Finite element graft stress for anteromedial portal, transtibial, and hybrid transtibial femoral drillings under anterior translation and medial rotation: an exploratory study.

Stress concentration on the Anterior Cruciate Ligament Reconstruction (ACLr) for femoral drillings is crucial to understanding failures. Therefore, we described the graft stress for transtibial (TT), the anteromedial portal (AM), and hybrid transtibial (HTT) techniques during the anterior tibial translation and medial knee rotation in a finite element model. A healthy participant with a non-medical record of Anterior Cruciate Ligament rupture with regular sports practice underwent finite element analysis. We modeled TT, HTT, AM drillings, and the ACLr as hyperelastic isotropic material. The maximum Von Mises principal stresses and distributions were obtained from anterior tibial translation and medial rotation. During the anterior tibia translation, the HTT, TT, and AM drilling were 31.5 MPa, 34.6 Mpa, and 35.0 MPa, respectively. During the medial knee rotation, the AM, TT, and HTT drilling were 17.3 MPa, 20.3 Mpa, and 21.6 MPa, respectively. The stress was concentrated at the lateral aspect of ACLr,near the femoral tunnel for all techniques independent of the knee movement. Meanwhile, the AM tunnel concentrates the stress at the medial aspect of the ACLr body under medial rotation. The HTT better constrains the anterior tibia translation than AM and TT drillings, while AM does for medial knee rotation.

Unique case study: Impact of single-session neuromuscular biofeedback on motor unit properties following 12 days of Achilles tendon surgical repair.

We explored the first evidence of a single-session neuromuscular biofeedback effect on motor unit properties, neuromuscular activation, and the Achilles tendon (AT) length 12 days after undergoing AT surgical repair. We hypothesized that immediate neuromuscular biofeedback enhances motor unit properties and activation without causing AT lengthening. After 12 days AT surgical repair, Medial Gastrocnemius (MG) motor unit decomposition was performed on a 58-year-old male before and after a neuromuscular biofeedback intervention (surface electromyography (sEMG) and ultrasonography), involving unressited plantar flexion. The analysis included motor unit population properties, sEMG amplitude, force paradigm, and AT length. There were increased MG motor unit recruitment, peak and average firing rate, coefficient of variation, and sEMG amplitude, and decreased recruitment and derecruitment threshold in the repaired AT limb. The non-injured limb increased the motor unit recruitment, and decreased the coefficient of variation, peak and average firing rate, inter-pulse interval, derecruitment threshold and sEMG amplitude. The AT length experienced -0.4 and 0.3 cm changes in the repaired AT and non-injured limb, respectively. This single-session neuromuscular biofeedback 12 days after AT surgery shows evidence of enhanced motor unit properties and activation without signs of AT lengthening when unresisted plantar flexion is performed in the repaired AT limb.

Distal overactivation of gastrocnemius medialis in persistent plantarflexion weakness following Achilles tendon repair.

Structural alterations of the triceps surae and Achilles tendon (AT) can promote plantarflexion weakness one-year following an AT repair, influencing the activation strategies of the Gastrocnemius Medialis (GM) muscle. However, this is yet to be demonstrated. We aimed to determine whether patients with plantar flexion weakness one-year after AT repair show altered GM spatial activation. In this cross-sectional and case-control study, ten middle-aged men (age 34 ± 7 years old, and 12.9 ± 1.1 months post-surgery) with a high AT total rupture score who attended conventional physiotherapy for six months after surgery, and ten healthy control men (age 28 ± 9 years old), performed maximal and submaximal (40, 60 and 90%) voluntary isometric plantarflexion contractions on a dynamometer. The peak plantar flexor torque was determined by isokinetic dynamometry and the GM neuromuscular activation was measured with a linear surface-electromyography (EMG) array. Overall EMG activation (averaged channels) increased when the muscle contraction levels increased for both groups. EMG spatial analysis in AT repaired group showed an increased activation located distally at 85-99%, 75-97%, and 79-97% of the electrode array length for 40%, 60%, and 90% of the maximal voluntary isometric contractions, respectively. In conclusion, patients with persistent plantar flexion weakness after AT rupture showed higher distal overactivation in GM.

Steadiness training improves the quadriceps strength and self-reported outcomes in persistent quadriceps weakness following nine months of anterior cruciate ligament reconstruction and failed conventional physiotherapy.

