Report

Miniaturised data loggers and radio frequency systems for tracking wheelchair activities

Investigating the accuracy and reliability of wheel mounted miniaturised data loggers (MDL)

Lead academic:
Professor Vicky Tolfrey
Additional academics:
Barry Mason
Funder:
The Peter Harrison Foundation

A radio-frequency based indoor tracking system (ITS) has recently being validated as an accurate and reliable system for quantifying the external demands of wheelchair sports.

Unfortunately the ITS can take a long time to install and calibrate, therefore it does have its limitations for use within elite sport. Wheel mounted miniaturised data loggers (MDL) offer a more practical solution however their accuracy and reliability has yet to be determined in relation to a valid criterion measure.

Methods

11 international Wheelchair Rugby players were monitored during 4 Wheelchair Rugby matches via the ITS and MDL (see figure). The MDL was sampled at both 1- (MDL-1) and 5-sec (MDL-5) intervals. During games the distance covered, peak speeds and times spent within arbitrary speed zones were collected and analysed.

Main findings and applications

  • No significant differences were observed between devices for the distances covered. Although no significant difference existed between MDL-1 and the ITS for the detection of peak speeds, MDL-5 significantly underestimated peak speeds.
  • Large random errors in the time spent in arbitrary speed zones were observed, particularly for MDL-5.
  • Although the MDL offers a practical alternative to the ITS and may be acceptable for quantifying the volume of activity during wheelchair sports, it should not be used to represent the high speed activities associated with wheelchair sports, especially at 5-sec intervals.
  • The MDL (top) and where it attaches to the wheelchair, and the tags of the ITS (bottom) and where they were worn by players.

Reference

  • Mason B, Lenton J, Rhodes J, Cooper R, Goosey-Tolfrey VL. (2014). Comparing the activity profiles of wheelchair rugby using a miniaturised data logger and
    radio-frequency tracking system. Biomedical Research International, Article ID 348048. DOI: