Reduction of blood flow to the limb using cuffs before or during exercise has become increasingly popular for training and rehabilitation. Our study tested the effects of cuff brand/width on ...pressures required to reach limb occlusion pressure (LOP) and developed, cross-validated, and compared accuracy of two LOP prediction equations to previously created methods. Supine LOP was determined in the distal popliteal artery using four different cuff brands/widths in 23 adult participants. Participants then had demographic and resting variables assessed, and two LOP prediction equations were developed from these variables and were compared to five previously developed models and a method using posterior tibial artery palpation for LOP assessment in an independent sample (n = 14 adult runners). For cuff comparison, the widest two cuffs had significantly lower LOP (mean ~149 mmHg) than the narrowest cuffs (mean ~176 mmHg), with the narrowest cuff unable to reach LOP. The eight methods used to predict LOP ranged in accuracy (mean absolute percent errors 3.9-23.0%), with highest accuracy in equations using mean arterial pressure (MAP) and BMI. Practitioners using blood flow reduction methods should be consistent with cuff use due to demonstrated differences across brands/widths. Equations using MAP and BMI appear best for prediction of leg LOP.
Our study assessed limb occlusion pressure (LOP) variability over time and between limbs. Collegiate athletes (n=42; Sample 1 = 15 soccer players, Sample 2 = 13 cross country runners, Sample 3 = 14 ...cross country runners) attended five visits separated by ≥48 hours (Sample 1), three visits separated by ~3 weeks each (Sample 2), or four visits separated by ~3 weeks each (Sample 3). For all samples, supine LOP was assessed in each leg (and also in each arm for Sample 3) using an automated system. Paired samples t-tests or RMANOVA were used to compare LOP between limbs and across trials, respectively. Additionally, agreement and variability across measures were assessed using intraclass correlations and mean absolute percent differences (MAPD). There were no significant differences in LOP across visits for any of the samples, with primarily moderate or good agreement (intraclass correlations r=0.29-0.88) and low variability (MAPD 4.3-9.0%). There were no significant differences in LOP between left and right limbs, with moderate to good agreement (r=0.74-0.93) and low variability (MAPD 3.2-7.2%). The demonstrated stability in LOP over time and between sides of the body suggests that LOP may not always need to be measured daily or bilaterally, adding feasibility to field-based implementation.
Blood flow restriction (BFR) may become ineffective or potentially dangerous without sufficient standardization. The purpose of this investigation was therefore to (1) assess the viability of ...multiple sizes of a novel BFR cuff to determine arterial occlusion pressure (AOP) and (2) compare resting arterial, venous and calf muscle pump (cMP)-mediated blood flow between the aforementioned conditions and a commonly employed wide-rigid, tourniquet-style cuff. In randomized, counter-balanced, and crossover fashion, 20 apparently healthy males (18–40 years) donned a widely employed wide-rigid (WR) cuff, along with the largest (NE) and manufacturer-recommended sizes (NER) of a novel narrow-elastic cuff. Participants subsequently assessed AOP, as well as (at 80%AOP) arterial, venous, and venous cMP flow relative to baseline values via ultrasound. All analyses were performed at a significance level of p < 0.05. Analyses revealed a significant condition effect for AOP (p < 0.001; ηp2 = 0.907) whereby WR was significantly lower than both NE and NER; in addition, the latter two did not differ. Compared with baseline, there were no statistically significant differences between cuffs for either arterial or cMP-mediated blood flow. Unsurprisingly, no participants demonstrated venous blood flow at 80% AOP. These findings support the viability of a novel narrow-elastic BFR product, evidenced by consistent AOP acquisition and equivocal blood flow parameters.
This study compared the efficacy and safety of minimal tourniquet pressure using either determined limb occlusion pressure (LOP) or estimated arterial occlusion pressure (AOP) for elective upper limb ...surgeries.
Forty patients undergone elective upper limb surgery under general hypotensive anesthesia were randomized into groups A and B, where tourniquet pressure was calculated using AOP estimation for group A and LOP determination for group B. AOP, LOP, the time needed to estimate the AOP and determine the LOP and set the tourniquet inflation pressure, tourniquet inflation pressure, initial and maximal systolic blood pressure, heart rate, intraoperative fentanyl requirement, arm circumference, and tourniquet time were recorded. Tourniquet performance was assessed, and signs of tourniquet-related complications were noticed.
