The psycho-hormonal influence of fatigue on amateur female soccer players
Soccer is rapidly becoming the most popular team sport played globally for both genders. However, literature describing the physical, physiological and psychological facets of female players is scarce. Various components such as fatigue, a stressful competitive atmosphere, perceived anxiety and negative mood states can increase cortisol secretion and consequently alter (optimum) performance. A typical match is comprised 95% of aerobic activities and a mere 5% of anaerobic activities, though literature suggest that it is the anaerobic actions that cause fatigue, heighten the perceived anxiety and increase cortisol secretion. Therefore, the main objectives of this study were to determine the effect of an aerobic and anaerobic fatiguing test (AFT) and a tournament on salivary cortisol and the psychological states of amateur female soccer players, and if a relationship existed between cortisol, anxiety, mood and/or the AFTs and match outcomes. The participants were 50 amateur female soccer players (age: 22.0 years; stature: 158.9 cm; mass: 55.5 kg) from two tertiary institutions, who completed the aerobic (Yo-Yo intermittent recovery test) and anaerobic fatiguing test (5-metre shuttle run test) over two consecutive days, two weeks prior to a tournament. Cortisol levels (saliva), anxiety (Spielberger state-trait anxiety inventory) and mood (incredibly short profile of mood states [ISP]) were measured immediately before (pre) and 15 minutes after (post) each fatiguing test. The same measurements were conducted an hour prior to (pre), and 15 minutes after (post) every match during a six-match tournament over five consecutive days while the players were fitted with GPS systems to monitor their external and internal loads. Immediately post-AFT, blood lactate (BLa-), maximal heart rate (HRmax) and rate of perceived exertion (RPE) were recorded. Statistical analysis included a linear mixed model in order to investigate time point differences. Afterwards, Pearson's rank correlation was used to examine the possible relationships between cortisol, anxiety, mood and/or the AFT's and match outcomes. An anaerobic fatiguing test led to significant cortisol and total mood disturbance (TMD) increases, with no relationship between cortisol or any psychological measurement. Cortisol correlated with BLa-, and TMD with RPE at post-AFT. Mood and anxiety scores correlated strongly at all times. An aerobic fatiguing test led to significantly increased cortisol and various mood subscales. Cortisol correlated positively with the absence of anxiety before, and with ISP-fatigue post-AFT. HRmax correlated with TMD before, and ISP-fatigue after the AFT. Furthermore, cortisol and BLa- and ISP-vigour and RPE correlated at post-AFT. The tournament led to significant cortisol and TMD increases. No direct relationship was observed between cortisol and/or mood and/or anxiety, though prior to a victory, cortisol correlated positively with TMD, ISP-tension, ISP-fatigue and ISP-depression. Prior to a defeat, cortisol and ISP-anger and ISP-confusion correlated positively and afterwards it correlated negatively with ISP-vigour. A defeat resulted in significantly higher TMD responses compared to a win. In conclusion, this is the first study to investigate the effect of two fatiguing tests and a tournament on the psycho-hormonal states of amateur female soccer players. Emphasis should be placed on maximising anaerobic-related training, as anaerobic activities affect the cortisol and mood fluctuations seen during a match. Implementing a mood questionnaire is useful to indicate underlying physiological and psychological stress. Lastly, ensuring a positive mood state (either concerning training or match facets) can be beneficial in altering the psycho-physiological stress reaction.
- Health Sciences