Submitted to the 2008 Annual Meeting of the American College of Sports Medicine for presentation

Physical Activity Monitor Recordings are Task and Population Dependent

Megan M. Duet, Daniel P. Heil, FACSM, Corey L. Black, Li Li, FACSM, Jan M. Hondzinski

Louisiana State University, Baton Rouge, LA

Montana State University, Bozeman, MT

Activity monitors are commonly placed on the waist. The waist’s’ proximity to the body’s center of mass has made it a good predictor of physical activity and energy expenditure in healthy people during whole body movement. It is unclear whether a similar prediction exists for populations with extremely low levels of physical activity. For example, people with peripheral neuropathy (PN) greatly reduce their daily activity because of pain, burning sensations or numbness induced movement impairments. Therefore, placement of activity monitors on the waist may not be appropriate to estimate physical activity/ energy expenditure in this population. Purpose: To compare the activity in people with PN. using accelerometry-based activity monitors (AM) to observe differences due to monitor placements. Methods: Five men (Mean±SD: 71±17 yrs, 85.6±10.3 kg, 28.6±3.2 kg/m² BMI) and 12 women (72±6 yrs, 71.1±12.0 kg, 27.5±4.3 kg/m² BMI) with PN, wear activity monitors while sitting quietly (control condition) or performing simulated daily activities: reading while sitting, floor sweeping, table dusting, laundry folding, bagging groceries, self-selected “slow” (52.6±15.1 m/min) and “brisk” (68.6±14.8 m/min) walking. Each subject was fit with 6 AMs on the left and right ankles, both wrists, and the anterior beltline. Activity data were summarized as mean activity levels (counts/min) for each monitor location and activity. Mean values across the 6 monitor locations were compared using a repeated measures ANOVA within each activity. Results: Mean values obtained by the monitors worn on the wrists were approximately 500-5000% higher than those on the waist and ankles in 5 non-walking tasks (P<0.05). For the walking trials, mean values were about 250% higher at the ankles compared to the waist and wrist values (P<0.05). No significant difference was observed between right and left ankles, wrists, or hip positions. Conclusions: Location of the monitors with the highest activity values was task dependent. Although arm movements were the most active for daily tasks in people with PN, this may not be true in other populations, where daily tasks may be more complex and require greater physical exertion. Future research should focus on considering common daily tasks of a particular population when monitoring physical activity.