Discriminatory Ability of Lower-Extremity Peak Torque and Rate of Torque Development in the Identification of Older Women With Slow Gait Speed.

The aim was to compare torque and rate of torque development of lower limb muscles between older women with functional and slow gait speeds to determine which muscle group is the best predictor of functional gait speed, and to establish strength thresholds needed for functional walking speed. Torque and rate of torque development of hip, knee, and ankle muscles were measured in older women who were divided in 2 groups according to gait speed: slow gait speed (<1.22 m·s-1) and functional gait speed (≥1.22 m·s-1). For each muscle group, 3 maximal isometric contractions were performed, and peak torque and rate of torque development were recorded. Older women with slow gait speed had lower peak torque than older women with functional gait speed for hip extension (28%), knee flexion (15%), knee extension (14%), and plantar flexion (16%) (all Ps < .05). Older women with slow gait speed had lower peak rate of torque development for hip flexion (29%), hip extension (37%), knee flexion (34%), knee extension (33%), and plantar flexion (19%) (all Ps < .05). Knee extension peak rate of torque development and hip extension peak torque were the better predictors of functional gait speed with thresholds of 2.96 N·m·s-1·kg-1 and 1.26 N·m·kg-1, respectively.

Neuromuscular performance in the hip joint of elderly fallers and non-fallers.

BACKGROUNDS: Low strength and neuromuscular activation of the lower limbs have been associated with falls making it an important predictor of functional status in the elderly. AIM: To compare the rate of neuromuscular activation, rate of torque development, peak torque and reaction time between young and elderly fallers and non-fallers for hip flexion and extension. METHODS: We evaluated 44 elderly people who were divided into two groups: elderly fallers (n = 20) and elderly non-fallers (n = 24); and 18 young people. The subjects performed three isometric hip flexion and extension contractions. Electromyography data were collected for the rectus femoris, gluteus maximus and biceps femoris muscles. RESULTS: The elderly had 49 % lower peak torque and 68 % lower rate of torque development for hip extension, 28 % lower rate of neuromuscular activation for gluteus maximus and 38 % lower rate of neuromuscular activation for biceps femoris than the young (p < 0.05). Furthermore, the elderly had 42 % lower peak torque and 62 % lower rate of torque development for hip flexion and 48 % lower rate of neuromuscular for rectus femoris than the young (p < 0.05). The elderly fallers showed consistent trend toward a lower rate of torque development than elderly non-fallers for hip extension at 50 ms (29 %, p = 0.298, d = 0.76) and 100 ms (26 %, p = 0.452, d = 0.68).The motor time was 30 % slower for gluteus maximus, 42 % slower for rectus femoris and 50 % slower for biceps femoris in the elderly than in the young. DISCUSSION: Impaired capacity of the elderly, especially fallers, may be explained by neural and morphological aspects of the muscles. CONCLUSION: The process of senescence affects the muscle function of the hip flexion and extension, and falls may be related to lower rate of torque development and slower motor time of biceps femoris.

Activation, strength, and resistance: Which variables predict the kinematics of women with and without patellofemoral pain?

INTRODUCTION: Investigating the possible relationship between neuromuscular changes and movement alterations could help to describe the mechanisms underlying patellofemoral pain (PFP). OBJECTIVE: To investigate whether activation and muscle strength of the trunk and lower limb and muscle resistance of the trunk predict the knee frontal and trunk sagittal kinematics in women with and without PFP. METHOD: Sixty women (PFP, n = 30; asymptomatic, n = 30) underwent the single-leg squat test to collect electromyographic and kinematic data. Activation of transversus abdominis/internal oblique, gluteus medius (GMed), and vastus medialis oblique (VMO); knee frontal and trunk sagittal angles were analyzed. Participants also underwent maximal isometric tests to determine lateral trunk, hip abductor, and knee extensor torques and performed a lateral trunk resistance test. Multiple regression was used to determine predictive models. RESULTS: In the PFP group, knee frontal angle (R2 = 0.39, p = 0.001) was predicted by GMed activation (ß = 0.23, p = 0.000) and hip abductor torque (ß = 0.08, p = 0.022). No variable was able to predict trunk sagittal kinematics in this group. In the asymptomatics, knee frontal angle (R2 = 0.16, p = 0.029) was predicted by hip abductor torque (ß = 0.07, p = 0.029), while trunk sagittal angle (R2 = 0.24, p = 0.024) was predicted by VMO activation (ß = 0.12, p = 0.016). CONCLUSION: Kinematics is predicted by the muscles acting in the respective planes, such that hip abductors capacities are related to the knee frontal alignment in both groups, and that of the VMO is related to the trunk sagittal alignment only in asymptomatic women.

Effect of different residential settings on gait kinematic parameters in older adults with cognitive impairment.

