Muscle power predicts frailty status over four years: A retrospective cohort study of the National Health and Aging Trends Study.

Objectives: Muscle power is a critical measure of physical capacity in older adults, however the association between muscle power and frailty is not well explored. The purpose of this study is to estimate the association between muscle power and frailty in community-dwelling older adults in the National Health and Aging Trends Study from 2011-2015. Methods: Cross-sectional and prospective analyses were performed on 4,803 community-dwelling older adults. Mean muscle power was calculated using the five-time sit-to-stand test, height, weight, and chair height and dichotomized into high-watt and low-watt groups. Frailty was defined using the five Fried criteria. Results: The low watt-group had higher odds of pre-frailty and frailty at baseline year 2011. In prospective analyses, the low-watt group that was pre-frail at baseline had increased hazards of frailty (AHR 1.62, 95% CI 1.31, 1.99) and decreased hazards of non-frailty (AHR 0.71, 95% CI 0.59, 0.86). The low-watt group that was non-frail at baseline had increased hazards of pre-frailty (1.24, 95% CI 1.04, 1.47) and frailty (1.70, 1.07, 2.70). Conclusions: Lower muscle power is associated with higher odds of pre-frailty and frailty and increased hazards of becoming frail or pre-frail over four years in those who are pre-frail or non-frail at baseline.

Identification of three movement phases of the hand during lateral and pulp pinches using video motion capture.

BACKGROUND: Hand injuries affect a person's ability to engage successfully in activities of daily living (ADLs). Video motion capture (VMC) facilitates measurement of dynamic movement. No study to date has used VMC as a means of quantifying the simultaneous movement patterns of all joints of all digits of the hand during active purposeful movement. METHOD: The purpose of this study was to analyze all joints of all five digits during active completion of the lateral and pulp pinches. VMC data were collected from four participants during completion of two pinches. Joint angles were plotted to facilitate identification of movement patterns. RESULTS: Range of motion recorded in all joints with VMC, excluding flexion of the thumb carpometacarpal of both pinches, coincided with the normative goniometric data. Three phases were observed: initiation, preshaping, and pinch phases. Patterns of movement in all digits were identified for the two pinches. CONCLUSION: VMC is a feasible and valid method for objectively quantifying dynamic movement of multiple joints simultaneously. The results provide new insight to the dynamics of hand movement as well as a basis for subsequent evaluations of movement patterns performed in ADLs and instrumental ADLs.