B. Lockmer, A. Ewing, C. Papadopoulos

Pacific Lutheran University, Tacoma, WA

Accelerometers offer detailed minute-by-minute information over extended periods pertaining to physical activity behavior. According to accelerometer data, less than 5% of older adults (>65 yr) meet physical activity guidelines making them the least active age group. Accelerometers are typically placed on the right hip. However, accelerometers only placed on the hip may not accurately determine exercise intensity during an entire workout in this population. PURPOSE: To examine energy expenditure and intensity levels during exercise classes for older adults as determined by accelerometers placed on the hip and wrist. METHODS: Twenty-five older adults (age: 76.4 ± 8.8 yrs, weight: 73.2 ± 18.1 kg, height: 1.63 ± 0.1 m) volunteered. All individuals participated in an exercise class that included periods of cardiovascular, strength, and balance exercises. Participants wore an accelerometer placed on the right hip (H) and an accelerometer placed on the right wrist (W). Accelerometer data were downloaded using 60 second epochs and low frequency extension. In order to quantify exercise intensity, cut points (cpm) of sedentary (≤ 100 cpm), light (101-799 cpm), and moderate (800-5722 cpm) intensity were used. A two-tailed independent t test was used to examine differences between H and W in energy expenditure (Kcals) and amount of time spent in sedentary, light, and moderate exercise intensity. Statistical significance was set at p < 0.05. RESULTS: The average time spent in light exercise intensity was 19.1 ± 4.5 and 7.4 ± 2.1 minutes for the H and W accelerometers, respectively. There was a significant (p < 0.01) difference between the two accelerometers for light intensity. The average time spent in moderate intensity activity was 11.4 ± 6.1 and 35.0 ± 4.2 minutes for the H and W accelerometers, respectively. There was a significant (p < 0.01) difference between the accelerometers for moderate exercise intensity. According to the accelerometers placed on the hip, the average amount of Kcals utilized was 37.0 ± 20.1 whereas the average estimated energy expenditure by the wrist accelerometers was 138.1 ± 68.7 Kcals. There was a significant (p < 0.01) difference in energy expenditure estimation between the two devices. CONCLUSION: The data suggests that in order to fully comprehend the intensity of an exercise class for older adults, accelerometers must be worn on both the hip and the wrist. Due to the increased times in each intensity and also the increased amount of calories utilized that were recorded by the wrist accelerometer, the data suggests that these exercise classes had more upper body and arm movements as compared to lower body movements.

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