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 (MDD90) 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 MDD90 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.