The aim of this study was to investigate the effects of multicomponent training on baroreflex sensitivity (BRS) and heart rate (HR) complexity of prefrail older adults. Twenty-one prefrail community-dwelling older adults were randomized and divided into multicomponent training intervention group (MulTI) and control group (CG). MulTI performed multicomponent exercise training over 16 weeks and CG was oriented to follow their own daily activities. The RR interval (RRi) and blood pressure (BP) series were recorded for 15 min in supine and 15 min in orthostatic positions, and calculation of BRS (phase, coherence, and gain) and HR complexity (sample entropy) were performed. A linear mixed model was applied for group, assessments, and their interaction effects in supine position. The same test was used to assess the active postural maneuver and it was applied separately to each group considering assessments (baseline and post-intervention) and positions (supine and orthostatic). The significance level established was 5%. Cardiovascular control was impaired in prefrail older adults in supine position. Significant interactions were not observed between groups or assessments in terms of cardiovascular parameters. A 16-week multicomponent exercise training did not improve HR complexity or BRS in supine rest or in active postural maneuver in prefrail older adults.

Frailty is related to a decrease in the physiological reserves, which causes difficulties in maintaining homeostasis. An example of physiological mechanisms for cardiovascular homeostasis is the baroreflex. The aim of this study was to compare baroreflex among frail, prefrail, and nonfrail individuals, in supine and orthostatic positions. Community-dwelling older adults were evaluated and categorized into frail, prefrail, or nonfrail groups, according to frailty phenotype. The RR interval (RRi) and systolic blood pressure (SBP) series were recorded for 15 min in the supine and 15 min in the orthostatic positions. Mean and variance of RRi and SBP, and baroreflex evaluated by phase, gain (α), and coherence (K2) were determined. A two-way repeated measures ANOVA, with Tukey's post hoc, was applied for group, position, and their interaction effects. The significance level established was 5%. Prefrail and frail participants did not present a significant decrease in mean values of RRi after postural challenge (893.43 to 834.20 ms and 925.99 to 857.98 ms, respectively). Frail participants showed a reduction in RRi variance in supine to orthostatic (852.04 to 232.37 ms2). Prefrail and frail participants showed a decrease in K2 after postural change (0.69 to 0.52 and 0.54 to 0.34, respectively). Frail participants exhibited lower values of K2 (0.34) compared to nonfrail and prefrail participants (0.61 and 0.52, respectively). Baroreflex indicated the presence of decoupling between heart period and SBP in frail and prefrail. Thus, reduced K2 might be a marker of the frailty process.

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.

Objective: The purpose of this study was to evaluate the effect of hip rotation on the electrical activity of the Vastus Medialis Obliquus (VMO), Vastus Lateralis Obliquus (VLO) and Vastus Lateralis Longus (VLL) muscles when squatting with 45º knee flexion, in association with the neutral position, 45º lateral rotation and 15 and 30º medial hip rotation. Method: 27 women were evaluated: 15 healthy women as a control group (21.1 ± 2.1 years) and 12 subjects with patellofemoral pain syndrome (PFPS) (21.0 ± 2.3 years). The electrical activity of the quadriceps muscle was detected using simple active differential surface electrodes, an eight-channel electromyography system and the Aqdados 7.2.6 software. The data were normalized by the mean squatting percentage at 75º with the hip in the neutral position RMS (µV). Two-way ANOVA with repeated measurements followed by the Tukey post hoc test (p<0.05) was used for statistical analysis. Results: The results revealed interaction between groups and muscles (p=0.00), independent of hip position (p=0.39), and there was no interaction between groups and hip positions (p=0.96). The VMO and VLL muscles of the PFPS group showed significantly greater electrical activity than did VMO (p=0.00) and VLL (p=0.04) muscles from the control group. On the other hand, the electrical activity of the VLO muscle did not present any significant difference between the groups (p=0.99). Conclusion: Under the experimental conditions utilized, the results suggested that hip rotation did not alter the electrical activity of the quadriceps portions in either group when squatting with 45º knee flexion.