Muscle enzyme and endocrine responses of elite players to Rugby League match play

The purpose of the present study was to examine the acute and short-term muscle enzyme and endocrine responses of players to Rugby League match play. Seventeen elite rugby league players were monitored for a single game. Saliva and blood samples were collected 24 h pre match, pre and post match and at 24 h intervals for a period of 5 days post game to determine plasma creatine kinase (CK) and salivary testosterone (sTest), cortisol (sCort) and testosterone:cortisol ratio (T:C). The magnitude of change in variables at each sample collection time point compared with 24 h pre game. Cortisol and CK displayed significant (p less than 0.05) pre to post match changes. CK increased significantly (p less than 0.05) post match with mean peak CK measured 24 h post game (889.25 ± 238.27 U L−1). Cortisol displayed a clear pattern of response with significant (p less than 0.05) elevations up to 24 h post-pre game, compared with 24 h pre. The hormonal and muscle enzyme profile identified a substantial acute muscle damage and catabolic state associated with the rigors of rugby league match play. A return to normal anabolic:catabolic status within 24–48 h indicates a minimum period of 48 h is required for hormonal homeostasis post competition whilst a more prolonged period of at least 5 days modified activity is required to achieve full recovery following muscle damage during match play