Oxygen uptake, respiratory exchange ratio, or total distance: a comparison of methods to equalize exercise volume in Wistar rats

This study compared strategies to equalize the volume of aerobic exercise performed with different intensities by Wistar rats, based on the distance covered during exercise bouts and energy expenditure (EE, isocaloric sessions) obtained from oxygen uptake (V̇O2) or respiratory exchange ratio (RER). Thirty-three male rats (270.5±12.8 g) underwent maximal exercise tests to determine V̇O2 reserve (V̇O2R), being randomly assigned to three groups: moderate-intensity continuous exercise at speed corresponding to 50% V̇O2R (MIC; n=11); high-intensity continuous exercise at 80% V̇O2R (HIC; n=11); and high-intensity intermittent exercise (HII; n=11) at 60% V̇O2R (3 min) and 80% V̇O2R (4 min). Exercise duration was calculated individually to elicit EE of 5 kcal in each session. No difference between groups was found for total running distance (MIC: 801±46, HIC: 734±42, HII: 885±64 m; P=0.13). Total EE measured by RER was systematically underestimated compared to values obtained from V̇O2 (HII: 4.5% and MIC: 6.2%, P<0.05). Total EE (calculated from V̇O2), and duration of HIC bouts (2.8 kcal and 30.8±2.2 min) were lower (P<0.0001) than in MIC (4.9 kcal and 64.7±1.8 min) and HII (4.7 kcal and 46.9±2.2 min). Predicted and actual values of total V̇O2, total EE, and duration of isocaloric sessions were similar in MIC and HII (P>0.05), which were both higher than in HIC (P<0.0001). In conclusion, the time to achieve a given EE in exercise bouts with different intensities did not correspond to the total distance. Therefore, the volume of aerobic exercise in protocols involving Wistar rats should be equalized using EE rather than total covered distance.

Influence of exercise modality on agreement between gas exchange and heart rate variability thresholds

The main purpose of this study was to investigate the level of agreement between the gas exchange threshold (GET) and heart rate variability threshold (HRVT) during maximal cardiopulmonary exercise testing (CPET) using three different exercise modalities. A further aim was to establish whether there was a 1:1 relationship between the percentage heart rate reserve (%HRR) and percentage oxygen uptake reserve ( % V ˙ O 2  R ) at intensities corresponding to GET and HRVT. Sixteen apparently healthy men 17 to 28 years of age performed three maximal CPETs (cycling, walking, and running). Mean heart rate and V ˙ O 2 at GET and HRVT were 16 bpm (P<0.001) and 5.2 mL·kg-1·min-1 (P=0.001) higher in running than cycling, but no significant differences were observed between running and walking, or cycling and walking (P>0.05). There was a strong relationship between GET and HRVT, with R2 ranging from 0.69 to 0.90. A 1:1 relationship between %HRR and % V ˙ O 2  R was not observed at GET and HRVT. The %HRR was higher during cycling (GET mean difference=7%; HRVT mean difference=11%; both P<0.001), walking (GET mean difference=13%; HRVT mean difference=13%; both P<0.001), or running (GET mean difference=11%; HRVT mean difference=10%; both P<0.001). Therefore, using HRVT to prescribe aerobic exercise intensity appears to be valid. However, to assume a 1:1 relationship between %HRR and % V ˙ O 2  R at HRVT would probably result in overestimation of the energy expenditure during the bout of exercise.

