Electromyographic Activation and Co-contraction of the Thigh Muscles During Pilates Exercises on the Wunda Chair.

Objective: The aim of the present study was to investigate whether Pilates exercises on the Wunda chair (Going Up Front and Mountain Climb) activate the muscles rectus femoris (RF) and biceps femoris (BF) in 2 situations (foot on the pedal and foot on the seat). Methods: Sixteen young female Pilates practitioners (18-35 years old) participated in this study. The muscles of their right leg were then submitted to electromyography analysis during the exercises. Results: Significant differences were found for the RF muscle (maximal voluntary isometric contraction [%MVIC]), which was assessed and compared between the 2 exercises (Going Up Front and Mountain Climb: F = 9.83; P = .03; np2 = 0.14); 2 conditions (foot on the pedal and foot on the seat: F = 40.02; P < .001; np2 = 0.90) and interactions (F = 14.49; P < .001; np2 = 0.20) and for BF muscle (%MVIC) in the comparisons between the 2 conditions (foot on the pedal and foot on the seat: F = 27.5; P < .001; np2 = 0.82) and interactions (F = 12.57; P < .001; np2 = 0.17). The percentage of cocontraction presented the significant difference in the comparisons between the 2 conditions (foot on the pedal and foot on the seat: F = 24.07; P < .001; np2 = 0.286). Conclusion: Both Pilates exercises activated the thigh core muscles in the moderate and high categories. The highest percentage of cocontraction levels were presented when the foot was resting on the pedal.

Structural Chirality of Polar Skyrmions Probed by Resonant Elastic X-Ray Scattering.

An escalating challenge in condensed-matter research is the characterization of emergent order-parameter nanostructures such as ferroelectric and ferromagnetic skyrmions. Their small length scales coupled with complex, three-dimensional polarization or spin structures makes them demanding to trace out fully. Resonant elastic x-ray scattering (REXS) has emerged as a technique to study chirality in spin textures such as skyrmions and domain walls. It has, however, been used to a considerably lesser extent to study analogous features in ferroelectrics. Here, we present a framework for modeling REXS from an arbitrary arrangement of charge quadrupole moments, which can be applied to nanostructures in materials such as ferroelectrics. With this, we demonstrate how extended reciprocal space scans using REXS with circularly polarized x rays can probe the three-dimensional structure and chirality of polar skyrmions. Measurements, bolstered by quantitative scattering calculations, show that polar skyrmions of mixed chirality coexist, and that REXS allows valuation of relative fractions of right- and left-handed skyrmions. Our quantitative analysis of the structure and chirality of polar skyrmions highlights the capability of REXS for establishing complex topological structures toward future application exploits.

Chiral structures of electric polarization vectors quantified by X-ray resonant scattering.

Resonant elastic X-ray scattering (REXS) offers a unique tool to investigate solid-state systems providing spatial knowledge from diffraction combined with electronic information through the enhanced absorption process, allowing the probing of magnetic, charge, spin, and orbital degrees of spatial order together with electronic structure. A new promising application of REXS is to elucidate the chiral structure of electrical polarization emergent in a ferroelectric oxide superlattice in which the polarization vectors in the REXS amplitude are implicitly described through an anisotropic tensor corresponding to the quadrupole moment. Here, we present a detailed theoretical framework and analysis to quantitatively analyze the experimental results of Ti L-edge REXS of a polar vortex array formed in a PbTiO3/SrTiO3 superlattice. Based on this theoretical framework, REXS for polar chiral structures can become a useful tool similar to x-ray resonant magnetic scattering (XRMS), enabling a comprehensive study of both electric and magnetic REXS on the chiral structures.

Are isokinetic leg torques and kick velocity reliable predictors of competitive level in taekwondo athletes?

