Effect of experimentally induced muscle pain on neuromuscular control of force production.

PURPOSE: Neural and peripheral effects of induced muscle pain on explosive force production were investigated. METHODS: Nine participants performed two maximal, six explosive, and six electrical stimulations induced (twitches and octets) isometric knee extensions before and after (15 min of rest) receiving an intramuscular injection of hypertonic saline (pain inducer) or isotonic (placebo) infusions in two laboratory visits separated by 7 days. RESULTS: It was observed a reduction of peak torque production in maximal voluntary contraction in both conditions (9.3 and 3.3% for pain and placebo, respectively) and in the rate of torque development in placebo (7%). There was an increase in the rate of torque development for twitch and octets (10.5 and 15.8%, respectively) in the pain condition and peak torque for twitch (12%) in both conditions (as did the total rate of torque development for octets). CONCLUSION: Force production decreases and increases during voluntary and involuntary contractions, respectively, suggesting that acute pain impairs force production via central mechanisms.

Breaking Barriers: Artificial Intelligence Interpreting the Interplay between Mental Illness and Pain as Defined by the International Association for the Study of Pain.

Low back pain is one of the main causes of motor disabilities and psychological stress, with the painful process encompassing sensory and affective components. Noxious stimuli originate on the periphery; however, the stimuli are recombined in the brain and therefore processed differently due to the emotional environment. To better understand this process, our objective was to develop a mathematical representation of the International Association for the Study of Pain (IASP) model of pain, covering the multidimensional representation of this phenomenon. Data from the Oswestry disability index; the short form of the depression, anxiety, and stress scale; and pain catastrophizing daily questionnaires were collected through online completion, available from 8 June 2022, to 8 April 2023 (1021 cases). Using the information collected, an artificial neural network structure was trained (based on anomaly detection methods) to identify the patterns that emerge from the relationship between the variables. The developed model proved to be robust and able to show the patterns and the relationship between the variables, and it allowed for differentiating the groups with altered patterns in the context of low back pain. The distinct groups all behave according to the main finding that psychological and pain events are directly associated. We conclude that our proposal is effective as it is able to test and confirm the definition of the IASP for the study of pain. Here we show that the fiscal and mental dimensions of pain are directly associated, meaning that mental illness can be an enhancer of pain episodes and functionality.

Sensory Integration for Postural Control in Rheumatoid Arthritis Revealed by Computerized Dynamic Posturography.

Rheumatoid arthritis (RA) is a systemic autoimmune disease that impairs mobility. How does sensory information influence postural responses in people with RA? The aim of this study was to evaluate the postural control of people with RA during a sensory organization test, comparing how sensory information influences postural responses in people with rheumatoid arthritis compared with healthy people. Participants were 28 women with rheumatoid arthritis (RA group) and 16 women without any rheumatoid disease (Control group CG). The Sensory Organization Test (SOT) was performed on a Smart Balance Master® (NeuroCom International, Inc., Clackamas, OR, USA) and center of pressure (COP) was measured. SOT conditions: SOT1 (eyes open, fixed support surface and surround; SOT2) eyes closed, fixed support surface and surround; and SOT5) eyes closed, sway-referenced support surface, and fixed surround. To compare the demographic and clinical aspects between groups, independent t-test or Mann-Whitney's U-test were used. Differences were found between groups. Between SOT conditions, for CG and RA, COP was faster for SOT-5 than SOT-1, while SOT-1 and SOT-2 presented similar COP velocity. For SOT-2 and SOT-5, COP was larger for the RA group. For both groups, SOT-1 presented the smallest COP, and SOT-5 showed the largest COP.

