title: Physical and temporal characteristics of under 19, under 21 and senior male beach volleyball players.
abstract: This study aimed to assess the effects of age groups and players' role (blocker vs. defender specialist) in beach volleyball in relation to physical and temporal variables, considering quality of opposition. 1101 rallies from Under 19 (U19), 933 rallies from Under 21 (U21), and 1480 rallies from senior (senior) (Men's Swatch World Championships, 2010-2011) were observed using video match analysis. Cluster analysis was used to set teams' competitive levels and establish quality of opposition as "balanced", "moderate balanced" and "unbalanced" games. The analyzed variables were: temporal (duration of set, total rest time, total work time, duration of rallies, rest time between rallies) and physical (number of jumps and number of hits done by defenders and blockers) characteristics. A one-way ANOVA, independent samples t-test and multinomial logistic regression were performed to analyze the variables studied. The analysis of temporal and physical characteristics showed differences considering age group, player's role and quality of opposition. The duration of set, total rest time, and number of jumps done by defenders significantly increased from the U19 to senior category. Multinomial logistic regression showed that in: a) balanced games, rest time between rallies was higher in seniors than in U19 or U21; number of jumps done by defenders was higher in seniors than in U19) and U21; b) moderate balanced games, number of jumps done by defenders was higher in seniors than in U21 and number of jumps done by blockers was smaller in U19 than U21 or seniors; c) unbalanced games, no significant findings were shown. This study suggests differences in players' performances according to age group and players' role in different qualities of opposition. The article provides reference values that can be useful to guide training and create scenarios that resemble a competition, taking into account physical and temporal characteristics. Key PointsPlayer roles, quality of opposition, and competitive level of the teams influence physical and temporal characteristics, and they may be taken into consideration during the training by strength and conditioning coaches and coaches.More experienced players adopt strategies to better manage their effort and rest time between rallies.The game strategy affects the physical actions done by players (e.g. tendency to serve more to one player of the team affects the number of jumps performed by this player).
authors.affiliation: Faculty of Sport, University of Oporto , Portugal.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Medeiros
authors.affiliation: Research Center in Sport Sciences, Health and human Development (CIDESD), University of Trás-os-Montes e Alto Douro at Vila Real , Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Marcelino
authors.affiliation: Faculty of Sport, University of Oporto , Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Mesquita
authors.affiliation: Faculty of Sport Sciences, University of Murcia , Spain.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Palao
keywords: Logistic regression; age groups; beach volley; match analysis; performance; player role; quality of opposition