Inspiratory muscle performance is related to seated balance function in people with SCI: an observational study

Published:December 16, 2021DOI:



      To examine the relationship between inspiratory muscle performance (IMP) and functional sitting balance (FSB) in persons with chronic SCI. We hypothesized that a moderate correlation would be found between IMP and FSB, and that individuals with better balance would have better IMP.


      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 (ID). Upper extremity motor score (UEMS) and level of injury (LOI) were taken from ISNCSCI exams. Spearman correlational analyses assessed relationships among these factors in the sample (n=37). Mann-Whitney U tests explored differences between two 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.


      Research Facility


      Volunteers with tetraplegia (n=21, ASIA Impairment Scale (AIS) A = 8, B= 7, C = 6) and paraplegia (n=16, AIS A= 9, B=4, C=3)

      Main Outcome Measures



      UEMS, MIP, SMIP, and LOI had moderate/high correlations with FIST-SCI scores (rs = 0.69, 0.53, 0.53, 0.49, respectively, p< .05). UEMS, MIP, and FIST-SCI scores were higher in the PG and ITG compared to the TG and ATG, respectively (p< .05). Further, SMIP and UEMS predicted FIST-SCI balance scores in the TG, accounting for 55% of total variance (p= 0.00) (FIST-SCI = 11.88 + 0.03(SMIP) + 0.425(UEMS)).


      The relationship between IMP and balance appears preserved after SCI. FSB was predicted, in part, via UEMS and SMIP in the TG. Future research should focus on the impact of SCI-based breathing interventions on FSB.


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