Original research Monitoring training loads, mood states, and jump performance over two periodized training mesocycles in elite young volleyball players Marcelo S Aoki 1 , Ademir FS Arruda 2 , Camila G Freitas 1 , Bernardo Miloski 1 , Pablo R Marcelino 1,3 , Gustavo Drago 3 , Murilo Drago 3 and Alexandre Moreira 2 Abstract The purpose of this study was to verify the effect of the periodized training program on internal training load, mood states, and vertical jump capacity of young volleyball players. Internal training load was measured using the session rating of perceived exertion (session-RPE) method. To assess mood states, the profile of mood states questionnaire was completed once a week. The vertical jump tests were performed before and after training period. The main findings were (1) the internal training load was greater during the preparatory mesocycle than during the competitive mesocycle, for both U16 and U19 groups; (2) the U19 completed a higher training load during preparatory mesocycle than U16; (3) despite the differences in the periodized training program, the U16 group presented a higher value for the total mood disturbance and for the subscales, tension, depression, anger, and fatigue; and (4) the vertical jump performance increased from the beginning to the end of the nine-week training period for U16 and U19 groups. Keywords Periodization, counter-movement jump, exercise intensity, rating of perceived exertion, squat jump, training program, vertical jump Introduction The training periodization is a key factor for athletes to achieve the best performance. In order to achieve effect- iveness, the training periodization largely depends on the systematic training monitoring process. It is widely accepted that the integrated training monitoring approach provide pertinent data which could be used to guide coaches’ decision-making process and drive further direction. 1–3 Despite the relevance of training monitoring, there is limited data in literature about this topic, 3 especially regarding youth team sports. A possible reason for the limited information avail- able regarding the training load distribution in youth team sport athletes is that there have been few practical and reliable methods to monitor the training load in team sports. In addition, these methods (e.g. GPS and heart rate monitors) present high cost, and there are operational difficulties for researcher to access elite young team sport athletes in a practical setting. It is also important to mention that these methods assess the performed external work (external training load); however, no information regarding internal responses (internal training load (ITL)) can be obtained. On the other hand, the session rating of perceived exertion (session-RPE) is a simple, useful, valid, and inexpensive method for quantifying ITL which was proposed by Foster et al. 4 This method has been sug- gested to be one of the most reliable tools for monitor- ing the training dose 4–9 and can provide a global indicator of exercise intensity. 10,11 The validation for 1 School of Arts, Sciences and Humanities, University of Sa ˜o Paulo, Sa ˜o Paulo, Brazil 2 School of Physical Education and Sport, University of Sa ˜o Paulo, Sa ˜o Paulo, Brazil 3 Integrated Support Center for Athletes—CIAA—E.C. Pinheiros, Sa ˜o Paulo, Brazil Corresponding author: Alexandre Moreira, Department of Sport, School of Physical Education and Sport, University of Sa ˜o Paulo, Av. Prof. Mello Moraes, 65, Cidade Universita ´ria, 05508-030 Sa ˜o Paulo, Brazil. Email: alemoreira@usp.br Reviewer: Larry Judge (Ball State University, USA) International Journal of Sports Science & Coaching 2017, Vol. 12(1) 130–137 ! The Author(s) 2016 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1747954116684394 journals.sagepub.com/home/spo