Validity of aneroid sphygmomanometer cuff to assess core muscle strength of low back in young healthy adults

Background of the study: Muscle strength measurement is a key component of physiotherapist’s assessment and is frequently used as an outcome measure. The core muscle grading is generally done using a pressure biofeedback unit (PBU). However, the high cost of the device limits its availability in poorly resourced healthcare settings. The use of alternate measures such as the aneroid sphygmomanometer cuff (AS) to assess core strength needs to be investigated. Objectives: To study the validity of the aneroid sphygmomanometer cuff for assessing the core muscles strength of low back in young healthy adults. Methodology: This observational study included normal healthy young adults in the age group of 20-30yrs (N=100) were enrolled in the study, after taking their consent to participate in the study.Core muscle strength was measured by AS cuff and PBU, with the help of Richardson and Jull’s core muscle grading method. Results: The Mean Age of the study group was 23.18yrs ± 1.63 (95% CI, 22.86 – 23.50). The Core muscle strength was 2 (95% CI, 1.51 – 1.91) with PBU and 1 (95% CI, 1.2-1.56) with AS. High concurrent validity was found between AS and PBU (rho = 0.856, p = 0.000). Conclusion: The aneroid sphygmomanometer cuff can be used instead of pressure biofeedback unit for assessing the strength of core muscles. The regression equation (PBU grading = 0.269+ (1.037) As grading) obtained will help the therapist to convert the grading using AS cuff to widely accepted, reliable and standardized grading using PBU which can be used for research purpose.