The effect of player numbers (balance, underload and overload) on

The effect of player numbers (balance, underload and overload) on the physical performance, physiological and perceptual demands of small sided games in senior club hurlers. A study submitted in partial fulfilment of the requirements for the degree of

Master of Science in Strength and Conditioning at

Limerick Institute of Technology by Fergus J Kennedy

August 2017

Abstract AIM: The aim of the study was to determine the effects of player numbers (balance, underload and overload) on running performance, heart rate response and perceived exertion of senior club players in small sided hurling games. BACKGROUND: SSGs have become an increasingly used method in hurling conditioning due to the similarities to game play. Recently the use of sweeper systems has resulted in extra defensive numbers, changing the traditional structure of game play. Research into hurling specific SSGs is needed to understand the demands that are placed on players using these variables. METHODS: Eleven senior club hurlers (age; 24 ± 5: height 180.2 ± 4.7 cm: body mass; 80.1 ± 5.6 kg: HR max; 186.6 ± 12 b.min-1) took part in the study during the in season competition period. Player numbers were manipulated into three different conditions of balanced, underload and overload. The effects of these conditions were evaluated in external loads of total distance (TD), relative distance (RD), high-speed running distance (HSR), very-high speed running distance (VHSR), max speed (MS), accelerations (n), decelerations (n), Internal (HR) loads of average heart rate (HRmean), peak heart rate (HRpeak) and perceptual (RPE) loads. RESULTS: TD and RD remained consistent between all conditions with trivial effect sizes observed. SSG balance observed the largest HSR distance (p=0.02), VHSR distance (p=0.276), MS (p=0.07) and RPE (p=0.032). SSG overload detected the highest peak heart rate (p=0.015) recording (95.03 ± 7.7 %HR max) and average heart rate (p=0.048) recording (83.8 ± 12.16 %HR max). SSG underload observed the largest rate of accelerations (p=0.186) and decelerations (p=0.028). CONCLUSION: SSG balance provides the most appropriate condition to replicate hurling match play considering the HSR, VHSR, MS and RPE observed. SSG overload may be used at specific times in the season for physiological adaptation based on the HRpeak and HRmean recorded, while SSG underload may be utilised when a focus on accelerations and decelerations is appropriate with a concurrent decrease in perceptual load imposed. The current study provides coaches with information on how to apply balanced and unbalanced conditions effectively in hurling SSGs.

2

Declaration This project is presented in part fulfilment of the requirements of the Masters of Science in Strength & Conditioning at Limerick Institute of Technology. It is entirely my own work and has not been submitted to any other university or higher education institution, or for any other academic award in this institute. I have exercised sensible attention to ensure that the work is original, and does not to the best of my knowledge break any law of copyright. Where use has been made of the work of other people it has been fully acknowledged and fully referenced. Signed: ________________________ ID Number: __________________________ Fergus J Kennedy Date: __________________________