OBJECTIVE: To compare the parameters of gait kinematics of older adults with cognitive impairment who live in community dwellings or those living or spending most of the time in non-family environment settings. METHODS: The sample was composed of 33 older adults of both sexes with cognitive impairment. Participants were separated into three groups: a community-dwelling older adult group comprised of 11 subjects; a semi-institutionalized older adult group comprised of 10 older adults attended in a geriatric daycare institution; and an institutionalized older adult group comprised of 12 older adults living in long-term institutions. Gait kinematics were recorded by pressure sensors (footswitches). Fifty gait cycles at self-selected pace were analyzed to obtain: gait speed, stride length, stance, swing, and stride time. The variability of these parameters was also analyzed. RESULTS: MANCOVA identified the main effect of groups (p < 0.001). Gait speed of older adults living in long-term institutions and older adults attended in geriatric daycare institutions was slower than community-living older adults (p < 0.001 and p = 0.04, respectively). Swing and stride time variability was higher in older adults living in long-term institutions (p = 0.003 and p = 0.001) and in older adults attended in geriatric daycare institutions (p = 0.02 and p = 0.001) than in community-dwelling older adults. CONCLUSION: The most important finding was that older adults with cognitive impairment who need non-family residential setting care had higher gait kinematics abnormalities, which may increase the risk of falls, compared to those who live in the community.

Comparação do desempenho funcional e parâmetros cinemáticos da marcha em idosos com fragilidade e saudáveis / Comparison of functional performance and kinematic gait parameters in frail and healthy elderly people

Objetivo: Comparar o desempenho funcional e as alterações cinemáticas da marcha em idosos saudáveis e em idosos com manifestações da síndrome da fragilidade, viventes na comunidade. Métodos: Estudo transversal do tipo caso-controle. Participaram do estudo 15 idosos, viventes na comunidade, separados em dois grupos, de acordo com a presença de manifestações de fragilidade: (n = 10) e controle (n = 5). Foram coletados dados sobre desempenho funcional, capacidade aeróbia, presença da síndrome da fragilidade e avaliação cinemática da marcha. Foram utilizados testes como: TC400m, dinamometria e SPPB. Para a análise de dados, foi utilizado o pacote estastístico PASW 18.0 (SPSS inc). Resultados: O tempo no teste de caminhada de 400m foi 11 segundos maior no grupo com sinais de fragilidade (p = 0,03), e a força de preensão palmar foi 25,8% maior no grupo sem fragilidade (p = 0,01). Conclusão: Concluimos que idosos frágeis possuem declínio no desempenho funcional em testes que avaliam a resistência aeróbia e a força muscular.

Objective: To compare functional performance and kinematic gait abnormalities in healthy elderly people and in elderly people with manifestations of the frailty syndrome, living in the community. Methods: A cross-sectional case-control study. Fifteen elderly people, living in the community, participated in the study. They were separated into two groups, according to the presence of manifestations of frailty (n = 10) and control (n = 5). Data on functional performance, aerobic capacity, presence of frailty syndrome, and kinematic gait assessment were collected. Tests, such as: TC400m, dynamometry, and SPPB were used. For data analysis, the statistical package PASW 18.0 (SPSS inc) was used. Results: The time in the 400m walk test was 11 seconds higher in the group with signs of frailty (p = 0.03), and handgrip strength was 25.8% higher in the group without frailty (p = 0.01). Conclusion: We conclude that frail elderly people have a decline in functional performance in tests that assess aerobic resistance and muscle strength.

The ability of gait kinematic parameters to predict falls in older adults with cognitive impairments living in long term institutions.

BACKGROUND: Cognitive impairments reduce adaptive responses and may increase the risk of falls. OBJECTIVES: To compare gait kinematics in older adults with cognitive impairments living in long term institutions and to identify the ability of gait kinematics to predict falls in older adults with cognitive impairments living in long term institutions. METHODS: Data of 23 older adults with cognitive impairments living in long term institutions were considered for this study. Fifty gait cycles were recorded during walking at a self-selected pace using footswitches sensors. The variables considered for the analysis were: speed; stride length; stance, swing and stride time; and the variability of these parameters. Fall status was recorded for a 6 month-period. FINDINGS: MANOVA found group effect (p = 0.025) for gait kinematics comparisons. Variability of stance (p = 0.01) and swing (p = 0.012) and stride time (p < 0.001) were higher in older fallers. Speed of older fallers was 31.8% slower than those of the non-fallers (p < 0.001). The kinematic variables that were able to predict falls were: stride time variability (p < 0.001), threshold of 0.4 s, sensitivity of 50% and specificity of 100%; and gait speed (p < 0.001), threshold of 0.65 m·s-1, sensibility and specificity of 50%. INTERPRETATION: Older adults living in an assisted living facility with a history of falls demonstrate increased kinematic variability while walking. However, the ability of gait kinematic parameters to predict falls was found to be weak. The results suggested that gait kinematic parameters are weak predictors of falls in older adults with cognitive impairments living in long term institutions.

Quadriceps muscle weakness influences the gait pattern in women with knee osteoarthritis.

