Blood Flow Restriction (BFR) – Blog

📄 A newly published study has explored the effect of Low-Load Blood Flow Restriction Resistance Training (BFR) in patients with Lateral Elbow Tendinopathy aka. Tennis elbow (LET).

📖 LET can develop as overuse or acutely after repeated action of the lateral muscles of the forearm.

🎯 Objective: To evaluate the effect of BFR VS LLRT + sham-BFR.

Design: RCT

⚗️⚙️ Methods: 46 patients were randomly assigned to BFR or LLRT.

All received soft tissue massage, general advice, a home exercise program, and either supervised exercises with BFR or sham-BFR (2/weekly for 6 weeks).

📌 Primary outcome measures were pain intensity, patient-rated tennis elbow evaluation (PRTEE) score, pain-free grip strength (PFGS), and global rating of change (GROC), measured at baseline, 6 weeks, and 12 weeks.

Between-group differences were assessed using mixed-effects models with participant-specific random effects for continuous data. GROC was analyzed using logistic regression.

📊 Results: Statistically significant between-group differences were found in favor of BFR compared to LLRT in pain intensity at 12 weeks (-1.54, 95% CI: -2.89 to -0.18; p=0.026).

PFGS at 6-weeks (0.20, 95% CI: 0.06 to 0.34; p=0.005).

PRTEE at 6- and 12-weeks follow-up (-11.92, 95% CI: -20.26 to -3.59; p=0.006) & (-15.23, 95% CI: -23.57 to -6.9; p<0.001), respectively.

At 6- and 12 weeks, patients in the BFR group had greater odds of reporting complete recovery or significant improvement (OR=6.0, OR=4.09), respectively.

💡 Conclusion: BFR was superior VS LLRT+sham-BFR for all primary outcomes. Considering the clinically significant between-group improvement (>11 points in PRTEE) and higher success rates in the BFR group.
It seems that 12 weeks of low-load BFR resistance training is superior compared to conventional low-load resistance training in the management of LET. Thus, it would be interesting to see how BFR compares to Heavy Slow Resistance (HSR) Training in the treatment of Lateral Elbow Tendinopathy!?

Source: Karanasios et al. (2022) Low-load resistance training with blood flow restriction is effective for managing lateral elbow tendinopathy: a randomized, sham-controlled trial.
doi.org/10.2519/jospt.2022.11211

🖇 This is a follow-up to the recent Post (August 24, 2022) presenting the LOP Device (V1.1).

📺 This time around we look at how to measure lower-body Limb Occlusion Pressure (LOP) with the Leg Cuff V3.1, as it can be a bit tricky compared to upper-body assessments.

🚫 If you have no interest in the product or have already been through the guide at fitcuffs.com/lop the content below might not be for you. But if you´re struggling with Leg LOP’s check at least section 7!?

1. Make sure the cuff is completely deflated.

2. Wear the Leg Cuff tight before inflation and please remember not to sit on it.

3. Position yourself or your client as displayed, resting the foot on the floor with a straight or slight bend knee.

4. Sit still – even the slightest movement or subtle muscle contraction/twitch can interfere with the calculation and make it impossible for the device to detect LOP.

5. Inflate to about 280 mmHg before you let the LOP Device deflate.

6. Before the cuff has been deflated below 230 mmHg, adjust the valve on the pressure gauge to slightly increase the rate of deflation. Only the very peak of the green pulse waves is accepted outside the app display.

🔄 7. An alternative method is displayed in the video. As you can also adjust the pressure gauge just a tiny bit, but before inflating the cuff, again for accelerating the rate at which air is released.

💡 A correct deflation rate is characterized by only the very peak of the pulse waves being out of bounds. As a rule of thumb aim for a deflation time of 20-50 seconds from 250 mmHg to 110 mmHg. But when the device has deflated below 230 mmHg, please remember not to adjust any further as this will interfere with the measurement.

⚠️ Disclaimer: When assessing conventional blood pressure (BP), you should always use a calibrated cuff in terms of size. The ideal cuff should have a bladder length that is 80% of the arm circumference, a width that is at least 40% of the arm circumference, and a length-to-width ratio of 2:1. That is why you cannot use Fit Cuffs product selection to measure BP.

Please check fitcuffs/lop.com for more information and remember not to hesitate leave a comment at Instagram.

