Relación entre el rendimiento en la prueba de estación unipodal y la velocidad del centro de presión en adultos mayores / Relationship between unipedal stance test score and center of pressure velocity in elderly

Introducción. Las caídas frecuentes son uno de los problemas de salud más importantes en los adultos mayores (AM). La prueba de estación unipodal (PEU) valora la estabilidad postural y es utilizada en la medición del riesgo de caídas. Sin embargo, existe poca información acerca de su relación con parámetros posturográficos (PP) que caracterizan a la estabilidad postural. Dentro de los PP que mejor describen la estabilidad postural se encuentra la velocidad del centro de presión (VCdP). El objetivo de este trabajo es examinar la relación entre el rendimiento en la PEU y la VCdP en adultos mayores. Material y métodos. Una muestra de 38 AM sanos fue dividida en dos grupos, según el rendimiento en la PEU: sujetos con bajo rendimiento en la PEU (BR, n=11) y alto rendimiento en la PEU (AR, n=27). En ambos grupos se examinó la correlación entre el tiempo de la PEU y VCdP media (VmCdP) registrada durante un examen posturográfico. Resultados. Se encontró una correlación inversa entre el tiempo de la PEU y la VmCdP en ambos grupos. Sin embargo, esta fue mayor el grupo de BR (r=−0,69; p=0,02) en comparación al grupo AR (r=−0,39; p=0,04). Conclusiones. En base a los resultados obtenidos en esta investigación, es posible concluir que el rendimiento en la prueba de estación unipodal tiene una relación inversa con la VmCdP, especialmente en sujetos con bajo rendimiento en la PEU(AU)

Introduction. Frequent falls are one of the most important health problems in the elderly population. The unipedal stance test (UPST), asses postural stability and is used in fall risk measures. Despite this, there is little information about its relationship with posturographic parameters (PP) that characterizes postural stability. Center of pressure velocity (CoPV) is one of the best PP that describes postural stability. The aim of this study was to analyze the relation between UST score and CoPV in elderly population. Materials and methods. A sample of 38 healthy elderly subjects where divided in two groups according to their UPST score, low performance (LP, n=11) and high performance (HP, n=27). The correlation between UPST score and COP mean velocity (CoPmV), recorded from a posturographic test, was analyzed between both groups. Results. An inverse correlation between UPST score and CoPmV was found in both groups. However, this was higher in the LP group (r=−0.69, P=.02) compared to the HP (r=−0.39, P=.04). Conclusions. Based on the results of this investigation, it may be concluded that the achievement on UPST has an inverse relationship with CoPmV, especially in subjects with low performance in the UPST(AU)

[Differences in biomechanical parameters during sit to stand transfer between elderly with and without history of frequent falls]. / Diferencias biomecánicas durante la transferencia de sedente a bípedo entre adultos mayores con y sin historia de caídas frecuentes.

INTRODUCTION: The phenomenon of frequent falls (FF) is a health problem in the older population, and is a reason why tools need to be designed for the objective assessment of the risk of FF. In this sense the use of biomechanical parameters could be of use in designing these. The aim of this work was to describe the biomechanical differences registered during a sit to stand transfer (STS) between subjects with and without a history of frequent falls. MATERIAL AND METHOD: A sample of sixty voluntary older adults were assessed, divided in two groups of thirty subjects. The first group was composed of older adults without history of frequent falls (WoHFF) and the other group with history of frequent falls (WHFF). In both groups the velocity of the mass centre, the anterior flexion of the trunk, the joint and support moments of the lower extremity and the time of execution during the TSB was assessed. RESULTS: The subjects WHFF generate a slower vertical velocity (P<0.001), lower slope (P<0.001), greater anterior trunk flexion (P<0.0001), lower support moment (P=0.001) and took longer in executing the STS (P=0.0001) than the group WoHFF. CONCLUSIONS: Differences exist in the biomechanical parameters registered during the STS between the elderly WHFF and WoHFF. The results indicate that the function of the hip extensor muscles could have an important role in the execution of the STS in subjects WHFF. The biomechanical parameters assessed during the STS should be considered as useful tools to distinguish between subjects WHFF and WoHFF, and should be considered in the design of tools to determine the risk of frequent falls.

[Differences in momentum development when standing up from a chair between elderly with and without frequent falls history]. / Diferencias en el desarrollo de momentum al levantarse desde una silla en adultos mayores con y sin historia de caídas frecuentes.

INTRODUCTION: The momentum of the upper body (UB) during transfer sit-to-stand (STS) could be sensitive to the deterioration of dynamic postural control, and also the risk of falls. The aim of this study is to quantify the differences in the momentum development on UB during the STS in a sample of fall and no-fall elderly subjects. MATERIAL AND MEHODS: The sample consisted of twenty three voluntary elderly subjects (n=23), six elderly adults with antecedents of frequent falls (more than two within a year period) and seventeen without histories of frequent falls. Through a motion analysis system we registered the kinematics of UB during STS, from which we calculated the momentum of UB. The determined analysis variables were: the maximum values of the vertical (P(V)M) and horizontal (P(H)M) lineal momenta, the minimum (L(Max)) and maximum (L(Min)) values of the angular momentum and maximum trunk flexion (thetaM(UB)). RESULTS: No difference was observed in P(H)M, L(Max) and L(Min) (P>0.05) between both groups. However, a significant difference was found for the variable P(V)M (P=0.03) and thetaM(UB) (P=0.03) between both groups. CONCLUSIONS: We can conclude that, for the sample studied, the frequent fall condition relates to a smaller capacity to develop vertical momentum and increase flexion of the upper body.