A small sided game session affects salivary metabolite levels in young soccer players

Abstract. BACKGROUND: The use of saliva for monitoring metabolic variations in physical exercise and in different sports gained ground in recent years. Several studies showed that saliva reflects biochemical changes useful for analytical purposes in clinical investigations and in physiological research. OBJECTIVE: The aim of this study was to explore the profile of salivary metabolite changes due to a session of small sided games (SSG) in elite soccer players, searching for a correlation between metabolic changes and athlete performance as GPSmeasured distances covered in the match. METHODS: Ten under-20 elite soccer players participated to the study. The game had an overall duration of 24 min and it consisted of 4 bouts of 6 min duration with 2 min passive recovery between exercise bouts. Saliva samples were collected before and after the game and physiological parameters evaluated, namely the distances covered by players and blood lactate. Samples were analyzed by Nuclear Magnetic Resonance spectroscopy. Orthogonal Projection of Latent-Structure (OPLS) was used to process the data. RESULTS: Multivariate data analysis showed that the SSG session affected salivary metabolite levels in players. We observed no relationship between concentrations of hematic and salivary lactate, nor found any changes in the metabolic profiles that correlate with the blood lactate values. Among the identified metabolites, taurine was instead found to correlate with distances covered by players during the game. CONCLUSIONS: Altogether these results point to a potential use of saliva to follow metabolic changes during an athletic competition, and opens the possibility of using this non-invasive biofluid for the study of athlete training state and performance.