BACKGROUND: Osteoarthritis is the most prevalent rheumatic disease in the population and is characterized by limitation of main functional activities of daily living, as the gait. Muscle strength is a variable that may be related to performance in daily tasks.Therefore, we to analyze the gait pattern in individuals with knee osteoarthritis (KOA) and to determine associations of gait variables with the level of muscle strength of knee extensors. METHODS: Sixty-seven female volunteers divided into 2 groups, a KOA group (KOAG, n = 36, 66.69 ± 7.69 years) and control (n = 31, 63.68 ± 6.97 years), participated in the study. The volunteers walked on a 10-m platform at their usual gait speed, using 2 pressure sensors positioned at the base of the hallux and calcaneus. The mean step time, support and double support times, swing time and gait speed were calculated. The evaluation of the quadriceps isometric torque was performed in an extensor chair, with hip and knee flexion at 90°. The procedure consisted of three maximal contractions of knee extension. Peak torque was determined by the highest torque value obtained after the onset of muscle contraction. For statistical analysis, one-way ANOVA and Pearson's correlation were used, with p <  0.05. RESULTS: The KOAG had a 54.76% longer support time, a 13% longer step time (p <  0.001), a 30% decrease in swing time (p <  0.001) and a 10.7% decrease in gait speed (p = 0.001) compared with controls. The quadriceps isometric torque was 34% (p = 0.001) lower in the KOAG. There was a correlation between kinematic variables and quadriceps torque. CONCLUSION: Weakness of the quadriceps muscle in women with KOA influences gait pattern, resulting in reduced speed associated with a shorter swing time and longer support time.

Neuromuscular efficiency of the quadriceps in women with and without patellofemoral pain / Eficiencia neuromuscular del cuádriceps en mujeres con y sin dolor patelofemoral / Eficiência neuromuscular do quadríceps em mulheres com e sem dor patelofemoral

ABSTRACT Patellofemoral pain (PFP) may contribute to less activation of the quadriceps muscle, favoring joint overload and pain. Neuromuscular efficiency (NME) is a variable that evaluates the relationship between the amount of neural stimuli and the ability to generate force of in a given muscle, with the most efficient being the one that produces greater muscle force, with less activation of muscle fibers. In this sense, this study aimed to evaluate the strength and NME of knee extensors in women with and without patellofemoral pain. A total of 24 adult women, recruited via a questionnaire, aged from 18 to 30 years, with and without patellofemoral pain, participated in this study. Anamnesis, anterior knee pain scale, and numerical visual scale were applied. Subsequently, the knee extensor strength, with a hand-held dynamometer, and the NME of vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) were assessed. For statistical analysis, appropriate tests were adopted to compare variables between groups and correlate them. In all statistical tests, a α<0.05 was adopted. Results showed that women with PFP had 61% lower NME in the VM and 52% in the VL, compared to the group without pain. No significant difference was found for knee extensor strength between groups. We conclude that pain negatively influences VM and VL recruitment but does not change quadriceps ability to generate strength.

RESUMEN El dolor patelofemoral (DPF) puede producir una menor activación del músculo cuádriceps, lo que lleva a una mayor sobrecarga y dolor en esta articulación. La eficiencia neuromuscular (ENM) es una variable que evalúa la relación entre la cantidad de estímulos neurales y la capacidad de determinado músculo de generar fuerza, con más eficiencia para el que produce mayor fuerza muscular, con menor activación de las fibras musculares. Así el objetivo del estudio fue evaluar la fuerza y la ENM de los extensores de rodilla en mujeres con y sin dolor patelofemoral. En este estudio participaron 24 mujeres, con edades entre 18 y 30 años, con y sin dolor patelofemoral, que han sido reclutadas por medio de un cuestionario. Se aplicaron la anamnesis, la escala de dolor anterior de rodilla y la escala visual numérica. Posteriormente, se realizaron evaluaciones de la fuerza extensora de la rodilla con dinamómetro manual y de la ENM del vasto medial (VM), vasto lateral (VL) y recto femoral (RF). Para el análisis estadístico, se adoptaron pruebas apropiadas para comparar variables entre grupos y correlacionarlas. En todas las pruebas estadísticas, el nivel de significación fue de α<0,05. Los resultados mostraron que las mujeres con DPF tenían el 61% menor ENM en el VM y el 52% en el VL en comparación con el grupo sin dolor. No hubo diferencias significativas para la fuerza extensora de la rodilla entre los grupos. Se concluye que el dolor influye negativamente en el reclutamiento de VM y VL, pero no cambia la capacidad de generar fuerza del cuádriceps.

RESUMO A dor patelofemoral (DPF) pode contribuir para menor ativação do músculo quadríceps, favorecendo maior sobrecarga e dor nesta articulação. A eficiência neuromuscular (ENM) é uma variável que avalia a relação entre a quantidade de estímulos neurais e a capacidade de geração de força de um determinado músculo, sendo mais eficiente aquele que produz maior força muscular, com menor ativação das fibras musculares. Nesse sentido, o objetivo do estudo foi avaliar a força e a ENM dos extensores de joelho em mulheres com e sem dor patelofemoral. Participaram deste estudo 24 mulheres, recrutadas por meio de um questionário, com idades entre 18 e 30 anos, com e sem dor patelofemoral. Foram realizadas a anamnese, a escala de dor anterior no joelho e a escala visual numérica e, posteriormente, a avaliação da força extensora de joelho, com dinamômetro manual, e a avaliação da ENM de vasto medial (VM), vasto lateral (VL) e reto femoral (RF). Para análise estatística, foram adotados os testes apropriados para comparação das variáveis entre os grupos e para correlação entre elas. Em todos os testes estatísticos foi adotado o nível de significância de α<0,05. Os resultados mostraram que mulheres com DPF apresentaram 61% menor ENM do VM e 52% do VL, em comparação ao grupo sem dor. Não se encontrou diferença significativa para força extensora de joelho entre os grupos. Concluímos que a dor influencia negativamente o recrutamento de VM e VL, mas não altera a capacidade do quadríceps de gerar força.

