The squat exercise recruits core muscles as much as localized exercises / O exercício de agachamento recruta músculos do tronco tanto quanto exercícios localizados

Abstract Introduction In the context of resistance training, which encompasses both strengthening and rehabilitation, the incorporation of global range exercises demands intense activation of the trunk muscle groups, which play a primary role in body stabilization. The squat, notorious for its complexity and effectiveness in activating stabilizers during execution, raises a central question: whether this exercise recruits the muscles more significantly compared to localized exercises, such as push-ups and trunk exten-sions. Objective To identify the degree of activation of the trunk muscles during squats and compare it with localized exercises for the trunk muscles: lumbar and abdominal. Methods Using surface electromyography, the activation of the iliocostalis, multifidus, internal oblique, external oblique and rectus abdominis muscles was evaluated. The sample included 16 physically active volunteers of both sexes. A repeated measures t-test (α < 0.05) was used as an analysis method. Results The iliocostalis, multifidus and internal oblique muscles showed similar levels of activation both in the squat and in their respective isolated exercises, while the rectus abdominis and external oblique muscles showed greater activity during trunk flexion. Conclusion It is possible to infer that squats are an effective exercise for training the iliocostalis, multifidus and internal oblique muscles, while localized exercises are more suitable for strengthening the external oblique and rectus abdominis muscles. Such conclusion can contribute to optimizing the planning of exercise sessions by replacing isolated trunk exercises with squats.

Resumo Introdução No contexto do treinamento resistido, que engloba tanto o fortalecimento quanto a reabilitação, a incorporação de exercícios de alcance global demanda uma intensa ativação dos grupos musculares do tronco, os quais desempenham um papel primordial na estabilização corporal. O agachamento, notório por sua complexidade e eficácia na ativação dos estabilizadores durante a execução, suscita uma questão central: se o agachamento recruta de forma mais acentuada a musculatura do tronco comparativamente a exercícios localizados, tais como flexões e extensões do tronco. Objetivo Identificar o grau de ativação dos músculos do tronco durante o agachamento e confrontá-lo com exercícios localizados para a musculatura do tronco: lombar e abdominal. Métodos Através da aplicação da eletromiografia de superfície, avaliou-se a ativação dos músculos iliocostal, multífido, oblíquo interno, oblíquo externo e reto abdominal. A amostra englobou 16 voluntários de ambos os gêneros, fisicamente ativos. Empregou-se um teste t de medidas repetidas (α < 0,05) como método de análise. Resultados Os músculos iliocostal, multífido e oblíquo interno manifestaram níveis semelhantes de ativação tanto no agachamento quanto em seus respectivos exercícios isolados, enquanto os músculos reto abdominal e oblíquo externo apresentaram maior atividade durante a flexão do tronco. Conclusão É possível inferir que o agachamento se configura como um exercício eficaz para o treinamento do iliocostal, multífido e oblíquo interno, enquanto os exercícios localizados se revelam mais indicados para o fortalecimento do oblíquo externo e dos músculos reto abdominais. Tais conclusões podem contribuir para a otimização do planejamento de sessões de exercícios, mediante a substituição de exercícios isolados de tronco pelo agachamento.

Gait analysis of a patient with severe motor impairment post- intensive care due to COVID-19: 1 year follow up and physical therapy / Análise da marcha de paciente com comprometimento motor grave após terapia intensiva por COVID-19: acompanhamento de 1 ano e fisioterapia

Abstract Introduction Viral infections, such as infection by SARS-CoV-2, can affect gait biomechanics, but this effect can be overlapped by consequences of critical illness and time in intensive care unit. Objective To report biomechanical alterations during the clinical evolution of a post-COVID-19 patient who presented severe motor impairment after intensive care. Methods Data was collected from the patient's chart at José Silveira Foundation and previous medical reports from the hospitalization period. The patient was wheelchair bound, with physiotherapy twice a week, and by the end of 1-year follow-up was able to walk independently. Three-dimensional gait analysis with kinetics and electromyography were conducted at three time points. Results All spatiotemporal gait parameters, kinematic, kinetic and electromyographic data was importantly altered when compared to the normal range of values. With physiotherapy, gait quality indicators showed important improvements and all muscles presented a significant increase in the magnitude of the electromyographic signal (at least a two-fold increase). Trunk kinematic alterations decreased significantly during this period. Kinetic and kinematic changes perceived in the hips, knees and ankles showed approximation to the expected pattern, however still without normalizing, and patient's muscle coordination improved over time. Conclusion This report has great clinical importance, as it describes, using an instrumented gait laboratory, the evolution of a patient with severe motor impairment post intensive care due to COVID-19, a condition in lack of description in the literature, which will help health professionals in the planning of rehabilitation strategies.