Efeitos da dor experimental no desempenho dos músculos flexores do cotovelo após oito semanas de treinamento de força: um estudo piloto / Effects of experimental pain on elbow flexor muscles performance after eight weeks of strength training: a pilot study

INTRODUÇÃO: O treinamento de força tem sido recomendado na reabilitação clínica, bem como no condicionamento físico de atletas. Não é incomum, em ambos os casos, a presença de dor durante a prática; no entanto, até o momento, não há informação consensual em relação aos efeitos da dor muscular aguda nas adaptações ao treinamento de força. OBJETIVO: O objetivo deste estudo piloto foi avaliar os efeitos da dor induzida experimentalmente na adaptação da força muscular após um período de treinamento de 8 semanas. MÉTODO: O estudo incluiu cinco voluntários saudáveis do sexo masculino e não treinados. Os participantes foram submetidos a um protocolo de treinamento de força (3x/semana durante 8 semanas) para os músculos flexores do cotovelo. A dor muscular aguda foi induzida no início de cada sessão de treinamento, por meio de infusão intramuscular de 2,5 ml de solução salina hipertônica (6%) no ventre do músculo bíceps braquial. A força dinâmica máxima (1RM) e a contração isométrica voluntária máxima (CIVM) foram medidas antes e após quatro e oito semanas de treinamento. RESULTADOS: A força dinâmica máxima aumentou, em média, 37,3% e 78,4% após quatro e oito semanas, respectivamente. Entretanto, pouca ou nenhuma diferença foi encontrada na CIVM (-1,7% e -3,0% após quatro e oito semanas, respectivamente). CONCLUSÃO: Após 24 sessões de treinamento de força, com dor muscular aguda induzida a cada sessão, voluntários saudáveis aumentaram sua capacidade de produzir força dinâmica máxima em mais de 75%; entretanto, a força isométrica apresentou apenas pequenas variações negativas.

INTRODUCTION: Strength training has been recommended in clinical rehabilitation, as well as in the physical conditioning of athletes. It is not uncommon, in both cases, the presence of pain during practice; however, to date, there is no consensual information about the effects of acute muscle pain on strength training adaptations. OBJECTIVE: The aim of this pilot study was to evaluate the effects of experimentally induced pain on muscle strength adaptation after an 8-week training period. METHOD: The study included five untrained, healthy male volunteers. Participants were submitted to a strength training protocol (3x/week for 8 weeks) for the elbow flexor muscles. Acute muscle pain was induced at the beginning of each training session through an intramuscular infusion of 2.5 ml of hypertonic saline (6%) into the biceps brachii muscle belly. Maximal dynamic strength (1RM) and maximal voluntary isometric contraction (MVIC) were measured at pre- and after four and eight weeks of training. RESULTS: Maximal dynamic strength increased, on average, 37.3% and 78.4% after four and eight weeks, respectively. However, little, if any, difference was found in MVIC (-1.7% and ­ 3.0% after four and eight weeks, respectively). CONCLUSION: After 24 strength training sessions, with acute muscle pain induced every session, healthy volunteers increased their ability to produce maximal dynamic strength by more than 75%; however, isometric strength presented only small negative changes.

The Strategy of the Brain to Maintain the Force Production in Painful Contractions-A Motor Units Pool Reorganization.

A common symptom in neuromuscular diseases is pain, which changes human movement in many ways. Using the decomposed electromyographic signal, we investigate the strategy of the brain in recruiting different pools of motor units (MUs) to produce torque during induced muscle pain in terms of firing rate (FR), recruitment threshold (RT) and action potential amplitude (MUAPAMP). These properties were used to define two groups (G1/G2) based on a K-means clusterization method. A 2.0 mL intramuscular hypertonic (6%) or isotonic (0.9%) saline solution was injected to induce pain or act as a placebo during isometric and isokinetic knee extension contractions. While isometric torque decreases after pain induction with hypertonic solution, this does not occur in isokinetic torque. This occurs because the MUs re-organized after the injection of both solutions. This is supported by an increase in RT, in both G1 and G2 MUs. However, when inducing pain with the hypertonic solution, RT increase is exacerbated. In this condition, FR also decreases, while MUAPAMP increases only for G1 MUs. Therefore, this study proposes that the strategy for maintaining force production during pain is to recruit MUs with higher RT and MUAPAMP.

Is coordination variability using vector coding different in overground and treadmill walking and running?

BACKGROUND: Coordination variability has been linked to overuse running injuries and has been studied both on a treadmill and over-ground. It is not clear, however, if the coordination variability data from over-ground locomotion can be compared with treadmill locomotion data. RESEARCH QUESTION: Therefore, the purpose of this study was to compare coordination variability of selected lower extremity couplings at different locomotor speeds during over-ground and treadmill walking and running. METHODS: Nineteen (10 female, 9 male) healthy, recreational collegiate runners participated in this study. Each participant performed in two different conditions: over-ground and on a treadmill at three walking speeds (1.2, 1.6, and 2.0 m•s-1) and three running speeds (2.8, 3.2, and 3.6 m•s-1). A modified vector coding technique was used to calculate coordination variability for five selected coupled segment and joint angles. Each of the segmental couples was analyzed separately using a two-way repeated measures ANOVA (Condition Χ Speed) implemented with one-dimensional statistical parametric mapping. RESULTS: While no interaction effects were observed for condition X speed, we saw increased coordination variability in the sagittal couples during overground compared with treadmill locomotion, which predominantly occurred during the stance phase. There were mixed results for changes in coordination variability as a function of gait speed. However, for the sagital plane couplings, coordination variability decreased with speed, particularly during the stance phase. SIGNIFICANCE: These results suggest that the controlled belt speed of the treadmill affects the intrinsic dynamics of human movement and this should be considered when making comparisons between treadmill and over-ground studies and in future study designs.

Joint-Position Sense Accuracy Is Equally Affected by Vision among Children with and without Cerebral Palsy.

We compared the effect of visual information on the dominant upper limb position sense of children with diplegic cerebral palsy (n = 10) and normally developing children (n = 10). An isokinetic dynamometer passively moved the dominant forearm in 120° of elbow flexion/extension until the volunteers stopped the machine to indicate that the elbow joint was positioned in the predetermined target angle. Participants performed this task five times in sequence with and without visual feedback of the elbow angle. We calculated the absolute and the relative position errors related to the final elbow position and the target angle. In both groups, absolute error was significantly higher when vision was occluded. Relative error was not affected by cerebral palsy or visual feedback. When vision was occluded, accuracy on this task was similarly impaired in both groups and precision was not disturbed.

A global view on how local muscular fatigue affects human performance.

There is a growing interest in scientific literature on identifying how and to what extent interventions applied to a specific body region influence the responses and functions of other seemingly unrelated body regions. To investigate such a construct, it is necessary to have a global multivariate model that considers the interaction among several variables that are involved in a specific task and how a local and acute impairment affects the behavior of the output of such a model. We developed an artificial neural network (ANN)-based multivariate model by using parameters of motor skills obtained from kinematic, postural control, joint torque, and proprioception variables to assess the local fatigue effects of the abductor hip muscles on the functional profile during a single-leg drop landing and a squatting task. Findings suggest that hip abductor muscles' local fatigue produces a significant effect on a general functional profile, built on different control systems. We propose that expanded and global approaches, such as the one used in this study, have great applicability and have the potential to serve as a tool that guarantees ecological validity of future investigations.

Reaction time and muscle activation patterns in elite and novice athletes performing a taekwondo kick.

