# A Standardised Car Seat Transfer Test: Reliability and Concurrent Validity

## TL;DR

This study developed a reliable and valid test to measure the ability to transfer into and out of a car seat, both in real vehicles and simulators.

## Contribution

The study introduces a standardized car seat transfer test with demonstrated reliability and concurrent validity.

## Key findings

- The test showed good interrater, intrarater, and test–retest reliability for car seat transfer times.
- Strong correlations were found between vehicle and simulator test times and physical function measures like gait speed and sit-to-stand performance.

## Abstract

Introduction: Transferring effectively into and out of a vehicle seat is required for functional mobility and social participation. Reliable and valid vehicle and simulator car seat transfer tests are limited. The aim of this study was to assess the reliability and concurrent validity of a car seat transfer test for application with a vehicle and a simulator car seat.

Methods: A cross-sectional study was conducted and reported according to the Guidelines for Reporting Reliability and Agreement Studies (GRRAS), the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statements and the National Statement on Ethical Conduct in Human Research 2007. Consecutive healthy adults who expressed interest and met the inclusion criteria were recruited for our study. A standardised vehicle and simulator car seat transfer test was undertaken on two visits, 7 days apart. WOMAC, hip and knee active range of motion assessment, self-selected gait speed measurement and the five-repetition sit-to-stand test were undertaken on the first visit.

Results: Complete data collection was performed with 42 healthy adults. There was good interrater (ICC = 0.99; 95% CI 0.99, 1.00), intrarater (ICC = 0.79; 95% CI 0.62, 0.89 to ICC = 0.91; 95% CI 0.76, 0.96) and test–retest reliability (ICC = 0.87; 95% CI 0.77, 0.93 to ICC = 0.94; 95% CI 0.89, 0.96) for car seat transfer test times for getting into and out of the vehicle and the simulator car seat. There were strong and significant correlations (r = 0.84–0.89) between the vehicle and simulator car seat test times; these times correlated significantly with measures of physical function including self-selected gait speed and five-repetition sit-to-stand test results (p < 0.001).

Conclusion: A standardised car seat transfer test is reliable and valid for testing car seat transfer ability in a vehicle and a simulator car seat.