S2- Lab 1- Assessment of Gait and Vertical Jumping

Question 1

What is a Pedotti diagram?

Answer 1

A vector diagram

Measures horizontal forces and vertical ground reaction forces.

Question 2

Sketch a graph of the horizontal and vertical forces during walking?

Answer 2

Upwards= Force (N )
Across= Time (s)

Above 0= forwards
Below 0=backwards

Question 3

Sketch a force trace of an athlete performing a vertical jump from stationary
1. Standing still on force plate

2. Point of take off
3. Flight phase
4. Peak force on landing

Answer 3

Middle of up axis= 1BW

Bottom of up axis= 0N

Straight dotted line from 1BW

1- flat line from 1BW

A dip down, a large dip up and BACK DOWN

2-3= a line on the 0N line

4- back up from 0N to top

Question 4

How do we calculate the height of the COM for a participant?

Answer 4

Using the reaction board

Height of the mass centre at take off = (H1)

Question 5

Define impulse?

Answer 5

A change in momentum

(note that for vertical impulse, the impulse due to the participants weight (mass x acceleration due to gravity) must first be subtracted)

Question 6

What did Dapena report (1988)?

Answer 6

For the take off step in high jump, the vertical COM velocity as the foot contacts the ground can be assumed to be -0.1ms-1

Question 7

What’s an equation of constant acceleration (example)?

Answer 7

(v2 = u2 + 2as)

Can be used to calculate flight height
(H2)

Question 8

What do H1, H2 and H3 stand for when calculating theoretical high jump performance?

Answer 8

Theoretical high jump performance= H1 +H2 -H3

H1= height of mass centre at takeoff

H2= flight height

H3= Dapenas optimal value of 0.02 for H3

Question 9

What background information is needed when looking at single footed jumps?

Answer 9

Momentum= mass x velocity

Impulse= change in momentum

METHOD: Record the ground reaction forces as your groups participant performs a running jump for maximum height using a single footed take off from the force plate

Question 10

How can we calculate the vertical CoM take off velocity of the jump?

Calculation- contact phase

Answer 10

Using time of contact and total vertical force integral from BioWare as inputs

Weight integral= weight x time of contact

Jump impulse= total vertical integral (computer) - weight integral

Jump impulse= change in momentum
= mass x (take off velocity- touchdown velocity)

Question 11

How can we calculate the vertical CoM take off velocity of the jump?

Calculation- flight phase

Answer 11

Use an equation of constant accelearation (v2 =u2 + 2as) to calculate free flight height (H2)

Using Daphne’s optimal value of 0.02 for H3 (ie: COM can pass 0.02 m below the bar) calculate the subjects theoretical high jump performance from H1, H2 and H3:

Theoretical jump performance= H1 + H2 - H3