RESUMO
The present study was conducted to provide normative values for lower-limb muscle power estimated through equations based on the 5 times sit-to-stand (5STS) test in Brazilian older women. In addition, we investigated the association between muscle power parameters and age. The study followed a cross-sectional design. Participants were community-dwelling women. Candidates were considered eligible if they were 18 years or older, lived independently, and possessed sufficient physical and cognitive abilities to perform all measurements required by the protocol. The 5STS test was performed as fast as possible using a standard protocol. Absolute, relative, and allometric muscle power measures were estimated using 5STS-based equations. Two thousand four-hundred seventy-one women participated in the present study. Results indicated that muscle power-related parameters decreased linearly with age. Women 60-69 years showed a marginal reduction in absolute (- 5.2%), relative (- 7.9%), and allometric (- 4.0%) muscle power. A larger reduction was observed in those 70-79 years and reached » of loss in participants ≥ 80, in comparison to middle-aged participants. Pearson's correlation and linear regression analyses indicated that power-related parameters were negatively associated with age. In conclusion, data of the present study provide normative values for lower-limb muscle power parameters according to 5STS-based equations. We observed that muscle power-related parameters declined with age, such that participants 60-69, 70-79, and ≥ 80 years displayed lower absolute and relative muscle power compared middle-aged women. A later decline was observed in allometric muscle power. Relative muscle power declined to a greater extent than other parameters, suggesting a possible window of opportunity for interventions.
Assuntos
Extremidade Inferior , Músculos , Pessoa de Meia-Idade , Humanos , Feminino , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Brasil , Vida Independente , Força Muscular/fisiologia , Músculo Esquelético/fisiologiaRESUMO
BACKGROUND: Self-assessed health status (SAHS) and physical performance measures (in particular, walking speed) are strong predictors of health-related events. Nevertheless, the possible interaction between them in predicting major outcomes has not been clearly explored. OBJECTIVE: The aim of the study is to evaluate the predictive and additive value for mortality of a SAHS measure and a walking speed test. METHODS: Data are from 2,139 Mexican-Americans aged >or=65 years enrolled in the Hispanic Established Populations for Epidemiologic Studies of the Elderly, and followed for 5.8 years. At the baseline visit, participants were asked to answer to the question 'How is your health in general?' presented as a four-level Likert item (i.e., poor, fair, good, excellent). They were also asked to 'walk down and back as fast as it felt safe and comfortable' along an 8-ft track. Cox proportional hazard models, receiver operating characteristic (ROC) curve, and specificity/sensitivity analyses were performed to evaluate the predictive value of SAHS and walking speed for mortality. RESULTS: The mean age of the sample was 72.1 years. Participants reporting 'poor' SAHS were more likely to die compared to those with 'excellent' SAHS, even after adjustment for potential confounders (HR 1.52, 95% CI 1.10-2.10). Similar results were obtained for participants with slow walking speed (<0.29 m/s; HR 1.68, 95% CI 1.27-2.24; reference group: walking speed >or=0.81 m/s). A statistically significant, but weak, correlation between SAHS and walking speed was observed (Pearson's r=0.069, p=0.001). No significant differences in areas under curves from ROC analyses were reported for the prediction of mortality when the SAHS and walking speed were tested (alone or in combination). Both tests presented high specificity (>or=80%) for the prediction of mortality. CONCLUSION: SAHS and walking speed are not only significant and independent predictors of mortality in older Mexican-Americans, but also present a similar predictive value. The additive prognostic value of the two measures is limited.