## 1 Effects of Congested Matches and Training Schedules on Salivary Markers in Elite Futsal Players  
**[PERSON] 1,2**(r)**, [PERSON] 1,3,*(r), [PERSON] 1,4,  
**[PERSON] 1,5**(r)** and [PERSON] 1,2**(r)  
1 BioVetMed & SportSci Research Group, University of Murcia, 30100 Murcia, Spain;  
[EMAIL_ADDRESS] (A.S.-L.); [EMAIL_ADDRESS] (A.M.-V.); [EMAIL_ADDRESS] (A.M.G.);  
[EMAIL_ADDRESS] (J.P.-O.)  
2 Department of Physical Activity and Sport, Faculty of Sport Sciences, University of Murcia, 30720 San Javier, Spain  
3 Research Group in Optimization of Training and Sports Performance (COERD), Department of Didactics of Music Plastic and Body Expression, Faculty of Sport Science, University of Extremadura, 10003 Caceres, Spain  
4 Faculty of Health Sciences, Isabel I University, 09003 Burgs, Spain  
5 Department of Animal Medicine and Surgery, Veterinary School, CEIR Campus Mare Nostrum (CMN), University of Murcia, 30100 Espinardo, Spain  
*Correspondence: [EMAIL_ADDRESS]  
Related Application: Monitoring salivary biomarkers demonstrates a potential application to assess the internal training load and recovery status of elite futsal players during congested competition periods, especially total protein and salivary immunoglobulin A. Tracking biomarker changes provides a practical tool for coaching staff to guide adjustments to training loads, nutrition, and recovery protocols to mitigate risks and optimize athlete performance and health.  
A congested match and training schedule could alter internal load, and this could be reflected in biomarkers of stress and immunity in elite futsal players. The aim of this study was to analyze the effects of a congested match and training schedule on internal load and levels of total protein, total oxidant status (TOS), total antioxidant capacity (TAC), oxidative stress index, and the concentrations of salivary immunoglobulin A (SIgA) in 17 professional players from the same Portuguese elite futsal club (age: 23.07 \(\pm\) 6.76 years old; height: 1.75 \(\pm\) 0.06 m; body mass: 75.47 \(\pm\) 7.47 kg; experience in playing in elite: 5.38 \(\pm\) 2.03 years) who performed 5 matches and 16 training sessions in a period of 27 days. The salivary content of total protein, TOS, TAC, oxidative stress index, and SIgA were calculated before and after the training sessions and the unofficial matches under study. Saliva sampling was conducted 10 min before each match or training session and 40 min after (post-match and post-training). The MANOVA of repeated measures showed a significant difference for total protein and SIgA (\(p<\) 0.01). Total protein (sphericity = 0.007; statistical power = 0.818) and SIgA (sphericity = 0.018; statistical power = 0.693) are highly correlated with the time factor. The main findings revealed several key points: (a) There was a significant increase in total protein, SIgA, and TAC during acute load (pre- vs. post-session) in both training and match contexts. Specifically, total protein and SIgA displayed notable increments in both training and match settings, while TAC exhibited significant increases exclusively during matches. (b) No changes in TOS and oxidative stress index were observed during acute load in either training or match contexts. (c) A positive trend was noted between the chronic load during a congested week of the precompetitive season and the decrease in total protein and SIgA levels. (d) Additionally, a positive correlation between internal training loads and oxidative/antioxidant responses was found, as expressed by the oxidative stress index, without significant differences (\(p\)-value > 0.05) in acute and chronic loads during congested matches and training schedules.  
oral mucosal immunity; internal load; biomarkers; fatigue; oxidative stress; recovery