Resumen: Background: Water-polo is the water sport with the highest incidence of injuries, with shoulder pain being the most common one. The understanding of risk factors and guidance on preventive measures is essential in this sport discipline. The aim of this study was to determine the effects of a specific 6-week training plan on range of motion (ROM) and joint strength levels in a group of professional water-polo players. Methods: Quasi-experimental study with a sample of 28 participants (age: 20.1 ± 2.5 years; height: 176.9 ± 6.2 cm; body mass: 74.6 ± 8.1 kg). Three study groups, which consisted of one control group and two experimental groups, were established. Two repeated measurements, pre and post intervention, were performed. During these measurements, ROM of the glenohumeral joint was analyzed both in external (ER) and internal (IR) rotation, as well as the maximal isometric strength. Conclusions: The application of a training program improved glenohumeral joint ROM. ER and IR evolve differently in both shoulders. ER improved only in the throwing arm only in the group undergoing intervention but for the non-dominant side, improvements were observed in both ER and IR, regardless of whether or not they had followed the intervention plan. No improvements were observed in either the isometric strength or contralateral asymmetries. Idioma: Inglés DOI: 10.3390/life12050758 Año: 2022 Publicado en: Life 12, 5 (2022), 758[10 pp.] ISSN: 2075-1729 Factor impacto JCR: 3.2 (2022) Categ. JCR: BIOLOGY rank: 34 / 92 = 0.37 (2022) - Q2 - T2 Factor impacto CITESCORE: 2.7 - Agricultural and Biological Sciences (Q2) - Earth and Planetary Sciences (Q3) - Biochemistry, Genetics and Molecular Biology (Q3)