3

Table of contents

List of Figures

Page 7

List of Tables

Page 8

List of Abbreviations

Page 9

Chapter 1: Introduction

Page 12

Study Aims

Page 13

Study Objectives

Page 13

Study Hypotheses

Page 14

Chapter 2: Review of Literature

Page 15

2.1 Introduction to Hurling

Page 16

2.2 Physical and Physiological Demands of Hurling

Page 16

2.3 Small Sided Games

Page 17

2.4 Training Effects of Small Sided Games

Page 17

2.5 Monitoring of Small Sided Games

Page 18

2.5.1 Heart Rate

Page 18

2.5.2 Global Positioning System (GPS)

Page 19

2.5.3 Rating of Perceived Exertion (RPE)

Page 20

2.6 Structural Variables in SSG

Page 21

2.6.1 Playing Area

Page 21

2.6.2 Game Duration & Work: Rest Ratio

Page 22

2.6.3 Coach Encouragement

Page 23

2.6.4 Game Design, Goal Type & Winning or Losing

Page 23

2.6.5 Player Numbers

Page 24

2.6.6 Overload & Underload

Page 25

Chapter 3: Methodology

Page 27

3.1 Aim of Study

Page 28

3.2 Experimental Design

Page 28

3.3 Participants

Page 28

3.4 Procedures

Page 29

3.4.1 Yo-Yo Intermittent Recovery Test Level 2 (Yo-Yo IR2)

Page 29

3.4.2 Small Sided Game Rules

Page 29 4

3.4.3 Familiarization Trials

Page 30

3.4.4 Player Numbers

Page 30

3.4.5 Standardised Warm Up

Page 31

3.4.6 GPS

Page 31

3.4.7 Heart Rate Monitoring

Page 31

3.4.8 RPE

Page 32

3.5 Statistical Analysis

Page 32

Chapter 4: Results

Page 34

4.1 Introduction

Page 34

4.2 Running Performance Metrics

Page 35

4.2.1 Total Distance

Page 35

4.2.2 Relative Distance Page

Page 37

4.2.3 High-speed Running Distance

Page 39

4.2.4 Very High-speed Running Distance

Page 41

4.2.5 Maximum Speed

Page 43

4.2.6 Accelerations

Page 45

4.2.7 Decelerations

Page 47

4.3 Heart Rate Performance Metrics

Page 49

4.3.1 Peak Heart Rate (% of Maximum Heart Rate)

Page 49

4.3.2 Average Heart Rate (% of Maximum Heart Rate)

Page 51

4.4 Perceptual Metrics

Page 53

4.4.1 Rating of Perceived Exertion

Page 53

Chapter 5: Discussion

Page 55

5.1 Introduction

Page 56

5.2 Running Performance Metrics

Page 57

5.2.1 Total Distance

Page 57

5.2.2 Relative Distance

Page 58

5.2.3 High-speed Running Distance

Page 59

5.2.4 Very High-speed Running Distance

Page 60

5.2.5 Maximum Speed

Page 61

5.2.6 Accelerations

Page 62

5.2.7 Decelerations

Page 63 5

5.3 Heart Rate Performance Metrics

Page 64

5.3.1 Peak Heart Rate (% of Maximum Heart Rate)

Page 64

5.3.2 Average Heart Rate (% of Maximum Heart Rate)

Page 65

5.4 Perceptual Metrics

Page 66

5.4.1 Rating of Perceived Exertion

Page 66

5.5 Limitations

Page 67

Chapter 6: Conclusions and Recommendations

Page 70

6.1 Conclusions

Page 70

6.2 Recommendations

Page 71

Chapter 7: References

Page 73

Chapter 8: Appendices

Page 85

Appendix 1: Participant Information Sheet

Page 86

Appendix 2: Pre Test Questionnaire

Page 87

Appendix 3: Standardised Warm Up Protocol

Page 89

Appendix 4: Rating of Perceived Exertion Scale Recording Sheet

Page 90

Appendix 5: Small Sided Game Rules and Set Up

Page 91

Appendix 6: Yo-Yo Intermittent Recovery Test Level 2 Results

Page 92

6

List of Figures

4.1 Total Distance Mean and Standard Deviation Bar Chart

Page: 35

4.2 Relative Distance Mean and Standard Deviation Bar Chart

Page: 37

4.3 High-speed Running Distance Mean and Standard Deviation Bar Chart

Page: 39

4.4 Very High-speed Running Distance Mean and Standard Deviation Bar Chart

Page: 41

4.5 Maximum Speed Mean and Standard Deviation Bar Chart

Page: 43

4.6 Accelerations Mean and Standard Deviation Bar Chart

Page: 45

4.7 Decelerations Mean and Standard Deviation Bar Chart

Page: 47

4.8 Peak Heart Rate Mean and Standard Deviation Bar Chart

Page: 49

4.9 Average Heart Rate Mean and Standard Deviation Bar Chart

Page: 51

4.10 Rating of Perceived Exertion Mean and Standard Deviation Bar Chart

Page: 53

7

List of Tables

4.1 Total Distance Descriptive Statistics

Page 35

4.2 Total Distance Effect Size Measures

Page 36

4.3 Relative Distance Descriptive Statistics

Page 37

4.4 Relative Distance Effect Size Measures

Page 38

4.5 High-speed Running Distance Descriptive Statistics

Page 39

4.6 High-speed Running Distance Effect Size Measures

Page 40

4.7 Very High-speed Running Distance Descriptive Statistics

Page 41

4.8 Very High-speed Running Distance Effect Size Measures

Page 42

4.9 Maximum Speed Descriptive Statistics

Page 43

