Does exercising bilaterally require measuring bilaterally? Bilateral versus unilateral tourniquet cuff inflation during measurement of arterial occlusion pressure: considerations for blood flow restriction exercise.

INTRODUCTION: It is recommended to use a tourniquet cuff pressure between 40-80% of the individuals' arterial occlusion pressure (AOP) during blood flow restriction (BFR) exercise. The AOP is usually determined in one limb for unilateral BFR exercise or in both limbs individually for bilateral BFR exercise. However, given that the tourniquet cuffs are inflated at both limbs simultaneously during bilateral BFR exercises (e.g., cycling, walking, and squat exercise), it is currently not known if the respective AOP also needs to be determined during bilateral tourniquet cuff inflation. Consequently, the present study aimed to compare the AOP during unilateral versus bilateral tourniquet cuff inflation in the lower extremities.

METHODS: In a randomized cross-over trial, the AOP of 25 young healthy participants was determined during unilateral and bilateral tourniquet cuff inflation in supine, seated, and standing position. All measurements were completed in one experimental session with a rest period of 5 min in between. At the beginning and end of each condition, heart rate and blood pressure were recorded.

RESULTS: Regardless of body position, AOP was higher during bilateral compared to unilateral tourniquet cuff inflation (mean difference = 3.2 mmHg [95% confidence interval: 1.0, 5.4], p = 0.006, d = 0.12). Furthermore, AOP and heart rate increased with change in body position from supine to seated to standing position (p < 0.001, d ≥ 0.76).

DISCUSSION: Even though there was a statistically significant difference in AOP between unilateral and bilateral tourniquet cuff inflation irrespective of body position, bilateral cuff inflation during AOP determination appears to have only minor impact on AOP in the lower extremities given the small mean difference and trivial effect size. However, since differences in AOP between unilateral and bilateral tourniquet cuff inflation of ≥ 30 mmHg have been recorded, practitioners must be aware of potentially pronounced differences between unilateral and bilateral cuff inflation during AOP determination in some individuals using the specific BFR device and AOP measurement protocol employed in this study. These results need to be verified for different inflation protocols, devices (i.e., manual versus automatic AOP determination), and populations (e.g., older adults, patients).