# Validity and Reliability of Using a Belt-Worn Accelerometer on the Lower Back to Monitor Physical Activity

## TL;DR

A belt-worn accelerometer on the lower back is a valid and reliable method for tracking physical activity, suitable for long-term studies on low back pain.

## Contribution

The belt-mounting method is shown to be valid and reliable for physical activity monitoring, enabling self-positioning by participants.

## Key findings

- Belt-mounted accelerometers produce similar results to skin-mounted ones during controlled and free-living activities.
- The belt method shows good day-to-day reliability for physical activity measurements.
- This method is suitable for long-term data collection in low back pain studies.

## Abstract

What are the main findings?
The belt method is valid and reliable for collecting daily physical activity when tested against the laboratory standard.Participants can position sensors correctly themselves with the belt method by following a set of instructions.

The belt method is valid and reliable for collecting daily physical activity when tested against the laboratory standard.

Participants can position sensors correctly themselves with the belt method by following a set of instructions.

What is the implication of the main finding?
The belt-mounting method can be used in future low back pain studies for identifying a dose–response effect on low back pain outcomes, in terms of physical activity.This method is participant friendly, demonstrates good day-to-day reliability, and can be used in trials to collect physical activity data over an extended period of time.

The belt-mounting method can be used in future low back pain studies for identifying a dose–response effect on low back pain outcomes, in terms of physical activity.

This method is participant friendly, demonstrates good day-to-day reliability, and can be used in trials to collect physical activity data over an extended period of time.

This study evaluated the validity and reliability of physical activity measurements collected using a belt-mounted accelerometer worn at the lumbar spine. The study consisted of two parts, with 10 healthy participants in each part. In part 1, physical activity measurements collected from a belt-mounted accelerometer were compared with that from a skin-mounted accelerometer during controlled exercises and free-living activities, with both accelerometers worn simultaneously at the same anatomical location. In part 2 physical activity measurements in controlled exercises were compared between two different days, with either the belt-mounted accelerometer or skin-mounted accelerometer worn singularly. The results demonstrated no significant difference in physical activity measurements between either mounting method, or between the two testing days during controlled activities. These results indicate that the belt-mounting method is valid and has good day-to-day reliability and can be used in studies requiring long-term data collection to assess the impact of physical activity-related rehabilitation and low back pain.