Fractionated reaction time can be used to determine distinct epochs known as pre-motor, response and movement times (MTs) of a reaction time task. The purpose of this study was to compare elite and novice athletes performing a taekwondo kick in terms of the fractionated reaction time and electromyography (EMG) activation patterns of the muscles of the striking lower limb and the lower back. We hypothesised that the pre-motor time, response time (RT) and MT would be the shorter for elite athletes compared to novices. We collected data on 13 elite and 10 novice athletes when performing a roundhouse kick. The experiment included EMG electrodes placed on five low back and lower extremity muscles and an electrogoniometer placed on the kicking knee. We found that pre-motor time was shorter and the RT was longer for elite athletes than novice athletes. Moreover, the integrated EMG of the main knee extensor does not differ between groups though other leg and trunk muscles do. The results allow coaches and teachers to understand this particular taekwondo kicking movement which could ultimately improve the technique in order to establish training and teaching goals.

Using a Support-Vector Machine Algorithm to Classify Lower Extremity EMG Signals During Running Shod/Unshod With Different Foot Strike Patterns.

The present study aimed to use a Support Vector Machine (SVM) algorithm to identify and classify shod and barefoot running as well as rearfoot and forefoot landings. Ten habitually shod runners ran at self-selected speed. Thigh and leg muscle surface electromyography (EMG) were recorded. Discrete Wavelet transformation (DWT) and Fast Fourier transformation (FFT) were used for the assembly of vectors for training and classification of a SVM. Using the FFT coefficients for the gastrocnemius and tibialis anterior muscles presented the best results for differentiating between rearfoot/forefoot running in the window before foot-floor contact possibly due to these muscles' critical role in determining which part of the foot will first touch the floor. The classification rate was 76% and 67% respectively, with a probability of being random of 0.5% and 4% respectively. For the same terms and conditions of classification, the DWT produced a reduction in the percentage of correctness of 60% and 53% with a probability of having reached these levels randomly of 15% and 35%. In conclusion, based on EMG signals, the use a FFT to train a SVM was a better option to differentiate running forefoot/rearfoot than to use the DWT. Shod/barefoot running could not be differentiated.

Um estudo de caso sobre treinamento isocinético: o esforço máximo é suficiente para o aumento de força? / A case study of isokinetic training: is maximal effort enough to increase strength?

INTRODUÇÃO: Dinamômetro isocinético é um equipamento eletrônico e mecânico, capaz de medir o torque gerado por um determinado segmento, bem como a potência e estimar fadiga, observando-se a variação do torque ao longo tempo. Este dispositivo também controla a velocidade do movimento angular, seja ele gerado por uma contração excêntrica ou concêntrica. Este tipo de equipamento tem sido utilizado tanto para avaliação como para treinamento de força. OBJETIVO: Verificar o efeito do treinamento de força, realizado exclusivamente no dinamômetro isocinético, na capacidade de gerar torque isométrico. MÉTODO: 2 homens, sedentários, saudáveis com idade de 23 e 24 anos realizaram 16 sessões de treinamento de força (sempre em esforço máximo e no modo concêntrico utilizando-se um dinamômetro isocinético) para os músculos flexores da articulação do cotovelo do membro dominante. As sessões foram compostas por um treinamento de quatro séries de oito repetições em uma amplitude de movimento de 130º, com velocidade fixada em 45º/s. As avaliações de contração isométrica voluntária máxima (CIVM) a 90º de flexão da articulação do cotovelo foram realizadas na primeira, oitava e décima sexta sessão. Espessura dos músculos flexores da articulação do cotovelo também foi medida, com ultrassonografia, nas mesmas sessões em que o torque máximo isométrico foi medido. RESULTADOS: Não houve diferença significativa no ganho de torque tam pouco na espessura muscular, ao final do treinamento. CONCLUSÃO: Treinamento de força, exclusivamente realizado no modo concêntrico no dinamômetro isocinético não provocou aumento da capacidade de gerar força isométrica, tam pouco aumento da espessura muscular. [AU]

INTRODUCTION: Isokinetic dynamometer is an electromechanical device that allows measuring the torque of a segment, as well as estimating power and fatigue by observing the variation of torque over time. This device also controls the speed of the angular movement, whether it is generated by an eccentric or concentric contraction. This equipment is utilized for both evaluation and strength training. OBJECTIVE: Verify the effects of strength training performed on an isokinetic dynamometer on the capacity to generate isometric torque. METHOD: Two healthy, sedentary men, aged 23 e 24 performed 16 strength training sessions (always at maximum effort) for elbow joint flexor muscles of the dominant limb. The sessions were composed by a training of four sets of eight repetitions in a range of movement of 130°, at 45º/s. The evaluations of maximal voluntary isometric contraction (MVIC) in a 90º of elbow flexion was realized in the first, eighth and sixteenth sessions. Thickness of the flexor muscles of the elbow joint was also measured with ultrasonography at the same sessions in which the maximum isometric torque was measured. RESULTS: There was no significant difference in torque gain or in muscle thickness at the end of the training protocol. CONCLUSION: Strength training, exclusively performed in the concentric mode on an isokinetic dynamometer did not caused an increase in the capacity to generate isometric torque and did not change muscle thickness. [AU]

Aerobic training in aquatic environment improves the position sense of stroke patients: A randomized clinical trial

AIMS: (Stroke patients often present sensory-motor alterations and less aerobic capacity. Joint position sense, which is crucial for balance and gait control, is also affected in stroke patients). To compare the effect of two exercise training protocols (walking in deep water and on a treadmill) on the knee position sense of stroke patients. METHODS: This study was designed as a randomized controlled clinical trial. Twelve adults, who suffered a stroke at least one year prior to the start of the study, were randomly assigned to one of two groups: 1) pool group submitted to aerobic deep water walking training; and 2) the treadmill group which was submitted to aerobic walk on a treadmill. Measurements: The position sense, absolute error and variable error, of the knee joint was evaluated prior to and after nine weeks of aerobic training. RESULTS: The pool group presented smaller absolute (13.9o versus 6.1o; p < 0.05) and variable (9.2o versus 3.9o; p < 0.05) errors after nine-weeks gait training than the treadmill group. CONCLUSIONS: Nine-week aerobic exercise intervention in aquatic environment improved precision in the position sense of the knee joint of stroke patients, suggesting a possible application in a rehabilitation program.(AU)

Are muscle activation patterns altered during shod and barefoot running with a forefoot footfall pattern?

This study aimed to investigate the activation of lower limb muscles during barefoot and shod running with forefoot or rearfoot footfall patterns. Nine habitually shod runners were asked to run straight for 20 m at self-selected speed. Ground reaction forces and thigh and shank muscle surface electromyographic (EMG) were recorded. EMG outcomes (EMG intensity [iEMG], latency between muscle activation and ground reaction force, latency between muscle pairs and co-activation index between muscle pairs) were compared across condition (shod and barefoot), running cycle epochs (pre-strike, strike, propulsion) and footfall (rearfoot and forefoot) by ANOVA. Condition affected iEMG at pre-strike epoch. Forefoot and rearfoot strike patterns induced different EMG activation time patterns affecting co-activation index for pairs of thigh and shank muscles. All these timing changes suggest that wearing shoes or not is less important for muscle activation than the way runners strike the foot on the ground. In conclusion, the guidance for changing external forces applied on lower limbs should be pointed to the question of rearfoot or forefoot footfall patterns.

The effect of gait training and exercise programs on gait and balance in post-stroke patients / O efeito do treinamento de marcha e programas de exercícios na marcha e equilibrio postural em pacientes após acidente vascular encefálico crônico

The aim of this review is to evaluate studies about gait training and exercise interventions applied to patients following chronic stroke on gait and balance. The studies included in this review were random clinical trials, including only chronic post-stroke individuals that evaluated gait and balance outcomes and with a PEDro scale score ≥ 7.0. Eight studies were selected. The results suggest gait and balance will only be affected in chronic post-stroke patients if training sessions last at least 30 minutes, are repeated three times a week, and maintained for at least five weeks. Gait training affects how chronic post-stroke individuals walk. They will probably walk faster and with a lower risk of falling; however, it is unclear whether the consequences of these procedures affect the quality of life.

