POSITIONING DECISIONS USING WEARABLES · USING WEARABLES: SOME INSIGHTS FROM THE INVASION-TERITORIAL TEAM SPORTS Dr Bill Gerrard Professor of Business and Sports Analytics, University

POSITIONING DECISIONS USING WEARABLES:SOME INSIGHTS FROM THE

INVASION-TERITORIAL TEAM SPORTS

Dr Bill Gerrard

Professor of Business and Sports Analytics, University of Leeds

N8 PRP Training SessionLeeds University Business School, 16th May 2018

THE ICE-CREAM SELLER PROBLEM

• Context: sunbathers equally spaced along beach; same brand of ice cream sold at same price by both ice-cream sellers

• Positioning problem: where will the two ice-cream sellers position themselves?

THE ICE-CREAM SELLER PROBLEM: PREDICTED OUTCOME

• Predicted outcome: both ice-cream sellers will position themselves in the centre of the beach

• Rationale: only differentiator is distance; incentive for each seller to set up next to each other to grab all the market on one side and share the market on the other side

THE ICE-CREAM SELLER PROBLEM: BEHAVIOUR DYNAMICS

25%25%25% 25%

25%75%

50% 50%

POLITICAL ELECTIONS OFTEN INVOLVE THE SAME POSITIONING LOGIC

THE POLITICAL LANDSCAPE

LEFT CENTRE RIGHT

SqueezedOut

THE POSITIONING DECISION

• Positioning decision: choosing how to optimally

allocate people/things/activities within a specified

space

• Three components in all positioning positions:

- Objective: what are you trying to achieve?

- Context: the relationship between positioning and

outcomes

- Constraints: space; resources

POSITIONING: DIFFERENT CONTEXTS BUT OFTEN A COMMON SOLUTION

• Positioning decisions occur in very different contexts:

- Economics – product positioning

- Politics – electoral positioning

- Geography – locations of cities, towns, villages

- Military conflicts – deployment of military forces

- Invasion-territorial team sports – game tactics

- Policing – what are your positioning decisions?

• But often share a common solution

Optimal Positioning = Median Location

CENTRAL LOCATION THEORY

• Central location theory = spatial

theory in urban geography

• Attempts to explain the reasons

behind the patterns of

distribution, size and numbers of

cities, towns and villages

• Key idea: think of space as

consisting of a series of hexagons

at different levels

ANALYSING SPACE - THINK HEXAGONS NOT CIRCLES OR SQUARES!!!

Why are hexagons the best unit for spatial analysis?

Circles: equi-distant from centre to edge but overlap/leave gaps

Squares: nest together without gaps/overlaps but edges not equi-

distant from centre

Hexagons: nesting property and better approximation to equi-

distance property of circles

THE IMPORTANCE OF SPACE IN TEAM SPORTS

• Invasion-territorial team sports: various codes of

football, rugby, hockey and basketball

• Essence of invasion-territorial sports:

THE CONTROL OF SPACE THROUGH THE

TACTICAL COORDINATION OF PLAYERS

• Spatial dimension is crucial to producing

performance analytics that supports coaching

decisions effectively

THE DIFFERENT LEVELS OF SPATIAL ANALYTICS

Level 3: Trajectory Data

Level 2: X,Y Event Data

Level 1: Zoned Frequency Data

GPSVideo Tracking

Video Analysis(Pitch Grid)

Video Analysis(Pitch Map)

LEVEL 1: EXIT PLAY IN RUGBY UNION

Aviva Premiership Final, May 2015

Bath 16 – 28 Saracens (HT 3 – 25)

• Frequency data indicates that a key factor in Bath’s defeat was their high number of turnovers conceded

• But it is only zoned data that provides a real tactical understanding

• Lesson: too many ball-in-hand plays in own half can be dangerous

Source: Opta data

LEVEL 2: AVERAGE PLAYER POSITION IN FOOTBALL

• Average position calculated based only on player actions

• Example: Ajax , vs AZ, Eredivisie R25, 2015/16, 0 – 60 mins (before substitutions)

LEVEL 3: WEARABLES IN ELITE TEAM SPORTS

LEVEL 3: WEARABLE OUTPUTS –LOCATION; DISTANCE; SPEED

LEVEL 3: MEASURING DEFENSIVE STRETCH IN BASKETBALL

• Basketball analytics is most advanced in analysing space

• CHAD (convex hull area of defence) provides a measure of

defensive stretch

• Allows quantification of impact of “floor-spacers” on attacking

team who stretch opposition defences (i.e. CHAD)

CHAD

Space to be attacked Space to be

created

LEVEL 3: POSITIONING ALGORITHM FOR DEFENDING IN FOOTBALL

• Blue Squares = team in

possession

• Blue Circle = player with

ball

• Black Diamonds =

defending team

• GKs excluded

• Positioning decision involves weighting demands to cover space, opposing players and the ball

• Algorithm currently can give too much weight to covering space in some situations

• Arrows indicate coaching interventions to adjust positioning decision

POLICING AND POSITIONING

•What are your positioning decisions?