The aim of this study is to analyze how isokinetic knee and hip peak torques and roundhouse kick velocities are related to expertise level (elite vs. sub-elite) in taekwondo athletes. Seven elite and seven sub-elite athletes were tested for kick-specific variables (KSV, composed of kinematic variables and power of impact) and for concentric isokinetic peak torque (PT) at 60°/s and 240°/s. First, KSVs and PTs were compared between groups, then PTs were correlated with KSVs. Parametric variables with larger effect sizes (Cohen's d) were entered in a stepwise linear discriminant analysis (LDA), generating an equation to estimate competitive level. Between-group differences were found in hip flexors (p = 0.04, d = 0.92) and extensors (p = 0.04, d = 0.96) with PT at 240°/s. Hip flexion PT at 60°/s and 240°/s correlated negatively with kick time (R = -0.46, p = 0.0499 and R = -0.62, p = 0.01 respectively). Hip flexion torque at 60°/s correlated positively (R = 0.52, p = 0.03) with peak linear velocity of the foot (LVF) and power of impact (R = 0.51, p = 0.03). Peak torque of hip extension at 60°/s and hip abduction at 240°/s also correlated with LVF (R = 0.56, p = 0.02 and R = 0.46, p = 0.0499). Hip extension at 60°/s correlated positively with peak linear velocity of the knee (R = 0.48, p = 0.04). The LDA showed an accuracy of 85.7% (p = 0.003) in predicting expertise level based on hip flexion and extension torques at 240°/s and on knee extension velocity during the kick. The study demonstrates that hip muscle strength is probably the dominant muscular factor for determining kick performance. Knee angular velocity combined with hip torques is the best discriminator for competitive level in taekwondo athletes.

The role of environment in the pathogenesis of keratoconus.

PURPOSE OF REVIEW: This study was conducted to demonstrate the importance of the environment in keratoconus (KC) genesis. RECENT FINDINGS: Genetic-related connective tissue disorders demonstrate the inconsistency of theories regarding KC pathogenesis since no corneal steepening was observed in the majority of these patients. Despite recent advances and decades of research into the genetics of KC, the identification of disease-causing KC genes has been frustrating. Variants found based on genome-wide and next-generation sequencing only seem to account for a small number of cases or play a limited role in KC pathogenesis. SUMMARY: The literature shows that mechanical manipulation may be the common underlying factor or the indispensable act precipitating the cascade of events leading to permanent corneal deformation. Hence, ophthalmologists have the opportunity to increase patient awareness about eye manipulation repercussions and treatment for ocular surface disorders. VIDEO ABSTRACT: http://links.lww.com/COOP/A42.

Core muscle activation during Pilates exercises on the Wunda chair.

OBJETIVES: The Pilates method, developed by Joseph Pilates (1886-1967), has been widely used to improve trunk stability, muscle flexibility and strength, physical fitness, and body awareness. To measure the electromyography of four trunk muscles during three Pilates exercises carried out of the wunda chair. DESING: cross-section study. METHODS: Sixteen women participated in this study with a height and body weight of 1.64 ± 0.04 m and 58.7 ± 7.4 kg, respectively, and a mean age of 27.6 ± 3.7 years. Rectus abdominis (RA), internal oblique (IO), longissimus (LO), and multifidus (MU) muscles was evaluated by electromyographic (EMG) tests activity during three Pilates exercises: going up front (GF), mountain climb (MC), and swan (SW). EMG was normalized and expressed in the time domain, by the RMS. RESULTS: The highest EMG values concerning the four muscles were observed for the MC exercise, followed by GF and SW (ANOVA: p = 0.0001, p = 0.04, p = 0.0002, and p = 0.0013, respectively). Our results show that the three Pilates exercises could recruit all the muscles, with a moderate activity intensity. The ANOVA; p < 0.05 showed significant difference between the muscles, concerning SW (p = 0.0002). CONCLUSION: Our results show that the three Pilates exercises could recruit all the muscles, with a moderate activity intensity.

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.

Co-contraction of the core muscles during Pilates exercise on the Wunda Chair.

BACKGROUND: The co-contraction of the core muscles has been reported as the key mechanism towards spinal stability. Classic Pilates exercises aimed at these muscles are known to improve the stability and strength of the trunk without damaging the deep structures of the spine. OBJECTIVE: To evaluate the co-contraction of the mobilizing (rectus abdominis; longissimus) and stabilizing (multifidus; internal oblique) trunk muscles during Pilates exercises - going up front, mountain climber, and swan. METHODS: Sixteen women, all Pilates practitioners, participated in the study. The stabilizing and mobilizing muscles of the trunk (right side) were submitted to electromyography to calculate the percentage of co-contraction during the exercises. One-way repeated measures analysis of variance (ANOVA) was used to verify the difference in %COCON between stabilizers and mobilizers among the three exercises. The post-hoc Bonferroni test (P< 0.01) was applied when necessary. The paired t-test (P< 0.01) was used to verify the difference in %COCON between stabilizers and mobilizers separately for each exercise. RESULTS: The co-contraction values of the stabilizers were higher than those of the mobilizers for all exercises. The going up front (stabilizers) and the swan (mobilizers) exercises showed the highest %COCON values. CONCLUSIONS: The Pilates method is effective for either rehabilitating pathologies or training the trunk muscles in healthy individuals and athletes.

