Accelerometer-Determined Intensity and Duration of Habitual Physical Activity and Walking Performance in Well-Functioning Middle-Aged and Older Women: A Cross-Sectional Study.

ABSTRACT

BACKGROUND: The association of physical activity (PA) intensities and duration spent in those activities with different walking tasks remains unclear. OBJECTIVES: To examine the association between the duration of PA intensities and three walking speeds (usual walking speed, maximal walking speed and zig-zag walking speed). DESIGN: Multiple linear regression analysis was used to estimate the association of age, BMI, maximum knee extension strength, light PA, moderate PA and vigorous PA with walking speeds. SETTING: University lab. PARTICIPANTS: Eighty-six older women (67 ± 7 years). MEASUREMENTS PA was measured for 30 consecutive days using the Lifecorder-EX accelerometer. Exercise intensity was categorized as light (levels 1-3), moderate (levels 4-6) and vigorous (levels 7-9) based on the manufacturer algorithms. Usual straight walking speed (20 m), maximal straight walking speed (20 m) and zig-zag walking speed tests (10 m) were performed by each participant. RESULTS: For the usual straight walking speed model (R2 = 0.296, SEE = 0.15 m/s), the significant predictors were BMI, knee extension strength, light PA and vigorous PA. For the maximal straight walking speed model (R2 = 0.326, SEE = 0.20 m/s), only age was a significant predictor. For the zig-zag walking speed model (R2=0.417, SEE = 0.14 m/s), age and maximum knee strength were significant predictors in the model. CONCLUSIONS: Overall, the results of this study suggest that vigorous PA and maximal knee extension strength are two important factors that are associated with different walking speeds in older women.