W5&6 Vision in Sport & Advance Cue Utilisation

Question 1

Eye structure

Answer 1

• cornea -> transparent thin outer layer
• pupil -> hole light enters through - size and amount of light entering controlled by intraocular muscles
• lens -> can change shape to focus different distances
• retina -> photosensitive - back of eye - retina senses light and converts to electrical signal
  -> rods - sensitive to dim light - peripheral vision
  -> cones - sensitive to bright light - detailed central vision
• optic nerve - transmits info to brain

Question 2

Binocular vision

Answer 2

• two eyes
• light hits retina at different point inn each eye
• that difference tells us how far away something is
• hemiretina -> hemi means half - two hemiretinas in each eye
• Nasal hemiretina -> closest to your nose so on the right in your left eye and left of right eye
• Temporal hemiretina -> on the outside
• The information from temporal hemiretinas doesn’t cross over when it goes through the optical nerve, whereas the two nasal parts do cross over
• This means that all information from the right half of your visual field goes down the left optic tract to your brain and all info from the left half of your visual field goes down the right optic tract to brain

Question 3

Types of eye movements

Answer 3

Fixations:
- Central visual field (within 3°)
- Duration 100 ms or longer
- Conscious processing
Saccades:
- Rapid eye movements
- Between fixations - not focused vision that can’t be processed as well
- Information is suppressed - not getting as much information and not being consciously processed

Question 4

Visual streams (Norma, 2002)

Answer 4

(Norma, 2002)
- where within the brain the info goes once it leaves the eye
Focal vision (ventral):
- Identification (“what?”)
- Central visual field
- Conscious
- Slower
Ambient vision (dorsal):
- Optical flow (“where?”)
- Central & peripheral visual field
- Nonconscious
- Faster

Question 5

Time course of visual information

Answer 5

• Everything from the eye goes through the occipital lobe, then there’s two different pathways
• Dorsal stream goes to parietal lobe
• Ventral stream goes to temporal lobe
• The dorsal and ventral streams then join up again as they both go to frontal lobe, which is where we consciously process and decide on a response
• Then that information goes through premotor & motor cortex, where we decide on and programme all of our movements/motor programmes within the brain
• Once it leaves the motor cortex we have decided what movement we want to do and send that information via efferent neurons with an action potential towards the appropriate motor units

Question 6

Time to contact - optical flow

Answer 6

• Further away = relatively small part of retina = look smaller
• Closer = larger part of retina = look bigger
• So the closer you are to contact with something, the more space on the retina it will take up
• how much electrical stimulation gives information around perceiving how much time there is until contact

Question 7

Time to contact (tau τ)

Answer 7

• need to know how big something is and how fast it is moving
• The mapping of visual information onto the retina can give us current size and the rate of expansion which can be perceived
• not consciously calculating time to contact it’s subconsciously perceived - you learn to perceive the combination of the two things

Question 8

Time to contact - table tennis example

Answer 8

(Bootsma & van Wieringen, 1990)
- table tennis players were perceiving time to contact with the ball and then varying parts of their swing to keep the final important contact consistent

Question 9

Time to contact - long jump example

Answer 9

(Lee et al., 1982)
- Long jumpers perceive time to contact to ensure correct take off by varying the vertical impulse they applied to the ground on the stride before take off

Question 10

Time to contact - diving example

Answer 10

(Sayyah et al., 2018)
- Perceived time to entry with water that told divers when to exit their pike position to speed up or slow down their rotation

Question 11

Interceptive tasks

Answer 11

• anything involving timing your movements in relation to something you are trying to catch/intercept/tackle (ball/opposition player)

Question 12

Interceptive tasks - image direction on retina

Answer 12

• imagine travelling in same direction on both retinas -> going to miss you on that side
• less speed difference between the two eyes - going to miss/pass wider

Question 13

Interceptive tasks - run to catch/intercept - rate of change of tau

Answer 13

• If you know time to contact is 1 sec and you can adapt your running speed to get there in 1 sec then you’ll be able to catch/intercept it
• The rate of change of tau is the most important thing here - need to know how quickly the time until contact is changing so you can speed up or slow down
• Rate of change of tau is indicated by a dot above it - tau-dot
• tau-dot = 0 -> both people moving at same speed, gap not changing
• If you want to close that gap you need a negative tau-dot
• A positive rate of change of tau means there would never be contact because the two things are getting further and further away
• The more negative tau-dot is, the faster you’re going to close the gap and get to the player to tackle them

Question 14

Interceptive tasks - rate of change of tau - balloon example

Answer 14

• letting out air in a balloon as it’s coming towards you so it changes size and people can’t catch it
• shows that people are using the rate of change of an object in their visual field to judge time to contact and catch it

Question 15

Counterargument to speed-accuracy trade off

Answer 15

• you’ve only got one maximum
• If you were told to run at 100% effort you might be more consistent than if you were told to run at 50% effort because how do you actually control that 50%
• more consistent in something that is maximal because there is no variability in ways that you can do it
• It’s often easier to time something maximally than sub-maximally