4.10 Maximum Speed Effect Size Measures

Page 44

4.11 Acceleration Descriptive Statistics

Page 45

4.12 Acceleration Effect Size Measures

Page 46

4.13 Deceleration Descriptive Statistics

Page 47

4.14 Deceleration Effect Size Measures

Page 48

4.15 Average Heart Rate Descriptive Statistics

Page 49

4.16 Average Heart Rate Effect Size Measures

Page 50

4.17 Peak Heart Rate Effect Descriptive Statistics

Page 51

4.18 Peak Heart Rate Effect Size Measures

Page 52

4.19 Rating of Perceived Exertion Descriptive Statistics

Page 53

4.20 Rating of Perceived Exertion Effect Size Measures

Page 54

8

List of Abbreviations

SSG: Small Sided Game FSG: Full Sided Game SSG balance: Balanced Conditions SSG underload: Underload Conditions SSG overload: Overload Conditions GAA: Gaelic Athletic Association RPE: Rating of Perceived Exertion A.U.: Arbitrary Units GPS: Global Positioning System TD: Total Distance HSR: High-speed Running VHSR: Very High-speed Running MS: Maximum Speed RD: Relative Distance HR: Heart Rate HRmax: Maximum Heart Rate HRmean: Average Heart Rate HRpeak: Peak Heart Rate m: Metre km: Kilometre kg: Kilogram

km.hr-1: Kilometres per hour m.min-1: Metres per minute VO2max: Maximal Oxygen Consumption VO2peak: Peak Oxygen Consumption CMJ: Countermovement Jump BLa: Blood Lactate Concentration mmol/L: Millimole per Litre

9

Yo-Yo IR1: Yo-Yo Intermittent Recovery Test Level 1 Yo-Yo IR2: Yo-Yo Intermittent Recovery Test Level 2 N: Population Size n: Sample Size p: Significance Level ES: Effect Size d: Cohen’s D Effect Size Measure SD: Standard Deviation CL: Confidence Limit η2: Eta Squared Effect Size Measure

10

Chapter 1: Introduction

11

Introduction

Hurling is an outdoor team game administered by the G.A.A. and is Ireland's second most popular sport. One of Ireland's indigenous games it shares a number of features with Gaelic football such as pitch dimensions, goals, number of players and terminology.

The sport has recently incorporated small sided games (SSG) as a training method Collins et al (2013). Small sided games are modified games played on reduced pitch area, regularly using adjusted rules and reduced player numbers. These games enable player exposure to situations they will face in match play, from this experience they will be able to improve their physiological, technical and tactical performance (Owen et al 2004). The first GAA based SSG research was conducted as recently as 4 years ago, where researchers concluded that SSG are an effective training stimulus for Gaelic football (Collins et al 2013)

Research into the demands of hurling have fallen behind other field sports, with sparse attempts made to measure physiological demand and running performance (Reilly and Doran 2001) (O'Donoghue et al 2004) (Collins, Reilly and Doran 2010). Recently, however, research has taken place that has given insights into physical performance, perceptual and physiological demands of hurling specific SSGs within a range of structural variables including pitch size, work: rest ratios, player numbers, game design, goal type and the effects winning or losing (Malone and Collins 2017b; Malone and Collins 2016; Malone et al 2017; Malone and Collins 2017a). This essential information can now be used to design appropriate training structures for conditioning, technical and tactical development in hurling teams. Further research is needed however to add to our understanding of the game.

Hurling match-play in recent years has seen a trend towards an increased number of players in defensive areas of the field; this has led to a move away from the traditional structure of game play in many cases. The use of SSGs designed to replicate these conditions are an option available to coaches with the use of overload and underload conditions. Overload and underload conditions may also be implemented to provide increased technical contacts or to develop certain tactical situations. Research is needed to identify the perceptual, technical, physical and physiological effects that these conditions place on players. To date there has been no studies that have examined the effects of player numbers in these parameters on physical performance, physiological and perceptual demands in hurling specific SSGs. The information 12

gathered may be useful to coaches who use SSG to develop physical, physiological, technical and tactical abilities in hurling players.

