Progression of Gait Changes in Older Adults With Mild Cognitive Impairment: A Systematic Review.

BACKGROUND AND PURPOSE: The identification of altered gait and its progression over time is important to gaining a better understanding of the clinical aspects of mild cognitive impairment (MCI) in older adults. The aim of the present systematic review was to determine changes in gait variables over time among older adults with MCI. METHODS: The PubMed, Web of Science, Scopus, and Science Direct databases were searched for relevant articles using the following keywords and Medical Subject Headings: Aged AND "Mild cognitive impairment" AND (gait OR locomotion). A hand search was also performed of the reference lists of the selected articles in an attempt to find additional records. The following were the inclusion criteria: longitudinal studies and clinical trials involving a control group without intervention; samples of individuals 65 years or older; and characterization of gait using a single or dual task. RESULTS AND DISCUSSION: The initial search led to the retrieval of 6979 studies, 9 of which met the inclusion criteria. The duration of follow-up among the studies ranged from 6 months to 2 years. Most trials investigated gait speed. Other gait variables were step length, time required to walk a given distance, and mean weekly gait speed. Altered gait progressed in older adults with MCI. The main alterations were gait speed and variability in daily number of steps in follow-up periods lasting more than 1 year. No significant changes in gait variables were found in shorter follow-up periods (up to 6 months). CONCLUSIONS: The progression of gait changes in older adults with MCI has been underinvestigated. MCI leads to reduced gait speed in longer follow-up periods. Such information can contribute to the determination of motor interventions for older adults with MCI, especially in the early stages.

Complexity of Knee Extensor Torque: Effect of Aging and Contraction Intensity.

ABSTRACT: 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.

Complexity of knee extensor torque in patients with frailty syndrome: a cross-sectional study.

BACKGROUND: Frailty syndrome is characterized by a marked reduction in physiological reserves and a clinical state of vulnerability to stress. Torque complexity analysis could reveal changes in the musculoskeletal systems that are the result of having the syndrome. OBJECTIVE: The aim of this study was to evaluate the complexity of submaximal isometric knee extensor torque in frail, pre-frail, and non-frail older adults. A secondary aim was to analyze the torque complexity behavior in different force levels in each group. METHODS: A cross-sectional study was conducted. Forty-two older adults were divided into three groups: non-frail (n=15), pre-frail (n=15), and frail (n=12). The data collected included body composition, five times sit-to-stand test, walking speed, and isometric knee extensor torque at 15, 30, and 40% of maximal voluntary contraction. The knee extensor torque variability was evaluated by coefficient of variation, and the torque complexity was evaluated by approximate entropy and sample entropy. RESULTS: The frail group presented a reduction in body mass and peak torque value compared to the non-frail group. Also, the frail group showed worse physical performance (on the five times sit-to-stand test and walking speed) compared to the pre-frail and non-frail groups. In addition, the frail older adults showed reduced torque complexity compared to the non-frail group. Finally, the association between torque complexity and force levels remained similar in all groups. CONCLUSION: Torque complexity is reduced in the presence of frailty syndrome.

Exercise training in older adults, what effects on muscle force control? A systematic review of randomized clinical trials.

AIM: To determine the magnitude of the effects of different exercise training (ET) modalities on variables of muscle force control in older adults. METHODS: Relevant articles were searched in PubMed, Web of Science, Science Direct and Scopus, using the keywords: Aged AND "Exercise Movement Techniques" AND ("Complexity of torque" OR "Complexity of force" OR "Variability of torque" OR "Variability of force" OR "Force Steadiness" OR "Force fluctuations"). To be included in the full analysis, the studies had to be randomized controlled trials in which older adults were submitted to ET programs and muscle force control assessment. RESULTS: The searches resulted in 702 articles from which 6 met all the inclusion criteria. The trials involved 171 healthy and functionally limited older adults (71.64 ± 1.53 years). Studies included resistance, steadiness and functional training programs. Training sessions were 2-3 time per week, lasted 6-16 months with intensities determined as percentage of the one repetition maximum loads. There is a heterogeneity regarding experimental set-up and data analysis parameters between studies. The findings show an improved muscle force control in older adults after ET. Such response is better evidenced by the assessment of the coefficient of variation (CV) of the force signals. There is moderate evidence that resistance training programs are effective to decrease CV of knee extensor force signals at lower force targets. CONCLUSIONS: The findings from this review suggest that ET programs are effective to improve muscle force control in older adults.

Pre-Frail Multicomponent Training Intervention project for complexity of biological signals, functional capacity and cognition improvement in pre-frail older adults: A blinded randomized controlled study protocol.

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.

Water exercise in coronary artery disease patients, effects on heart rate variability, and body composition: A randomized controlled trial.

BACKGROUND AND PURPOSE: It is important to assess the effectiveness and efficiency of water-based training programs in order to prescribe it as an alternative in cardiac rehabilitation for patients who have coronary artery disease (CAD). In these patients, autonomic dysfunction is an important physiological change strongly associated with adverse outcomes, morbidity, and mortality. Given that the beneficial effects of physical training in CAD patients have been traditionally evidenced with programs involving land-based aerobic exercises, this study aims to evaluate the effects of water aerobic exercise training (WAET) on the autonomic modulation of heart rate (HR) and body composition, in the rehabilitation of CAD patients. METHODS: Twenty-six male subjects with CAD were randomly divided into a training group (n = 14), submitted to the WAET, and a control group (n = 12). The WAET consisted of 3 weekly sessions on alternate days, totalling 48 sessions. The analysis of HR variability was used to evaluate the autonomic modulation of HR, from the recording of R-R intervals for 15 min, at rest in the supine position, and the body composition was evaluated through the bioelectrical impedance analysis. RESULTS: Only the training group participants had improvement in the HR variability indices; patterns without variation decreased (0V, p = .005) and an increase of patterns of two different variations (p < .001), Shannon entropy (p = .02), and normalized conditional entropy (p = .03), whereas the control group had an increase of 0V (p = .04) and a decrease of normalized conditional entropy (p = .01). All body composition variables remained unchanged. CONCLUSIONS: The WAET protocol improved the cardiac autonomic modulation of patients with CAD and can be considered as exercise training strategy in cardiac rehabilitation programs.