Identification of sarcopenic obesity in postmenopausal women: a cutoff proposal

Sarcopenic obesity is the combination of reduced fat-free mass (FFM) and increased fat mass (FM) with advancing age but there is lack of clear criteria for its identification. The purposes of the present investigation were: 1) to determine the prevalence of postmenopausal women with reduced FFM relative to their FM and height, and 2) to examine whether there are associations between the proposed classification and health-related variables. A total of 607 women were included in this cross-sectional study and were separated into two subsets: 258 older women with a mean age of 66.8 ± 5.6 years and 349 young women aged 18-40 years (mean age, 29.0 ± 7.5 years). All volunteers underwent body composition assessment by dual-energy X-ray absorptiometry. The FFM index relative to FM and height was calculated and the cutoff value corresponded to two standard deviations below the mean of the young reference group. To examine the clinical significance of the classification, all older participants underwent measurements of quadriceps strength and cardiorespiratory fitness. Values were compared between those who were classified as low FFM or not, using an independent samples t-test and correlations were examined. The cutoff corresponded to a residual of -3.4 and generated a sarcopenic obesity prevalence of 19.8 percent that was associated with reduced muscle strength and aerobic fitness among the older participants. Also, the index correlated significantly with the health-related fitness variables. The results demonstrated reduced functional capacity for those below the proposed cutoff and suggested applicability of the approach as a definition for sarcopenic obesity.

Correlação entre flexibilidade das articulações glenoumerais e coxofemorais e o desempenho funcional de idosas fisicamente ativas / Association between flexibility of the glenohumeral and hip joints and functional performance in active elderly women

OBJETIVO: Investigar a relação entre a flexibilidade da flexão e extensão das articulações glenoumerais (GU) e coxofemorais (CF) e o desempenho funcional (DF) de idosas funcionalmente independentes e fisicamente ativas. MÉTODOS: Determinou-se em 22 voluntárias (idade=70±6 anos) seis conjuntos de amplitudes de movimentos por goniometria ativo-assistida (ADM) na flexão e extensão das GU e CF. O DF foi determinado pelos testes: velocidade de caminhada habitual (VCH) e máxima (VCM); levantar e sentar em cadeira (LSC); Timed up and Go Test (TUGT); vestir blusa (VBL); subir degraus (SE); levantar do decúbito dorsal (LDD); pegar moeda no solo (PMS); teste de caminhada de seis minutos (TC6M). As associações entre as variáveis ADM e o DF foram testadas por técnicas de correlação simples e múltipla. RESULTADOS: Houve correlações significantes (p<0,05) entre as ADM de CF e os testes LSC (r=0,42 e r=0,45), SE (r=0,52 e r=0,53) e TC6M (r=0,58 e r=0,59) (lados direito e esquerdo, respectivamente). A correlação múltipla ratificou esses resultados (r²=0,51; p<0,05), indicando que 51 por cento da variância nos testes deveu-se à ADM de CF. Não houve associações significantes entre as ADMs de GU e os testes de DF. CONCLUSÕES: Verificou-se associação significante entre a flexibilidade ativo-assistida de CF e alguns testes específicos de DF. Nenhuma relação foi identificada para ADM de GU. Estudos adicionais são necessários para elucidar as relações entre flexibilidade passiva de diferentes grupos articulares e a funcionalidade de idosos.

OBJECTIVE: To investigate the relationship between flexibility of flexion and extension of the glenohumeral and coxofemoral joints and functional performance among physically active and functionally independent elderly women. METHODS: Six sets of range of motion (ROM) measurements relating to flexion and extension of the glenohumeral and coxofemoral joints were determined in 22 volunteers (age 70±6 years), using assisted-active goniometry. Functional performance was measured using the following tests: normal walking speed (NWS); maximum walking speed (MWS); sit-to-stand test (SST); timed up and go test (TUGT); putting on a blouse (PBL); going up stairs (GUS); rising from dorsal decubitus (RDD); picking up a coin from the floor (PCF); and 6-minute walk test (6WT). The relationships between the ROM variables and functional performance were tested using simple and multiple regression techniques. RESULTS: There were significant correlations (p<0.05) between coxofemoral ROM and the SST (r=0.42 and r=0.45), GUS (r=0.52 and r=0.53) and 6WT (r=0.58 and r=0.59) (right and left sides, respectively). The multiple regression ratified the results (r²=0.51; p<0.05), thus indicating that coxofemoral ROM accounted for 51 percent of the variance in the tests. There were no significant correlations between the glenohumeral ROMs and the functional performance tests. CONCLUSIONS: There was a significant association between assisted-active flexibility of the coxofemoral joint and some specific functional performance tests. No relationship involving glenohumeral ROM was identified. Additional studies are needed in order to elucidate the relationships between passive flexibility of different joint groups and functional performance in elderly people.