Is it possible to predict falls in older adults using gait kinematics?

BACKGROUND: Gait kinematic parameters have been reported as an important clinical tool to assess the risk of falls in older adults. However, the ability of these parameters to predict falls in the older population is still unclear. OBJECTIVE: To identify the ability that gait kinematic parameters present to predict fall in older adults. METHODS: Data from 102 older adults, who live in a community setting, were considered for this study. For data collection, older subjects had to walk on a 14 meter-walkway in their preferred gait speed. The incidence of falls was recorded at baseline together with gait kinematics and then every three months during the period of the study. The ability of gait kinematic parameters to predict falls was tested using the ROC curve. RESULTS: Stance time variability, swing time, and stride length presented a sensitivity to predict falls in older adults higher than 70%. CONCLUSION: Gait kinematic parameters, such as stance variability, swing time, and stride length may predict future falls in older adults.

Relationship of scapular dyskinesis with the pattern of activation of periescapular muscles during exercise / Relação da discinese scapular com o padrão de ativação dos músculos periescapulares durante exercicios

abstract The aim of the present study was to analyze the activation pattern of the serratus anterior (SA), upper trapezius (UT), and lower trapezius (LT) muscles during periscapular exercises in individuals with and without ED, and to identify which proposed exercise presents greater activation of the periscapular muscles. Fourteen women, aged between 18 and 30 years, participated in this study, divided into a control group (n = 8) and a dyskinesis group (n = 8). The determination of the presence of ED was performed according to the analysis of scapular movement during arm elevation, using the yes/no classification. To evaluate muscle activation, electromyography signals of the SA, UT, and LT muscles were collected during exercise. The exercise protocol was composed of three repetitions of the exercises: punch up, wall slide, and scaption. The results showed that the ED group showed less activation of the AS and TT than the control group. During the scaption and wall slide exercises, the DE group showed less activation of the AS in relation to those without DE. There was no difference in muscle activation between the exercises. That individuals with dyskinesis have less activation of the muscles that control scapular mechanics and that the type of exercise did not influence the activation of the periscapular muscles.

resumo O objetivo do presente estudo foi analisar o padrão de ativação dos músculos serrátil anterior (SA), trapézio superior (TS) e trapézio inferior (TI) durante exercícios periescapulares em indivíduos com e sem DE, e identificar qual exercício propostos apresenta maior ativação da musculatura periescapular. Participaram deste estudo 14 mulheres, com idade entre 18 e 30 anos, divididas em grupo controle (n = 8) e grupo discinese (n=8). A determinação da presença de DE foi realizada de acordo com a análise do movimento da escápula durante elevação do braço, usando a classificação sim/não. Para avaliação da ativação muscular, sinais eletromiográficos dos músculos SA, TS e TI foram coletados durante o exercício. O protocolo de exercício foi composto por três repetições dos exercícios: punch up, wall slide e scaption. Os resultados mostraram que o grupo DE apresentou menor ativação do SA e TI em relação ao grupo controle. Durante os exercícios scaption e wall slide, o grupo DE apresentou menor ativação do SA em relação àqueles sem DE. Não houve diferença na ativação muscular entre os exercícios. Concluímos que indivíduos com discinese apresentam menor ativação dos músculos que controlam a mecânica da escápula e que o tipo de exercício não influenciou na ativação da musculatura periescapular.

Postural alteration, low back pain, and trunk muscle resistance in university students / Alteração postural, dor lombar e a resistência dos músculos do tronco em jovens universitárias

Abstract Introduction: Low back pain, the most prevalent musculoskeletal disorder, is common in individuals with postural changes and has a high incidence in university students. Trunk muscle instability and weakness can contribute to the presence of low back pain. However, no research has investigated the relationship between low back pain in conjunction with postural changes and the resistance of the trunk stabilizing muscles. Objective: To analyze the correlation between postural alterations and muscular resistance of the trunk of women with and without low back pain. Methods: Forty university women were recruited and divided into a group with low back pain (n = 20; 20.85 ± 1.69 years) and a group without low back pain (n = 20; 20.05 ± 2.54 years). On the first day, the postural assessment was carried out by photogrammetry with Kinovea software. On the second day, the resistance tests of the trunk flexor and extensor muscles, lateral and ventral plank, bridge, and lumbar traction were performed through the traction dynamometer. Pearson's correlation test was applied to verify the relationship between the analyzed variables, Student's T test was used for comparison between groups, and a significance level of p < 0.05 was adopted. Results: There was no correlation between the variables related to postural changes and muscle resistance tests (p > 0.05). There was a difference between the groups only for the bridge exercise test (p = 0.04) and vertical alignment of the head, left lateral view (p = 0.041), and right lateral view (p = 0.034). Conclusion: This study did not show a direct and significant relationship between postural changes in young university students with and without complaints of low back pain and resistance of the trunk-stabilizing muscles.

