Assessment of Maximum Dynamic Inspiratory Pressure
Related Experiment Video
Updated: Feb 7, 2026

Synthesis and Microdiffraction at Extreme Pressures and Temperatures
Published on: October 7, 2013
Paulo Eugênio Silva1,2, Karina Livino de Carvalho3, Murillo Frazão4
1Physical Therapy Division, University Hospital of Brasília, Brasília, Brazil, and Health Sciences and Technologies PhD Program, University of Brasília, Brazil. pauloeugenio.bsb@gmail.com.
Background:
Inspiratory muscle strength has been considered an important marker of ventilatory capacity and a predictor of global performance. A new tool has become available for dynamically evaluating the maximum inspiratory pressure (the S-Index). However, the proper assessment of this parameter needs to be determined. Thus, the aim of the present study was to investigate the number of inspiratory maneuvers necessary to reach a maximum and reliable S-Index and the influence of inspiratory muscle warm-up on this assessment.
Method:
We performed a retrospective study from the database of 432 healthy subjects who underwent S-Index tests and inspiratory muscle warm-up or sham. The effect of repeated maneuvers on the S-Index and the impact of inspiratory muscle warm-up were analyzed by using the intraclass correlation coefficient and unpaired t test.
Results:
We analyzed 81 subjects, (55% men), mean ± SD age 38.1 ± 9.6 y, 43 subjects in the inspiratory muscle warm-up group. Maximum and reliable S-Indexes were reached at the eighth maneuver in both groups preceding inspiratory muscle warm-up or sham, 102 cm H2O (95% CI 95-109 cm H2O); intraclass correlation coefficient 0.96; P < .001. Only the inspiratory muscle warm-up group presented a significant increase in the S-Index after warm-up, 13.5 cm H2O (95% CI 10-17), P < .001.
Conclusions:
Eight maneuvers were necessary to reach maximum and reliable values of the S-Index preceding inspiratory muscle warm-up or sham. Moreover, inspiratory muscle warm-up preceding S-Index assessment improved inspiratory muscle performance.
Related Concept Videos
Maximum Deflection
The maximum deflection occurs at a specific point, known as point O, where the tangent to the deflection curve is horizontal. To find point O, the slope of the tangent at any...
Static, Stagnation, Dynamic and Total Pressure
Assessing Blood pressure in the Leg
Preparation:
Maximum Power Transfer
By substituting the entire circuit with...
Maximum Size of Aggregate
Vapor Pressure