Background Persistent quadriceps weakness may occur after anterior cruciate ligament reconstruction, limiting the strength gain. However, steadiness strengthening might change the inability to gain strength. Hence, we determined whether strength training with force steadiness and visual biofeedback can improve knee quadriceps torque, self-reported pain and knee stability in patients with persistent quadriceps weakness after knee anterior cruciate ligament reconstruction. Methods Twenty-five patients (aged 43.7 ± 12.2 years) with persistent quadriceps weakness following knee anterior cruciate ligament reconstruction and 34-weeks of physiotherapy performed unilateral strength training for both lower limbs. Four-weeks of conventional physiotherapy at week-30 were given, confirming the inability to gain torque. Then, steadiness training (isometric knee extension with visual biofeedback) was given for 7-weeks. Knee quadriceps peak torque, strength improvement, determination of responders to the intervention, coherence of strength gain between limbs, and self-reported outcomes (pain and knee stability) were obtained. Descriptive statistics and data inference using mixed-ANOVA, McNemar test, and χ2 test were described. Findings Quadriceps torque in the reconstructed knee improved (98.2 ± 47.2-155.2 ± 78.9 Nm; p = 0.031) for most patients (84%). Nevertheless, the torque was lower than the healthy side maintaining asymmetry (155.2 ± 78.9 vs. 209.5 ± 101.8 Nm; p = 0.026). There was high (20%) and medium coherence (80%) between limbs. Knee stability and pain improved in 72% of the patients (p < 0.001). Interpretations Steadiness training after anterior cruciate ligament reconstruction followed 9 months of surgery and failed conventional physiotherapy, improves the persistent weakness and self-reported outcomes, but gain strength was dissimilar between limbs.

Do the heel-rise test and isometric strength improve after Achilles tendon repair using Dresden technique?

BACKGROUND: Achilles' tendon ruptures result in impaired plantar flexion strength and endurance. It is interesting to know the plantar flexion strength, the number of heel-rise repetitions, and the maximal calf circumference following Achilles' tendon ruptures repair. METHODS: Both the injured and non-injured legs of thirty male patients with Achilles' tendon ruptures treated with the percutaneous Dresden technique were compared with the ankle function of 30 healthy participants. Rehabilitation involved partial weight-bearing for three weeks and then increased to full weight-bearing and ankle exercises. RESULTS: The injured legs had weaker plantar flexion strength (1.64 ± 0.17 Nm/kg) compared with the non-injured legs (1.91 ± 0.24 Nm/kg; p = 0.002) and the healthy participants' legs (1.93 ± 0.32 Nm/kg; p < 0.001). The non-injured leg had greater ability in doing heel-rise repetitions (39.4 ± 6.1 rep.) compared with the injured legs (37.2 ± 5.7 rep.; p < 0.023) and the healthy participants' legs (31.0 ± 13.0 rep.; p < 0.001). CONCLUSIONS: The injured leg had not recovered full isometric strength but had improved heel-rise repetition.

Does the change of direction deficit measure the time of change of direction?

Abstract Aim: To determine whether the change of direction (COD) deficit can represent the time of the change of direction in professional under 17 years old (U-17) soccer players. Methods: Sixteen young soccer athletes performed the adapted 505 agility test with the stationary stance (2 straight lines of 5 m) and the 10 m linear running test (LR). In both tests, the partial and total times were recorded every 2.5 m by time gates (0-2.5 m; 2.5-7.5 m; 7.5-10 m). The best performances were recorded and used to determine the COD deficit (difference between the time for the LR and 505 tests). The paired t-test compared the initial acceleration (0-2.5 m) time, the COD time (2.5-7.5 m), and the COD deficit among the tests. Results: Times in the LR test were significantly shorter in the initial acceleration phase (0-2.5 m), and the change of direction deficit was also lower than the change of direction time (2.5-7.5 m) for both sides (p = 0.005). Conclusion: When an athlete is aware of an upcoming change of direction, a lower initial acceleration results in biases for determining the change of direction deficit. Therefore, acceleration capacity might not be suitable to assess using the 505 agility test.

Green Tea Extract Preserves Neuromuscular Activation and Muscle Damage Markers in Athletes Under Cumulative Fatigue.

A main implication of cumulative fatigue is the muscle damage that impairs neuromuscular function and training adaptations. These negative effects may limit performance when athletes exercise in consecutive days. In this regard, antioxidant supplementation has gain popularity among athletes. Green tea supplementation has been advocated as a strategy to improve exercise recovery due to the activity of its catechins with high antioxidant and anti-inflammatory potential. Here we performed a triple blinded placebo control experiment to determine the effect of green tea extract (GTE) from Camellia sinensis on muscle damage, oxidative stress, and neuromuscular activity in athletes submitted to consecutive sessions of exercise and fatigue. Sixteen trained amateur male athletes were randomly assigned to a GTE supplemented (500 mg/day) or placebo group during 15 days. Effects of supplementation were tested during repeated trials of submaximal cycling at 60% of peak power output performed after a protocol for cumulative fatigue of knee extensors. Muscle damage and oxidative stress showed lower magnitudes in response to fatigue after GTE supplementation. Placebo group showed impaired neuromuscular activity and higher muscle damage and oxidative stress compared to the GTE group during the cycling trials under fatigue. In summary, GTE supplementation showed positive effects on neuromuscular function in response to a condition of cumulative fatigue. It suggests GTE supplementation may have potential to serve as a strategy to improve performance and recovery in conditions of cumulative exercise.

Changes in the ankle muscles co-activation pattern after 5 years following total ankle joint replacement.