RESUMO O objetivo desta revisão é avaliar estudos sobre intervenções com treino de marcha e exercícios específicos sobre marcha e equilíbrio postural, aplicados a pacientes após acidente vascular encefálico em fase crônica. Os estudos incluídos nesta revisão foram ensaios clínicos randomizados, incluindo apenas indivíduos pós-acidente vascular encefálico em fase crônica que avaliaram marcha e equilíbrio postural, com uma pontuação em escala PEDro ≥ 7.0. Oito estudos foram selecionados. Os resultados sugerem que a marcha e o equilíbrio somente são afetados em pacientes crônicos pós-acidente vascular encefálico se as sessões de treinamento tiverem duração mínima de 30 minutos, forem repetidos três vezes por semana, e mantidos durante pelo menos cinco semanas. O treino de marcha e os exercícios afetam a forma como os indivíduos pós-acidente vascular encefálico em fase crônica andam. Eles provavelmente andarão mais rápido e com menor risco de quedas; no entanto, não está claro se as consequências destes procedimentos afetam a qualidade de vida.

Semi-rigid brace and taping decrease variability of the ankle joint position sense / Órtese semi-rígida e bandagem funcional diminuem a variabilidade do senso de posição da articulação do tornozelo / Órtesis semi-rígida y vendaje funcional reducen la variabilidad de la sensación de posición articular del tobillo

The present study investigated the effect of taping and the semi-rigid ankle brace on ankle joint position sense. Sixteen healthy women (20.8 ± 2.3 years old) actively placed the ankle in a target position. The experimental conditions were: 1) wearing no orthosis device, 2) using semi-rigid brace, and 3) wearing ankle taping. Absolute error (AE) and variable error (VE) were calculated to obtain the joint position sense. We found an interaction effect between condition and target angle at 15o of plantar flexion for the variable VE, which showed smaller errors during the use of taping and semi-rigid brace. In conclusion, the use of ankle joint orthoses, whether taping or semi-rigid brace, decrease the variability of the position sense at 15o of plantar flexion, potentially decreasing ankle sprains occurrence...

"Órtese semi-rígida e bandagem funcional diminuem a variabilidade do senso de posição da articulação do tornozelo." O presente estudo investigou o efeito da bandagem funcional e da órtese semi-rígida no senso de posição da articulação do tornozelo. Dezesseis mulheres saudáveis (20.8 ± 2.3 anos) posicionaram seus tornozelos ativamente nas posições alvo. As condições experimentais foram: 1) sem o uso de órtese, 2) com órtese semi-rígida de tornozelo e 3) com bandagem funcional. O erro absoluto (AE) e o erro variável (EV) foram calculados para a obtenção do senso de posição. Houve efeito da interação dos fatores condição e ângulo alvo somente para o EV obtido a 15o de flexão plantar, cujos valores foram menores tanto com o uso de bandagem funcional, quanto com o uso de órtese semi-rígida. Pode-se concluir que o uso de dispositivos de tornozelo, seja bandagem funcional ou órtese semi-rígida, diminui a variabilidade do senso de posição da articulação do tornozelo a 15o de flexão plantar, o que sugere uma possível diminuição do risco de ocorrência de entorse de tornozelo...

"Órtesis semi-rígida y vendaje funcional reducen la variabilidad de la sensación de posición articular del tobillo." El objetivo del presente estúdio era poder conocer los efectos de los vendajes y de las tobilleras semi-rígidas en la sensación de posición articular de la articulación del tobillo. Dieciséis mujeres sanas (20,8 ± 2,3 años) tomaron sus tobillos activamente en posiciones de destino. Las condiciones experimentales fueron: 1) sin usar ningún dispositivo ortopédico, 2) con órtesis semi-rígida, y 3) con vendaje funcional. Los errores absolutos (EA) y los errores variables (EV) fueron calculados para obtener la sensación de posición articular. Hubo un efecto de la interacción entre la condición y el ángulo de destino a 150 flexión plantar sólo para el EV, el cual mostró menores errores en cuenta con vendaje funcional, como así también con la órtesis semi-rígida. En conclusión, el uso de órtesis de tobillo, ya sean la vendaje o bien órtesis semi-rígida, reducen la variabilidad de la sensación de posición articular a 150 flexión plantar, lo que sugiere una posible disminución en el riesgo de esguince de tobillo...