Resumo Introdução Infecções virais, como a infecção por SARS-CoV-2, podem afetar a biomecânica da marcha, mas esse efeito pode ser sobreposto por consequências de doença crítica e tempo em unidade de terapia intensiva. Objetivo Relatar as alterações biomecânicas durante a evolução clínica de um paciente pós-COVID-19 que apresentou comprometimento motor severo após terapia intensiva. Métodos Os dados foram coletados a partir do prontuário do paciente na Fundação José Silveira e dos relatórios médicos anteriores referentes ao período de inter-nação. O paciente estava em cadeira de rodas, com fisioterapia duas vezes por semana, e ao final de 1 ano de acompanhamento era capaz de deambular de forma independente. A análise tridimensional da marcha com cinética e eletromiografia foi realizada em três momentos. Resultados Todos os parâmetros espaço-temporais da marcha, dados cinemáticos, cinéticos e eletromiográficos estavam significativamente alterados quando comparados com a faixa normal de valores. Com a fisioterapia, os indicadores de qualidade da marcha apresentaram melhorias importantes e todos os músculos apresentaram um aumento significativo na magnitude do sinal eletromiográfico (aumento de pelo menos duas vezes). As alterações cinemáticas do tronco diminuíram significativamente neste período. As alterações cinéticas e cinemáticas percebidas nos quadris, joelhos e tornozelos mostraram aproximação do padrão esperado, porém ainda sem normalização, e a coordenação muscular do paciente melhorou com o passar do tempo. Conclusão Este relato é de grande importância clínica, pois descreve, por meio de um laboratório de marcha instrumentado, a evolução de um paciente com comprometimento motor severo após terapia intensiva por COVID-19, quadro pouco descrito na literatura, o que ajudará profissionais de saúde no planejamento de estratégias de reabilitação.

Biomecânica estática e da marcha em gestantes eutróficas e obesas / Static biomechanics and gait in eutrophic and obese pregnant women

Mais de 50% da população mundial encontra-se na faixa de sobrepeso e de obesidade, caracterizando uma epidemia global e, com isso, atingindo mulheres em idade reprodutiva.Quando da associação de obesidade e gravidez, esse risco pode estar amplificado, acentuando alterações do equilíbrio e postura, ampliando a taxa de acidentes por queda.(AU)

More than 50% of the world population is in the overweight and obesity zone, characterizing a global epidemic and with these reaching women of reproductive age. When associated with obesity and pregnancy, this risk may be amplified, accentuating alterations on balance and posture, increasing the rate of accidents by fall.(AU)

Pilates instruction affects stability and muscle recruitment during the long stretch exercise.

PURPOSE: To examine pelvic stability with and without instruction regarding the voluntary recruitment of the 'powerhouse' muscles during a long stretch exercise on the Pilates Reformer. SCOPE: Evaluation of the muscle activity and pelvic stability during a Pilates exercise of 12 physically active volunteers. Volunteers performed five repetitions of the long stretch in sets of two, one with and one without instruction regarding the voluntary recruitment of the powerhouse muscles. Electromyography of the external oblique (EO), multifidus (MU), gluteus maximus (GM) and adductor longus (AL) muscles and pelvic angle stability were recorded. CONCLUSION: When asked to perform the exercise with instruction regarding the voluntary recruitment of the powerhouse muscles, all muscles were more activated, with the exception of the EO. In the voluntary recruitment situation, lumbopelvic stability, as measured by the coefficient of variation of the pelvic angle, was higher than in instances without instruction. Lumbopelvic stability undergoes changes with and without instruction regarding the voluntary recruitment of the powerhouse muscles when the long stretch exercise is performed on a Reformer.

Vastus lateralis muscle architecture to estimate knee extension moment of older individuals / Arquitetura do músculo vasto lateral para estimar o momento de extensão do joelho de indivíduos idosos / Arquitectura de los vasto lateral para estimar el momento de la extensión de la rodilla de las personas ancianas

The aim of this study was to compare the knee extension moment of older individuals with the muscle moment estimated through a biomechanical model. This was accomplished by using (1) the specific muscle architecture data of individuals, and (2) the generic muscle architecture available in the literature. The muscle force estimate was determined using a model with the muscle architecture from cadavers and the individual vastus lateralis muscle architecture of sixteen older volunteers. For the muscle moment comparison, all of the volunteers performed maximal voluntary isometric contractions (MVIC) in five different knee extension position angles. The architectural data was acquired using both resonance and ultrasound imaging. Both estimated muscle moments (generic and individual) were higher than the experimental. The architecture of the other vastii may be necessary to make the model more accurate for the older population. Although other factors inherent to ageing, such as co-contractions, fiber type percentage, and passive forces are not considered in the model, they could be responsible for the differences between moments in older people.

