Metabolismo óseo en ciclistas adolescentes

Resumen

La práctica del ciclismo aporta grandes beneficios para la salud ya que produce una mejora de la condición física general, principalmente a través de un aumento en el consumo máximo de oxígeno, un aumento de la masa muscular, además de prevenir la acumulación de grasa corporal, lo que lleva a disminuir los riesgos de padecer enfermedades cardiovasculares y diferentes tipos de cáncer, entre otras enfermedades. Sin embargo, en términos de masa ósea, las evidencias parecen indicar que presenta un efecto neutro o incluso negativo, ya que un alto porcentaje de los ciclistas profesionales presentan osteopenia en la edad adulta. En lo que respecta a la práctica de actividad física y deportiva en niños y adolescentes, se ha determinado que es beneficiosa para la salud del hueso, aunque no todos los deportes tienen el mismo efecto, siendo los deportes de impacto los que presentan un mayor efecto osteogénico. El ciclismo es considerado un deporte de bajo impacto y varios estudios señalan que los ciclistas adolescentes podrían presentar niveles de masa ósea inferiores a los obtenidos por sujetos de su misma edad. En este sentido, el estudio de los marcadores metabólicos del hueso y de la vitamina D en ciclistas adolescentes podría aportar información relevante sobre los procesos de formación y resorción ósea en este grupo poblacional. Por lo tanto, el objetivo principal de la presente Tesis Doctoral ha sido mejorar el conocimiento sobre el efecto que tiene la práctica del ciclismo sobre el metabolismo óseo en una muestra española de adolescentes ciclistas entrenados. El estudio abarca una parte teórica de análisis y revisión de la literatura, plasmado en una revisión sistemática, y otra parte experimental en la que participaron 22 ciclistas varones adolecentes, junto a 20 adolescentes varones sanos normo-activos, que constituyeron el grupo control. Se evaluó su composición corporal mediante antropometría; los marcadores metabólicos objeto de estudio, es decir, la osteocalcina (OC), el propéptido aminoterminal del procolágeno de tipo I (PINP), y el isómero beta de telopéptido carboxilo terminal del colágeno tipo 1 (beta-CTx), se midieron en suero y se determinaron por inmunoensayo de electroquimioluminiscencia (ECLIA), cuantificándose además en plasma la forma activa de la vitamina D [25(OH)D], mediante ensayo por inmunoabsorción ligado a enzimas (ELISA). Los resultados de este documento muestran que los valores de los marcadores óseos varían en función de la edad tanto en ciclistas como en controles, siendo los sujetos más jóvenes los que presentan un mayor remodelado óseo en relación a los más mayores. En el caso de los ciclistas, los tres marcadores analizados, es decir, los marcadores de formación OC y PINP, y el marcador de resorción beta-CTx, son mayores en los sujetos más jóvenes (menores de 17 años). En el grupo control, únicamente el marcador de formación PINP difiere en función de la edad, siendo mayor en los sujetos más jóvenes (menores de 17 años). Los ciclistas menores de 17 años presentan valores más altos en los marcadores de formación (OC, PINP) y en la forma activa de la vitamina D, respecto a los controles de su misma edad. Se encontró una interacción significativa de edad x grupo en los tres marcadores analizados. En el periodo de 1 año de duración disminuyen los marcadores de formación (OC y PINP) tanto en ciclistas como en controles. En relación a la vitamina D, sólo disminuye en los ciclistas, pasado un año. En conclusión, los resultados sugieren que el remodelado óseo disminuye a lo largo de la adolescencia, tanto en los ciclistas como en los controles normo-activos. 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