Effects of resistance exercise on ascendent aorta on ovariectomized elderly rats

Studies have shown a strong relationship between menopause, diet, physical inactivity and presence of risk factors causing endothelial and tissue damages, leading to increased risk of developing cardiovascular disease. The aim of this study was to investigate the influence of resistance training on the effects of estrogen deprivation in aortic collagen and elastic tissue in aging. Fifteen Wistar female rats, 4 months-old, average weight 240 g were studied. All animals were ovariectomized at 6 months of age, after divided into 3 groups (n = 5): Sedentary adult (13 months), Sedentary old and Trained old (both with 17 months). All animals were ovariectomized at 6 months of age. The animals were observed for 8 months after its ovariectomy and then submitted to resistance training protocol during 12 weeks. At the end of the experiment the animals were euthanized. Samples of the ascending aorta were sectioned, fixed, processed and stained for examination by light microscopy. Photomicrographs were used for stereological study and analyzed the following parameters: body weight, volume density of collagen fibers and elastic lamellae. No significant difference was found between the initial and final weights in the studied groups. Resistance training attenuates the increase in volume density of elastic lamellae (21%) and collagen fibers (16%), when compared with the sedentary older group.

Influence of resistance training in left ventricle of ovariectomized elderly rats

Several cardiovascular changes evoked by aging affect negatively the quality of people’s lives, among them is the reduced functional capacity. Menopausal women, affected by the suspension of the ovarian hormones, suffer more intensely from metabolic and cardiovascular changes. It is known that physical training causesbiochemical, electrical, morphological, and mechanical adaptations in the cardiac muscle, which togetherprovide an improvement in the cardiac function. The goal of the present study was to evaluate theeffect of resistance training in the left ventricle of ovariectomized rats through stereological analysis. Westudied  15  Wistar female rats, 4 months- old, average weight 240 g. All animals were ovariectomized at9 months of age and then divided into 3 groups of five individuals as follows: Ovariectomized Sedentary Adult(13 months) (OSA), Ovariectomized Sedentary Elderly (17 months) (OSE), and Ovariectomized TrainedElderly (17 months) (OTE). The rats were monitored for 13 months and subsequently underwent resistancetraining for 12 weeks. The stereological analysis was performed using light microscopy techniques and dataobtained for each group were tabulated and statistically compared using ANOVA and post hoc Tukey tests(p ≤ 0.05). It was verified that training decreased volume density of myocyte, interstitium and collagen fibersfollowed by increased volume density of capillaries, when compared with the ovariectomized sedentary elderly(OSE). Our data suggest that resistance training minimizes changes in the myocardium of elderly rats deprivedof ovarian hormones.

Effectiveness of resistance training exercises in spastic diplegia cerebral palsy: a review

