Concurrent Validity of the Static and Dynamic Measures of Inspiratory Muscle Strength: Comparison between Maximal Inspiratory Pressure and S-Index.

Objective: To verify the concurrent validity between the inspiratory muscle strength (IMS) values obtained in static (maximal inspiratory pressure [MIP]) and dynamic (S-Index) assessments.

Methods: Healthy individuals were submitted to two periods of evaluation: i) MIP, static maneuver to obtain IMS, determined by the Mueller's maneuver from residual volume (RV) until total lung capacity (TLC); ii) and S-Index, inspiration against open airway starting from RV until TLC. Both measures were performed by the same evaluator and the subjects received the same instructions.