INTRODUCTION

Volleyball is a team sport that alternates between high athletic intensity and relatively less strenuous moments during the play (^{González-Ravé et al., 2011}). When playing, the players perform different movements (e.g., jump, dive, roll, rapid forward and lateral movements) that require strength, power, agility and speed (^{Lidor & Ziv, 2010}). Gonzales-Rave and colleagues demonstrated that body composition has a crucial role in determining athletic performance in volleyball players (González-Ravé et al.).

A volleyball team has 12 players, of which 6 will be playing at any one time. These players have different functions while the game is in play (^{Gabbett & Georgieff, 2007}), which can generally be classified as: hitters (outside and opposite), setters, blockers and ‘liberos’. The differentiation of each function requires definition of the anthropomorphic and physiological profiles relevant to each, to adequately respond to the necessary performance and tactical demands (^{Sheppard et al., 2009}a,b).

The anthropometric profile and the somatotype characterisation of top volleyball players can provide useful information on not only the physical conditions of the athletes, but also on their potential performance in relation to the function that they have during the volleyball game (^{Gualdi-Russo & Zaccagni, 2001}). Statistical anthropometric data are available for top volleyball players of various nationalities and ages (Gualdi-Russo & Zaccagni; ^{Duncan et al., 2006}; ^{Carvajal et al., 2012}). However, there are fewer data available relative to volleyball players from the lower Divisions (^{Nikolaidis et al., 2012}; Nikolaidis, 2013) and to the best of our knowledge, there are no data relative to such non-professional Italian athletes in the literature.

The goal of the present study was to compare the anthropometric characteristics, body composition, and somatotypes across non-professional female Italian volleyball players in relation to the different Divisions their team plays in and the different functions that they have during the game.

MATERIAL AND METHOD

The sample (N = 74) was composed of 62 volleyball players from different Divisions (Division B in the national leagues, and Divisions C and D in the regional leagues) and function (hitters: n. 27, setters: n. 10, middle blockers: n. 12, liberos: n. 10, all-rounders: n. 13). To provide further comparisons, 12 beach volleyball players were also analysed. The mean age for all 74 of these athletes was 23.58, s = 7.74 years.

Volleyball is highly specialised sport discipline where each player has determined functions according to their playing position: setters are the playmaker of the team and partecipate in every phase of the game; they are involved in blocking and defence too; hitters are intensely involved in spiking and blocking and, secondary, in defense; the middle blockers are the players that execute the most blocks; at the same time they are involved in hit and, less intensely, in dig actions; opposite players execute most of the spikes of its team but also have an important role blocking; sometimes they play a role in defence and reception; libero player is specialized in reception and defence; he plays in the back court and cannot serve, set inside of the 3 meter line, or spike. The anthropometric profile of a group of players with mixed functions through the course of the season was also defined, with these players classified into the category of ‘all-rounders’.

The anthropometric measures (Table I) were taken following the International Society for the Advancement of Kinanthropometry (ISAK) recommendation. The thickness of the subcutaneous fat folds was measured using Harpenden skinfold callipers, with an accuracy of 0.2 mm. The data were then processed to obtain the following parameters: body mass index (BMI), fat mass percentage (FM%), arm muscle area (AMA), thigh muscle area (TMA), and somatotype (^{Brozek et al., 1963}; ^{Heat & Carter, 1967}; ^{Jackson et al., 1980}; ^{Cagnazzo & Cagnazzo, 2009}).

Statistical data processing was performed using the SPSS Statistics V22.0 software (IBM). Initially, the normality of the data was determined using KolmogorovSmirnov tests, and the homogeneity of the variance using Levene tests. Subsequently, descriptive analysis was performed according to the volleyball Divisions (i.e., B, C, D) and the player functions.

The differences between the means for the various Divisions and player functions were analysed using non-parametric Mann-Whitney tests. Significance was set at P <0.05. Using the intraclass correlation coefficient (ICC), the differences between the means of all of the measurements collected at three different times were also analysed, to define possible intra-observer errors. The ICCs were interpreted based on the classification proposed by ^{Fleiss (1986}).

RESULTS

Table I shows the anthropometric and somatotype (i.e., endomorphy, mesomorphy, ectomorphy) data of the volleyball players according to the volleyball player status (i.e., Divisions B, C, D, beach volleyball). Table II gives the results of the Mann- Whitney U tests where statistically significant differences were seen between the anthropometric and somatotype measures of the volleyball players in the categories studied.

