Objective: : This study aimed to compare four methods of measuring or estimating height among wheelchair users, to determine whether these methods result in significantly different estimates, and to determine which method is most accurate.
Design: : Height data were obtained for 141 wheelchair users. Height estimates included asking for self-report and measuring recumbent length, knee height, and armspan. All analyses were conducted separately for men and women. A two-group confirmatory factor analysis assessed which measure provided the best estimate of height in this population. It also tested the measurement invariance of the four height estimates between men and women and whether there were significant differences across these estimates within each sex.
Results: : Confirmatory factor analysis findings indicated that the four measures yielded significantly different height estimates and body mass index values for both men and women. For both sexes, armspan resulted in the longest estimate, and measured recumbent length resulted in the shortest, with the reverse pattern for body mass index values. The common variance estimates were outstanding for recumbent length (92%) and knee height (>83%) and were very good for self-report (>75%), whereas the common variance for armspan was poor (<42%).
Conclusions: : The measurement method used to estimate height yields significantly different values for both height and body mass index among wheelchair users who cannot stand to be measured using a stadiometer. Recumbent length yields the most accurate height estimate for wheelchair users. However, when logistical and practical considerations pose difficulties for obtaining this measure, height estimates based on knee height and self-report may provide reasonable alternatives.