Study Aim The aim of the study was to determine the effects of player numbers (balance, underload and overload) on running performance, heart rate response and perceived exertion of senior club players in small sided hurling games

Study objectives 1. To record and analyse the difference between running performance data of total distance (m), relative distance (m.min-1), high-speed running (m), very high-speed running (m), max speed (km.hr-1), acceleration (n), decelerations (n) between balanced, underload and overloaded small sided senior club hurling games using global positioning systems (GPS) technology in club hurlers

2. To record and analyse the difference between heart rate responses of average heart rate (%HRmax), peak heart rate (%HRmax) between balance, underload and overloaded small sided club senior hurling games using heart rate monitoring

3. To record and analyse the perceived exertion between balanced, underload and overloaded small sided club senior hurling games using ratings of perceived exertion (RPE)

13

Study Hypothesis

Hypothesis 1: There is no difference between running performance data of total distance (m), relative distance (m.min-1), high-speed running (m), very high-speed running (m), max speed (km.hr-1), acceleration (n), decelerations (n), between balanced, underload and overloaded small sided club senior club hurling games

Hypothesis 2: There is no difference in heart rate responses of average heart rate (%HR rate (%HR

max

) and peak heart

max

) between balance underload and overloaded small sided club senior hurling

games

Hypothesis 3: There is no difference in RPE between balanced, underload and overloaded small sided club senior hurling games

14

Chapter 2: Review of Literature

15

2.1 Introduction to Hurling

Hurling is a team game played with a hurley (stick) and sliotar (ball). It is an invasion game played on grass with a pitch area of 90 metres wide and 145 meters long (Cullen et al 2013). Two teams compete for scores consisting of goals (3 points) and points (1 point). Teams consist of fifteen players each divided into positions of goalkeeper, backs, midfielders and forwards. The game requires extraordinary hand eye coordination for skills that include catching the ball with one hand and striking in the air (Reilly and Collins 2008). The hurley can be used to strike or prevent an opponent from striking by blocking or hooking (Reilly and Collins 2008). Games consist of two halves, Inter-county games are 70 minutes in duration divided into two 35 minute halves, while inter-club and underage games span 30 minutes per half.

2.2 Physical and Physiological Demands of Hurling Hurling is an intermittent game with aerobic activity interspersed with high-intensity efforts that follow the pattern of the game. Reilly and Collins (2008) note that the movements are stochastic in nature, where the timing of high-speed running follows the ebb and flow of competitive play. Collins et al (2010) demonstrated the high physical load subjected to elite players during match play when noting a high aerobic load with episodes of high anaerobic activity. The sport requires high-speed running, rapid accelerations and decelerations combined with change of direction, jumping and player contact (Reilly and Collins 2008). Change of direction, acceleration and speed over 10 metres is critically important and considered a prerequisite for success at elite level (Donnelly et al 2003). Time in play in elite level match play was noted at 1846 ± 81 s that accounted for 41% of game duration. There were 100 ± 5 activity periods reported with the ball in play for an average of 19 s while the ball was out of play for an average of 28 s (Collins et al 2010). Scores and attempted scores accounted for the majority of time the ball was out of play at 35 and 23% while side-lines and foul play accounted for the majority of the rest. The mean heart rate recorded during game time was 163 ± 14 bpm in the first half and 160 ± 15 bpm in the second half. The figures accounted for 83% of age related HRmax. The researchers observed that fifty-nine percent of total match time was spent under 85% HRmax concluding that the ratio of aerobic to anaerobic work was 4;3. Total distance (7689 ± 1270m, 6564 ± 1205m), high-intensity distance (≥17 km.hr-1) (1174 ± 374m, 868 ± 319m), max speed (29.8 ±2.1 km.hr-1, 29.1 ±1.9 km.hr-1) and average speed (6.1 16

± 1 km.hr-1, 5.7 ± 1.2 km.hr-1) was previously reported for elite and sub elite hurling players respectively (Malone, Collins and Doran 2016). Significant differences in high-intensity distances covered between positions were also reported with midfield, half forward line and half back line positions recording the highest physical demand.

2.3 Small Sided Games

Small sided games have become increasingly used method of training in Gaelic games sports, hurling and Gaelic football. The increased popularity of SSGs can be attributed to the relevance held to tactical, technical and physiological elements of game play. SSGs can replicate movement patterns, physiological demands and technical skills involved in competitive match play (Gabbett & Mulvey 2008). The involvement of the ball in SSG can have additional beneficial effects on player motivation and specificity (Hill-Haas 2009), while Collins et al (2013) observe SSGs provide an effective method of training for Hurling and Gaelic football teams.