Resumo Introdução: A lombalgia, transtorno músculoesquelético mais prevalente, é comum em indivíduos com alterações posturais, que são de alta incidência em universitários. Instabilidade e fraqueza dos músculos do tronco podem contribuir para a presença da dor lombar. Não encontrou-se, contudo, pesquisas que tenham investigado a relação da dor lombar em conjunto com as alterações posturais e a resistência dos músculos estabilizadores do tronco. Objetivo: Analisar a correlação entre alterações posturais e resistência muscular do tronco de mulheres com e sem dor lombar. Métodos: Foram recrutadas 40 mulheres universitárias divididas em grupo com dor lombar (n = 20; 20,85 ± 1,69 anos) e grupo sem dor lombar (n = 20; 20,05 ± 2,54 anos). No primeiro dia, realizou-se a avaliação postural por fotogrametria com software Kinovea; no segundo dia, os testes de resistência dos músculos flexores e extensores de tronco, prancha lateral e ventral, ponte e tração lombar através do dinamômetro de tração. Aplicou-se o teste de correlação de Pearson para verificar a relação entre as variáveis analisadas, teste t de Student para comparação entre os grupos e adotou-se nível de significância de p < 0,05. Resultados: Não houve correlação entre as variáveis referentes às alterações posturais e testes de resistências musculares (p > 0,05); houve diferença entre os grupos apenas para o teste de exercício ponte (p = 0,04) e para o alinhamento vertical da cabeça vista lateral esquerda (p = 0,041) e vista lateral direita (p = 0,034). Conclusão: Este estudo não evidenciou relação direta e significativa entre as alterações posturais em jovens universitárias com e sem queixa de dor lombar com a resistência dos músculos estabilizadores do tronco.

Rate of force development and muscle activation of trunk muscles in women with and without low back pain: A case-control study.

OBJECTIVE: To evaluate the rate of force development (RFD) and the rate of electromyography rise (RER) of global and local trunk muscles in women with and without low back pain. DESIGN: Cross-sectional study. SETTING: Laboratory setting. PARTICIPANTS: Twenty-eight women divided into low back pain (LBP, n = 14) and control groups (CG, n = 14) participated in this study. MAIN OUTCOME MEASURES: Subjects performed isometric contractions of trunk using an isokinetic dynamometer, and simultaneously the electromyography (EMG) signals were collected for global (rectus abdominis and longissimus thoracic) and local (internal oblique and multifidus) muscles. All variables were calculated using Matlab software. RESULTS: Symptomatic subjects showed lower RFD during trunk extension and it was correlated to a reduced RER mainly in the trunk extensor musculature (p < 0.05). During trunk flexion, LBP exhibited a delayed time to reach peak RFD (p < 0.05) compared to CG. RER for global anterior muscle was higher than for local muscle (p < 0.05) and it was more persistent in asymptomatic women. CG also presented greater activation amplitude for both agonist and antagonist trunk muscles, mainly the global ones. CONCLUSION: Symptomatic women showed lower RFD and it was correlated to a reduced capacity of rapid muscle activation mainly in the trunk extensor musculature.

Equilibrium in women with osteoporosis submitted to balance training with and without an oscillating vibratory pole.

OBJECTIVES: An eight-week balance training program, with and without oscillation of vibratory pole, was shown to have a medium-term persistence effect on the performance of elderly physically-active women with osteoporosis. METHODS: The 29 women who completed the study were randomly separated into two groups: an Oscillating Pole Group (OPG; 69.6 ± 5.8 years; n = 14) and a Non-Oscillating Pole Group (NPG; 70.9 ± 7.4 years; n = 15). The improvement in equilibrium was evaluated using the Berg Balance Scale before training, after training and in the Follow-Up (eight-weeks after the conclusion of the training). RESULTS AND DISCUSSION: The NPG presented both Post-Training (p = .018 relative to pre-training) and Follow-Up (p = .007) improvements in equilibrium. The improvement for OPG was near significant (p = .051 relative to pre-training) in Post-Training and significant (p = .038) in the Follow-Up. There were no significant differences between Post-Training and Post-Follow-Up (p = .999) for either group or in the intergroup comparisons (no statistically-significant effect of oscillation of the pole).

Peak torque, reaction time, and rate of torque development of hip abductors and adductors of older women.

Impaired muscle function at the hip has been implicated to be a major factor related to falls in older adults. Therefore, the aim of this study was to analyze the rate of torque development (RTD), reaction time (RT), and peak torque (PT) of hip abductors and hip adductors in young women (YW), older women nonfallers (ONF), and older women fallers (OF). Eighteen YW and 44 older women divided among OF (n = 20) and ONF (n = 24) performed maximum isometric hip abductor and adduction contractions on a dynamometer. YW had 40% greater PT and 61.5% greater RTD for hip abductors than the ONF. Compared with OF, YW had 47.5% greater PT and 68% greater RTD. OF showed less RTD at 150 ms (31%) and 200 ms (34.5%) than ONF for hip abductors. PT of hip adductors was 52% greater in YW than in the two older groups, whereas RTD was 71% greater. OF showed less RTD than ONF for hip abductors according to standardized effect sizes. No RT differences were observed between the three groups. We conclude that older women (OF and ONF) have less strength and ability to develop force rapidly than YW for hip abductors and adductors. Low hip strength and slowed force development in ONF during hip abduction may increase fall risk in older women.