Electromyographic evaluation of trunk core muscles during Pilates exercise on different supporting bases.

OBJECTIVE: To evaluate the electromyographic (EMG) activity of the rectus abdominis (RA) and internal oblique (IO) muscles during Pilates exercise on different trunk supporting bases. METHODS: Sixteen female Pilates practitioners participated in the study. EMG of the RA and OI muscles was evaluated during the double leg stretch (DLS) exercise on three different supporting bases - mat, long box, and short box. Trunk stability varies according to the size and type of the base. To normalize the data, the RMS value (EMG) obtained during the DLS exercise was divided by the RMS value from the torque test - the maximal voluntary isometric contraction (MVIC) - and multiplied by 100 (%MVIC). One-way repeated-measured analysis of variance (ANOVA) and Bonferroni tests were used to compare data concerning the supporting bases and Student t-test regarding the muscles (p < 0.05). RESULTS: The comparison among the bases involving each muscle - RA or IO (p < 0.05) - showed significant difference (%MVIC) between the mat and the short box. No significant difference was observed between the muscles concerning the exercise on the mat (p = 0.9266), on the long box (p = 0.5113) and on the short box (p = 0.2972). CONCLUSION: The short box increased the activity of the rectus abdominis and internal oblique muscles during exercise. The DLS exercise was able to challenge the stability of the trunk and thus recruit its stabilizer and mobilizer muscles at the same intensity.

Avaliação eletromiográfica do exercício swan na Wunda Chair: Co-ativação dos músculos do core / Electromyographic evaluation of the swan exercise in the Wunda Chair: Co-activation of the core muscles

A principal finalidade do método Pilates é desenvolver uma automação dos músculos do core. Sendo assim, o objetivo deste estudo foi analisar a razão eletromiográfica dos músculos Oblíquo Interno (OI) e Reto do Abdômen (RA) localizados na parte anterior do tronco, a razão eletromiográfica dos músculos Multífido (MU) e Longuíssimo do Tórax (LO) localizados na parte posterior do tronco, e também a razão ântero-posterior (A/P=RA+IO/LO+MU) desses músculos durante o exercício swan do método Pilates, realizado sobre a Wunda Chair. Na comparação entre as três razões, foram encontradas diferenças estatísticas (p = 0,0103), apenas entre as razões ântero-posterior (A/P), e entre a razão dos músculos localizados na parte posterior do tronco (MU/LO). Os resultados demonstraram que houve um predomínio na atividade eletromiográfica dos músculos da região posterior em relação aos músculos da região anterior do tronco e que os músculos estabilizadores apresentaram maior atividade eletromiográfica em comparação com os músculos globais ou mobilizadores. O exercício swan pode ser utilizado como forma de treinamento para a musculatura do tronco, e como consequência gerar maior estabilidade a coluna vertebral, pois o exercício prioriza a diminuição da carga sobre a coluna vertebral. (AU)

The main purpose of the Pilates method is to develop an automation of core muscles. Thus, the aim of this study was to analyze the electromyographic ratio of the Internal Oblique (IO) and Rectus Abdominis (RA) muscles located in the anterior part of the trunk, the electromyographic ratio of the Multifidus (MU) and Longissimus Thoracis (LO) muscles, located in the posterior part of the trunk, and also the ratio antero- posterior (A/P=RA+IO/LO+MU) of these muscles during the swan exercise of the Pilates, performed on the Wunda Chair. In the comparison between the three ratios, statistical differences (p = 0.0013) were found only between the antero-posterior (A/P) ratios and the ratio of the muscles located in the posterior part of the trunk (MU/LO). The results showed a predominance of the electromyographic activity in the muscles of the posterior region in relation to the muscles of the anterior region of the trunk. The stabilizing muscles presented greater electromyographic activity in comparison to the global or mobilizing muscles. The swan can be used as training for the trunk muscles, and therefore generates greater stability of the spine, since exercise prioritizes the decrease of the load on the spine. (AU)

Effect of Pilates Mat Exercises on Neuromuscular Efficiency of the Multifidus and Internal Oblique Muscles in a Healthy Ballerina.

