Rubens A. da Silva

Age-related differences in time-limit performance and force platform-based balance measures during one-leg stance

Poor posture control has been associated with an increased risk of falls and mobility disability among older adults. This study was conducted to assess the test-retest reliability and sensitivity to group differences regarding the time-limit (TLimit) of one-leg standing and selected balance parameters obtained with a force platform in older and young adults. A secondary purpose was to assess the relationship between TLimit and these balance parameters. Twenty-eight healthy older adults (age: 69±5years) and thirty young adults (age: 21±4years) participated in this study. Two one-leg stance tasks were performed: (1) three trials of 30s maximum and (2) one TLimit trial. The following balance parameters were computed: center of pressure area, RMS sway amplitude, and mean velocity and mean frequency in both the anterio-posterior and medio-lateral directions. All balance parameters obtained with the force platform as well as the TLimit variable were sensitive to differences in balance performance between older and young adults. The test-retest reliability of these measures was found to be acceptable (ICC: 0.40-0.85), with better ICC scores observed for mean velocity and mean frequency in the older group. Pearson correlations coefficients (r) between balance parameters and TLimit ranged from -0.16 to -0.54. These results add to the current literature that can be used in the development of measurement tools for evaluating balance in older and young adults.

Electromyographic Effect of Mat Pilates Exercise on the Back Muscle Activity of Healthy Adult Females

OBJECTIVE The purpose of this study was to examine back muscle activity during 3 traditional mat Pilates exercises. METHODS Eleven healthy female volunteers, aged between 18 and 30 years, participated in this cross-sectional study. Surface electromyography (sEMG) of lumbar extensor muscles was recorded simultaneously with kinematics data to identify the phases of movement. Three mat Pilates back exercises were compared: (1) swimming, (2) single leg kick with static prone back extension, and (3) double leg kick. Root mean square values of each muscle were recorded with 2 pairs of surface electrodes placed bilaterally on one lumbar extensor muscle (at L5). During phases of each exercise, sEMG signals were identified by video analysis. Electrical muscle activation was normalized by the maximal voluntary isometric contraction and used to compare back muscle activity among exercises. A 2-way repeated measures analysis of variance was performed to assess the differences in activation level during the exercises. RESULTS The value of electrical muscle activity in the lumbar extensors ranged between 15% and 61% of MIVC for the 3 types of Pilates mat work exercise. The swimming exercise increased lumbar extensor activity (29% on average) in comparison to the other 2 Pilates conditions. Interestingly, the double leg kick exercise generated significantly more lumbar extensor activity (26% on average) than the single leg kick. CONCLUSIONS For this group of participants, the swimming exercise increased muscle activation relative to the other 2 exercise modes.

Physical activity in daily life in physically independent elderly participating in community-based exercise program

BACKGROUND It is unclear whether participation in exercise programs specifically developed for elderly translates into a more active lifestyle. OBJECTIVES To compare the objectively measured level of physical activity in daily life (PADL) between physically independent elderly who participate or do not participate in community-based exercise programs; and to evaluate which factors are associated with the higher level of PADL in these subjects. METHOD 134 elderly participants in community-based exercise programs (PG) and 104 non-participants (NPG) had their level of PADL measured using pedometers during 7 days. OTHER MEASUREMENTS 6-minute walking test (6MWT), incremental shuttle walking test (ISWT), muscle strength, flexibility and balance. RESULTS The PG had higher 1-week mean daily step count than NPG (8314 [IQR 5971-10060] vs. 6250 [IQR 4346-8207] steps/day, p<0.0001), as well as higher step count in any day of the week. There was a higher proportion of physically active subjects (>8000 steps/day) in PG than in NPG (37% vs. 16%, respectively; p<0.001), as well as the proportion of sedentary subjects (<5000 steps/day) (14% vs. 33%, respectively; p<0.001). Participation in exercise programs, 6MWT and ISWT explained a higher daily steps count (model r(2)=0.56, p<0.0001). CONCLUSIONS In physically independent elderly, a higher level of physical activity in daily life occurs in those who participate in community-based exercise programs, regardless of the weekday and including non-program days. Participation of elderly in community-based exercise programs should be more systematically available and encouraged due to its close link to higher activity levels and better exercise capacity.