Systolic arterial blood pressure was comparable between the groups. Less time was recorded for measuring AOP or LOP and set the minimal inflation pressure (in second) in group A than in group B (62 ± 2 for group A vs. 120 ± 3 for group B; P < 0.001). The estimated AOP in group A was significantly higher than the determined LOP in group B (118 ± 2 vs. 91 ± 2; P < 0.001). Tourniquet inflation pressures were not significantly different between the groups. Tourniquet performance was excellent or good in all patients in both groups.
Arterial occlusion pressure estimation or LOP determination methods to set the tourniquet inflation pressure with hypotensive anesthesia can provide effective minimal inflation pressure and satisfactory surgical field for upper extremity surgeries without tourniquet-related complications.
Objective:
Measurement of arterial occlusion pressure (AOP) is essential to the safe and effective use of blood flow restriction during exercise. Use of a Doppler ultrasound (US) is the “gold ...standard” method to measure AOP. Validation of a handheld Doppler (HHDOP) device to measure AOP could make the measurement of AOP more accessible to practitioners in the field. The purpose of this study was to determine the accuracy of AOP measurements of the brachial and femoral arteries using an HHDOP.
Methods:
We simultaneously measured AOP using a “gold standard” US and a HHDOP in the dominant and non-dominant arms (15 males; 15 females) and legs (15 males; 15 females).
Results:
There were no differences in limb circumference or limb volume in the dominant and non-dominant arms and legs between males and females or between the dominant and non-dominant arms and legs of males and females. The differences between US and HHDOP measures of AOP in the dominant and non-dominant arms and legs were either not significant or small (<10 mmHg) and of little practical importance. There were no sex differences in AOP measurements of the femoral artery (
p
> 0.60). Bland–Altman analysis yielded an average bias (−0.65 mmHg; −2.93 mmHg) and reasonable limits of agreement (±5.56 mmHg; ±5.58 mmHg) between US and HHDOP measures of brachial and femoral artery AOP, respectively.
Conclusion:
HHDOP yielded acceptable measures of AOP of the brachial and femoral arteries and can be used to measure AOP by practitioners for the safe and effective use of blood flow restriction. Due to the potential differences in AOP between dominant and non-dominant limbs, AOP should be measured in each limb.
Blood flow restriction training using a practical (non‐pneumatic) elastic cuff has recently increased in popularity. However, a criticism of this method is that the pressure applied and the amount of ...blood flow restriction induced is unknown. The aim was to quantify blood flow following the application of an elastic cuff and compare that to what is observed using a more traditional pressurized nylon cuff. Thirty‐five young participants (16 men and 19 women) visited the laboratory once for testing. In a randomized order (one condition per arm), an elastic cuff (5 cm wide) was applied to one arm and blood flow was measured following the cuff being pulled to two distinct lengths; 10% and 20% of the resting length based on arm circumference. The other arm would follow a similar protocol but use a pressurized nylon cuff (5 cm wide) and be inflated to 40% and 80% of the individuals resting arterial occlusion pressure. There was a main effect of pressure for blood flow with it decreasing in a pressure‐dependent manner (High < Low, P < 0.001). The mean difference (95% CI) in blood flow between cuffs was −5.9 (−18.9, 7.0) % for the lower pressure and −4.0 (−13.2, 5.1) % for the higher pressure. When the relative changes for each cuff were separated by sex, there were no differences in the changes from Pre (P ≥ 0.509). The application of a pressure relative to the initial belt length, which is largely dependent upon arm circumference, appears to provide one method to standardize the practical blood flow restriction pressure for future research.
Purpose:
In this systematic review and meta-analysis, blood flow restriction (BFR) with low-load resistance training (BFR-RT) was compared with high-load resistance training (HL-RT) on muscle ...strength in healthy adults. The characteristics of cuff pressure suitable for muscle strength gain were also investigated by analyzing the effects of applying different occlusion pressure prescriptions and cuff inflation patterns on muscle strength gain.
Methods:
Literature search was conducted using PubMed, Ovid Medline, ProQuest, Cochrane Library, Embase, and Scopus databases to identify literature published until May 2023. Studies reporting the effects of BFR-RT interventions on muscle strength gain were compared with those of HL-RT. The risk of bias in the included trials was assessed using the Cochrane tool, followed by a meta-analysis to calculate the combined effect. Subgroup analysis was performed to explore the beneficial variables.