2.4 Training effects of SSG

Collins et al (2013) demonstrated the beneficial training effects of SSGs in a Gaelic football senior club team environment where they identified an improvement in 5m sprint speed, repeated sprint ability (RSA) and aerobic endurance performance from an 8 week SSG training protocol. The effect on these 3 critical aspects of performance is notable, an improvement in counter movement jump (CMJ) height, 10m and 20m sprint times were also reported that failed to reach statistical significance but of interest nonetheless. Much of the research on SSG s in team sports has been conducted in disciplines such as soccer and rugby. Comparing physiological effects of SSGs and traditional conditioning, the majority of the research shows similar training effects of SSGs protocols and traditional conditioning. Reilly and White (2005) concluded that SSG are an acceptable alternative to formal interval training to maintain fitness in a range of performance measured variables including aerobic capacity, CMJ, RSA, peak power (W), 5m, 10m and 20m sprint times. A significant improvement in 5m time was recorded in the SSG population. The author postulates the increased intensity of the SSG requiring more explosive movements of acceleration and aerial duels could explain the increase 17

in 5m performance. In adult rugby players SSGs have resulted in significant changes (p < 0.05) in 10m (-5.2%), 20m (-3.2%), 40m (-3%) speed, muscular power (vertical jump) (+4.7%), and maximal aerobic power (+4.7%) over a nine-week training programme conducted over two seasons. Traditional conditioning methods (running activities with no skill elements) resulted in significant changes (p < 0.05) in 10m speed and maximal aerobic power only. Interestingly traditional conditioning methods resulted in decrease in muscular power (vertical jump) (5.2%) while the SSG method resulted in a significant increase (4.7%) (Gabbett 2006). Sassi et al (2005) studied acute physiological responses in elite Spanish footballers in SSG and Interval training. The SSG comprised of 4v4 and 8v8 conditions while interval training consisted of 4 x 1000m with 150 seconds recovery between bouts. The SSG elicited a greater %HRmax response in comparison to the interval training (91%HRmax v 85%HRmax). Differences between HR responses have been documented depending on player numbers with smaller numbers generally generating an increased HR response (Malone and Collins 2017a, Foster et al 2010). The variability of exercise stimulus however is greater in SSGs than in structured conditioning programmes, this is a reflection of the stochastic nature of SSGs which require different responses depending on the ebb and flow of the game (Hill-Haas et al 2011). Mindful selection of SSG formats and training protocols is necessary to induce optimal fitness and performance benefits (Hill-Haas et al 2011).

2.5 Monitoring SSG

2.5.1 Heart Rate

Heart rate is one of the most common physiological metrics used to determine exercise internal training load (Alexandre et al 2012). HR is used as method of measuring exercise intensity, with HRmax frequently used as a criterion for reaching peak effort in gauging maximal aerobic capacity (Howley et al 1995) HR has a linear relationship with V02 and has been used by amateur and professional players in soccer SSG environments as well as a number of other sports (Bangsbo 1993, Drust 2000). A majority of studies that have studied SSG have used %HRmax as an exercise intensity measure (Hill-Haas et al 2010, Hill-Haas et al 2009). The YoYo IR (intermittent recovery) tests 1 and 2 are used to evaluate an individual's ability to recover from intense exercise and have been shown to be more accurate measurement of performance than maximum oxygen uptake (Bangsbo et al 2008). Heart rate expressed as a percentage of HRmax during the Yo-Yo IR1 is inversely related to work performed at high-intensity during 18

