Analysis of isokinetic muscle function and postural control in individuals with intermittent claudication

BACKGROUND: Intermittent claudication (IC) is a debilitating condition that mostly affects elderly people. IC is manifested by a decrease in ambulatory function. Individuals with IC present with motor and sensory nerve dysfunction in the lower extremities, which may lead to deficits in balance. OBJECTIVE: This study aimed to measure postural control and isokinetic muscle function in individuals with intermittent claudication. METHOD: The study included 32 participants of both genders, 16 IC participants (mean age: 64 years, SD=6) and 16 healthy controls (mean age: 67 years, SD=5), which were allocated into two groups: intermittent claudication group (ICG) and control group (CG). Postural control was assessed using the displacement and velocity of the center of pressure (COP) during the sensory organization test (SOT) and the motor control test (MCT). Muscle function of the flexor and extensor muscles of the knee and ankle was measured by an isokinetic dynamometer. Independent t tests were used to calculate the between-group differences. RESULTS: The ICG presented greater displacement (p =0.027) and speed (p =0.033) of the COP in the anteroposterior direction (COPap) during the MCT, as well as longer latency (p =0.004). There were no between-group differences during the SOT. The ICG showed decreased muscle strength and power in the plantar flexors compared to the CG. CONCLUSION: Subjects with IC have lower values of strength and muscle power of plantiflexores, as well as changes in postural control in dynamic conditions. These individuals may be more vulnerable to falls than healthy subjects.

A influência da dupla tarefa no controle postural de adultos jovens / La influencia de doble tarea en el control postural de adultos jóvenes / The influence of dual-tasking on postural control in young adults

O objetivo deste estudo foi verificar a influência da dupla tarefa no equilíbrio postural de adultos jovens. Fizeram parte do estudo 20 universitários (10 homens e 10 mulheres) com idade média de 25 anos. O equilíbrio postural foi avaliado pelo Sensory Organization Test (SOT), utilizando o Smart Equitest(tm) da NeuroCom(r) International, que avalia a habilidade do indivíduo para usar os diferentes sistemas do controle postural (somatossensorial, vestibular e visual) para se manter em equilíbrio nas 6 condições de conflito sensorial apresentadas pelo sistema. Os sujeitos foram avaliados em tarefa única (manutenção do equilíbrio) e dupla tarefa (manutenção do equilíbrio em conjunto com tarefa cognitiva de cálculo mental), de modo randomizado. O equilíbrio foi mensurado através do escore de equilíbrio, comparando diferenças angulares entre os deslocamentos anterior e posterior máximos. Foi utilizado o teste de Wilcoxon com nível de significância p(0,05 para comparar as médias dos escores de equilíbrio entre a situação sem e com dupla tarefa. Os escores de equilíbrio nas condições do SOT evidenciaram diferença estatisticamente significativa na condição 1 (olhos abertos, plataforma e entorno visual fixos; p=0,018) e na condição 6 (olhos abertos, plataforma oscila e entorno visual fixo; p=0,008), com redução do equilíbrio com a dupla tarefa em ambas. Os resultados mostraram que durante a dupla tarefa, composta pelas quatro operações aritméticas, o controle postural é influenciado negativamente com maior oscilação dos sujeitos. Assim, a complexidade da tarefa secundária pode ter sido o principal motivo para os menores escores de equilíbrio encontrados.

Este artículo tuvo por objetivo verificar la influencia de doble tarea en el equilibrio postural de adultos jóvenes. Se han hecho parte del estudio 20 universitarios (10 hombres y 10 mujeres) con promedio de edad de 25 años. El equilibrio postural se evaluó por el Sensory Organization Test (SOT), con uso del Smart Equitest(tm) de la NeuroCom(r) International, el que evalúa la habilidad del sujeto en el uso de los distintos sistemas de control postural (somatosensorial, vestibular y visual) con el fin de mantenerse en equilibrio en las 6 condiciones de conflicto sensorial presentadas por el sistema. Se han evaluados los sujetos en una sola tarea (manutención del equilibrio) y de doble tarea (manutención del equilibrio en relación con la tarea cognitiva de cálculo mental), del modo aleatorizado. Se midió el equilibrio a través de la puntuación de equilibrio, al comparar diferencias angulares entre el desplazamiento anterior y posterior máximos. Se ha hecho la prueba de Wilcoxon con el nivel de significancia p(0,05 para comparar las medias de las puntuaciones de equilibrio entre la situación sin o con doble tarea. Las puntuaciones de equilibrio en las condiciones del SOT han mostrado diferencias estadísticas significativas en la Condición 1 (ojos abiertos, plataforma y entorno visual fijos; p=0,018) y en la Condición 6 (ojos abiertos, plataforma que oscila y entorno visual fijo; p=0,008), con la reducción de equilibrio con doble tarea en ambas las condiciones. Los resultados mostraron que durante la doble tarea, que consiste en las cuatro operaciones aritméticas, el control se influyó negativamente con mayor oscilación de los sujetos. De esa manera, la complejidad de la tarea secundaria puede ser la principal razón para las menores puntuaciones de equilibrio encontradas.

The aim of this study was to investigate the influence of dual-tasking on postural balance in young adults. Participants were 20 college students (10 men and 10 women) with a mean age of 25 years. Postural balance was evaluated by the Sensory Organization Test (SOT), using the Smart Equitest(tm) NeuroCom(r) International, which evaluates the individual's ability to use the different systems of postural control (somatosensory, vestibular and visual) to keep in balance in the 6 conditions of sensory conflict presented by the system. The subjects were evaluated while single-tasking (maintaining balance) and dual-tasking (maintaining balance in conjunction with cognitive mental calculation task) in randomized order. Balance was measured by using the balance score, comparing the angular differences between the maximum anterior and posterior displacements. The Wilcoxon test with significance level of p(0.05 was used to compare the mean scores of balance between the situation with and without dual task. The balance scores in SOT conditions were analyzed and demonstrated statistically significant differences in condition 1 (eyes open, fixed platform and visual surroundings; p=0.018) and condition 6 (eyes open, platform swings and fixed visual surroundings; p=0.008), with reduced balance when dual-tasking in both conditions. The results showed that while performing dual tasks, consisted of four arithmetic operations, the posture control is negatively affected, resulting in a greater oscillation of the subjects. Thus, the complexity of the secondary task may have been the main reason for the lower balance scores found.