Evaluation of Respiratory Muscle Endurance and Strength using Surface Electromyography

Purpose: Determining respiratory muscle strength, neural drive, and endurance on exertion is essential to further improve diagnostic accuracy and potentially obtain prognostic information for respiratory diseases.

Methods: Respiratory muscle function-specific examinations of the right and left hemidiaphragm, the sternocleidomastoid (SCM), and intercostal muscles (ICM) were conducted using an sEMG-based assessment of the muscle activity in a group of healthy participants (n=50). These examinations comprised maximum sniff nasal inspiratory pressure (SNIP), maximal inspiratory pressure (PI Max), and maximal expiratory pressure (PE Max) as volitional inspiratory muscle strength measures. SNIP, PI Max, and PE Max were determined before, immediately after, and one hour after the end of the endurance protocol.

Results: A total of 50 participants (22 men, average age 43±20 years) were evaluated. During SNIP and PI Max, inspiratory muscle strength increased both immediately after and one hour following the endurance test, peaking with an 8.46% rise one hour post-test (p<0.01). The EMG analysis (n=10) revealed different activation levels of the respiratory muscles over time. Before the endurance test, the diaphragm showed the highest activation during the inspiratory maneuver, which significantly decreased after the endurance test and one hour later (p<0.001 for amplitude and AUC). The SCM showed peak activation immediately after the endurance test (p<0.001 for amplitude; p<0.01 for AUC), while the ICM reached peak activation one hour after the endurance test (p<0.001 for amplitude and AUC).

Conclusion: The results imply a progressive compensation mechanism in which the accessory muscles (SCM and ICM) are consecutively recruited over time as diaphragm fatigue endures.

Publikationsverlauf

Artikel online veröffentlicht:
18. März 2025