Postural balance and physical activity in daily life (PADL) in physically independent older adults with different levels of aerobic exercise capacity

Balance impairs with aging and may cause mobility limitations and functional decline. We aimed to evaluate postural balance and PADL in physically independent older adults with different levels of exercise capacity. One hundred fifty seven physically independent individuals, aged 60 years or older were evaluated. Postural balance assessment was performed during one-legged stance test using a force-platform and maximum exercise capacity with the incremental shuttle walking test (ISWT). PADL was assessed subjectively by the modified Baecke questionnaire and objectively using a pedometer. Based on the performance achieved in the ISWT, according to the percentage of the predicted value, the older adults were separated into 3 groups: low performance group (LP group, ISWT < 80% predicted, n = 32, 19 women), normal performance group (NP group, 80 ≤ ISWT ≤ 100% predicted, n = 30, 22 women) and high performance group (HP group, ISWT > 100% predicted, n = 95, 67 women). The HP group showed better postural balance when compared to LP groups (p < 0.001) and also higher levels of PADL measured with pedometer (p < 0.001). There was a modest correlation (r = 0.45) between exercise capacity and PADL in the LP group and a weak correlation between exercise capacity and balance (r = -28) in the HP group. Physically independent older adults with more preserved exercise capacity have better postural balance and higher levels of PADL in comparison to those older adults who show a poorer condition in terms of exercise capacity.

Back muscle fatigue of younger and older adults with and without chronic low back pain using two protocols: A case-control study.

The purpose of this study was to compare back muscle fatigue of younger and older participants with and without chronic low back pain (CLBP). Twenty participants without and 20 with nonspecific CLBP participated in this study. Each group contained 10 younger (50% males; mean age: 31 ± 6 yrs) and 10 older adults (50% males; age mean: 71 ± 7 yrs). Two isometric fatigue protocols were presented randomly: (1) to maintain the unsupported trunk at the horizontal position while on a 45° Roman chair for a minute, and (2) to maintain a 10% of body weight box close to the trunk in the upright position for a minute. Surface electromyography (EMG) signals from the back (multifidus and iliocostalis) and one hip (biceps femoris) muscles were recorded bilaterally, and the median frequency fatigue estimate from linear regression slopes of the EMG time-series was computed. There were no significant (P > 0.05) age effects, and group-by-age interaction in both isometric and functional fatigue tasks. However, the CLBP groups (both younger and old) displayed more back fatigue than people without CLBP in both fatigue protocols (P < 0.01; effect size varying of d = 0.17-0.32). This study was sensitive to discriminate that individuals with CLBP did present significantly more pronounced EMG back fatigue than people without CLBP, in both younger and older adults. These results have significant clinical implications for low back pain rehabilitation programs with regard to endurance assessment in both younger and older.

Prática habitual de atividade física afeta o equilíbrio de idosas

INTRODUCAO: Os sistemas responsaveis pela manutencao do controle postural naturalmente entram em declinio com o avanco da idade, o que pode comprometer a capacidade de manter a postura nos limites de estabilidade, influenciando no equilibrio das estruturas corporais e, consequentemente, aumentando os riscos de quedas. OBJETIVO: Verificar o impacto da pratica habitual de atividade fisica sobre os parâmetros estabilograficos, equilibrio estatico e dinâmico de idosos fisicamente independentes. MATERIAIS E METODOS: Trata-se de um estudo transversal e descritivo. A amostra foi composta de 77 mulheres com idade entre 60 a 75 anos estratificadas em cinco grupos de acordo com a pratica de atividade fisica classificada pelo International Physical Activity Questionnaire (IPAQ). Foi utilizada a plataforma de forca para avaliacao estabilografica, Teste de Apoio Unipodal (TAU) - equilibrio estatico, e o Timed Up and Go (TUG) - equilibrio dinâmico. RESULTADOS: Foram observadas diferencas estatisticamente significantes em todos os parâmetros estabilometricos analisados exceto na velocidade de oscilacao no eixo X. Por outro lado, os resultados referentes aos testes funcionais nao apresentaram diferencas significativas entre os grupos, entretanto, para o TUG verificou-se uma tendencia a boa mobilidade funcional com o aumento da pratica habitual de atividade fisica. CONCLUSAO: A pratica habitual de atividade fisica mais elevada representa melhora na estabilidade corporal quantificada pela estabilometria, fato este nao demonstrado nos testes neuromotores.

