Leg extensor power, cognition, and functional performance in independent and marginally dependent older adults.

BACKGROUND physical and cognitive function must be integrated and optimised in performance of daily activities. Age-related loss of physical function can result in poor performance of necessary daily activities and possibly lead to increased dependency and a change of living status. OBJECTIVES (1) to evaluate average differences in physiological, cognitive, and functional performance of older adults from two different levels of independence, (2) to examine contributions of leg power, cognition, and functional performance to level of independence. DESIGN cross-sectional study of self-reported 'independent' versus 'marginally dependent' older adults. SUBJECTS 35 older adults (77.2 +/- 6 years) were placed into independent (n = 18) or marginally dependent (n = 17) groups based upon the Medical Outcomes Study SF36 physical function scores (independent: SF36PF > or = 85, marginally dependent: SF36PF < 85) and living status. METHODS assessment of physical function includes the dependent variable, SF36PF. Assessment of physical, cognitive, and functional performance include the independent variables of leg extensor power, reaction time, processing speed, memory, attention, and functional performance. Functional performance is assessed by the Continuous Scale Physical Functional Performance Test. RESULTS independent older adults have greater performance on leg power, reaction time, processing speed, memory, and functional performance than marginally dependent older adults. Functional performance is an independent predictor of level of independence. Leg power and cognition were separate small but significant predictors of independence. CONCLUSIONS independent older adults have greater physiological, cognitive and functional performance than marginally dependent older adults. Individuals with greater functional performance tend to remain independent.