Age-related alterations in the activation of trunk and lower limb muscles during walking.

BACKGROUND: Walking is a complex motor task that requires an integrated coordination of the trunk, lower limb, and upper limb movements. Previously, few studies have investigated the activation pattern of trunk muscles during walking. However, the mechanisms by how aging affects the recruitment of trunk muscles during walking remain unclear. OBJECTIVE: The present study aimed to compare the activation of trunk and lower limb muscles during walking in younger and older women. METHODS: Fifteen younger women between 18 and 30 yr and 19 older women between 60-82 yr walked on the treadmill at a self-selected speed, while 1-min surface electromyography (EMG) signals were recorded from the multifidus, internal oblique, gluteus maximus, rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius lateralis. EMG signals were processed and a linear envelope was calculated at an initial stance (50 ms after heel contact) and final stance (50 ms before toe-off). RESULTS: Compared with younger women, older women had 52.32% lower activation of the internal oblique (p = 0.027) and 39.95% lower activation of the rectus femoris (p = 0.003) at initial stance. CONCLUSION: Results of this study demonstrated that older women had lower activation of trunk and knee muscles during the initial stance, which may have resulted from weakness and balance impairments caused by aging.

Acute effect of partial body weight suspension on the level of cocontraction and gait biomechanics in women with knee osteoarthritis / Efeito agudo da suspensão parcial de peso corporal no nível de cocontração e biomecânica da marcha em mulheres com osteoartrite de joelho / Efecto agudo de la suspensión parcial de peso corporal en el nivel de co-contracción y biomecánica de la marcha en mujeres con osteoartritis de rodilla

Abstract Introduction: Knee osteoarthritis (OAK) is one of the most prevalent rheumatic diseases in the population, characterized by functional limitation and gait difficulties with profound clinical relevance, as walking is the most frequently performed daily activity. These functional limitations may be more pronounced when the disease is associated with obesity. Objective: To investigate the effect of different body weight suspension percentages on gait biomechanical variables and co-contraction percentages in women with OAK. Method: Fourteen women aged 50-75 years, with a body mass index between 26 and 35 and radiological diagnosis of OAK participated in the study. On the first day, anamnesis and familiarization with gait on the treadmill was performed. On the second day, treadmill gait assessment was performed using partial body weight support (SPPC) in three conditions-15%, 30%, and 45% suspension. During the evaluation, electromyographic and kinematic data were collected. The variables analyzed were percentage of hip (gluteus maximus/rectus femoris), knee (femoral biceps/vastus lateralis), and ankle (anterior tibial/lateral gastrocnemius), and length and step widths. A one-way analysis of variance was conducted, with a significance level of p < 0.05. Results: There was no significant difference in the length and step width and the level of co-contraction between the running conditions analyzed. Conclusion: Body weight suspension using SPPC during treadmill running did not alter the biomechanical variables of the gait of women with OAK.

Resumo Introdução: A osteoartrite de joelho (OAJ) é a uma das doenças reumáticas mais prevalentes na população, caracterizada por causar limitação funcional, sendo as dificuldades de marcha de grande relevância clínica por ser a atividade diária mais realizada. Essas limitações funcionais podem ser mais acentuadas quando a doença está associada a obesidade. Objetivo: Investigar o efeito de diferentes porcentagens de suspensão do peso corporal no percentual de cocontração e nas variáveis biomecânicas da marcha em mulheres com OAJ. Método: Estudo transversal no qual participaram do estudo 14 mulheres com idade entre 50-75 anos, IMC entre 26-35, com diagnóstico radiológico de OAJ. No primeiro dia foi realizado anamnese e familiarização da marcha na esteira. No segundo dia, foi realizado avaliação da marcha em esteira utilizando suporte parcial de peso corporal (SPPC) em três condições: 15%, 30% e 45% de suspensão. Durante a avaliação foram coletados dados eletromiográficos e cinemáticos. As variáveis analisadas foram: percentual de cocontração do quadril (glúteo máximo/reto femoral), joelho (bíceps femoral/vasto lateral) e tornozelo (tibial anterior/gastrocnêmio lateral); comprimento e largura do passo. Para análise estatística foi aplicado o teste Anova One Way, com nível de significância de p<0,05. Resultados: Não houve diferença significativa para o comprimento e largura de passo, assim como para o nível de cocontração entre as condições de marcha analisadas (p>0.05). Conclusão: A suspensão do peso corporal usando SPPC durante a marcha em esteira não altera o percentual de cocontração e as variáveis biomecânicas da marcha de mulheres com OAJ.

