The relationship between physical capacity and match performance in elite Australian football: A mediation approach

Abstract

The aim of this study was to verify if yo-yo intermittent recovery test (level 2) (yo-yo IR2) score is linked to Australian football (AF) performance through match exercise intensity. Six week prospective study design. Twenty-one data sets were recorded from nine individual players that completed the yo-yo IR2, and played an Australian Football League match in the first five rounds of the 2010 season wearing a global positioning system (GPS) unit. Simple mediation modelling was used to analyse the inter-relationship between yo-yo IR2 score, match exercise intensity and AF performance. Playing position and experience were also incorporated into the model to identify conditional affects. A significant direct relationship was observed between yo-yo IR2 and number of ball disposals (p < 0.1) and a significant indirect relationship was observed between yo-yo IR2 and number of ball disposals through distance travelled at high intensity (HIR m min⁻¹) (p < 0.1). Moderation analysis showed that playing position affected the relationship between of yo-yo IR2 and HIR m min⁻¹ (p < 0.1) and HIR m min⁻¹ and total ball disposals (p < 0.1). Playing experience also significantly affected the relationship between HIR m min⁻¹ and total ball disposals. This study is the first to identify the effects of yo-yo IR2 on total ball disposals through HIR m min⁻¹ performed during AF matches, and that playing position and playing experience affect these interactions.

Introduction

Due to advances in player tracking technology, recent studies examining the match demands of top level team sports have provided an improved understanding of the requirements of competition.1, 2 In addition, recent studies in soccer have shown that training physical capacities (such as endurance qualities) can positively impact on match exercise intensity.3, 4 However, at present, there is little empirical knowledge about the contribution of specific physical capacities to Australian football (AF) performance, nor if match exercise intensity mediates this relationship.

In a recent conceptual model of factors affecting soccer performance, Impellizzeri and Marcora⁵ suggested that tactical, technical and physical performance were relevant constructs of team ranking. It was also reported that high intensity activity (match exercise intensity) is a causal indicator of overall physical performance, and valid field tests provide an indication of the capacity of the athlete to produce high intensity activity.⁵ This model suggests that match exercise intensity may mediate the effect (i.e. act in a causal sequence between two variables)⁶ of physical capacity on performance in soccer. However, further conditional circumstances (e.g. gender, age, etc.) may also impact on these relationships. These variables are defined as moderators and can be incorporated into a mediation model.⁶ Some studies have identified relationships, exclusively in soccer, between training adaptations and improved physical capacity, improved physical capacity and match exercise intensity, and match exercise intensity and team success.4, 7, 8 However a mediation analysis has not yet been conducted to determine if these relationships are linked.

Studies on soccer players have shown that improvements in aerobic endurance are matched with increased distance8, 9 and increased involvement with the ball.⁸ Gains in these qualities may also improve match exercise intensity and subsequently impact on similar performance variables in AF. In support of this, several studies have shown that higher endurance qualities (i.e. maximal oxygen uptake, yo-yo IR2) and anaerobic qualities (i.e. 5 and 10 m sprint time) components are important for elite AF players.10, 11 For example, Young et al.¹⁰ found that the yo-yo intermittent recovery (level 2) (yo-yo IR2) was significantly higher in starters compared to non-starters at the start of an Australian Football League (AFL) season. Furthermore, the yo-yo IR2 has been identified to have a strong relationship with high intensity distance travelled in soccer.3, 7 Together, these studies show that the yo-yo IR2 is a relevant physical capacity test of high intensity intermittent endurance for team sports, suggesting the model of Impellizzeri and Marcoa⁵ also applies to AF. Currently, the relationships between yo-yo IR2 performance and physical and playing performance in AF has not been identified.

This study, therefore, aims to identify: (1) if there is a relationship between yo-yo IR2 score and various performance measures in AF (i.e. ball disposals, player impact score and coaches rating), (2) if match exercise intensity is a mechanism of the relationship; and (3) if playing position and playing experience impact on these relationships.