Original research
Creatine kinase and its relationship with match performance in elite Australian Rules football

https://doi.org/10.1016/j.jsams.2013.05.005Get rights and content

Abstract

Objectives

The purpose of this study was to examine the relationships of pre-match creatine kinase on match performance measures in elite Australian Rules football.

Design

Repeated measures single cohort longitudinal.

Methods

Twenty-nine elite Australian Rules football players were assessed across a competitive season. Creatine kinase was collected 24–36 h pre-match, and investigated against two measures of match performance; performance ranking scores (based on playing statistics) and coach's performance ratings. Multi-level modelling was applied and player characteristics were considered as moderating variables in the analysis.

Results

Average player pre-match creatine kinase was 485% greater than baseline values. Six-minute running performance was negatively related with average player pre-match creatine kinase (r = −0.432, p = 0.019). Creatine kinase was negatively associated with performance ranking scores (r = −0.149, p = 0.035), although increases in playing experience reversed this relationship (p = 0.003). Coach's subjective ratings declined with elevations in pre-match creatine kinase (p = 0.002).

Conclusions

Increases in creatine kinase from baseline to pre-match indicate residual muscle damage. Small decrements in match performance were explained by increases in pre-match creatine kinase. However, player characteristics related to age and experience appear to be important moderating variables. Elevated pre-match creatine kinase likely represents a state of incomplete recovery from the preceding week, and over time, residual muscle damage. Creatine kinase monitoring may be most appropriately used with young and inexperienced players, and those with lower aerobic running performance to assist in the modulation of training and recovery loads to optimise match preparation and performance.

Introduction

Muscle damage results in muscle soreness, decreased range of motion, swelling, and functional performance decrements.1 In field team sport, plasma creatine kinase (CK), an indirect marker of muscle damage, has been used to quantify the extent of muscle damage imposed by training and competition.2, 3, 4 Following muscle damage, increased membrane permeability results in the release of CK from the muscle cell into the plasma.5 Plasma levels reflect total circulating CK, with post-exercise increases believed to be representative of CK release from damaged muscle tissue.5 Significant CK concentration [CK] elevations have been reported for up to five days post elite rugby league match play.2 Moreover, reduced power, strength and sprint ability have been observed for up to 72 h alongside elevated [CK] following elite soccer competition.6 As such, CK has been proposed as an early indicator of player fatigue7 and a potential monitor of player recovery status.8 Prescribing appropriate recovery and training is essential to ensure that functional performance decrements do not affect subsequent match performance. The application of CK monitoring as a practical athlete monitoring tool used to guide future training has not been established across a competitive season in elite team sport.

Australian Rules football (ARF) is a contact team sport characterised by repeated high-intensity passages of play.9 In team sports such as ARF where physically demanding matches are played on a weekly basis, monitoring player recovery and fatigue is essential to optimising athlete management and performance capacity.10, 11 Buchheit et al.11 advocated the use of physiological and wellness measures to monitor the recovery and fatigue status of elite ARF players. These measures were sensitive to daily fluctuations in training load and changes in running performance. Furthermore, Cormack et al.12 investigated the use of countermovement jump flight time:contraction time as an indicator of neuromuscular fatigue status across an elite ARF season and observed a substantial decrease in this variable on 60% of measurement occasions. Additionally, this variable displayed a small correlation (r = 0.24 ± 0.13) with match performance.12 Similar associations between neuromuscular fatigue and reduced match performance in elite ARF have been identified by Mooney et al.13 Following soccer match play, reductions in neuromuscular function have been observed alongside significant increases in [CK].14 Indeed, in high performance sport, it is important for scientists to have valid tools that can be used in athlete monitoring systems to guide future training. However, at present there are few studies that have shown the relationship between measures used in athlete monitoring systems and competitive performance.

