Monitoring for overreaching in rugby league players

Eur J Appl Physiol. 2007 Feb;99(3):313-24. doi: 10.1007/s00421-006-0345-z. Epub 2007 Jan 12.


The aim of this study was to identify indicators of non-functional overreaching (NFOR) in team sport athletes undertaking intensive training loads. Eighteen semi-professional rugby league players were randomly assigned into two pair matched groups. One group completed 6 weeks of normal training (NT) whilst the other group was deliberately overreached through intensified training (IT). Both groups then completed the same 7-day stepwise training load reduction taper. Multistage fitness test (MSFT) performance, VO2 (max), peak aerobic running velocity (V (max)), maximal heart rate, vertical jump, 10-s cycle sprint performance and body mass were measured pre- and post-training period and following the taper. Hormonal, haematological and immunological parameters were also measured pre-training and following weeks 2, 4 and 6 of training and post-taper. MANOVA for repeated measures with contrast analysis indicated that MSFT performance and VO2 (max) were significantly reduced in the IT group over time and condition, indicating that a state of overreaching was attained. However, the only biochemical measure that was significantly different between the IT and NT group was the glutamine to glutamate (Gln/Glu) ratio even though testosterone, testosterone to cortisol (T/C) ratio, plasma glutamate, and CK activity were significantly changed after training in both groups. Positive endurance and power performance changes were observed post-taper in the IT group confirming NFOR. These changes were associated with increases in the T/C ratio and the Gln/Glu ratio and decreases in plasma glutamate and CK activity. These results indicate that although there was no single reliable biochemical marker of NFOR in these athletes, the Gln/Glu ratio and MSFT test may be useful measures for monitoring responses to IT in team sport athletes.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Anaerobic Threshold
  • Biomarkers / blood
  • Body Mass Index
  • Creatine Kinase, MM Form / blood
  • Cumulative Trauma Disorders / blood
  • Cumulative Trauma Disorders / physiopathology*
  • Exercise Tolerance
  • Football*
  • Glutamic Acid / blood
  • Glutamine / blood
  • Heart Rate
  • Humans
  • Hydrocortisone / blood
  • Male
  • Muscle Fatigue*
  • Muscle, Skeletal / physiopathology*
  • Oxygen Consumption
  • Physical Endurance*
  • Physical Exertion*
  • Prospective Studies
  • Reproducibility of Results
  • Testosterone / blood
  • Time Factors


  • Biomarkers
  • Glutamine
  • Glutamic Acid
  • Testosterone
  • Creatine Kinase, MM Form
  • Hydrocortisone