Question 16

What cues to cricket batters use? (study)

Answer 16

(Müller & Abernethy, 2006)
- visual occlusions
- no occlusion -> all players were pretty accurate, with higher-skilled batters being slightly more accurate
- occluded pre-bounce -> still both groups were still quite successful
-> Tells us that batters weren’t using information from after the bounce anyway because they perform just as well with information after the bounce removed
- When occluded pre-release, lower skilled batters can’t bat accurately at all really whereas higher-skilled batters were still almost 50% accurate
-> Tells us that higher level batters are able to use earlier information (before the ball is even released)

Question 17

Tracking a ball - cricket batters (study)

Answer 17

(Land & McLeod, 2000)
- cricket batters wearing eye tracking goggles
- all levels of batter tried to track the ball from the first 100-200ms of the flight of the ball
- The elite batters then make a saccade to where they predict the ball is going to bounce
- lower level batters are less accurate at using the early information to predict the bounce
- After the bounce the lite then tracked the ball again - might be using this late information just to check they’ve got it right and maybe adjust if something changes
- The elite saccade allowed longer viewing before and after the bounce

Question 18

Cricket bowling machine

Answer 18

• Removes the pre-release information which batters use
• If the most important information to a batter is before release then why are we coaching people by firing balls from a machine where that pre-release information isn’t available
• good for reducing bowlers workload and avoiding injuries to bowlers

Question 19

Sidearm thrower

Answer 19

• Allows bowler to put a bit more speed on it without a full run up and bowling speed
• coach could use it, don’t need actual bowlers
• reduces workload on bowlers

Question 20

Effect of delivery method - deterministic model applied to cricket batting

Answer 20

(Peploe et al., 2018, 2019)
- The idea is to start with your outcome of interest, then look at what factors cause that, then what factors cause that, until you get to the actual technique things that a coach could change
- Distance ball travels is a function of the angle and speed of the ball when it leaves the bat
- The angle of the ball is determined by the angle of the bat when they make contact with the ball
- Ball launch speed is a combination of bat-ball impact location (middle of the bat sweet spot better than edge of bat) and bat speed at impact
- bat speed is where the technique starts to come in
- X-factor is something that comes from golf and baseball research
-> If you can your shoulders and leave your hips behind then the two lines will separate and create an X
- lead elbow extension
-> Extending the lead arm down into the ball instead of keeping it flexed
- Wrist uncocking
-> Using the wrist, cocking and uncocking the wrist is better than keeping it flexed
- X-factor most important, lead elbow extension 2nd, wrist uncocking 3rd
-> Proximal to distal sequence (kinetic chain)

Question 21

Effect of delivery method study

Answer 21

(McErlain-Naylor et al., 2020)
- compared technique of cricket batters against 3 different delivery types
-> real bowler, bowling machine, sidearm thrower
- Against a bowler, when there’s the most possible visual info available, the batters had the biggest X-factor
- Against the sidearm thrower, where there’s an intermediate amount of visual info available, batters had the most lead elbow extension
- Against a bowling machine, batters had the most wrist uncocking
- The more visual information available, the more proximally/centrally dominant the batters technique becomes
- it’s important to start centrally and then use the kinetic chain to transfer that energy and momentum
- By not providing as much visual information, there’s an assumption that the batters are starting their movement late so unable to go through the full sequence, so have to emphasise the later parts rather than the earlier central parts of the movement

Question 22

Task-relevant cues - better cricket bowling machine

Answer 22

• Now have bowling machines that display a fake bowler running up and bowling so batters can at least time their actions based on when it looks like the ball is going to be released
• They do use technique data on bowlers e.g. if they’re about to play Australia they can put that bowler on the machine - unsure how successful this is though

Question 23

Modified Perceptual Training Framework - general background

Answer 23

(Hadlow et al., 2018)
- The cube is a 3D shape so just saying there are 3 important factors and each of them are on a continuum - bit like a 3D graph
- Each axis has a bad end and a good end so you end up with one top corner of the cube being an ideal and the opposite bottom corner being a bad position
- The closer you get to this ideal top corner, the more likely the training is to actually transfer to improvements in competition
- The idea is that if you invented a new training technique, instead of having to do a study to test it you could just ask 3 questions about where it lies on each axis and then you can see how good that training will be

Question 24

Modified Perceptual Training Framework - the 3 axes

Answer 24

(Hadlow et al., 2018)
- targeted perceptual function
- stimulus correspondence
- response correspondence

Question 25

Modified Perceptual Training Framework - targeted perceptual function axis

Answer 25

(Hadlow et al., 2018)
low-order to high-order
low-order (visual)
- only training visual information
- Not training your ability to perform actions based on the visual information
- Anything that’s just trying to train your eyes and improve your vision is lower order
high-order (perceptual-cognitive)
- Involves your brain and CNS more
- You’re actually having to think