📄 Source: Pickering et al. (2005) Recommendations for Blood Pressure Measurements in Humans and Experimental Animals: Part 1: Blood Pressure Measurement in Humans: A Statement for Professionals From the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research
DOI: 10.1161/01.HYP.0000150859.47929.8e

📄A Meta-Analysis have recently explored the effect of relative pressure and relative load on strength gains.

Introduction:
Important parameters for BFR are % of Limb Occlusion Pressure (LOP) and % of 1RM.

Background:
Individualizing pressure (% of LOP) produces uniform physical-stress VS fixed pressures.

High-Load Resistance Training (HLRT) seems superior for strength VS Moderate/Low-Load resistance training.

🔎Aims:
Determine a minimal and optimal %LOP for BFR + minimum % of 1RM, volume load, and total reps required for significant strength gains.

Method:
PRISMA guidelines. 775 identified articles, 21 included in the meta-analysis.

📊Results:
BFR at 1RM ≤20% or ≥80% inferior VS no-BFR HLRT.

≤50% and ≥ 80% of LOP did not produce significant strength gains VS controls.

BFR at ≥30 %1RM matching no-BFR HLRT (70–80% 1RM).

40–60% 1RM BFR may produce results exceeding no-BFR HLRT!?

⚠️Limitations:
Hypertrophy may be achieved at different %LOP and/or %1RM.

💡Conclusion:
% of 1RM appears to be more important VS % of LOP.

50–80% LOP seems to be the sweet spot.

💬Discussion:
Future studies should compare gender, age, and training experience discrepancies.

Thus, mentioned in the Introduction, no analysis of the optimal volume load, and/or total repetitions were included!?
Also worth noting is the lack of analysis and/or comparison as the proposed Pressure-Load Continuum!?
Looking at previous meta-analysis when utilizing 30% of 1RM, there is no additional effect at ≥50% LOP!?

Mechanistically, it seems using loads >40% 1RM intramuscular occlusion occurs naturally for most muscle groups relative to inter-individual variance in muscle size..

Page 5 – “Interestingly 40% 1RM with BFR produces significantly greater strength improvements when moderate pressure was applied (70% LOP), but significantly lower strength improvements at low-moderate pressure (40% LOP).”

This statement seems rather bold as only 2 of the included original papers explored 40% of 1RM and the high pressure study combined No-HLRT + BFR training sessions..

Primary Source:
Das & Paton (2022) Is There a Minimum Effective Dose for Vascular Occlusion During Blood Flow Restriction Training?

Secondary source:
Queiros et al. (2021) Myoelectric Activity and Fatigue in Low-Load Resistance Exercise With Different Pressure of Blood Flow Restriction- A Systematic Review and Meta-Analysis
Loenekke et a. (2014) Blood flow restriction pressure recommendations: the hormesis hypothesis
Ilett et al. (2019) The Effects of Restriction Pressures on the Acute Responses to Blood Flow Restriction Exercise
Cerqueira et al. (2021) Repetition Failure Occurs Earlier During Low-Load Resistance Exercise With High But Not Low Blood Flow Restriction Pressures: A Systematic Review and Meta-analysis
Pignanelli et al. (2019) Low-load resistance training to task failure with and without blood flow restriction- Muscular functional and structural adaptations
Loenneke et al. (2015) Effects of exercise with and without different degrees of blood flow restriction on torque and muscle activation
Dankel et al. (2017) Are Higher Blood Flow Restriction Pressures More Beneficial When Lower Loads Are Used
Counts et al. (2016) Influence of relative blood flow restriction pressure on muscle activation and muscle adaptation

Brachiation is the hanging movement focused on the upper limbs with the shoulders in full flexion and elbows in full extension. Put simply it is the form of overhead movement whereby one swings across from one arm to the other.

🚦Something to do or absolutely NOT to do mingled with BFR!🚫?

🚦Or can it be prescribed and justified relative to strength levels, previous experience with brachiation and the actual goal with this unusual mixture!?

Any thoughts, like possible relative or absolute contraindications for brachiation attenuated with BFR?🔎🗯💡

Let us know what You think in the comments at Youtube or Instagram.

In a newly published pilot study, the authors explored the safety and tolerance of Blood Flow Restriction Training (BFR) post- Anterior Cruciate Ligament Reconstruction (ACLR) in teenagers.

Introduction

The effectiveness and safety of BFR have been well studied in adult subjects, however, there is limited data concerning adolescents. It was hypothesized that adverse events and patient tolerance will be consistent with previously pub­lished literature. So, the present study explored if any side effects occurred and reported patient tolerance to BFR Training post ACLR.