O objetivo deste estudo foi comparar o momento de extensão do joelho de idosos com momento muscular estimado por modelo biomecânico, utilizando (i) arquitetura muscular específica dos indivíduos e (II) arquitetura muscular genérica disponível na literatura. Para a estimativa da força muscular foi utilizado um modelo com a arquitetura muscular de cadáveres, e também com a arquitetura do vasto lateral de dezesseis voluntários idosos. Para a comparação todos voluntários realizaram contrações isométricas voluntárias máximas em cinco ângulos. Os dados de arquitetura foram adquiridos por meio de ultrassonografia e por ressonância magnética. Ambos os momentos estimados (genéricos e individuais) foram maiores do que experimental. A arquitetura dos outros músculos do quadríceps pode ser necessária para modelo ser mais preciso para a população idosa. Outros fatores inerentes ao envelhecimento não foram considerados no modelo, como cocontrações, tipagem de fibras e forças passivas, e devem ser responsáveis pelas diferenças entre os momentos.

El objetivo de este estudio fue comparar el torque extensión de la rodilla de ancianos con torque muscular estimado por modelo biomecánico, usando (i) la arquitectura muscular específica de los individuos y (II) (II) la arquitectura muscular genérica disponible en la literatura. Para la estimación de la fuerza muscular se utilizó un modelo con arquitectura muscular de cadáveres, y también con la arquitectura del vasto lateral de dieciséis voluntarios ancianos. Para la comparación todos los voluntarios realizaron contracciones isométricas voluntarias máximas en cinco ángulos. La arquitectura fue adquirida por ecografía y por resonancia magnética. Ambos las torques estimadas (genéricas y individuales) fueron mayores que el experimental. La arquitectura de los otros músculos de los cuádriceps puede ser necesaria para hacer el modelo más preciso para la población anciana. Otros factores inherentes envejecimiento no se consideran en el modelo, como co-contracciones, el tipo de fibra y fuerzas pasivas, y deben ser responsables de las diferencias entre las torques.

Muscle strategies for leg extensions on a "Reformer" apparatus.

Considering the kinematics of leg extensions performed on a Reformer apparatus, one would expect high activation of hip and knee extensor muscle groups. However, because of the bi-articular nature of some lower limb muscles, and the possibility to vary the direction of force application on the Reformer bar, muscles can be coordinated theoretically in a variety of ways and still achieve the desired outcome. Hence, the aim of this study was to determine the knee and hip moments during leg extensions performed on the Reformer apparatus and to estimate the forces in individual muscles crossing these joints using static optimization. Fifteen subjects performed leg extensions exercises on the Reformer apparatus using an individually chosen resistance. To our big surprise, we found that subjects performed the exercise using two conceptually different strategies (i) the first group used simultaneous hip and knee extension moments, (ii) while the second group used simultaneous hip flexion and knee extension moments to perform the exercise. These different strategies were achieved by changing the direction of the resultant force applied by the subject's feet on the Reformer bar. While leg extensions on the Reformer apparatus have been thought to strengthen the hip and knee extensors muscles, our results demonstrate that patients can perform the exercise in a different and unexpected way. In order to control the hip and knee moments and achieve the desired outcome of the exercise, the direction of force application on the Reformer bar must be controlled carefully.

Effects of neuromuscular electrical stimulation and low-level laser therapy on the muscle architecture and functional capacity in elderly patients with knee osteoarthritis: a randomized controlled trial.

OBJECTIVES: To determine the effects of low-level laser therapy in combination with neuromuscular electrical stimulation on the muscle architecture and functional capacity of elderly patients with knee osteoarthritis. DESIGN: A randomized, evaluator-blinded clinical trial with sequential allocation of patients to three different treatment groups. SETTING: Exercise Research Laboratory. SUBJECTS: A total of 45 elderly females with knee osteoarthritis, 2-4 osteoarthritis degrees, aged 66-75 years. INTERVENTION: Participants were randomized into one of the following three intervention groups: electrical stimulation group (18-32 minutes of pulsed current, stimulation frequency of 80 Hz, pulse duration of 200 µs and stimulation intensity fixed near the maximal tolerated), laser group (low-level laser therapy dose of 4-6 J per point, six points at the knee joint) or combined group (electrical stimulation and low-level laser therapy). All groups underwent a four-week control period (without intervention) followed by an eight-week intervention period. MAIN MEASURES: The muscle thickness, pennation angle and fascicle length were assessed by ultrasonography, and the functional capacity was assessed using the 6-minute walk test and the Timed Up and Go Test. RESULTS: After intervention, only the electrical stimulation and combined groups exhibited significant increases in the muscle thickness (27%-29%) and pennation angle (24%-34%) values. The three groups exhibited increased performance on the walk test (5%-9%). However, no significant differences in terms of functional improvements were observed between the groups. CONCLUSIONS: Neuromuscular electrical stimulation reduced the deleterious effects of osteoarthritis on the quadriceps structure. Low-level laser therapy did not potentiate the effects of electrical stimulation on the evaluated parameters.

