Evaluation of manual wheelchair skills: is objective testing necessary or would subjective estimates suffice?

OBJECTIVE: To test the hypothesis that subjective estimates of the ability to perform manual wheelchair skills, by wheelchair users and the therapists working with them, accurately reflect the results of objective testing.
DESIGN: Within-subject comparisons.
SETTING: Kinesiologic laboratory in a rehabilitation center. PARTICIPANTS: Twenty-one wheelchair users and their therapists.
INTERVENTIONS: The wheelchair users and their therapists subjectively estimated how the wheelchair users would perform manual wheelchair skills, followed by an objective assessment. MAIN OUTCOME MEASURES: Wheelchair Skills Test (WST, version 2.4), a set of 50 standardized skills.
RESULTS: The Spearman correlation coefficients between the total objective and subjective scores were.95 for the wheelchair users and.75 for the therapists. The mean difference between the total objective and subjective scores was statistically significant (P=.0002) for the wheelchair users (who overestimated their abilities by an average of 17.9%). The percentage concordance between subjective and objective scores for individual skills ranged from 57.1% to 100% for the wheelchair users and 50% to 100% for the therapists, with 25% and 35% of skills, respectively, for which there were no statistically significant associations (at a Bonferroni-adjusted alpha level of.001) between the objective and subjective scores. The skills that were misestimated by both were moving the armrests away, reaching a high object, transferring out of and into the wheelchair, folding the wheelchair, incline ascent, negotiation of gravel and irregular surfaces, and small curb ascent.
CONCLUSION: Although subjective ratings by wheelchair users and their therapists provide excellent and good estimates respectively of overall manual wheelchair abilities, objective testing should be performed when accurate assessments of many specific manual wheelchair skills are required.