BACKGROUND: The Hintegra® arthroplasty provides inversion-eversion stability, permits axial rotation, ankle flexion-extension, and improvements of the gait patterns are expected up to 12 months of rehabilitation. However, sensorimotor impairments are observed in ankle flexors/extensors muscles after rehabilitation, with potential negative effects on locomotion. Here we determined the timing and amplitude of co-activation of the tibialis anterior and medial gastrocnemius muscles during gait by assessing non-operated and operated legs of patients with total ankle replacement, 5 years after surgery. METHODS: Twenty-nine patients (age: 58 [5.5] years, height: 156.4 [6.5] cm, body mass: 72.9 [6.5] kg, 10 men, and 19 women) that underwent Hintegra® ankle arthroplasty were included. Inclusion criteria included 5 years prosthesis survivorship. The onset and offset of muscle activation (timing), as well as the amplitude of activation, were determined during barefoot walking at self-selected speed by surface electromyography. The timing, percentage, and index of co-activation between the tibialis anterior and medial gastrocnemius were quantified and compared between non-operated and operated legs. FINDINGS: The operated leg showed higher co-activation index and temporal overlapping between tibialis anterior and medial gastrocnemius during gait (p < 0.001). INTERPRETATION: The neuromuscular changes developed during the process of degeneration do not appear to be restored 5 years following arthroplasty. The insertion of an ankle implant may restore anatomy and alignment but neuromuscular adaptations to degeneration are not corrected by 5 years following joint replacement.

Effect of green tea extract supplementation on exercise-induced delayed onset muscle soreness and muscular damage.

Previous studies addressed the antioxidant and anti-inflammatory role of compounds from green tea in different human tissues. Positive antioxidant and anti-inflammatory effects were described for brain tissues. Whether similar effects are observed in the skeletal muscle, green tea supplementation could be a strategy to reduce delayed onset muscle soreness resultant of exercise. Here we determine the effect of green tea extract supplementation on exercise-induced muscle soreness, muscle damage and oxidative stress. We performed a randomized triple blind placebo control study. Twenty non-trained men performed sessions of exercise to induce delayed onset muscle soreness in the triceps sural muscle group before and after 15 days of supplementation (500 mg/day) with green tea extract (n = 10) or a placebo (n = 10). Muscle soreness was evaluated using a visual scale. Blood samples were taken at different moments to determine serum blood markers of muscle damage, oxidative stress and antioxidant status. We found that exercise induced delayed onset muscle soreness. Supplementation reduced muscle damage but muscle soreness did not change. Plasma oxidative damage marker and antioxidant status did not show an effect of supplementation. As a conclusion, green tea extract supplementation did not reduce the sensation of delayed onset muscle soreness but reduces the marker of muscle damage after exercise. It suggests the green tea extract supplementation has positive effects on muscle recovery after strenuous exercise.

Biomechanical properties of different techniques used in vitro for suturing mid-substance Achilles tendon ruptures.

BACKGROUND: The Dresden technique preserves the paratenon during Achilles tendon repair and may improve the plantarflexor mechanism when combined with mobilization during early rehabilitation. However, the surgical repair design for Achilles tendon ruptures can affect rates of re-rupture or lengthening. Therefore, the aim of this study was to determine the biomechanical properties of the Krackow, Double-Kessler, Double-Dresden, and Triple-Dresden techniques used for repairing mid-substance Achilles tendon ruptures during cyclical and maximum traction. METHODS: Sixty mid-substance bovine tendons repaired after transverse rupturing were divided randomly into four groups by repair technique: Krackow, Double-Kessler, Double-Dresden, and Triple-Dresden. Cyclical tractions of 4.7, 5.8, 7.9, and 11.7mm (equivalent to 5°, 8°, 10°, and 15° of dorsal flexion, respectively) were applied to determine gapping, tensile strength, nominal suture stress, repair deformation, and specimens with clinical failure (gap>5mm). Maximal traction was applied to measure maximum strength and failure type (i.e. suture, knot, or tendon). FINDINGS: The Triple-Dresden technique resulted in decreased gapping, nominal suture stress, repair deformation, and quantity of specimens with clinical failure as compared to the other techniques. Furthermore, Triple-Dresden tendons showed greater comparative tensile and maximum strength. During maximal traction testing, this technique presented tendon failure, whereas the Krackow, Double-Kessler, and Double-Dresden techniques had suture failures. INTERPRETATION: Triple-Dresden repair results in better cyclical and maximum traction strengths, suggesting that this technique might be more appropriate when performing early mobilization after mid-substance Achilles tendon rupture repair.

Effects of plantar foot sensitivity manipulation on postural control of young adult and elderly / Efeitos da manipulação da sensibilidade plantar sobre o controle da postura ereta em adultos jovens e idosos

ABSTRACT Introduction: Subjects with sensorial losses present balance deficits. Although such condition is often observed among elderly, there is discussion concerning the dependence on sensorial information for body sway control in the elderly without sensorial losses. Purpose: We investigated the effects of foot sensitivity manipulation on postural control during upright standing in young adults and independent elderly (n = 19/group). Methods: Plantar sensitivity was evaluated by esthesiometry, and speed of center of pressure shift data during upright posture were evaluated for each foot using a baropodometer while the subjects were standing with eyes open or closed. The young adult group was evaluated for center of pressure in normal conditions and after plantar sensitivity disturbance, by immersing their feet in water and ice. Results: Young adults did not show alterations in their center of pressure after sensorial perturbation and presented, even under sensorial perturbation, better postural control than elderly subjects. The elderly showed lower foot sensitivity and greater center of pressure oscillation than young adults. Conclusion: Elderly subjects seem to rely more on foot sensitivity for control of body sway than young adults. In the elderly, a clinical intervention to improve foot sensitivity may help in upright posture maintenance.

