The project consists of a cross-sectional study in which anthropometric variables, general and specific performance variables of volleyball will be measured, and the biological maturity stage will be calculated. The main objective is to establish a relationship between the biological maturation state, the anthropometric characteristics and the performance in physical fitness tests in volleyball players between 12 and 15 years of age. To do this, there will be all the clubs in the Region of Murcia that have federated teams in these categories.

Inclusion Criteria:

• To play volleyball in a regular basis
• To have between 12 and 15 years
• To participate in volleiball competitions with the team

Exclusion Criteria:

• To be injured in the moment of the measurement session
• To have skipped most of the training sessions the last month
• To have less than a year of experience playing volleyball

The sample objetive of the present study are all the volleyball players of Región of Murcia, Spain, that meet the inclusion criteria and voluntarily decide to take part in the study.