game play (Bangsbo 2008). Both Yo-Yo tests can be used to quickly determine the maximum heart rate for an individual (Bangsbo 2008). In a Hurling SSG environment percentage of HRmax and rate of perceived exertion (RPE) was monitored in inter-club senior hurlers (Malone and Collins 2017b). A higher peak heart rate (HRpeak) (P = 0.004; d = 1.93 ± 0.61) and RPE (P = 0.04; d = 0.54 ± 0.21) were reported in larger pitch areas placing a larger physiological demand on players than medium and small pitch sizes. Senior club hurlers were also monitored in SSGs where 4 a side games reported a higher relative exercise intensity in comparison to 5 a side (mean change: 6 ± 2 %; p = 0.001; d = 1.9 ± 0.2) and 6 a side games (mean change: 12 ± 2 %; p = 0.001; d = 2.9 ± 0.8) (Malone and Collins 2017a). In the same study, 4 a side normal play rules with small goals reported a larger relative intensity than 4 a side possession play rules (mean change: 5 ± 2 %; p = 0.01; d = 1.3 ± 0.3). A similar trend was seen in 5 a side games where normal play in small goals reported larger internal workload than possession play (mean change: 7 ± 2 %; p = 0.004; d = 0.3 ± 0.1,) and regular goals (mean change 8 ± 2 %; p = 0.004; d = 0.3 ± 0.1). 6 a side games reported the largest relative intensity using regular goals however with a significant difference between small goals (mean change: 11 ± 3 %; p = 0.001; d = 2.0 ± 0.1;) and possession play (mean change: 10 ± 3 %; p = 0.04; d = 1.9 ± 0.3). In soccer SSG heart rate has been categorized into zones of internal work e.g. Zone 1 (90% HRmax) (Hill-Haas et al 2010) In senior club hurlers HR zones have also been used to describe internal workload (zone 1 (95%HRmax) (Malone and Collins 2016) where losing teams in SSG spent more time in HR zones lower than 85% than winning teams (mean difference: 3.5 min; p = 0.023; d = 2.52 ± 0.53). Winning teams spent more time above 95% HRmax (mean difference: 2.5 min; p = 0.013; d = 2.64 ± 0.34) additionally winning teams recorded a higher average heart rate (HRavg) (mean difference: 10%; p = 0.012; d = 2.57 ± 0.43) and peak heart rate (HRpeak) (mean difference: 8%; p = 0.012; d = 2.50 ± 0.53) in comparison to losing teams.

2.5.2 Global Positioning Systems (GPS)

The use of GPS in team sports allows the measurement of player position, velocity and movement patterns. The primary use of GPS has been to monitor running and specific positional demands of team sports to assist in the training and energy system development of athletes (Cummins 2013) Activity profiles have been developed in the literature based on total distance covered and distance in specific velocity bands, while GPS has also been used to 19

monitor fatigue and establish notably intense stages of game play (Aughey 2011). Since GPS has been validated it has been extensively used in Australian football, hockey, cricket, soccer, rugby league and union (Aughey 2011). The use of GPS in SSGs has also become widely used to monitor physical demands and work rate under various conditions and its applications to match play (Hill-Haas et al 2008, Hill-Haas et al 2011, Dellal et al 2011). The use of GPS for work rate monitoring is typically divided into speed zones that range from 0 - 36 km.hr-1. A number of studies have used 7 speed zones of walking (0 - 5.2 km.hr-1), jogging (5.3 - 7.6 km.hr1

), low speed running (7.7 - 10.2 km.hr-1), moderate speed running (10.3 - 13.9 km.hr-1), high-

speed running (14 - 17.1 km.hr-1), sprint running (17.2 - 26.7 km.hr-1) and maximum sprinting (>26.7

km.hr-1) (Brandes et

al

2012,

Hill-Haas

et

al

2009a,

Impellizzeri et

al

2006, Rampinini et al 2007). There has been a large variance within sports regarding the definitions and criteria of each zone that make comparisons between and within sports difficult to frame Cummins (2013). The use of GPS has recently been employed in studies investigating the demands of hurling specific SSGs where total distance (m), high-speed running distance (≥17 km.hr-1), very high-speed running distance (≥22 km.hr-1), total accelerations (n), acceleration distance (m), peak and mean velocity (km.hr-1) were considered (Malone et al 2016). Further hurling SSG studies investigating the effect of changing structural variables including rest intervals, game design, goal type and player numbers on physical and physiological demands of the game have also employed the use of GPS while documenting equivalent metrics and also including maximum speed (km.hr-1) and average speed (km.hr-1) (Malone and Collins 2017a, Malone et al 2017, Malone and Collins 2017b).

2.5.3 Rate of Perceived Exertion (RPE)

Borgs RPE is a tool used to appraise subjective perception of effort during exercise (Scherr et al 2012). RPE asks the athlete to rate the intensity of an exercise bout. RPE has been commonly used as a measure of exercise intensity in small sided games (Abrantes et al 2012, Dellal et al 2011). The validity of RPE as an indicator of training intensity in an intermittent soccer game environment has previously been demonstrated (Coutts et al 2009). Foster et al (2001) notes the practicality of using the RPE, commenting that it is easy to use, reliable and consistent with objective measures of exercise intensity. Foster et al (2001) who developed session RPE (sRPE) observed a highly correlated relationship between sRPE and HR zone method of measuring exercise intensity during different forms of exercise. Developed by Borg (1982) the original scale ran from 6-20 corresponding with increasing levels of perceived intensity. 20