RESUMO Introdução: Pessoas com perdas sensoriais apresentam déficits de equilíbrio. Embora esse quadro seja comum em idosos, ainda se discute o quanto idosos sem doenças que afetam as vias sensoriais dependem dessa informação para controlar oscilações corporais durante o controle da postura. Objetivo: Investigar os efeitos da perturbação da sensibilidade plantar sobre o controle da postura ereta em adultos jovens e idosos independentes (n = 19/grupo). Métodos: A sensibilidade plantar foi avaliada com estesiômetro e dados de velocidade e deslocamento do centro de pressão durante a postura de pé foram avaliados para cada pé com um baropodômetro, em condições de olhos abertos e fechados. O grupo de adultos jovens foi avaliado quanto ao centro de pressão nas condições normal e pós-perturbação da sensibilidade plantar, pela imersão dos pés em água e gelo. Resultados: Adultos não apresentaram alterações no centro de pressão em resposta à perturbação sensorial e tiveram, mesmo na condição de perturbação sensorial, melhor controle postural do que idosos. Idosos apresentaram menor sensibilidade plantar e maior oscilação do centro de pressão do que os adultos jovens. Conclusão: Idosos pareceram depender mais da sensibilidade plantar para manter o controle postural do que adultos jovens. Em idosos, intervenções clínicas que melhorem a sensibilidade plantar podem auxiliar na tarefa de manter a postura de pé.

Influence of saddle height and exercise intensity on pedalling asymmetries in cyclists / Influência da altura do selim e intensidade do exercício sobre assimetrias na pedalada de ciclistas

Abstract Pedaling asymmetries quantified during stationary cycling, when cyclist body positioning and intensity remain unchanged, may not fully reproduce the training and competition situations, in which cyclists experience different intensities and may opt for different saddle positioning aiming at power output optimization. Previous studies showed that torque and power can be asymmetric in cyclists. It is not clear whether changes in saddle height and exercise intensity may affect asymmetries. The aim of the present study was to determine pedaling asymmetries during cycling at different saddle heights and different exercise intensities. Twelve competitive cyclists performed an incremental maximal test, a constant-load (“heavy” intensity domain), and a Wingate test. Constant load and the Wingate tests were repeated using three different saddle heights (reference and lower or higher by 2.5% of the distance from the pubic symphysis to the ground). Crank torque was recorded throughout the pedaling cycle. Asymmetry (higher torque for the preferred limb) was found in all saddle heights (p<0.001) in both intensities. Asymmetry index was similar across the saddle positions (p>0.05) in both intensities. Our results suggest that asymmetric cyclists present a consistent pattern regardless of small changes in the saddle height or in exercise intensity. For practical implication, cyclists producing asymmetric torque may be adapted to this condition so they are continuously exposed to asymmetric effort and overload on the lower limbs.

Resumo Assimetrias na pedalada quantificadas durante o ciclismo estacionário, em que a postura do ciclista e a intensidade não mudam significativamente, podem não reproduzir situações de treino e competições em que os ciclistas experimentam diferentes intensidades e optam por mudar a postura no selim para otimização da potência. Estudos prévios mostraram assimetrias no torque e potência de ciclistas. Não é claro se mudanças na posição do selim e intensidade afetam essas assimetrias. O objetivo do presente estudo foi determinar as assimetrias na pedalada durante o ciclismo em diferentes alturas de selim e diferentes intensidades de esforço. Doze ciclistas competitivos realizaram um teste incremental máximo, um teste de carga constante (domínio severo) e um teste de Wingate. Os testes de carga constante e Wingate foram repetidos usando três alturas de selim (referência e 2,5% abaixo ou acima da referência, que foi medida pela distância da sínfise púbica até o solo). O torque gerado no pedivela foi medido durante todo o ciclo de pedalada. Assimetrias (maior torque na perna preferida) foram encontradas em todas as alturas de selim (p<0,001) em ambas as intensidades. O índice de assimetria foi similar em todas as alturas de selim (p<0,05) em ambas as intensidades. Os resultados sugerem que ciclistas assimétricos apresentam um padrão consistente independente de pequenas mudanças na posição do selim ou intensidade do exercício. Como implicação prática, ciclistas produzindo torque assimétrico podem estar adaptados a esta condição e sendo continuamente expostos a esforços e sobrecargas assimétricas nos membros inferiores.