Resumen Introducción: Una de las enfermedades reumáticas más prevalentes en la población, la osteoartritis de rodilla (OAJ) se caracteriza por causar limitación funcional, siendo las dificultades de marcha de gran relevancia clínica por ser la actividad diaria más realizada. Estas limitaciones funcionales pueden ser más intensas en asociación con la obesidad. Objetivo: Investigar el efecto de diferentes porcentajes de suspensión de peso corporal sobre las variables biomecánicas de la marcha y el porcentaje de cocontracción en mujeres con OAJ. Método: Participaron en el estudio 14 mujeres con edad entre 50-75 años, IMC entre 26-35, con diagnóstico radiológico de OAJ. En el primer día se realizó anamnesis y familiarización de la marcha en la cinta de correr. En el segundo día, se realizó una evaluación de la marcha en la cinta utilizando soporte parcial de peso corporal (SPPC) en tres condiciones: 15%, 30% y 45% de suspensión. Durante la evaluación se recogieron datos electromiográficos y cinemáticos. Las variables analizadas fueron: porcentaje de cocontración de la cadera (glúteo máximo/recto femoral), rodilla (bíceps femoral/vasto lateral) y tobillo (tibial anterior/gastrocnémio lateral); longitud y anchura del paso. Para el análisis estadístico se aplicó la prueba Anova One Way, con un nivel de significación de p <0,05. Resultados: No hubo diferencia significativa para la longitud y anchura del paso, así como para el nivel de cocontración entre las condiciones de marcha analizadas. Conclusión: La suspensión del peso corporal con SPPC durante la marcha en cinta no alteró las variables biomecánicas de la marcha de mujeres con OAJ.

Discriminant analysis of neuromuscular variables in chronic low back pain.

BACKGROUND: Investigation and discrimination of neuromuscular variables related to the complex aetiology of low back pain could contribute to clarifying the factors associated with symptoms. OBJECTIVE: Analysing the discriminative power of neuromuscular variables in low back pain. METHODS: This study compared muscle endurance, proprioception and isometric trunk assessments between women with low back pain (LBP, n=14) and a control group (CG, n=14). Multivariate analysis of variance and discriminant analysis of the data were performed. RESULTS: The muscle endurance time (s) was shorter in the LBP group than in the CG (p=0.004) with values of 85.81 (37.79) and 134.25 (43.88), respectively. The peak torque (Nm/kg) for trunk extension was 2.48 (0.69) in the LBP group and 3.56 (0.88) in the GG (p=0.001); for trunk flexion, the mean torque was 1.49 (0.40) in the LBP group and 1.85 (0.39) in the CG (p=0.023). The repositioning error (degrees) before the endurance test was 2.66 (1.36) in the LBP group and 2.41 (1.46) in the CG (p=0.664), and after the endurance test, it was 2.95 (1.94) in the LBP group and 2.00 (1.16) in the CG (p=0.06). Furthermore, the variables showed discrimination between the groups (p=0.007), with 78.6% of the individuals with low back pain correctly classified in the LBP group. In turn, variables related to muscle activation showed no difference in discrimination between the groups (p=0.369). CONCLUSION: Based on these findings, the clinical management of low back pain should consist of both resistance and strength training, particularly in the extensor muscles.

Muscle recruitment and co-contraction when walking in young women with chronic lumbar pain / Recrutamento e cocontração muscular durante a marcha em mulheres jovens com dor lombar crônica / Reclutamiento y co-contracción muscular durante la marcha en mujeres jóvenes con dolor lombar crónica

Abstract Introduction: The lumbar pain is the main musculoskeletal complaint reported by the active population, and it prevents daily activities such as walking. Objective: To assess muscle recruitment and the co-contraction of the trunk muscles during different walking speed in individuals with and without chronic lumbar pain. Method: Thirty-four sedentary young women attended the study, in which 18 belonged to the lumbar pain team (LPT) and 16 to the team without lumbar pain (WLP). We assessed the electromyography activity of the internal oblique (IO) local muscle and lumbar multifidus (MUL), and global external oblique (EO), abdominal rectus (AR) and lumbar iliocostalis (LIC), during walking. The electromyography analysis was performed from the average of the linear envelope value, normalized by the peak of muscle activation. The muscle co-contraction (IO/MUL, EO/LIC, AR/LIC, IO/EO, and the abdominal/paravertebral muscle groups) was calculated with the Falconer and Winter formula. The Shapiro-Wilk test, Multivariate Analysis, mixed Variance Analyses with Bonferroni post-hoc, and Pearson (p < 0.05) correlation coefficient were made by the statistical analysis. Results: In the WLP we could notice that the higher the speed, the higher the MUL activation. The co-contraction data demonstrated that IO/MUL muscles activate 20% more in the LPT, during the preferred speed; however, in the WLP, the results showed that the higher the walking speed, the higher the EO/LIC (21.8%) and IO/MUL (17.8%) muscles activation. Conclusion: The recruitment of local muscles doesn't differ among the evaluated groups and conditions; however, in WLP, the higher the MUL muscle action, the higher the walking speed.