Relação entre testes funcionais e plataforma de força nas medidas de equilíbrio em atletas

INTRODUCTION: Few studies have correlated the balance measurements based in functional tests and force platform in athletes.OBJECTIVE: to determine the relationship between three functional balance tests with the main measurements of the force platform in athletes.METHODOLOGY: Fifteen female athletes, indoor soccer and handball players, aged between 13 and 17 years, participated of this study. The athletes performed tree functional tests: 1) the star excursion balance test, 2) the lateral jump, and 3) the figure eight test; as well as the one leg-stance test on a force platform with the eyes open for 30 seconds. The parameters of center of pressure (COP) of the foot were calculated by stabilographic analysis. For all the tests (functional and platform), tree trials attempts were made, and the mean value retained for the analyses.RESULTS: The correlations between the functional tests and the force platform were from r = 0.01 to -0.69 (weak to moderate), depending on the COP variable. The best correlations (r = -0.69) were found between the star excursion balance test and the COP area, indicating that when a greater distance was reached, the better the postural balance. Secondly, a weak to moderate correlation was found between the figure eight test and COP area (e.g. r = 0.43). The side hop test did not present good correlation with the values obtained on the force platform.CONCLUSION: This study shows that to evaluate balance in athletes practicing indoor soccer and handball, the Star excursion balance test may be used in the absence of a force platform, to identify possible balance deficits.INTRODUCCION: Pocos estudios han correlacionado las medidas de equilibrio entre las principales pruebas funcionales y la plataforma de fuerza en los atletas. OBJETIVO: Determinar la relacion entre tres pruebas de equilibrio funcionales con las principales medidas de la fuerza en la plataforma de los atletas. METODO: Quince atletas del sexo femenino que practican el futbol de salon y balonmano, entre 13 y 17 anos participaron en el estudio. Los atletas realizaron tres pruebas funcionales: 1) Star excursion balance test, 2) salto lateral y 3) salto figura ocho, ademas de una prueba unipodal sobre una plataforma de fuerza con los ojos abiertos durante 30 segundos. Los parametros del centro de la presion de los pies (COP) se calcularon por analisis estabilografica. Para todas las pruebas (funcionales y plataforma), se llevaron a cabo tres ensayos y el promedio fue utilizado para su analisis. RESULTADOS: Las correlaciones entre las pruebas funcionales y la plataforma de fuerza fueron r = 0,01 a -0,69 (leve a moderada), en funcion de la variable COP. La mejor correlacion (r = -0,69) se encontro entre el rango de la prueba Star Excursion Balance y el area del COP, lo que indica que cuanto mayor es la distancia que se logra, mejor es el equilibrio. En segundo lugar, se encontro correlacion debil a moderada entre la prueba en figura de ocho y el area del COP (por ejemplo, r = 0,43). La prueba de salto lateral mostro una buena correlacion con las pruebas en la plataforma de fuerza. CONCLUSION: Este estudio demostro que para la evaluacion del equilibrio de los atletas del sexo femenino de futbol de salon y balonmano, el Star excursion balance test se puede utilizar en la ausencia de una plataforma de fuerza para identificar posibles deficiencias en el equilibrio.