Impact of two different dual tasks on obstacle crossing in elderly / Impacto de duas tarefas duplas diferentes em idosos durante a transposição de obstáculos / Impacto de dos dobles tareas diferentes en las personas mayores durante la transposición de obstáculos

ABSTRACT The performance of a dual task increases risk of falling during walking in the elderly. Such impact of a dual task may depend on its complexity regarding information processing. Therefore, different dual task configurations may elicit different demands for information processing. We investigated whether different dual task configurations can differently affect the performance of obstacle crossing in the gait of elderly. Ten independent elderly performed vertical obstacle crossing while performing two dual tasks during walking: (a) with auditory input (variation of Stroop task), and (b) without auditory input (report the days of the week in reverse sequence). We hypothesized that a dual task effect would be related with the type of dual task input, and the auditory input would require further information processing and therefore could have larger impact on gait. We found that performance of obstacle crossing was similar regardless of the dual task configuration. Both dual task conditions affect the obstacle crossing in the same extent in the elderly.

RESUMO O desempenho de uma dupla tarefa pode aumentar o risco de quedas durante a marcha em idosos. O impacto de uma dupla tarefa pode depender de sua complexidade em relação ao processamento de informação. Diferentes configurações de duplas tarefas deduzem diferentes demandas para o processamento de informação. Neste estudo investigamos se diferentes configurações de duplas tarefas podem afetar o desempenho da transposição de obstáculo na marcha de idosos. Dez idosos independentes foram avaliados durante a marcha cruzando um obstáculo vertical enquanto desempenhando duas duplas tarefas: (a) com input auditório (variação da tarefa de Stroop), e (b) sem imput auditório (falar os dias da semana em ordem reversa). Nós hipotetizamos que um efeito da dupla tarefa seria relacionado com o tipo de seu input, e o input auditório requereria maior processamento de informação; portanto, poderia ter maior impacto na marcha. Nós encontramos que o desempanho de transpor obstáculo foi similar nas duas condições de dupla tarefa. Sendo assim, ambas duplas tarefas testadas afetam a transposição de obstáculo na mesma medida em idosos.

RESUMEN El desempeño de una doble tarea puede aumentar el riesgo de caídas durante la marcha en personas mayores. El impacto de una doble tarea puede depender de su complejidad en cuanto al procesamiento de información. Las distintas configuraciones de dobles tareas infieren distintas demandas para dicho procesamiento. En este estudio se investigó si las distintas configuraciones de dobles tareas pueden afectar el rendimiento de la transposición de obstáculo en la marcha de personas mayores. Han participado diez personas mayores independientes y evaluadas durante la marcha cruzando un obstáculo vertical mientras hacían dos dobles tareas: (a) con input auditorio (variación de la tarea de Stroop) y (b) sin input auditorio (hablar los días de semana en orden reverso). Se dedujo que el rendimiento de la doble tarea estaría relacionado con el tipo de su input, y el input auditorio exigía un mayor procesamiento de información; por lo tanto, podría tener un mayor impacto en la marcha. Se encontró que el rendimiento en la superación de obstáculos fue semejante en las dos condiciones de doble tarea evaluadas. Así, ambas afectan a la superación del obstáculo en igual medida en personas mayores.

Análise da variabilidade e repetibilidade da pressão plantar durante a marcha de idosos / Variability and repeatability analysis of plantar pressure during gait in older people

RESUMOIntrodução:A repetibilidade e a variabilidade da pressão plantar em avaliações da marcha são componentes importantes na avaliação clínica do idoso. Contudo, pouco é conhecido sobre a consistência dos padrões de pressão plantar em idosos.Objetivo:Analisar a variabilidade e repetibilidade da pressão plantar durante da marcha de idosos, considerando valores médios, picos e assimetrias.Métodos:A pressão plantar foi avaliada em quatro diferentes dias em 10 idosos (cinco mulheres), com idade média ± desvio-padrão de 73 ± 6 anos, durante o andar descalço em velocidade preferida. Os dados de pressão plantar foram comparados entre as pisadas em cada dia e entre os diferentes dias de avaliação.Resultados:Dados de pressão média e pico foram similares entre os diferentes dias de avaliação. Os índices de assimetria observados foram similares entre os diferentes dias avaliados.Conclusão:A pressão plantar (média e pico) apresentou um padrão consistente nos idosos. Contudo, os índices de assimetria observados sugerem que idosos estejam sistematicamente expostos a cargas assimétricas durante a locomoção. Essa observação requer futuras investigações, especialmente em relação ao impacto dessas assimetrias na origem de doenças articulares.

ABSTRACTIntroduction:Repeatability and variability of the plantar pressure during walking are important components in the clinical assessment of the elderly. However, there is a lack of information on the uniformity of plantar pressure patterns in the elderly.Objective:To analyze the repeatability and variability in plantar pressure considering mean, peak and asymmetries during aged gait.Methods:Plantar pressure was monitored in four different days for ten elderly subjects (5 female), with mean ± standard-deviation age of 73 ± 6 years, walking barefoot at preferred speed. Data were compared between steps for each day and between different days.Results:Mean and peak plantar pressure values were similar between the different days of evaluation. Asymmetry indexes were similar between the different days evaluated.Conclusion:Plantar pressure presented a consistent pattern in the elderly. However, the asymmetry indexes observed suggest that the elderly are exposed to repetitive asymmetric loading during locomotion. Such result requires further investigation, especially concerning the role of these asymmetries for development of articular injuries.