Physical training has frequently been indicated for ballet dancers to strengthen their trunk muscles, improve their performance, and avoid injuries. The current authors hypothesized that these dancers could benefit from Pilates exercises to stabilize their trunk muscles and improve joint stability and neuromuscular efficiency (NME). Our study aimed at evaluating the NME and isometric strength of the internal oblique (IO) and multifidus (MU) muscles in a healthy 24-year-old classical ballerina before and after an 8-week Pilates exercise intervention. The muscles were tested with electromyography (EMG) and a dynamometer, and the resulting torque and EMG values were used to calculate the NME. Based on the results, the Pilates exercises could improve the NME of the muscles tested, since the torque increased and the EMG activity decreased after the intervention.

Updated geriatric cardiology guidelines of the brazilian society of cardiology ­ 2019 / Atualização das diretrizes em cardiogeriatria da sociedade brasileira de cardiologia ­ 2019

Development: The Department of Geriatric Cardiology of the Brazilian Society of Cardiology (Departamento de Cardiogeriatria da Sociedade Brasileira da Cardiologia) and the Brazilian Geriatrics and Gerontology Society (Sociedade Brasileira de Geriatria e Gerontologia). (AU)

Hip, Knee, and Ankle Functional Demand During Habitual and Fast-Pace Walking in Younger and Older Women.

This study compared functional demand (FD) between older and younger women walking at habitual and fast speed and determined strength thresholds necessary to maintain FD below 80%. FD was calculated by expressing walking flexion and extension joint torques of the ankle, knee, and hip as a percentage of maximal strength. Young women had an average FD of 65% across joint actions and speeds, whereas older women had FD of 90%. In older women, the greatest FD occurred in the hip musculature. The hip, knee, and ankle extensor strengths required to maintain FD below 80% were 1.66, 1.86, and 0.57 Nm/kg, and flexor strengths were 1.24, 0.49, and 0.69 Nm/kg, respectively. Older women have limited functional reserve to increase gait speed and rely heavily on available hip strength during walking. This study identifies strength targets for the hip, knee, and ankle that will assist in maintaining FD of older women at a sustainable level.

Comparison of the effects of different physical activities on laterality and asymmetry values through side bridge test

Aim: To compare the effects of different physical activities on laterality and asymmetry values through the side bridge test. Methods: the assessments were carried out in 45 subjects between 18 and 30 years old, 15 Crossfit-trained individuals, 15 weight trained and 15 sedentary. The subjects performed the side bridge test on both sides. After checking the normality and homogeneity of the data, we selected the appropriate statistical analysis for the comparison of the variables, adopting a significance level of α <0.05. Results: there was no statistical difference in the balance ratio; however, significant difference was found in the side bridge test endurance time, in which the Crossfit group obtained longer times on both sides than the other two groups. The side bridge test is a test of simple execution and that in this study the Crossfit group presented better results in the endurance time in the side bridge test. Conclusion: the results of the ratio asymmetry and endurance time are not sufficient to evaluate the resistance of the core muscles but could be an evaluation tool, the side bridge test can be introduced in postural training programs.(AU)

Neuromuscular efficiency of the multifidus muscle in pilates practitioners and non-practitioners.

BACKGROUND: Pilates exercises help stabilize the vertebral segments by recruiting the abdominal and spinal muscles. Pilates training may increase joint stability and improve neuromuscular efficiency (NME). OBJECTIVE: This study aimed to evaluate NME of the multifidus (MU) muscle through electromyography (EMG) analysis and torque test, applied to practitioners and non-practitioners of Pilates. METHODS: Participants included thirty women: Pilates practitioners (n = 15) and non-practitioners (n = 15). They were tested for trunk extension. Their right and left MU muscles were submitted to EMG to estimate NME. Results concerning torque, EMG, and NME from all participants were compared. RESULTS: Statistical analysis concerning isometric torque peak (p = 0.0275) and NME (p = 0.0062) showed significant difference (Student t test; p < 0.05) between practitioners and control. No significant difference (p = 0.3387) in EMG was observed. CONCLUSION: Our results suggest Pilates exercises is effective in training spinal muscles to improve NME in women.

Isometric pre-conditioning blunts exercise-induced muscle damage but does not attenuate changes in running economy following downhill running.