In the team sport context, the majority of research has focused on the post-match muscle damage response to a single match.3, 6 Given the individual variability in plasma [CK],7 it is necessary to establish individual baseline measures and an individual profile of expected responses over a significant timeframe so that decisions regarding individual athlete responses to training can be made.7, 12 In American intercollegiate football, the sensitivity of CK as a marker of muscle damage across a season has been advocated.15 Given the need for longitudinal studies to establish accurate trends, investigations into the utility of CK monitoring in the assessment of recovery from preceding muscle damage and its impact on subsequent match performance across a competitive season are required. This may elucidate findings that have practical relevance for long-term athlete monitoring by enhancing the implementation of athlete training and recovery modulations to optimise match performance.3, 8

The purpose of this study was to examine the influence of pre-match plasma [CK] on match performance in elite ARF. It was hypothesised that elevated pre-match [CK] would adversely affect match performance as a result of inadequate recovery within the week or residual muscle damage across the season.

Section snippets

Methods

Twenty-nine elite male ARF players (age: 22.9 ± 3.2 years; height: 188.0 ± 7.5 cm; weight: 86.7 ± 7.6 kg) participating in the Australian Football League (AFL), the highest level of competition in the sport, participated in the study. Matches were played on a weekly basis from March to September. A repeated measures single cohort longitudinal study design was employed. Approval of the study protocol was granted by the Deakin University Human Research Ethics Committee, with informed consent obtained

Results

Average player pre-match [CK] (376 ± 161 U L−1) across the season were 485% greater than individual player baseline [CK] (78 ± 52 U L−1). Considerable variability was observed in average pre-match [CK] across the season for each player (range = 145–849 U L−1). Aerobic performance (six-minute run) (r = −0.432, p = 0.019) was negatively related to pre-match [CK] (Table 1).

Individual match performance, expressed as a performance ranking score, displayed a significant, albeit small, negative relationship with

Discussion

Average player pre-match [CK] across the season was 485% greater than individual baseline [CK]. With baseline values indicative of players in a rested state, this finding highlights considerable residual muscle damage evident in players throughout the season. In the present study, elevations in pre-match [CK] have been attributed to inadequate recovery from the preceding week, while elevations in [CK] across consecutive weeks are indicative of residual muscle damage. Creatine kinase has been

Conclusion

Elevations in pre-match [CK] compared to baseline values indicate that players appear to be carrying an element of underlying muscle damage across the season. In the presence of elevated pre-match [CK], match performance was negatively affected, with this finding more pronounced for inexperienced players. Elevated pre-match [CK] in any given week is most likely attributable to inadequate recovery from the previous match. Sustained elevations in [CK] throughout the season or across consecutive

Practical implications

  • Elevated pre-match creatine kinase is associated with decreased match performance in elite Australian Rules football.

  • Differences may exist between experienced and inexperienced players in regards to their ability to cope with the physical demands of elite Australian Rules football.

  • Creatine kinase monitoring would be most appropriately used with young and inexperienced players, and those with lower aerobic running performance.

Acknowledgments

The authors would like to thank the players and staff of the Richmond Football Club for their participation and support of this project. No external financial support was provided for this study.

References (30)

  • A.J. Gray et al.

    Match analysis and the physiological demands of Australian football

    Sports Med

    (2010)
  • P.B. Gastin et al.

    Perceptions of wellness to monitor adaptive responses to training and competition in elite Australian football

    J Strength Cond Res

    (2012)
  • M. Buchheit et al.

    Monitoring fitness, fatigue and running performance during a pre-season training camp in elite football players

    J Sci Med Sport

    (2013)
  • S.J. Cormack et al.

    Neuromuscular and endocrine responses of elite players during an Australian rules football season

    Int J Sports Physiol Perform

    (2008)
  • M.G. Mooney et al.

    Impact of neuromuscular fatigue on match exercise intensity and performance in elite Australian football

    J Strength Cond Res

    (2013)
  • Cited by (0)

    View full text