Implicações do exercício regular sobre o controle postural em idosos / Implications of regular exercise on postural control in the e lderly

Objetivo: a partir de uma revisão da literatura, identificar as implicações do exercício regular sobre o controle postural em idosos. Método: revisão integrativa da literatura desenvolvida nas bases de dados SCOPUS e SciELO, utilizando os descritores “postural balance” or “postural control” or “balance” and “aged”, considerando trabalhos publicados nos últimos cinco anos e nos idiomas português ou inglês. Resultados: dos 23 estudos selecionados, identificou-se uma prevalência de estudos no ano de 2012 e nos periódicos Brazilian Journal of Physical Therapy e Revista Brasileira de Geriatria e Gerontologia. Os estudos foram agrupados em duas categorias: 1) Implicações da prática de atividade física sobre o controle postural; e 2) Exercícios físicos capazes de atuar sobre o controle postural. Conclusões: o exercício implica de maneira positiva sobre o controle postural, atuando em múltiplos aspectos motores e cognitivos desde que seja realizado de maneira regular e com intensidade adequada para que a fadiga muscular não acarrete em aumento no risco de quedas.

Aim: from a review of the literature, to identify the implications of regular exercise on postural control in the elderly. Method: integrative review of literature developed in the databases SCOPUS and SciELO, using the descriptors “postural balance” or “postural control” or “balance” and “aged”, considering papers published in the past five years in Portuguese or English. Results: 23 studies were selected. A prevalence of studies published in the year 2012 and in the periodicals Brazilian Journal of Physical Therapy and The Brazilian Journal of Geriatrics and Gerontology. The studies were grouped into two categories: 1) Implications of the practice of physical activity on postural control; and 2) Potential exercises to improve postural control. Conclusions: physical exercise impacts positively on postural control in the elderly, when performed regularly and at adequate intensity in order to avoiding falling risk due to muscle fatigue.

Influência da velocidade da marcha sobre a pressão plantar em sujeitos com osteoartrite unilateral de joelho / Influence of gait speed on plantar pressure in subjects with unilateral knee osteoarthritis

Objetivos Alterar a velocidade da marcha é uma estratégia comum para manipular a intensidade de exercício de caminhada, mas pode repercutir em maiores forças de impacto e consequente sobrecarga articular. Neste estudo analisamos os efeitos do aumento da velocidade da marcha sobre a pressão plantar e assimetrias na marcha em idosos com osteoartrite (OA) unilateral de joelho. A hipótese do estudo era de que o membro acometido receberia maior sobrecarga que o acometido durante o andar nas diferentes velocidades. Métodos Doze idosos com OA unilateral de joelho caminharam por um corredor de 10 m onde pisavam em um tapete instrumentado para medidas de pressão plantar. Cada participante caminhou cinco vezes em três diferentes velocidades autosselecionadas (preferida, lenta e rápida). Os resultados foram comparados entre as velocidades e entre os membros inferiores. Resultados As velocidades avaliadas diferiram entre si (p<0,05). A pressão média e o pico de pressão aumentaram com as mudanças entre as velocidades lenta e rápida (p<0,05); a velocidade do centro de pressão aumentou e o tempo de apoio simples diminuiu com o aumento da velocidade (p<0,05). Assimetrias não foram observadas entre o membro acometido e o contralateral. Conclusões O aumento na velocidade da marcha lenta para rápida em sujeitos com OA unilateral afeta a pressão plantar tanto no membro acometido quanto no contralateral, sem a observação de assimetrias. .

Objective Changing gait speed is a common strategy to manipulate exercise intensity during physical exercise, but may elicit higher impact forces and consequent joint loading. Here we analyzed the effects of increasing walking velocity on plantar pressure and asymmetries in elderly with knee osteoarthritis (OA). Our hypothesis was that the contralateral limb could receive higher loading compared to the OA limb in the different walking speeds tested. Methods Twelve elderly with unilateral knee OA walked at different self-selected speeds along a 10 m pass way stepping on an instrumented mat for measurement of plantar pressure at preferred, slow and fast gait speeds. Five steps were recorded for each speed. Plantar pressure data were compared between the speeds and legs. Results speeds were significantly different between them (p<0.05). Mean and peak plantar pressure increased when speed changed from slow to fast (p<0.05). Velocity of the center of pressure increased and the single stance time decreased when walk speed was increased (p<0.05). Any asymmetries were observed. Conclusion Increasing gait speed from slow to fast in subjects with unilateral knee OA significantly affected variables of plantar pressure, but asymmetries between committed and contralateral leg were not detected. .

