Influence of an Inspiratory Muscle Fatigue Protocol on Healthy Youths on Respiratory Muscle Strength, Vertical Jump Performance and Muscle Oxygen Saturation. A randomized controlled trial.

Abstract Background: Inspiratory muscle fatigue has been shown to have effects on limbs blood flow and physical performance. This study aimed to evaluate the influence of an inspiratory muscle fatigue protocol on respiratory muscle strength, vertical jump performance and muscle oxygen saturation in healthy youths. Methods: A randomized controlled clinical trial, employing double-blinding, was conducted with twenty-four participants aged 18-45 years, non-smokers and engaged in sports activity at least three times a week for a minimum of one year. Participants were randomly assigned to three groups: Inspiratory Muscle Fatigue (IMFG), Activation, and Control. Measurements of vertical jump, diaphragmatic ultrasound, muscle oxygen saturation, and maximum inspiratory pressure were taken at two stages: before the intervention (T1) and immediately after treatment (T2). Results: Results: The IMFG showed lower scores in muscle oxygen saturation and cardiorespiratory variables after undergoing the diaphragmatic fatigue intervention compared to the activation and control groups (p < 0.05). As for the vertical jump variables, intragroup differences were found (p < 0.01), but no differences were found between the three groups analyzed (p > 0.05). Conclusions: Inspiratory muscle fatigue appears to negatively impact vertical jump performance, muscle oxygen saturation and inspiratory muscle strength in healthy youths. Trial registration: ClinicalTrials.gov ID: NCT06271876. Date of registration 02/21/2024. https://clinicaltrials.gov/study/NCT06271876