial and temporal characteristics of motion (____) remain constant.
Without forces (Kinetic), the spatial and temporal characteristics of motion (Kinematics) remain constant.
Newton’s first law?
1st Law: Inertia - A body will maintain a state of rest or constant velocity unless acted on by an external force that changes the state.