Bilateral assessment of knee muscle relationships in healthy adults / Avaliação bilateral de relacionamentos de músculos do joelho em adultos saudáveis / Evaluación bilateral de las relaciones de músculos de la rodilla en adultos sanos

Asymmetric performance of flexor and extensor muscles of the knee may be a risk factor for knee injuries, especially the anterior cruciate ligament. Additionally, asymmetries in power and work may have correlations with fatigue and performance during functional tasks. Among untrained individuals, such asymmetries may be of potential interest for training prescription. Here, we investigated the bilateral performance of knee flexors and extensors muscle groups of untrained individuals. We quantified the torque-angle and torque-velocity relationships, as well as work, power and asymmetry indexes in 20 untrained male (25 ± 4 years old; height 1.74 ± 0.05 m; body mass 76 ± 9 kg). No significant asymmetry was observed for torque-angle and torque-velocity relationships, work and power output for knee flexor and extensor muscle groups (p < .05). Our results suggest that untrained male present symmetry in the knee flexion and extension bilateral performance. Changes in this behavior due to physical training must be monitored...

"Avaliação bilateral de relacionamentos de músculos do joelho em adultos saudáveis." Assimetrias na produção de força de músculos flexores e extensores do joelho são fatores de risco para lesões de joelho, especialmente do ligamento cruzado anterior. Assimetrias na potência e trabalho produzido podem ter correlação com fadiga e desempenho em tarefas funcionais. Se existentes em sujeitos não treinados, assimetrias podem ser importantes para a prescrição de treinamento. Neste estudo investigamos o desempenho bilateral dos grupos musculares flexor e extensor do joelho em sujeitos não treinados. Nós quantificamos as relações torque-ângulo e torque-velocidade, bem como o trabalho, a potência e índices de assimetrias em 20 homens saudáveis, não treinados (25 ± 4 anos, estatura de 1,74 ± 0,05 m e massa corporal de 76 ± 9 kg). Nenhuma assimetria significativa foi observada para as relações torque-ângulo, torque-velocidade, trabalho ou potência produzida para flexão e extensão do joelho (p < 0,05). Nossos resultados sugerem que sujeitos não treinados apresentaram simetria no desempenho bilateral para flexão e extensão de joelho. Mudanças nestas características em resposta ao treinamento físico devem ser monitoradas...

"Evaluación bilateral de las relaciones de músculos de la rodilla en adultos sanos." Asimetría en el rendimiento de los músculos flexores y extensores de la rodilla es un factor de riesgo en la lesión de rodilla, especialmente en la lesión del ligamento cruzado anterior. Asimetrías en potencia y trabajo pueden tener correlaciones con fatiga y un menor rendimiento en tareas funcionales. Se ha observado en sujetos desentrenados, como las asimetrías pueden ser un interés potencial en la prescripción de entrenamiento. El presente estudio investigó el rendimiento bilateral de los grupos musculares flexores y extensores de la rodilla en sujetos desentrenados. Se cuantificaron las relaciones entre el ángulo de torque y la velocidad de contracción, así como el trabajo, potencia e índices de asimetría en 20 hombres desentrenados sanos (edad: 25 ± 4 años; altura: 1,74 ± 0,05 m; peso: 76 ± 9 kg). No se observaron asimetrías significantes para la relación entre el ángulo de torque y la velocidad de contracción, el trabajo y la potencia de los grupos musculares flexores y extensores de la rodilla (p < 0,05). Nuestros resultados sugieren que sujetos desentrenados presentan simetría en el rendimiento bilateral de flexión y extensión de rodilla. Cambios en este comportamiento en respuesta al entrenamiento físico deberían ser estudiados...

Memory deficits and oxidative stress in cerebral ischemia-reperfusion: neuroprotective role of physical exercise and green tea supplementation.

Ischemic stroke is a major cause of morbidity and mortality all over the world. Among impairments observed in survivors there is a significant cognitive learning and memory deficit. Neuroprotective strategies are being investigated to minimize such deficits after an ischemia event. Here we investigated the neuroprotective potential of physical exercise and green tea in an animal model of ischemia-reperfusion. Eighty male rats were divided in 8 groups and submitted to either transient brain ischemia-reperfusion or a sham surgery after 8 weeks of physical exercise and/or green tea supplementation. Ischemia-reperfusion was performed by bilateral occlusion of the common carotid arteries during 30 min. Later, their memory was evaluated in an aversive and in a non-aversive task, and hippocampus and prefrontal cortex were removed for biochemical analyses of possible oxidative stress effects. Ischemia-reperfusion impaired learning and memory. Reactive oxygen species were increased in the hippocampus and prefrontal cortex. Eight weeks of physical exercise and/or green tea supplementation before the ischemia-reperfusion event showed a neuroprotective effect; both treatments in separate or together reduced the cognitive deficits and were able to maintain the functional levels of antioxidant enzymes and glutathione.