Question 26

Modified Perceptual Training Framework - stimulus correspondence axis

Answer 26

(Hadlow et al., 2018)
How well does the stimulus you’re being presented with correspond to the one you see in competition?
Generic (alpha-numeric)
- lower end
- Responding to letters and numbers
Behavioural correspondence
- The stimulus behaves in the right way but might not look right
- E.g. football manager with a football pitch with dots on
Visual and behavioural correspondence
- E.g. watching a video of the sport - looks real and the things are behaving in a realistic way
Sport-specific (performance environment)
- Gold-standard best end
- Actually being within a sports environment reacting to real players

Question 27

Modified Perceptual Training Framework - response correspondence axis

Answer 27

(Hadlow et al., 2018)
Same as stimulus correspondence but for response - how well does the response you have to give correspond with the response you have to give in competition?
Generic (verbal/written)
- lower end
- Just verbally saying which way you would dive
Sport-specific (natural skill performance)
- Actually performing the action

Question 28

Modified Perceptual Training Framework - putting it al together

Answer 28

(Hadlow et al., 2018)
- At the desirable end, you’re actually making decisions based on realistic stimuli and performing realistic responses

Question 29

Advance cue utilisation

Answer 29

“ability to make accurate predictions based on contextual information available early in the action sequence” (Abernethy, 1987)

Question 30

Advance cue utilisation - the problem

Answer 30

• The problem is any movement where the time it takes to perform the movement is similar to or less than the amount of time you actually have available
• E.g. a football penalty kick - ball reaches the goal faster than goalkeepers can dive to the corner of the goal

Question 31

Methods of studying advance cue utilisation

Answer 31

• Occlusion studies: temporal and spatial occlusions
• Reaction time paradigm -> Showing the whole thing but looking at when did they initiate their response
• Lab vs field based: control vs context -> in a lab you can control what information is available and monitor responses but lab studies lack context
  -> ecological validity: Is is realistic?

Question 32

Advance cue utilisation - badminton study

Answer 32

(Abernethy & Russell, 1987)
- when occluded just before impact where most of the difference between novices and experts opened up here
- Suggesting that experts are able to use visual information early on to anticipate

Question 33

Advance cue utilisation - football penalties study

Answer 33

(Williams & Burwitz, 1993)
- 4 options - top right, top left, bottom right, bottom left
- temporal and spatial occlusions
- Early occlusions there’s the biggest difference between experienced and inexperienced
- Most often it was the height people got wrong, especially when occluded really early
- Needed later information to determine height of penalty

Question 34

Advance cue utilisation - visual fixations during penalties

Answer 34

(Savelsberg et al., 2002)
- Expert players looked at fewer locations and fixated for longer durations
- As the player ran up, novices were progressively looking more at the trunk, arms and hips
- Whereas experts were looking at the head early on in the approach then later looking at the kicking leg, non-kicking leg, and ball
-> The non-kicking leg specifically was fixated on a lot

Question 35

Disguise vs deception

Answer 35

Disguise:
- Hiding true intentions
- performed to keep an opponent in suspense and maintain outcome ambiguity - to conceal one’s true intention (Helm et al., 2017)
- Successful disguise would result in opponent having a chance level of success (success = 50:50)
Deception:
- Actively trying to mislead and suggest false intentions
- performed to deliberatively mislead an opponent for the purpose of triggering an incorrect motor response (Jackson et al., 2006)
- Successful deception would result in opponent having below chance level success (success = 0%)

Question 36

Deception and expertise

Answer 36

• Experts are usually less susceptible to deception
• Experts better at predicting outcome of deceptive actions (Brault et al. 2012)
• Experts not affected as much by deceptive actions (Jackson et al. 2006)

Question 37

Rugby study

Answer 37

(Warren-West & Jackson, 2002)
- studying rugby tackling/side-step
- The expertise effect (difference between higher skilled and less skilled players) was bigger for the deceptive movements than the genuine ones
- For both groups of players for deceptive movements, performance gets worse and then starts to increase again
- Higher skilled players less susceptible to deception
- Higher skilled players better able to detect when they’d been deceived
- Higher skilled players were less bias towards perceiving actions as genuine

Gaze results:
- Lower-skilled spent more time viewing the head
- Higher-skilled spent more time viewing the hips

How?
two possible explanations:
- same timing for both groups but the lower-skilled players were more susceptible so got deceived more and their success decreased more during that susceptibility to deception
- both groups have the same pattern but for the experts it’s shifted forwards - experts get deceived earlier because they pick up on earlier cues but they also correct themselves earlier because they’re picking up on earlier cues to detect that

Question 38

Rugby follow up study

Answer 38

(Warren-Westgate et al., 2021)
- participants in lab with markers on to track their movement and stood on force plate
- watching video of an opponent running towards you and had to actually step in the direction to tackle the person
- various temporal occlusions

Results:
- Earlier detection facilitates skilled responses to deceptive actions
- Higher-skilled players were detecting the deceptive step earlier to they were able to correct themselves earlier