Exercise training in older adults, what effects on muscle oxygenation? A systematic review.

AIM: To determine the effects of different modality of exercise training programs on muscle oxygenation in older adults. METHODS: Relevant articles were searched in PubMed, Web of Science, Science Direct and Scopus, using the keywords: "Aged" AND "Muscle oxygenation" AND (Exercise OR "Exercise therapy" OR "Exercise Movement Techniques" OR Hydrotherapy), without limitation concerning the publication date. To be included in the full analysis, the study had to be a randomized controlled trial in which older adults participants (mean age: 65 years at least) were submitted to an exercise-training program and muscle oxygenation assessment. RESULTS: The searches resulted in 1238 articles from which 7 met all the inclusion criteria. The trials involved 370 older adults (68.7±1.7years), healthy and with peripheral arterial disease. Studies included resistance and endurance exercises as well as walking sessions. Training sessions were 2-6 time per week, lasted 3-24 months and with different training intensity throughout studies. After a long-term resistance training, healthy older adults showed enhanced muscle oxygen extraction capacity, regulation of vessels and vascular endothelium function; endurance training is reported to improve microvascular blood flow and matching of oxygen delivery to oxygen utilization, muscle oxidative capacity and muscle saturation, and walking sessions results in better muscle oxygen availability and muscle oxygen extraction capacity in older adults with peripheral arterial disease. CONCLUSIONS: This review supports the fact that depending on the clinical status of the participants and the modality, exercise training improves different aspects of the muscle oxygenation in older adults.

Função autonômica cardíaca e nível de atividade física de pacientes com doença arterial coronariana / Cardiac autonomic function and level of physical activity in patients with coronary artery disease

O objetivo deste estudo foi verificar a relação entre modulação autonômica da frequência cardíaca (FC) e nível da atividade física habitual (AFH) em pacientes com doença arterial coronariana (DAC). Estudo transversal, amostra de 26 homens (59,6±4,2 anos), com tempo de 16±3 meses de diagnóstico da doença, divididos em dois grupos: usuários (GB, n=12) e não usuários de betabloqueadores (GSB, n=14). Para avaliar a modulação autonômica foi utilizada a variabilidade da frequência cardíaca (VFC) pelo registro dos intervalos R-R durante 15 minutos na condição de repouso na postura supina. Para avaliar o nível de AFH foi utilizado o questionário de Baecke. O escore total da AFH apresentou correlação positiva com os índices da VFC, para o GB e GSB, respectivamente: raiz quadrada da média dos quadrados das diferenças entre intervalos R-R normais adjacentes (r=0,499; P=0,039 e r=0,612; P=0,010), poder da banda de alta frequência (r=0,675; P=0,008 e r=0,470; P=0,045), entropia de Shannon (r=0,594; P=0,021 e r=0,453; P=0,042), entropia condicional normalizada (r=0,805; P=0,001 e r=0,559; P=0,019) e padrões de duas variações diferentes (r=0,872; P<0,001 e r=0,630; P=0,008); e correlação negativa com os índices: poder da banda de baixa frequência (r=-0,675; P=0,008 e r=-0,470; P=0,045), razão baixa/alta frequência (r=-0,675; P=0,008 e r=-0,466; P=0,047) e padrões sem variação (r=-0,782; P=0,001 e r=-0,684; P=0,004). Em pacientes com DAC, o maior nível de AFH está associado a maior modulação parassimpática e menor modulação simpática para o coração em repouso, sugerindo que níveis mais elevados de atividade física relacionam-se a melhor modulação autonômica cardiovascular nesta população.

The aim of this study was to investigate the relation between the autonomic modulation of heart rate (HR) and the level of habitual physical activity (HPA) in patients with coronary artery disease (CAD). This is a cross-sectional study with a sample of 26 men (age 59.6 ± 4.2) with CAD diagnosed for a mean time of 16±3 months, divided into two groups, users (GB, n=12) and non-users of beta-blockers (GSB, n=14). To evaluate the autonomic modulation, the analysis of heart rate variability (HRV) was performed from the registration of rest RR intervals for 15 minutes in the supine posture. Baecke questionnaire was applied to verify the level of HPA. The HPA total score correlated positively with indices of HRV respectively for GB and GSB: square root of the mean squared differences of successive normal RR intervals (r=0.499; P=0.039 and r=0.612; P=0.010), power of high frequency component (r=0.675; P=0.008 and r=0.470; P=0.045), Shannon entropy (r=0.594; P=0.021 and r=0.453; P=0.042) and normalized conditional entropy (r=0.805; P=0.001 and r=0.559; P=0.019), patterns of two different variations (r=0.872; P<0.001 and r=0.630; P=0.008), and correlated negatively with power of low frequency component (r=-0.675; P=0.008 and r=-0.470; P=0.045), low/high frequency ratio (r=-0.675; P=0.008 and r=-0.466; P=0.047) and no variation pattern (r=-0.782; P=0.001 and r=-0.684; P=0.004). In patients with CAD, high level of HPA was related to increased parasympathetic and reduced sympathetic modulation to the heart at rest, suggesting that higher levels of physical activity are related to better cardiovascular autonomic modulation in this population.