Running economy (RE) is impaired following unaccustomed eccentric-biased exercises that induce muscle damage. It is also known that muscle damage is reduced when maximal voluntary isometric contractions (MVIC) are performed at a long muscle length 2-4 days prior to maximal eccentric exercise with the same muscle, a phenomenon that can be described as isometric pre-conditioning (IPC). We tested the hypothesis that IPC could attenuate muscle damage and changes in RE following downhill running. Thirty untrained men were randomly assigned into experimental or control groups and ran downhill on a treadmill (-15%) for 30 min. Participants in the experimental group completed 10 MVIC in a leg press machine two days prior to downhill running, while participants in the control group did not perform IPC. The magnitude of changes in muscle soreness determined 48 h after downhill running was greater for the control group (122 ±â€¯28 mm) than for the experimental group (92 ±â€¯38 mm). Isometric peak torque recovered faster in the experimental group compared with the control group (3 days vs. no full recovery, respectively). No significant effect of IPC was found for countermovement jump height, serum creatine kinase activity or any parameters associated with RE. These results supported the hypothesis that IPC attenuates changes in markers of muscle damage. The hypothesis that IPC attenuates changes in RE was not supported by our data. It appears that the mechanisms involved in changes in markers of muscle damage and parameters associated with RE following downhill running are not completely shared.

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

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

Comparison of lower limb strength in younger and older female adults / Comparação da força muscular de membro inferior em mulheres jovens e idosas

Age-related weakness results in slow movements, altered motor control, and higher sense of effort during activities of daily living. Thus, when an older adult performs tasks closer to the maximum functional capacity it may contribute to the onset of fatigue and increased risk of falling. Objective: The present study aimed to compare lower limb strength and strength ratio (isokinetic strength/isometric strength) in younger and older adults. Twenty one (66 older±6 years) and nineteen younger (22±2 years) women participated in this study. The maximum isometric and isokinetic strength were assessed at hip, knee and ankle joints at sagittal plane. Peak isometric and isokinetic torque were normalized by body mass (Nm. kg -1) and strength ratio was calculated dividing the maximum isokinetic strength over the maximum isometric strength of each joint in each movement. The evaluation of habitual gait speed was conducted on a walkway measuring 14 meters long. Younger adults had 11.6% higher ankle extension strength ratio (p = 0.013) and 17.6% higher ankle flexion strength ratio (p = 0.001) than older female adults. The isometric peak torque was higher in younger adults than in older adults during all movements tested (p < 0.001). The isokinetic peak torque was higher in younger adults than in older adults during all the movements tested (p < 0.001). Older female adults were weaker than younger women in all movements (flexion and extension) and lower limb joints assessed (hip, knee and ankle), which may predispose them to fatigue and increased risk of falling....(AU)

A fraqueza muscular decorrente do envelhecimento resulta em movimentos lentos, alteração do controle motor e maior sensação de esforço durante a realização das atividades de vida diária. Dessa maneira, quando o idoso realiza suas tarefas diárias próximo de sua máxima capacidade funcional pode favorecer a fadiga precoce e aumento do risco de quedas. Objetivo: o presente estudo teve como objetivo comparar a força de membros inferiores e a razão de força (força isocinética/força isométrica) em jovens e idosos. Vinte e uma idosas (66±6 anos) e dezenove jovens (22±2 anos) participaram desse estudo. A máxima força isométrica e isocinética foram avaliadas para o quadril, joelho e tornozelo. O pico de torque isométrico e isocinético foram normalizados pela massa corporal (Nm.kg-1) e a razão de força foi calculada por meio da divisão entre a máxima força isocinética e a máxima força isométrica. A avaliação da velocidade habitual de marcha foi realizada em uma passarela de 14 metros de comprimento. Os jovens apresentaram 11,6% maior razão de força de extensão do tornozelo e 17,6% maior razão de força de flexão do tornozelo em relação às voluntárias idosas. O pico de torque isométrico foi maior em jovens em relação aos idosos para todos os movimentos avaliados. O pico de torque isocinético foi maior em jovens em relação às voluntárias idosas para todos os movimentos avaliados. Mulheres idosas são mais fracas em relação às jovens para todos os movimentos (flexão/extensão) e todas as articulações avaliadas (quadril, joelho e tornozelo), o que pode predispor à fadiga e aumento do risco de queda....(AU)