People with chronic low back pain have poorer balance than controls in challenging tasks

Abstract Purpose: To compare the balance of individuals with and without chronic low back pain during five tasks. Method: The participants were 20 volunteers, 10 with and 10 without nonspecific chronic low back pain, mean age 34 years, 50% females. The participants completed the following balance tasks on a force platform in random order: (1) two-legged stance with eyes open, (2) two-legged stance with eyes closed, (3) semi-tandem with eyes open, (4) semi-tandem with eyes closed and (5) one-legged stance with eyes open. The participants completed three 60-s trials of tasks 1–4, and three 30-s trials of task 5 with 30-s rests between trials. The center of pressure area, velocity and frequency in the antero-posterior and medio-lateral directions were computed during each task, and compared between groups and tasks. Results: Participants with chronic low back pain presented significantly larger center of pressure area and higher velocity than the healthy controls (p < 0.001). There were significant differences among tasks for all center of pressure variables (p < 0.001). Semi-tandem (tasks 3 and 4) and one-leg stance (task 5) were more sensitive to identify balance impairments in the chronic low back pain group than two-legged stance tasks 1 and 2 (effect size >1.37 vs. effect size <0.64). There were no significant interactions between groups and tasks. Conclusions: Individuals with chronic low back pain presented poorer postural control using center of pressure measurements than the healthy controls, mainly during more challenging balance tasks such as semi-tandem and one-legged stance conditions. Implications for Rehabilitation People with chronic low back had poorer balance than those without it. Balance tasks need to be sensitive to capture impairments. Balance assessments during semi-tandem and one-legged stance were the most sensitive tasks to determine postural control deficit in people with chronic low back. Balance assessment should be included during rehabilitation programs for individuals with chronic low back pain for better clinical decision making related to balance re-training as necessary.

Effects of Holding an External Load on the Standing Balance of Older and Younger Adults With and Without Chronic Low Back Pain

Objective: The purpose of this study was to assess the effect of holding an external load on the standing balance of younger and older adults with and without chronic low back pain (CLBP). Methods: Twenty participants with and 20 without CLBP participated in the study. Each group contained 10 younger (50% men) and 10 older adults (50% men). Participants were instructed to look straight ahead while standing on a force platform during two 120‐second trials with and without holding an external load (10% of body mass). The center of pressure area, mean velocity, and mean frequency in the anteroposterior and mediolateral directions were measured. Results: Older adults had worse standing balance than younger adults did (P < .001, d = 0.20). There were no significant balance differences between participants with and without CLBP within age groups during standing balance condition. However, holding the external load significantly increased postural instability for both age groups and CLBP status, with mean effect size across center of pressure variables of d = 0.82 for older participants without CLBP and d = 2.65 for younger participants without CLBP. These effects for people with CLBP were d = 1.65 for subgroup of older and d = 1.60 for subgroup of younger participants. Conclusion: Holding an external load of 10% of body mass increased postural instability of both younger and older adults with and without CLBP.

Influence of the presence of Temporomandibular Disorders on postural balance in the elderly

Purpose To investigate the influence of the presence of Temporomandibular Disorders (TMD) on postural balance in elderly individuals. Methods The study sample consisted of 150 elderly: 103 women (67.7±5.0 years) and 47 men (69.3±5.5 years). Evaluation of the presence and severity of TMD included an anamnesis questionnaire, an evaluation of the temporomandibular joint (TMJ), and a muscular examination, which allowed the division of the elderly into 2 groups: G1 (experimental, n=95), with TMD; G2 (control, n=55), without TMD. Postural balance was assessed by means of the one-leg stance test (OLST) on a force platform (BIOMEC400), thus permitting the following measurements: center of foot pressure (COP); mean sway velocity (MV) and frequency (MF) of COP in both the anteroposterior (VAP and FAP) and medial/lateral (VML and FML) directions. The statistical analysis of data was performed using independent t-test, Variance Analysis, and Chi Square test (α=5%). Results Presence of TMD was observed in 63.3% of the individuals (Group 2), with different degrees of severity (mild: 42.7%, moderate: 14.7%, severe: 6%). Significantly higher TMD was observed for women (73.8%) compared with men (40.4%) (p=0.0002). No significant difference was found in between the groups for all balance parameters, e.g., presence and severity of TMD, presence of pain to palpation of TMJ and of masticatory and cervical muscles. Conclusion The presence and severity of TMD, in addition to the presence of pain to palpation of TMJ and masticatory and cervical muscles did not alter the variables related to postural balance in this population.