Resumo Introdução: A dor lombar (DL) é a principal queixa musculoesquelética relatada na população ativa e incapacita atividades do cotidiano, como a marcha. Objetivo: Avaliar o recrutamento e co-contração dos músculos do tronco durante diferentes velocidades de marcha em indivíduos com e sem DL crônica. Método: Participaram 34 mulheres jovens, sedentárias, 18 compuseram o grupo DL (GDL) e 16 o grupo sem DL (GC). Foi avaliada a atividade eletromiográfica dos músculos locais oblíquo interno (OI) e multífido lombar (MUL), e globais oblíquo externo (OE), reto abdominal (RA) e iliocostal lombar (ICL), durante a marcha. A análise eletromiográfica foi realizada a partir da média do valor de envelope linear, normalizada pelo pico de ativação muscular. A co-contração muscular (OI/MUL, OE/ICL, RA/ICL, OI/OE e os grupos musculares abdominais/ paravertebrais) foi calculada com a fórmula de Falconer e Winter. A análise estatística foi feita por meio do teste Shapiro-Wilk, Análise Multivariada, Análise de Variância mista com pos-hoc bonferroni e coeficiente de correlação de Pearson (p < 0,05). Resultados: No GC podemos perceber que, quanto maior a velocidade, maior a ativação do MUL. Os dados de co-contração demonstraram que os músculos OI/MUL ativam 20% a mais no GDL, durante a velocidade de preferência, no GC, os resultados mostram que quanto maior a velocidade de marcha, maior a ativação dos músculos OE/ICL (21,8%) e OI/MUL (17,8%). Conclusão: O recrutamento dos músculos não difere entre os grupos e condições, contudo foi observado no GC que quanto maior a ação do músculo MUL maior é a velocidade de marcha.

Resumen Introducción: El dolor lumbar (DL) es la principal queja musculoesquelética relatada e incapacita actividades de lo cotidiano, como la marcha. Objetivo: Evaluar el reclutamiento y la co-contracción músculos del tronco durante diferentes velocidades de marcha en individuos con y sin DL. Método: Participaron 34 mujeres jóvenes, sedentarias, 18 compusieron grupo DL (GDL) y 16 grupo sin DL (GC). Se evaluó la actividad electromiográfica de los músculos oblicuo interno (OI) y externos (OE), multífido lumbar (MUL), recto abdominal (RA) e iliocostal lumbar (ICL) durante la marcha. El análisis electromiográfico fue realizado a partir del promedio del valor de sobre lineal, normalizado por el pico de activación muscular. La cocontracción muscular (OI/MUL, OE/ICL, RA/ICL, OI/OE y grupos de músculos abdominales/paravertebrales) se calculó utilizando la fórmula Falconer y Winter. El análisis estadístico fue realizado por Shapiro-Wilk, Análisis Multivariado, Análisis de Variedad mixta con pos-hoc bonferroni y coeficiente de correlación de Pearson (p < 0,05). Resultados: En el GC podemos percibir que, cuanto mayor es la velocidad, mayor es la activación del MUL. Los datos de co-contracción demostraron que los músculos OI/MUL activan un 20% más en el GDL, durante la velocidad de preferencia, sin embargo, en el GC, los resultados muestran que cuanto mayor la velocidad de marcha, mayor la activación de los músculos OE / ICL (21,8%) y OI/MUL (17,8%). Conclusión: El reclutamiento de los músculos no difiere entre los grupos y condiciones, contenido observado en el GC que cuanto mayor es la acción del músculo MUL mayor es la velocidad de marcha.

Antagonist coactivation of trunk stabilizer muscles during Pilates exercises.

The purpose of this study was to compare the antagonist coactivation of the local and global trunk muscles during mat-based exercises of Skilled Modern Pilates. Twelve women performed five exercises and concurrently, surface EMG from internal oblique (OI), multifidus (MU), rectus abdominis (RA) and iliocostalis lumborum (IL) muscles was recorded bilaterally. The percentage of antagonist coactivation between local (OI/MU) and global muscles (RA/IL) was calculated. Individuals new to the practice of these exercises showed differences in coactivation of the trunk muscles between the exercises and these results were not similar bilaterally. Thus, in clinical practice, the therapist should be aware of factors such as compensation and undesirable rotation movements of the trunk. Moreover, the coactivation of global muscles was higher bilaterally in all exercises analyzed. This suggests that the exercises of Skilled Modern Pilates only should be performed after appropriate learning and correct execution of all principles, mainly the Centering Principle.

Cardiac autonomic responses induced by a single bout of exercise with flexible pole.

BACKGROUND: Flexible poles are tools used to provide rapid eccentric and concentric muscle contractions. It lacks in the literature studies that analyze acute cardiovascular responses in different exercises performed with this instrument. It was investigated the acute effects of exercise with flexible poles on heart period in healthy women. METHODS: The study was performed on 32 women between 18 and 25 years old. It was evaluated the heart rate variability (HRV) in the time (SDNN, RMSSD and pNN50) and frequency domain (HF, LF and LF/HF ratio). The subjects remained at rest for 10 minutes. After the rest period, the volunteers performed the exercises with the flexible poles. Immediately after the exercise protocol, the volunteers remained seated at rest for 60 minutes and HRV were analyzed. RESULTS: It was observed no significance changes in the time domain (SDNN: p = 0.14; RMSSD: p = 0.8 and pNN50: p = 0.86) and frequency domain indices (LF (nu): 0.4; LF (ms(2)): p = 0.34; HF (nu): p = 0.4; HF (ms(2)): p = 0.8 and LF/HF ratio: p = 0.3) between before and after single bout of exercise with flexible pole. CONCLUSION: A single bout of exercise with flexible pole did not significantly change cardiac autonomic regulation in healthy women.