Understanding Human Patterns (LOIL 2)

Question 1

state 2 additional facts about the Stretch-Shortening Cycle in reference to efficiency and running

Answer 1

1. the SS cycle is also responsible for making movements more efficient
2. the metabolic cost of running reduces by approx 30% due to elastic storage and return of tendons in the leg, reducing the work done by the muscles

Question 2

state what it is meant by the key term - Gait

Answer 2

gait is the word used to describe a pattern of movement of the limbs during locomotion

Question 3

what type of gait is running and walking said to be, and why ? (3 points)

Answer 3

1. both running and walking are SYMMETRICAL forms of gait
2. the two legs and arms go through the same movement pattern out of phase with one another
3. each leg moves through a stance and a swing phase in a stride

Question 4

state what it is meant by the key term - stance phase

Answer 4

in the stance phase, the leg is in contact with the ground and is supporting body weight

Question 5

state what it is meant by the key term - swing phase

Answer 5

in the swing phase, the leg is not in contact with the ground, and it being swung forward to be positioned for the next stance phase

Question 6

what occurs during walking gait, but not in running gait ?

Answer 6

during walking gait, there are periods of single support (one leg on the ground) and periods of double support (both legs on the ground)

Question 7

state 3 differences between running and walking gait

Answer 7

Walking:

1. always one limb on the ground
2. double stance phases
3. leg is relatively stiff

Running:

1. flight phase between each step
2. bouncing gait
3. leg is relatively swingy

Question 8

what is the calculation for running velocity ?

Answer 8

V = SL x SF

Question 9

as speed increases, what happens to running performance ? (2 facts)

Answer 9

1. as speed increases, the amount of time spent in the stance relative to the swing (duty factor) decreases
2. this means that greater forces are required from the muscles to support body weight

Question 10

explain the following in 3 points - ‘Running Stance Phase Joint Action’

Answer 10

1. limb is retracted with hip extension
2. the leg absorbs energy as the knee flexes and ankle dorsiflexes during the 1st half of the stance, actively stretching the quadriceps and the triceps surae
3. as the joint re-extends during the 2nd half of the stance phase, they propel the body into flight (or float) phase

Question 11

explain the following in 5 points - ‘Running Swing Phase Joint Action’

Answer 11

1. the hip flexes to protract the limb and then begins to extend just prior to the hip strike
2. the knee flexes as a result of energy storage during the toe off phase
3. knee extends in the 2nd half of the swing
4. combination of hip flexion and knee extension stretch bi-articular ham-string muscles
5. ham-string muscles are active at this part of the stride, therefore undergo an eccentric contraction

Question 12

how can you use ‘protocol timing equipment’ to measure running speed ? (3 points)

Answer 12

1. when an object (eg - a runner) cuts the beam, it gives a signal to the timer to start the count
2. the timer is stopped by cutting the second beam
3. knowing distance and time taken, you can calculate the average speed

Question 13

state 3 advantages of measuring kinematic video

Answer 13

1. it doesn’t interfere with the athlete
2. easy to perform
3. very transportable

Question 14

state 2 disadvantages of measuring kinematic video

Answer 14

1. very time consuming

2. digitising errors

Question 15

GRF can be measured in what 3 ways ?

Answer 15

1. vertical: supports BW
2. anterior-posterior: accelerated and decelerates the COM
3. mediolateral: side to side stability and turning

Question 16

state 2 ways of measuring muscular strength

Answer 16

1. isokinetic dynamometer

2. hand held dynamometer

Question 17

state 1 way of measuring muscle activation

Answer 17

EMG

Question 18

state 2 ways of measuring muscular force

Answer 18

1. simulation modelling

2. indwelling transducers

Question 19

state 1 way of measuring muscle length and architecture

Answer 19

ultrasound

Question 20

what 3 things are you able to measure with EMG ?

Answer 20

1. when a muscle is turned on and off
2. whether a muscle is active or passive during a movement
3. the magnitude of the activation

Question 21

what can’t an EMG measure, and why ?

Answer 21

1. can’t measure muscle force

2. muscle force is dependent on activation, fibre length and contraction velocity