The running shoe comfort assessment tool (RUN-CAT): Development and evaluation of a new multi-item assessment tool for evaluating the comfort of running footwear.

Comfort is important for running shoe prescription in athletes to enhance performance and potentially decrease injury risk. A three-stage process was used to develop a new running footwear comfort assessment tool (RUN-CAT): (i) a survey of 282 runners to identify meaningful items of comfort, (ii-a) field testing of 100 runners who assessed the comfort of different shoes, (ii-b) item reduction using bootstrap aggregation and weightings using multiple regressions to identify a final set of items, and (iii) defining test-retest reliability, standard error of measurement (SEM), minimal detectable difference (MDD ₉₀ ) and minimal important difference (MID) values for the final tool. Of the 19 initial items, after item reduction, four were included in the final tool: heel cushioning, shoe stability, forefoot cushioning and forefoot flexibility. Reliability of the overall comfort score was good to excellent (within-day ICC 0.88, between-day 0.70) with all four components displaying good reliability (ICC >0.70). The SEM of the comfort score was 2.8 points and the MDD ₉₀ was 6.5 mm. Subject nominated MID values ranged from 9.3 to 9.9 mm. The RUN-CAT demonstrates excellent reliability, acceptable measurement error and can discriminate between footwear models. Clinicians and researchers can incorporate the RUN-CAT to optimise running shoe comfort in athletes.