Prescribing Blood Flow Restricted Exercise: Limb Composition Influences the Pressure Required to Create Arterial Occlusion

CONTEXT: As blood flow restriction gains popularity across different populations (eg, young and older adults) and settings (eg, clinical and sports rehabilitation), the accuracy of blood flow restricted percentage becomes crucial. We aimed to compare manually measured arterial occlusion pressure (AOP) among young adults to understand whether lower limb composition affects the pressure required to achieve AOP. The results will shed light on the adequacy of published calculations used to estimate AOP in practical and research settings. DESIGN: An observational cross-sectional study design was implemented to examine the relationship between lower limb composition, lower limb circumference, and measured AOP. METHODS: Twenty-two participants (12 males, 26 [4] y, 1.74 [0.07] m, 73.2 [12.5] kg) underwent a whole-body Dual-energy X-ray Absorptiometry scan before AOP (in millimeters of mercury) and lower limb circumference (in centimeters) were determined. In a supine position, a 10-cm wide cuff was manually inflated on the dominant leg to the point where a pulse could no longer be detected by a Doppler ultrasound of the posterior tibial artery to determine AOP. Lower limb composition (fat, muscle, and bone mass [in grams]) was obtained from the Dual-energy X-ray Absorptiometry scan. RESULTS: Lower limb muscle mass had a moderate negative relationship with AOP (r2 = .433, β = -0.004) and a moderate positive relationship with lower limb circumference (r2 = .497, β = 0.001). Lower limb circumference had the weakest relationship with AOP (r2 = .316, β = 0.050) of all measures. CONCLUSIONS: The reported relationships between lower limb muscle mass, lower limb circumference, and AOP suggest that as muscle mass increases, lower limb circumference also increases, yet AOP decreases. This implies that limb circumference should not be used as the primary measure for calculating AOP within the sampled population. We recommend individually measuring AOP when implementing blood flow restriction in all exercise modalities.