Efeitos de um programa de treinamento resistido com volume e intensidade moderados e velocidade elevada sobre o desempenho funcional de mulheres idosas / Effects of a programme of resistance training with volume and intensity moderates and high speed on functional performance of old women

A tensão muscular pode ser influenciada pela velocidade de movimento, sendo um componente importante da prescrição do treinamento da força em idosos. Esse estudo observou os efeitos de 12 semanas de treinamento resistido (TR), realizado com intensidade e volume moderados e velocidade elevada, porém não explosiva, sobre a força/potência muscular (FM) e o desempenho funcional (DF). Para tal, 24 idosas (68,7±9 anos) fisicamente ativas, foram igualmente distribuídas em grupos controle (GCO) e experimental (GEX). O GEX realizou, 2 X por semana durante 12 semanas, de série única de 10 a 15 repetições de exercícios com intensidade relativa de 50 a 70% de 1RM e fase concêntrica das contrações fixada em menos de 1 seg. O grupo controle não praticou exercícios de força. A FM foi aferida pelo teste de 1RM nos exercícios leg press horizontal (LPH) e flexão dos joelhos na cadeira (CF). Mediu-se o DF através do tempo para realizar as seguintes tarefas: a) caminhada de 10 metros (C10); b) levantar da posição ajoelhada (LPA); c) levantar e sentar de uma cadeira (LSC). Não havia diferenças entre os grupos na linha de base. Ao fim da intervenção, a ANOVA de duas entradas para medidas repetidas seguida da verificação post-hoc de Fisher (p<0,05), demonstrou não haver diferenças significativas para GCO. No GEX foram observados incrementos significativos em todos as medidas de FM (LPH, p<0,0001; CF, p<0,0001) e DF (CAM10, p<0,0001; LSC, p=0,004; LPA, p=0,005). Conclui-se que idosas fisicamente ativas podem ter melhoria significativa de FM e DF em decorrência de TR realizado com intensidade e volume moderados e velocidade elevada.

It has been suggested that lower extremity muscle power and strength are important for physical function in older adults. However, the majority of studies investigating the effects of training on muscle power are based on isokinetic exercises and few studies have determined the effects of isoinertial resistance training (RT) on muscle power and strength and functional performance in older adults. The purpose of the present study was to evaluate the effects of a 12 weeks RT in muscle strength and functional performance in healthy, active, older women. Twentyfour independent and active older women (aged 60-85 years) were assigned either to a control group (CG, n=12), or to a RT group (RTG, n=12). The RTG trained 10 exercises for whole body with one set of 10-15 repetitions at 50 to 70% of 1-repetition maximum (1-RM) released with high-velocity (concentric phase ≤1sec), 2 days per week for 12 weeks. The CG did not perform strength exercises. Both groups were evaluated in 1-RM lower body strength in horizontal leg press (HLP) and knee flexion (KF), maximal walking speed (MWS); kneel rise time (KRT); fivetimes-sit-to-stand test (FTSST) before and after the training period. There was no significant difference between groups in base-line (p<.05). After the 12 weeks, the 2-way ANOVA showed inter and intragroups significant differences (p<.05). RTG significantly increased the results for all 1RM tests: HLP (p<.0001); KF (p<.0001) and physical performance: MWS (p<.0001); KRT (p=.005); FTSST (p=.004). In conclusion, strength training of moderate volume/intensity and high-velocity can promote gains in tasks related with lower extremity muscle power in elder women.