Table III gives the descriptive results of the analysis carried out on these volleyball players subdivided by their functions in the team, with the results of the Mann-Whitney U tests here given in Table IV.

The analysis of the data reproducibility through the intraclass correlation coefficients showed a strength of agreement as defined by Fleiss of ‘very good’ for all of the measures (Table V).

Table I Descriptive statistics according to volleyball player status. 

Table II Results of Mann-Whitney analysis (U) for evaluation of the significance (p) of the mean differences between the various levels of player status. 

^{n, number of players used in each of the comparisons; U, Mann-Whitney statistic; significance for p ≤0.05 indicated in bold}.

Table III Descriptive statistics according to volleyball player functions. 

Table IV Results of Mann-Whitney analysis (U) for evaluation of the significance (p) of the mean differences between the various player functions. 

^{n, number of players used in each of the comparisons; U, Mann-Whitney statistic; significance for p ≤0.05 indicated in bold.}

Table V Analysis of the reproducibility of the measures (n = 74, for all) through the intraclass correlation coefficients, which demonstrate the strength of agreement according to Fleiss of ‘very good’ for all measures. 

^{abehind the knee}.

DISCUSSION

In professional volleyball, each position requires specific motor skills, and these are reflected in the anthropomorphic characteristics of the players. Generally, in professional tournaments (Divisions A1, A2), the liberos and setters are the shorter athletes; furthermore, the liberos are the players with lower body weight (^{Marques et al., 2009}; ^{Trajkovic et al., 2011}; Carvajal et al.).

The volleyball players of the Italian Division B had a markedly lower height and weight than that of the compatriot elite players (Gualdi-Russo & Zaccagni). The mean heights of Italian amateur volleyball players are lower than those of Greek amateur athletes, while their mean weight is in line with what was reported for their Greek counterparts (Nikolaidis). The Italian players have higher FM% than the Greek amateur colleagues (Nikolaidis).

The anthropometric profile of the volleyball players who have different functions when playing in the team is related to the technical and tactical needs that are requested of them. Regarding to the professional volleyball players, the blockers are taller and get better blocks performance; conversely, the setters need to be faster and more agile, and therefore well muscled, dynamic players who are relatively short, are preferred for this function (Gualdi-Russo & Zaccagni; Carvajal et al.). The same trend is observed in the amateur Italian volleyball players.

The mean somatotype across the full player sample examined in the present study was 5.39, s = 0.89 - 4.07, s = 1.79 - 2.47, s = 1.13. The endomorphic component thus prevails over the other components, regardless of the Division (i.e., Divisions B, C, D) and the player function. Setters and liberos show higher mesomorphy, that is the expression of increased musculoskeletal system development.

The higher presence of the endomorphic component distinguishes the Italian Division B, C and D players from those of Divisions A1 and A2, for whom mesomorphy dominates. In particular, the Italian Division B tournaments are played by athletes with different physical characteristics from those of the elite leagues (i.e., Divisions A1, A2): stature and good musculoskeletal system development appear to be selective parameters for the players to gain access to the elite tournaments.

No statistically significant differences are observed among the Italian players in the different Divisions relative to body weight, FM%, TMA, and the degree of endomorphism and ectomorphism. The Division B players are statistically taller than the Division C players, but have a comparable height to the players in Division D. This last similarity might be explained by the participation in Division D tournaments by players originally from higher Divisions and now towards the ends of their careers. Contrary to expectations, the Division C athletes showed significantly higher AMA and mesomorphic component than the Division B players.

The anthropometry and somatotype of Italian amateur volleyball players are comparable to those of the Italian beach volleyball players. Indeed, there were no significant differences between these two types of volleyball players, with the sole exceptions of AMA and the mesomorphic component, which were also limited to the comparisons with the Division C players.

CONCLUSION

The high stature and a good muscular development (demonstrated by the prevalence of the mesomorphic component over the others) characterizes the elite players and differentiates them from those of lower categories.

Regarding the amateur sector, the anthropometric profiles do not clearly distinguish the higher ranking volleyball players (i.e., Division B) from the others (C and D Divisions). The jump in class between the lower Divisions (i.e., Divisions C, D) and Division B is dictated not so much by the physical qualities of the players, but rather by their technical skills.

In Italian amateur tournaments (i.e., Divisions B, C, D), the different functions of the players show anthropometric data distributions that tend to reflect those of the elite athletes; i.e., the blockers and hitters are taller and have a more developed ectomorphic component, while the mesomorphic component prevails in the setters and liberos.