Week 1 Flashcards
What is biomechanics
Synthesis of biology and mechanics that seeks to
understand and explain human movement
Biomechanics is used in the analysis of: name 4
Sports technique Improve performance Predict performance Monitor rehab Assess equipment Design equipment Postural deficiencies Work environments Prevent injuries
Describes motion
A movement that occurs without force - Kinematics
The study of forces that cause motion
Kinetics
Two types of Kinetics
Torque and Force
Three types of Kinematics
Displacement, Velocity, Acceleration
Kinematics and Kinetics can be both Linear and _______
Angular
Scalar measurement
A physical quantity that is described by its magnitude
Vector measurement
Vector is a measurement that refers to both the magnitude of the unit and the direction of the movement the unit has taken
Examples of scalar measurements
Mass, distance, speed, time
Examples of vector measurements
Force, displacement, velocity, acceleration
Qualitative in reference to biomechanics
Implies that description of motion is done without the use of numbers
Quantitative in reference to biomechanics
Implies that description is made with numbers
3 types of motion
Linear - translatory motion
Angular - rotation around an axis
General - combination of both linear and angular
Rectilinear
Straight line - 100m run
Curvilinear
Slight curve to the linear motion - long jump
Two types of axis in angular motion
Internal and external axis
What plane would elbow flexion be in from the anatomical position
Sagittal plane
What plane would hip abduction be in from the anatomical position
Frontal plane
Internal rotation of the leg would be in what plane
Transverse plane
Linear displacement
Vector - Change in location from the initial to the final position (must contain direction)
Linear velocity
Vector - The rate of change in displacement
Linear velocity equation
𝑣 =∆ 𝑑 / ∆ 𝑡
∆ = change
Linear acceleration
The rate of change in velocity
Linear acceleration equation
𝑎 =∆ 𝑣 / ∆ 𝑡
broken down into:
𝑎 = 𝑣f − 𝑣i / 𝑡f − 𝑡i
vf = velocity final vi = velocity initial tf = time final ti = time initial
(∆ = change)
What is the average acceleration of a runner who is travelling at a
velocity of 2 m/s forwards at 1 second and at 6 m/s by 7 seconds?
a = 0.66 m/s2 forwards
Average velocity
Velocity throughout a given time period
e.g. Velocity of golf club throughout swing
Instantaneous velocity
Velocity at a precise point in time (at an instant)
e.g. Velocity of golf club upon impact with ball
Instantaneous velocity equation
𝑣𝑖 = 𝑑𝑖+1 − 𝑑𝑖 −1 / 𝑡𝑖+1 − 𝑡𝑖 −1
vi = velocity at an instant (i) in time (measured in m/s)
di + 1 = displacement at frame after instant (measured in m)
di - 1 = displacement at frame before instant (measured in m)
ti + 1 = time at frame after instant (measured in s)
ti - 1 = time at frame before instant (measured in s)
Usain bolt’s 100m sprint. 6 frames were captured with his time and displacement.
Calculate the instantaneous velocity of frame 5 with the values of frame 4 (4.85s & 60m) and frame 6 (9.58s & 100m)
8.46 m/s
rounded to two decimal places
Instantaneous acceleration equation
𝑎𝑖 = 𝑣𝑖+1 − 𝑣𝑖 −1 / 𝑡𝑖+1 − 𝑡𝑖 −1
Does -ve acceleration mean you’re slowing down?
No as you could be accelerating in a negative direction
When you are at maximum velocity, what is your acceleration?
zero