An instrumented footbar for evaluating external forces in Pilates.

The intensity of Pilates exercises is almost exclusively based on experience. Therefore, knowing the precise amount of effort that is exerted during exercises could be useful for professionals conducting exercise assessments and for future research using inverse dynamics (ID) analyses. The reformer is an apparatus that contains a carriage on rails to which resistance is applied via springs attached to the carriage. Subjects apply force to a footbar to displace the carriage, but the magnitude and direction of this force are unknown and need to be quantified if the ID approach is to be used. This study aimed to develop and describe a device built with commercial load cells attached to the reformer's footbar, with the device capable of measuring the direction and magnitude of the force exerted on the reformer's footbar, and to compare the force found using the device with the force estimated using the springs' parameters. To illustrate the device's use, one volunteer performed footwork exercises at different speeds and with different foot support positions and loads. External force estimated by the springs' level of deformation was significantly different (P < .001) from the magnitude of force acquired using the device, showing that the estimation is imprecise.

Effects of added elastic tubes on open-chain knee extensor strength training.

Attaching elastic tubes (ETs) to resistance training machines can affect the exercise load profile. The purpose of this study was to assess the training effects of added ETs, which were strategically attached to provide additional loads only during the deceleration phase of the knee extension exercise. Twenty-two healthy participants, assigned to either an experimental group (with ETs) or a control group (without ETs), participated in a 12-week strength-training program using a knee extension exercise machine. The acceleration effects were quantified and a method of attaching the ETs to the knee extension machine was developed. The effects of the added ETs were analysed by testing dynamic and isometric maximum contractions at four knee flexion angles (10 degrees, 30 degrees, 50 degrees, and 80 degrees). Analyses of covariance with the initial values as the covariate were used to examine the ETeffects. A greater increase in isometric maximum strength was found in the experimental group than in the control group at knee flexion angles of 10 degrees [effect size (ES) = 2.25] and 30 degrees (ES = 1.18). No significant difference in the dynamic maximum strength was found between the groups. The use of ETs increased strength at smaller knee flexion angles with quadriceps that were relatively short.

Avaliação da Força de Atrito em máquina de musculação durante exercícios de extensão de joelho / Evaluation in Resistance training machines during knee extension exercises

Durante exercícios realizados em máquinas de musculação, a força de atrito (FA) entre seus componentes mecânicos pode influenciar na magnitude da sobrecarga oferecida pela máquina para o praticante do exercício. No entanto, pouco se sabe sobre como medir esse atrito e qual seu real efeito. Assim, os objetivos deste estudo foram (i) descrever uma técnica para medição da FA em máquinas de musculação, e (ii) exemplificar a técnica quantificando a FA de uma máquina de musculação durante exercício em diferentes velocidades e cargas. Foram utilizados diagramas de corpo livre, equações da mecânica clássica além da medição dos ângulos articulares com eletrogoniômetro, e da força aplicada ao cabo de aço com célula de carga, para estimar a força de atrito. Para testar a metodologia, um indivíduo realizou repetições do exercício variando cargas e velocidade de execução. As cargas avaliadas foram 3kg, 6 kg e 9 kg; e as velocidades foram 30º/s, 60º/se 120º/s. A FA, expressa em percentual da carga, mostrou-se crescente com o incremento de velocidade e decrescente com o aumento da carga. Resultados em torno 40% obtidos para a menor carga e maior velocidade sugerem que a força de atrito deve ser um fator levado em consideração na escolha e manutenção de equipamentos de musculação.

During exercises performed in weight training machines, the friction force (FF) between its mechanical components can influence the magnitude of the overload offered by the machine on force of the exercise. However, little is known about how to measure this friction and what its real effect. Thus the objectives of this study were (i) describe a technique for measuring FF in weight training machines, and (ii) exemplify the technique, by quantifying the FF of the weight training machine at different exercise speeds and loads. For this, a subject performed repetitions of the exercise in different loads and speeds. The loads evaluated were 3 kg, 6 kg and 9 kg; and the speeds were 30°/s, 60°/s and 120°/s. The FF, normalized by selected load, increased significantly with the increasing of the speed and decreased with increasing of the load. Results for friction force around 40% found for highest speed and lowest load show that take the FF in count it's an important factor to consider during muscle equipment choice and maintaining.