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Exercise with blood flow restriction (BFR) is emerging as an effective training option to increase muscle size and strength, in healthy, clinical, and athletic populations. However, the need for specialized equipment and associated costs present a major barrier to its accessibility. The purpose of this study was to develop a practical method to implement BFR in the lower body using a thigh sphygmomanometer. Specifically, we aimed to 1) explore what factors should be accounted for when setting pressures with this type of restrictive cuff and 2) generate both a lab‐based and field‐based prediction equation to estimate arterial occlusion pressure (AOP). We hypothesized that measures of limb size and blood pressure would constitute significant predictors of lower body AOP. We also hypothesized that a multiple linear regression model including significant predictors would explain approximately 50% of the variance in AOP. Thirty‐eight normotensive healthy adults (age: 24±5 yrs, BMI: 25±4) visited the laboratory for one testing session. Brachial and femoral systolic (SBP) and diastolic (DBP) blood pressures were taken in the seated position. Next, thigh circumference, muscle thickness of the anterior thigh, and maximal isometric knee extension strength was assessed. Lean thigh volume was estimated using anthropometric measures. Lastly, lower body AOP was assessed in the seated position using an 18cm wide thigh sphygmomanometer and Doppler ultrasound (156±12 mmHg). A multiple linear regression analysis including brachial and femoral SBP and DBP, thigh circumference, muscle thickness, lean thigh volume, and maximal isometric knee extension strength was performed to assess which variables constituted significant predictors of AOP. Regression analysis was then repeated with only significant variables to generate both a lab‐based and field‐based prediction equation for AOP. Thigh circumference (β = 0.322, part = 0.876), brachial SBP (β = 0.362, part = 0.463) and isometric knee extension strength (β = 0.421, part = 0.076) constituted significant predictors of AOP. A lab‐based model including thigh circumference (β=0.278, part = 0.754), brachial SBP (β=0.492, part = 0.549), and isometric knee extension strength (β=0.306, part = 0.055) explained 56% of the variance in AOP. A field‐based model including only thigh circumference (β=0.316, part = 0.857) and brachial SBP (β=0.515, part = 0.658) explained 47% of the variance in AOP. Our results indicate that thigh circumference, brachial SBP, and isometric knee extension strength serve as predictors of AOP in the lower body when utilizing an 18cm wide sphygmomanometer as a restrictive cuff. Further, a field‐based prediction equation including thigh circumference and brachial SBP offers a practical way to estimate AOP. Future work will build upon this prediction equation by utilizing subjective measures of cuff tightness, effort, and muscle pain to further adjust exercising cuff pressures to an appropriate level. Results will help to provide researchers and practitioners with a pract...

For implementation of exercise with blood flow restriction (BFR), cuff pressures should be based on arterial occlusion pressure (AOP). Limb circumference and blood pressure have been identified as predictors of AOP and used to set appropriate exercising cuff pressures. However, it is unclear whether these predictors are consistent across BFR cuffs of varying width. Our purpose was to compare predictors of lower-body AOP in a variety of commonly utilized cuff widths. We hypothesized that limb circumference would be a stronger predictor when using narrower cuffs while blood pressure would be a stronger predictor when using wider cuffs.Healthy normotensive adults (women=44, men=76; age:23±4yrs; BMI:25±4) underwent measurements of thigh circumference (TC) and systolic (SBP) and diastolic blood pressure (DBP). Lower-body AOP was assessed (via Doppler ultrasound) in the post-tibial artery in a seated position with an 11, 13, and 18cm wide pneumatic cuff. Models of hierarchical linear regression were constructed to predict AOP in each of the cuffs using TC, SBP, and DBP as predictor variables. A linear mixed effects model including AOP as the outcome variable was fit. The model included fixed effects of TC, SBP, DBP, cuff width, TC x cuff width, SBP x cuff width, and DBP x cuff width, and a random intercept for participants.AOP was 188±28, 170±20, and 152±15mmHg, for the 11, 13, and 18cm cuff, respectively. For the 11cm cuff, TC (β = 0.66, part = 3.46), SBP (β = 0.17, part = 0.48), and DBP (β = 0.21, part = 3.46) were significant predictors that explained 74% of AOP variability. For the 13cm cuff, TC (β = 0.56, part = 2.06), SBP (β = 0.25, part = 0.48), and DBP (β = 0.22, part = 0.59) were significant predictors that explained 69% of AOP variability. In the 18cm cuff, TC (β = 0.35, part = 0.10) and SBP (β = 0.48, part = 0.72) were significant predictors that explained 57% of the AOP variability. There were significant main effects of TC, SBP, DBP, and cuff width on AOP, and significant interactions of TC x cuff width and SBP x cuff width (all P<0.05). Results indicated that when using a narrow cuff, AOP was largely based on TC and when using a wider cuff, AOP was based mostly on SBP. Differences are likely due to wider cuffs transmitting pressures more efficiently into underlying soft tissues, thereby reducing the influence of TC on AOP and shifting greater influence towards blood pressure. Our results support and expand on previous work in a small sample (n=12) reporting that AOP depends more on TC as cuff width decreases. Together, these data provide evidence that cuff width should be considered when selecting factors to estimate AOP and establish appropriate pressures during lower-body BFR exercise. This work was supported by the Michigan Tech Health Research Institute This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.