Frailty has been described as a clinical state of vulnerability to stress, consequence from decline of resilience and physiological reserves and progressive decline on ability of homeostasis maintenance. The aim of this study was to evaluate the complexity of R-R intervals (RR) in resting supine (REST) and standing (STAND) position in 3 groups: frail, pre-frail and non-frail. Eighty older people (60-94 years old) were divided into frail group (n = 6), pre-frail (n=36) and non-frail group (n=38). The RR series were recorded at REST and during STAND for 10 minutes in each position. Short sequences of RR were analyzed by conditional entropy (CE) and approximate entropy (ApEn). Position, group and interaction effects were evaluated by two-way repeated-measures ANOVA. CE indicated only position effect while ApEn showed only group effect. ApEn seems to be more suitable for assessing changes in the complexity in frailty syndrome.

Fiogbé, E, Vassimon-Barroso, V, Catai, AM, de Melo, RC, Quitério, RJ, Porta, A, and Takahashi, ACdM. Complexity of knee extensor torque: effect of aging and contraction intensity. J Strength Cond Res 35(4): 1050–1057, 2021—Assessing the knee extensors' torque complexity in older adults is relevant because these muscles are among the most involved in functional daily activities. This study aimed to investigate the effects of aging and isometric contraction intensity on knee extensor torque complexity. Eight young (24 ± 2.8 years) and 13 old adults (63 ± 2.8 years) performed 3 maximal (maximum voluntary contraction [MVC], duration = 10 seconds) and submaximal isometric contractions (SICs, targeted at 15, 30, and 40% of MVC, respectively) of knee extensors. Torque signals were sampled continuously, and the metrics of variability and complexity were calculated basing on the SIC torque data. The coefficient of variation (CV) was used to quantify the torque variability. The torque complexity was determined by calculating the corrected approximate entropy (CApEn) and sample entropy (SampEn) and its normalized versions (NCApEn and NSampEn). Young subjects produced greater isometric torque than older adults, and the CV was similar between both groups except at the highest force level (40% MVC) where young subjects' value was higher. The major novel finding of this investigation was that although the knee extensor torque complexity is reduced in older adults, its relationship with contraction intensity is similar to young subjects. This means that despite the age-related decrease of the interactions between the components of the neuromuscular system, the organization of force control remains preserved in older adults, at least up to just below the force midrange.

Aim Frailty syndrome is related to decreased physiological complexity, functional capacity and cognition. Physical exercise has been suggested to slow down and reverse this syndrome. However, evidence of its effectiveness is not as straightforward as conventionally admitted, as there is a lack of trials with rigorous methodology. The purpose of this study was to describe the Pre‐Frail Multicomponent Training Intervention protocol. Methods Cardiovascular, motor control and neuromuscular systems of pre‐frail older adults will be assessed by measuring the complexity of the output of these systems. Functional capacity and cognition will be assessed by specific tools. A 16‐week training protocol will be carried out on three alternate days, with 60‐min sessions, and combining aerobic, muscle strength, flexibility and balance exercises. The objective of this intervention is to improve the cardiovascular, motor control and neuromuscular systems, as well as functional capacity and cognition of pre‐frail older adults. The assessment of these systems will be carried out using gold standard devices. Results The results of the present study might allow clinical and functional support for the evaluation of the variables analyzed. Conclusion This protocol is easily reproducible and requires low‐cost materials, thus the Pre‐Frail Multicomponent Training Intervention could be a therapeutic strategy for pre‐frail older adults. Geriatr Gerontol Int 2019; 19: 684–689.

Objetivo: A proposta desse trabalho foi investigar o efeito da rotação do quadril na atividade elétrica dos músculos Vasto Medial Oblíquo (VMO), Vasto Lateral Oblíquo (VLO) e Vasto Lateral Longo (VLL) no agachamento a 45º de flexão do joelho associado à posição neutra, rotação lateral a 45º e rotação medial a 15 e 30º de quadril. Materiais e Método: Foram avaliadas 27 mulheres, sendo 15 mulheres normais do grupo Controle (21,1±2,1 anos) e 12 portadoras de Síndrome da Dor Femoropatelar (SDFP) (21,0±2,3 anos). A atividade elétrica do músculo quadríceps foi captada por eletrodos ativos diferenciais simples de superfície, eletromiógrafo de 8 canais e programa Aqdados 7.2.6. Os dados foram normalizados pela porcentagem da média do agachamento a 75º com o quadril em posição neutra-RMS (μV). A análise estatística utilizada foi a ANOVA two way com medidas repetidas e Turkey post hoc (p≤0,05). Resultados: Os resultados evidenciaram interação entre grupos e músculos (p=0,00), independente da posição do quadril (p=0,39) e não houve interação entre grupos e posições do quadril (p=0,96). Os músculos VMO e VLL do grupo SDFP apresentaram atividade elétrica significativamente maior que o VMO (p=0,00) e VLL (p=0,04) do grupo controle. Por outro lado, a atividade elétrica do músculo VLO não apresentou diferença significativa entre os grupos (p=0,99). Conclusão: Os resultados dessa pesquisa, nas condições experimentais utilizadas, sugerem que a rotação do quadril não influenciou a atividade elétrica das porções do quadríceps nos dois grupos no agachamento a 45º de flexão do joelho.

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