A Prediction Equation For Blood Flow Restriction Exercise That Accounts For Cuff Width

Abstract

Exercise with blood flow restriction (BFR) is an effective strategy to increase muscle size, strength, and function in a variety of populations. However, the determination of arterial occlusion pressure (AOP) needed for BFR exercise prescription requires specialized equipment that limits its accessibility. Previously, researchers have developed prediction equations to estimate AOP using limb circumference and blood pressure. These equations are specific to certain cuff widths and no single equation is available that accounts for varying cuff width. Additionally, it is unclear whether the influence of limb circumference and blood pressure on AOP is consistent across cuffs of varying width. PURPOSE: Our primary purpose was to develop a single prediction equation that estimates AOP in the lower body for a variety of different cuff widths. A secondary purpose was to explore the influence of thigh circumference and systolic blood pressure (SBP) on AOP when using cuffs of varying width. METHODS: Thirty-seven normotensive adults (age: 25 ± 5 yrs, BMI: 25 ± 4 kg/m2) underwent measurements of thigh circumference (TC) and SBP. Next, lower body AOP was assessed (via Doppler ultrasound) in the seated position with an 11, 13, and 18 cm wide cuff. Multiple linear regression analysis including TC, SBP, and cuff width was performed to generate a prediction equation for AOP. A linear mixed effects model was fit, which included AOP as the outcome variable, fixed effects of TC, SBP, cuff width, TC x cuff width, and SBP x cuff width, and a random intercept for participants. RESULTS: For the 11, 13, and 18 cm cuff, AOP was 182 ± 22 mmHg, 168 ± 16 mmHg, and 155 ± 14 mmHg. A model including TC (β = 0.475, part = 2.091), SBP (β = 0.233, part = 0.540), and cuff width explained 63% of the variance in AOP. There were significant main effects of TC, SBP, and cuff width on AOP, and a significant interaction of TC x cuff width (all P < 0.05). CONCLUSION: Our prediction equation including TC and SBP offers a way to estimate AOP in the lower body for a variety of commonly used cuff widths. This equation may help researchers and practitioners implement BFR without the need for specialized equipment. Preliminary results also suggest that the influence of TC on AOP varies with cuff width and thus may need to be taken into account when estimating lower body AOP.