Impact of Inspiratory Muscle Warm-up on the Reliability of a Novice Evaluator. Effect of Sex and Body Composition

The reliability of maximal inspiratory pressure (MIP) measurementas an indicator of respiratory muscle motor capacity has been debated in both normal and impaired respiratory function contexts.This study aimed to determine whether a specific warm-up of the inspiratory muscles produces significant changes in inter-rater reliability of MIP measurement in healthy individuals between a novice kinesiology (NK) and an expert (EK).A secondary objective was to examine whether sex and body composition influence reliability outcomes.Fifty-seven university students were recruited.All participants underwent MIP assessment by two evaluators.The expert evaluator followed the ATS/ERS protocol, whereas the novice evaluator applied the ATS/ERS protocol plus inspiratory muscle warm-up.Group allocation was randomized to minimize learning effects.Fifty-four participants were included in the analysis.The intraclass correlation coefficient (ICC) for the total sample was 0.896 (95 % CI: 0.814-0.942;p = 0.0001).Among overweight participants and males, a small clinical difference favored the EK (Cohen's d = 0.240 and 0.309, respectively).In the multivariate analysis, sex and number of attempts significantly contributed to MIP values for the NK.Specifically, identifying as female decreased MIP by 23.532 cmH 2 O, and each additional attempt increased MIP by 6.717 cmH 2 O. High inter-rater reliability was observed regardless of sex or body composition.A small clinical difference between evaluators was noted in the overweight and male groups.For the NK, the multivariate model revealed a significant interaction between sex and number of attempts in predicting MIP values.