Results:
Nineteen articles (42 outcomes), with a total of 458 healthy adults, were included in the meta-analysis. The combined effect showed higher muscle strength gain with HL-RT than with BFR-RT (
p
= 0.03, SMD = −0.16, 95% CI: −0.30 to −0.01). The results of the subgroup analysis showed that the BFR-RT applied with incremental and individualized pressure achieved muscle strength gain similar to the HL-RT (
p
= 0.8, SMD = −0.05, 95% CI: −0.44 to 0.34;
p
= 0.68, SMD = −0.04, 95% CI: −0.23 to 0.15), but muscle strength gain obtained via BFR-RT applied with absolute pressure was lower than that of HL-RT (
p
< 0.05, SMD = −0.45, 95% CI: −0.71 to −0.19). Furthermore, muscle strength gain obtained by BFR-RT applied with intermittent pressure was similar to that obtained by HL-RT (
p
= 0.88, SMD = −0.02, 95% CI: −0.27 to 0.23), but muscle strength gain for BFR-RT applied with continuous pressure showed a less prominent increase than that for HL-RT (
p
< 0.05, SMD = −0.3, 95% CI: −0.48 to −0.11).
Conclusion:
In general, HL-RT produces superior muscle strength gains than BFR-RT. However, the application of individualized, incremental, and intermittent pressure exercise protocols in BFR-RT elicits comparable muscle strength gains to HL-RT. Our findings indicate that cuff pressure characteristics play a significant role in establishing a BFR-RT intervention program for enhancing muscle strength in healthy adults.
Clinical Trial Registration:
https://www.crd.york.ac.uk/PROSPERO/#recordDetails
; Identifier: PROSPERO (CRD42022364934).
Purpose
We compared the effects of different protocols of blood-flow restriction training (BFRT) with different occlusion pressures and/or exercise intensities on muscle mass and strength. We also ...compared BFRT protocols with conventional high-intensity resistance training (RT).
Methods
Twenty-six subjects had each leg allocated to two of five protocols. BFRT protocols were performed at either 20 or 40 % 1-RM with either 40 or 80 % occlusion pressure: BFRT20/40, BFRT20/80, BFRT40/40, and BFRT40/80. Conventional RT was performed at 80 % 1-RM (RT80) without blood-flow restriction. Maximum dynamic strength (1-RM) and quadriceps cross-sectional area (CSA) were assessed at baseline and after 12 weeks.
Results
Regarding muscle mass, increasing occlusion pressure was effective only at very low intensity (BFRT20/40 0.78 % vs. BFRT20/80 3.22 %). No additional increase was observed at higher intensities (BFRT40/40 4.45 % vs. BFRT40/80 5.30 %), with no difference between the latter protocols and RT80 (5.90 %). Exercise intensity played a role in CSA when comparing groups with similar occlusion pressure. Muscle strength was similarly increased among BFRT groups (~12.10 %) but to a lesser extent than RT80 (21.60 %).
Conclusion
In conclusion, BFRT protocols benefit from higher occlusion pressure (80 %) when exercising at very low intensities. Conversely, occlusion pressure seems secondary to exercise intensity in more intense (40 % 1-RM) BFRT protocols. Finally, when considering muscle strength, BFRT protocols seem less effective than high-intensity RT.
Purpose The blood flow restriction (BFR) training is an effective approach to promoting muscle strength, muscle hypertrophy, and regulating the peripheral vascular system. It is recommended to use to ...the percentage of individual arterial occlusion pressure (AOP) to ensure safety and effectiveness. The gold standard method for assessing arterial occlusive disease is typically measured using Doppler ultrasound. However, its high cost and limited accessibility restrict its use in clinical and practical applications. A novel wearable BFR training device (Airbands) with automatic AOP assessment provides an alternative solution. This study aims to examine the reliability and validity of the wearable BFR training device. Methods Ninety-two participants (46 female and 46 male) were recruited for this study. Participants were positioned in the supine position with the wearable BFR training device placed on the proximal portion of the right thigh. AOP was measured automatically by the software program and manually by gradually increasing the pressure until the pulse was no longer detected by color Doppler ultrasound, respectively. Validity, inter-rater reliability, and test-retest reliability were assessed by intraclass correlation coefficients (ICC) and Bland-Altman analysis. Results The wearable BFR training device demonstrated good validity (ICC = 0.85, mean difference = 4.1 ± 13.8 mmHg 95% CI: −23.0 to 31.2), excellent inter-rater reliability (ICC = 0.97, mean difference = −1.4 ± 6.7 mmHg 95% CI: −14.4 to 11.7), and excellent test-retest reliability (ICC = 0.94, mean difference = 0.6 ± 8.6 mmHg 95% CI: −16.3 to 17.5) for the assessment of AOP. These results were robust in both male and female subgroups. Conclusion The wearable BFR training device can be used as a valid and reliable tool to assess the AOP of the lower limb in the supine position during BFR training.
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