Isometric muscle force, rate of force development and knee extensor neuromuscular efficiency asymmetries at different age groups / Assimetrias na força muscular isométrica, taxa de desenvolvimento de força e na eficiência neuromuscular de extensores do joelho em diferentes faixas de idade

The aim of this study was to evaluate force, rate of force development and knee extensor neuromuscular efficiency asymmetries in children, adults and elderly. Each subject performed maximal isometric voluntary contractions (MIVC) and submaximal trials (15% and 30% MIVC). Maximal force, rate of force development (RFD) and neuromuscular efficiency were evaluated and compared between groups and between preferred and non-preferred lower limb. Children (mean age 8.4, SD 0.7 yrs), female adults (mean age 23.2, SD 3.5 yrs) and elderly (mean age 65.9 SD 7.0 yrs) were evaluated. RFD was higher in young adults, and similar between children and elderly. Neuromuscular efficiency decreased significantly with aging (P<0.05). Inter-limb asymmetries were observed for force and RFD in favor of the preferred lower limb in the elderly (P<0.05). Force and RFD asymmetries in the elderly are supported by the right hemisphere-aging model contributing to increased motor asymmetries. It was suggested that both physical assessment and training in the elderly should consider asymmetries that apparently are inherent to the aging process. A simple protocol for maximal and submaximal force assessment may be useful for delineating impairments in force and power in the elderly.

Neste estudo, avaliamos assimetrias na força, taxa de desenvolvimento de força (TDF) e eficiência neuromuscular de extensores de joelho em crianças, adultos e idosos. Cada sujeito realizou contrações isométricas voluntárias máximas e submáximas (15% e 30% da contração isométrica voluntária máxima). Força máxima, TDF e eficiência neuromuscular foram avaliadas e comparadas entre os grupos e entre perna preferida e não-preferida. Foram avaliadas crianças (média de idade de 8,4 ± 0,7 anos), adultos (média de idade de 23,2 ± 3,5 anos) e idosos (média de idade de 65,9 ± 7,0 anos), do sexo feminino. A TDF foi maior em adultos jovens, e similar entre crianças e idosos. A eficiência neuromuscular diminuiu significativamente com o envelhecimento (P<0,05). Foram observadas assimetrias em força e TDF em favor da perna preferida em idosos (P<0,05). Assimetrias em força e TDF em idosos podem ser justificadas por fatores neurais, como a mudança em favor do hemisfério cerebral direito, levando a assimetrias motoras. Este resultado sugere que tanto a avaliação física quanto o treinamento em idosos deve levar em consideração assimetrias, que parecem ser inerentes ao processo de envelhecimento. Assim, um protocolo simples para avaliar a força máxima e submáxima pode ser útil para quantificar déficits de força e potência em idosos.

Influence of mental practice and movement observation on motor memory, cognitive function and motor performance in the elderly / Influência da prática mental e observação do movimento sobre a memória motora, função cognitiva e desempenho motor em idosos

BACKGROUND: With aging, it is important to maintain cognitive and motor functions to ensure autonomy and quality of life. During the acquisition of motor skills, it is necessary for the elderly to understand the purpose of the proposed activities. Physical and mental practice, as well as demonstrations, are strategies used to learn movements. OBJECTIVES: To investigate the influence of mental practice and the observation of movement on motor memory and to understand the relationship between cognitive function and motor performance in the execution of a sequence of digital movements in the elderly. METHOD: This was a cross-sectional study conducted with 45 young and 45 aged subjects. The instruments used were Mini-Mental State Examination (MMSE), Manual Preference Inventory and a Digital Motor Task (composed of a training of a sequence of movements, an interval and a test phase). The subjects were divided into three subgroups: control, mental practice and observation of movement. RESULTS: The elderly depend more strongly on mental practice for the acquisition of a motor memory. In comparing the performances of people in different age groups, we found that in the elderly, there was a negative correlation between the MMSE score and the execution time as well as the number of errors in the motor task. CONCLUSIONS: For the elderly, mental practice can advantage motor performance. Also, there is a significant relationship between cognitive function, learning and the execution of new motor skills. .

CONTEXTUALIZAÇÃO: Com o envelhecimento, é importante a manutenção da função motora e cognitiva para garantir autonomia e qualidade de vida. Durante a aquisição de habilidades motoras é necessário que o idoso seja capaz de compreender o objetivo das atividades propostas e, para isso, a prática física e mental, assim como a demonstração, são estratégias usadas para o indivíduo aprender os movimentos. OBJETIVOS: Verificar a influência da prática mental e da observação do movimento sobre a memória motora e a relação entre a função cognitiva e o desempenho motor na execução de uma sequência de movimentos digitais em idosos. MÉTODO: Estudo transversal, realizado com 45 jovens e 45 idosos. Foram utilizados: Miniexame do Estado Mental (MEEM); Inventário de Preferência Manual de Edinburgh e Tarefa Motora Digital (composta por fase de treino, intervalo e teste). Os sujeitos foram divididos em três subgrupos: controle, prática mental e observação do movimento. RESULTADOS: Observou-se que idosos parecem depender mais da prática mental para a aquisição de uma memória motora e, na comparação do desempenho entre as faixas etárias, houve diferença no tempo de execução; nos idosos, observou-se correlação negativa entre o escore do MEEM e o tempo de execução e o número de erros na tarefa motora. CONCLUSÕES: Para idosos, a prática mental parece favorecer o desempenho motor, assim como existe uma relação significativa entre a função cognitiva e o aprendizado e execução de novas habilidades motoras. .