A Study into the Reliability of the Data Flow from GPS Enabled Portable Fitness Devices to the Internet.

The growth in availability and affordability of portable fitness devices (PFDs) has facilitated a concomitant growth in the collection and sharing of what are assumed to be reliable measures of exercise and physical activity. This data is increasingly used by fitness trainers to track performance progression, and plan training. Whilst the reliability and validity of these devices has been reported, investigation into the variance in the data at different access points is less well examined.