Using Fitness Devices and Global Positioning System (GPS)

Technology in Measuring Energy Expenditure and Distance Walked

Over Flat and Incline Surfaces

Rebecca ReedArizona Space Grant Consortium

The University of Arizona April 17, 2010

A special thanks to: • Nobuko Kay Hongu, PhD (Mentor):

Assistant Professor and Extension Specialist, Department of Nutritional Sciences

• Scott Going, PhD: Professor, Department Nutritional Sciences

• Barron Orr, PhD: Arid Lands Studies (UA); Geospatial Extension Specialist

• Martha Mosqueda (Advisor): Department of Nutritional Sciences

Overview

1. Relevance and Purpose of study 2. Methodology

-Technology 3. Results 4. Analysis & Conclusions

Relevance and Purpose • Accurate measure of Physical Activity (PA)

– Research studies with PA as outcome or intervention

– Losing weight, maintaining healthy weight

Purpose: Evaluate the accuracy of five fitness devices in estimating distance and energy expenditure (EE), as compared to the criterion and standard values, while traversing flat and incline surfaces

Technology

Garmin Forerunner 305 (GPS watch)

Omron HJ-720

pedometer

RT3 accelerometer

Actigraph GT1M

accelerometer

Omron HJ-303 pedometer

Methodology

N= 21 (10 female, 11 male) Gender, height, weight, age recorded

Instrumentation

ParticipantParticipantFlat Surface

3x TrialsData

Averages

Inclined Surface

5 km/hr3 km/hr3 km/hr 5 km/hr

3x Trials

Distance

4 Devices5 Devices

EE

Statistical Analysis of Results

• Calculated mean difference scores (Device A-Device B) – Example (RT3 EE- HJ720 EE) = 23.95 kcal

• Used ANCOVAs to determine significant differences in mean difference scores

Results and Significance

3 km/hr 5 km/hr

3 km/hr 5 km/hr

EE Mean Measurements

Stairs

Track

***

****

*

***

****

*Significantly different from RT3; P <0.05

*

Results and SignificanceDistance Mean Measurements

3 km/hr 5 km/hr

3 km/hr 5 km/hr

Stairs

** **

*

*Significantly different from standard; P <0.05

Conclusions • It matters what fitness

device you use • Fitness devices are

valuable tools • Increase PA in children

and youth

Acknowledgements Catalina Foothills High School Arizona Coopertive Extensions

Office of Arid Land Studies Nutritional Sciences Department

Physiology Department

Thank you!

How does GPS work ?

• 24 satellites orbiting Earth – Transmit electromagnetic waves to GPS

receiver • Can calculate distance between GPS

receiver and satellites– Receiver location can be measured

• Use trilateration to determine position, speed, elevation