[en] Introduction: Stiffness and reduced flexibility in the posterior chain, together with the associated decrease in range of motion (ROM), can manifest at an early age. Due to its biomechanical nature, this condition can lead to lumbar pain as well as a variety of other future complications. The factors that cause this phenomenon are widely diverse, ranging from physical trauma to differences in the sexes. In the past, the loss of extensibility and the increase in tension were associated with muscle shortening. Nowadays, various studies hypothesise that this reduction in flexibility of the neuromusculo-skeletal system is caused by a change in the mechanosensitivity of tissue cells. In order to tackle such a condition, we rely on different tools and methods which include, but are not limited to, neurodynamic movement and stretching. Objectives: To compare the efficiency of passive neurodynamic movement and passive stretching in young adults with reduced flexibility of the posterior chain muscles though the use of the Sit-andReach test. Material and methods: This study contemplates an analysis of longitudinal parallel data with the aim of comparing two techniques – neurodynamics and stretching – through the use of the Sit-andReach test. An experimenter will conduct a blind analysis of random samplings. Evaluations will take place before and shortly after the treatments, as well as 24 h later. For maximum medical improvement, both interventions will be performed passively for 4 minutes, a total time of 8 minutes. Results: Fifteen participants were assigned to control and treatment groups. Participants in the treatment groups showed a significant improvement between the first and second measurement, with slightly better results in the stretching group. The measurements taken at 24h post administration of the treatment indicated no change in the results. The control group showed a slight improvement, but significantly inferior to those in treatment groups. Lastly, no significant differences were found between the two treatments, possibly due to the reduced size of the pilot study.

[gl] Introdución: A rixidez e a redución da flexibilidade a nivel da cadea posterior, xunto coa diminución do ROM asociado, está presente dende idades moi temperás podendo dar lugar a nun futuro a diversas doenzas como a dor lumbar, debido as súas influencias biomecánicas. Os factores que provocan este fenómeno son moi diversos, dende traumatismos ata as diferenzas entre sexos. No pasado críase que a perda de extensibilidade e o aumento de tirantez estaban asociadas a un acortamento muscular propiamente dito. Hoxe en día, diversos estudos barallan a hipótese de que esta redución na flexibilidade do sistema neuro-músculo-esquelético se debe a un cambio na mecanosensibilidade dos tecidos. Para abordar dita afectación, cóntase con diferentes ferramentas entre as que destacan a mobilización neuromenínxea e os estiramentos. Obxectivos: Comparar a eficacia da neurodinamia e dos estiramentos (ambos pasivos) na poboación adulta nova con restrición a nivel da cadea posterior, mediante a proba Sit-and-Reach. Material e métodos: Plantéxase o desarrollo dun ensaio clínico controlado en paralelo co fin de comparar dúas técnicas, neurodinamia e estiramentos, mediante a proba Sit-and-Reach, onde o explorador será cego e a selección da mostra aleatoria. As avaliacións levaranse a cabo tanto antes como despois dos tratamentos e tamén as 24 horas. Ambas intervencións serán realizadas de forma pasiva durante 4 minutos por cada MMII facendo un total de 8 minutos de tratamento. Resultados: Realízase un estudo piloto cunha mostra de 15 participantes onde se observa unha mellora significativa dos grupos de intervención entre a primeira medición e a segunda, sendo máis pronunciada na de estiramentos. Na medición realizada as 24 horas mantivéronse os resultados acadados. O grupo control segue unha tendencia a mellora pero que non foi significativa, sendo bastante inferior con respecto aos grupos de tratamento. Por último, non se encontraron diferenzas significativas entre ambos tratamentos debido posiblemente ó reducido tamaño da mostra.