Inspiratory Muscle Performance Is Related to Seated Balance Function in People With Spinal Cord Injury: An Observational Study

Abstract

Objective: To examine the relationship between inspiratory muscle performance (IMP) and functional sitting balance (FSB) in persons with chronic spinal cord injury (SCI). We hypothesized that a moderate correlation would be found between IMP and FSB and that individuals with better balance would have better IMP. Design: The SCI-specific modification of the Function in Sitting Test (FIST-SCI) measured FSB. The IMP measures included (1) maximal inspiratory pressure (MIP), (2) sustained MIP (SMIP), and (3) inspiratory duration. Upper extremity motor score (UEMS) and level of injury (LOI) were taken from International Standards for Neurological Classification of Spinal Cord Injury examinations. Spearman correlational analyses assessed relationships among these factors in the sample (N=37). Mann-Whitney U tests explored differences between 2 comparison group pairs (tetraplegia group [TG] vs paraplegia group [PG]; independent transfer group [ITG] vs assisted transfer group [ATG]). Regression analysis examined variables predictive of FSB in the TG. Setting: Research facility. Participants: Volunteers with tetraplegia (n=21, American Spinal Injury Association Impairment Scale (AIS) A=8, B=7, C=6) and paraplegia (n=16, AIS A=9, B=4, C=3) (N=37). Intervention: Not applicable. Main Outcome Measures: IMP, LOI, UEMS, FIST-SCI. Results: UEMS, MIP, SMIP, and LOI had moderate to high correlations with FIST-SCI scores (ρ=0.720 (P