Recently the scale has been modified to the Borg Cr-10 consisting of a scale from 1-10. In a soccer SSG study the Cr-10 scale was applied along with HR to assess internal load, providing both a psychological and physiological load (Christopher et al 2016). In youth soccer players’ correlations between sRPE and HR based training load were all significant (P < 0.01 to P < 0.001) (Impellizzeri et al 2004) Data was collected in senior club hurlers to investigate the perceived demands of pitch sizes with results outlining that an increased RPE was reported as pitch size increases (P = 0.04; d = 0.54 ± 0.21) (Malone and Collins 2017) corresponding with results from HR and GPS metrics. Large effects were detected (P = 0.001; d = 1.83 ± 0.91) between small and medium pitch sizes.

2.6 Structural Variables in SSG

2.6.1 Playing Area

Playing area can be changed both in absolute and relative terms that may impact the intensity of SSGs. Relative pitch area per player is the total pitch area divided by the number of players. A number of soccer studies have investigated the effects of pitch area on intensity. The majority of studies report increased measures of intensity (HR, RPE) the larger the relative playing area utilised (Rampini et al 2007, Owen et al 2004). In senior club hurling the influence of relative pitch size on running performance, perceptual demands and physiological responses has been investigated (Malone and Collins 2017b). Significant differences in highspeed running distance (P = 0.003; d = 2.73 ± 0.91), very high-speed running distance (P = 0.004; d = 1.73 ± 0.91) and RPE (P = 0.04; d = 0.54 ± 0.21) between all pitch sizes of large, medium and small (80 x 20m, 60 x 20m, 40 x 20m) were observed. This is reflected in high speed running distance covered of 354 ± 111m, 254 ± 72m and 198 ± 62m in large, medium and small pitches respectively. The total distance covered during SSGs were 739 ± 189m, 509 ± 250m and 315 ± 89m correlating to a relative distance of 185 ± 46m.min-1, 127 ± 36 m.min1

and 79 ± 22m.min-1 for large, medium and small pitch sizes respectively. Previous research

with senior club hurlers reported the total relative running demands of hurling game-play at 127 m.min-1 with 24 m.min-1 covered at high-speed (≥17 km.hr-1) (Malone et al 2013) Notably the medium pitch area (60x20m) was most closely related to match play at total relative running demands of 127 m.min-1 and high-speed running reported at 27 m.min-1. In inter-county senior Gaelic football players MS was observed for varying pitch sizes (40 x 20m, 60 x 20m, 80 x 21

20m) with 24.2 ± 2.5 km.hr-1, 26.1 ± 3.5 km.hr-1and 30.1 ± 2.6 km.hr-1 respectively. Results corresponded to a significant difference (p = 0.001) and small effect size (d = 0.60) between conditions. This is a recurring theme seen in SSG research as maximum speed (MS) increases concurrently with pitch sizes (Casamichana and Castellano 2010) (Castellano, Casamichana and Dellal, 2013). Acceleration instances (n = 12 ± 4, n = 20 ± 6 and n = 25 ± 4) for small, medium and large pitch areas respectively were also observed in senior inter-county Gaelic footballers with significant differences (p = 0.002) between each pitch size (40 x 20m, 60 x 20m, 80 x 20m) recorded (Malone, Solan and Collins 2016).

2.6.2 Game Duration and Work: Rest Ratios (W: R ratio)

W: R ratios are a critical component governing the intensity of SSGs. By manipulating work and rest periods the volume and intensity can be altered to meet the metabolic goals of the session (Jeffreys 2004). A majority of studies have used an interval format with consecutive bouts alternating with periods of recovery (Klusemann et al 2012, Fanchini et al 2011). Other studies have used a continuous regimen (e.g. 10 minutes) (Jones and Dust 2007). In an interval format, the duration of the work bout interspersed with recovery period are used to determine the W: R ratio. W: R ratios used in SSGs range from 4:1 to 1:4 (Little and Williams 2007, Owen et al 2004). The large variance in duration, W: R ratios and number of bouts used between studies make comparisons difficult. In adolescent soccer players, different recovery durations were imposed on 3 a side, 4 x 4 minute SSGs. 1-minute rest conditions induced significantly higher %HRmax (P