Cerebral Palsy presents itself in a clinical form of spastic diplegia, where neurological sequels are predominant in the lower limbs and substantially affects the capacity to walk. Traditional methods of physiotherapy intervention emphasize the techniques of neurological rehabilitation at the expense of progressive resistance exercises.The goal of the present research is to fulfill a bibliographic review concerning the period of 1985 to 2012 about studies that investigated the effect of resistance exercises applied to cerebral palsy children carrying spastics’ diplegia. The Scielo, MEDLINE, PubMed, EMBASE, CINAHL, Sports Discus, DARE, PsychInfo, ERIC, Ausport-Med, AMI, Cochrane and PEDro databases were used to conduct a literature search using keywords without restrictions. In this systematization, a search was conducted using the keywords: cerebral palsy, progressive resistance exercise, diplegia, gross motor function measure (GMFM). Literature have shown that the restrict capacity to generate force is as debilitating or more than it is the muscle spasticity, potentially causing more restriction to the movement than the spasticity itself. Children with normal motor development, as well as carrying spastic diplegia increase their capacity to generate strength when submitted to a resistive training, not only on lower limbs, but also on upper limbs. Furthermore, several studies have shown that diplegic cerebral palsy children improve their motor ability due to strength training, thought it still remains to be proved that strength training leads to a substantial change for the better allowing that there is ascension of category for functional capacity.

Effects of aerobic exercise on soleus muscle of rats with metabolic syndrome

Introduction: Studies have shown a strong relationship between physical activity and the presence of cardiovascular risk factors such as hypertension, insulin resistance, diabetes, dyslipidemia and obesity that characterize the metabolic syndrome. Moreover, the practice of regular physical activity has been recommended for the prevention and treatment of this syndrome. Objectives: The aim of this study was to analyze by histomorphometric techniques, the effect of aerobic exercise in the soleus muscle of rats with metabolic syndrome. Methodology: A total of 15 male Wistar rats, 150 days old, divided into three groups (n = 5): sedentary, control (C); metabolic syndrome (MS) and trained, metabolic syndrome (TMS). The induction of MS was performed using fructose in the drinking water of animals. From the 9th week of induction, animals in the Training groups underwent exercise treadmill belt (Imbramed TK-01) with moderate intensity (50-70% of maximum speed achieved in the stress test). Physical training was conducted for nine weeks, with a frequency of 5 times per week, for about 60 minutes. The procedures were approved by the Ethics Committee of the São Judas Tadeu University (protocol Nr 060/2007). At the end of the experiment the animals were euthanized by decapitation. The right soleus muscle was sectioned, fixed and treated for conducting conventional histology, and the slides stained by HE and Picrosirius methods. Photomicrographs of 10 fields per animal were captured by light microscope, transferred to the image analysis program (Software Axio Vision, Zeiss). We measured the cross-sectional areas of muscle fibers and to analyze the volume densities of muscle fibers, capillaries, and interstitial collagen fibers, was used stereological method (252 points). The statistical analysis used was ANOVA One Way and Tukey test (p < 0.05)...

Experimental muscle pain challenges the postural stability during quiet stance and unexpected posture perturbation.

UNLABELLED: Musculoskeletal pain impairs postural control and stability. Nine subjects stood as quietly as possible on a moveable force platform before, during, and after experimental pain in the right leg muscles. A moveable force platform was used to measure the center of pressure and provided unexpected perturbations. Lower limb muscle activity, joint angles, and foot pressure distributions were measured. Hypertonic saline was used to induce pain in the vastus lateralis, vastus medialis, or biceps femoris muscle of the right leg. Compared to baseline and control sessions, pain in the knee extensor muscles during quiet standing evoked: 1) larger sway area, greater medial-lateral center of pressure displacement and higher speed (P < .05); 2) increased sway displacement in the anterior-posterior direction (P < .05); and 3) increased electromyography (EMG) activity for left tibialis anterior and left erector spinae muscles (P < .05). Pain provoked longer time to return to an equilibrium posture after forward EMG activity for, and pain in vastus medialis muscle decreased the time for the maximum hip flexion during this perturbation (P < .05). These results show that muscle pain impairs postural stability during quiet standing and after unexpected perturbation, which suggest that people suffering from leg muscle pain are more vulnerable to falls. PERSPECTIVE: This article presents the acute responses to leg muscle pain on the postural control. This measure could potentially help clinicians who seek to assess how pain responses may contribute to patient's postural control and stability during quiet standing and after recovering from unexpected perturbations.