Material & Methods

Study design: Prospective Cohort Study.

Participants: 29 Patients between 12 and 18 years of age who underwent ACLR.

Post-ACLR Rehab Protocol: All patients initiated formal physical therapy within one week of surgery and followed a standardized BFR protocol over the 12-week early rehabilitation phases starting as early as 8.72 (±3.32) days post-op.

30x15x15x15 reps with 30 s. inter-set rest, 3/weekly. Patients had 8 min. to complete the target of 75 repetitions for 3 different exercises.

Limb Occlusion Pressure (LOP) was measured for each limb individ­ually at the beginning of every train­ing session, using continuous BFR at 80% LOP. Thus, allowed to request a reduction of LOP during exercise based on their tolerance.

Progression & Tolerance: Rating of perceived exertion (RPE) of 1RM was estimated using the modified OMNI-RES scale and the initial load was 20-30% 1RM.

Upon completion of exercises, patients reported side effects and potential adverse events were logged for calculation of frequencies of those during the 12-week intervention

Results

535 total BFR sessions were completed. There were 0 reports of subcutaneous hemorrhage, fainting, or deep vein thrombosis (DVT).

Reporting of minor side effects included itchiness (7.85%), lower extremity paresthesia (2.81%), and dizziness (0.75%).

Conclusion

As expected, this preliminary data suggests that Occlusion Training is safe with only minor side effects in the adolescent population after ACLR and no major side effects were reported. Thus, further data is needed for a definitive deter­mination of the safety profile in this population.

Primary Source: Prue et al. (2022) Side Effects and Patient Tolerance with the Use of Blood Flow Restriction Training after ACL Reconstruction in Adolescents: A Pilot Study.

LOP is defined as the minimum pressure required to stop arterial and venous blood flow to the corresponding limb, at a specific time, in a specific position with a specific cuff being applied. Aka. 100% LOP.

The Pressure-Load Continuum in Blood Flow Restriction Training (BFR Training):
In occlusion Training when utilizing higher pressures (70~80% LOP) use lighter loads (20~25% 1RM) & with higher loads (30~45% 1RM) use less pressure (40~50% LOP)

Research facilities & Universities that have participated in the study of the Bluetooth Device vs. doppler ultrasound: Research facilities & Universities that have participated in the study of the Bluetooth Device vs. doppler ultrasound:

Unpublished – El-Zein (2020) (Thesis) the use of a portable Bluetooth Device to measure blood flow restriction training pressure requirements: a validation study.

Unpublished – Schmidt (2021) (Thesis) Validity and reliability of an oscillatory blood pressure measurement device to determine the arterial occlusion pressure in healthy adults for blood flow restriction training exercise protocols: a cross-sectional study.

How the Bluetooth Device performs and compares to Handheld doppler:

Independent comparative product testing at 3 separate research institutions around the globe are all showing very good validity of the Bluetooth Device. I.e., Inter-Rater Reliability (Correlations) and Test-Retest Reliability (Intra-Class Correlation Coefficient) – (ICC):

The Bluetooth Device has a variance of only 1-5% by comparing the Bluetooth Device vs. LOP assessment by Handheld Doppler Ultrasound and the second “golden standard” Doppler Pulse Wave Ultrasound.

In conclusion, the research shows a clinically acceptable agreement between the different methods of LOP measurement.

The guide – see also fitcuffs.com/lop:

1. Download the corresponding 3. party app to your phone – You will receive information concerning the app together with the tracking number of Your parcel. ⇩

2. Connect Your phone with the Bluetooth Device via the app interface. ⇩

3. Attach the Cuff to the corresponding limb. – Remember, to have a tight fit for the lower body. ⇩

4. Connect the Bluetooth Device with the Fit Manometer & Cuff. ⇩

5. Be completely still and follow the displayed guide on the app. – Remember, the Bluetooth Device will automatically deflate the cuff. ⇩

6. After successful measurements, You will find SYS (LOP) in the top left corner. ⇩

7. Detach the Bluetooth Device from the Cuff and Pressure Gauge.⇩

8. Set the pressure relative to the measured LOP (40-80%), but without the Bluetooth, Device attached!

❔Problems with lower body measurements, see the “Troubleshooting” section at fitcuffs.com/lop

secondary source:

Babbs (2012) Oscillometric measurement of systolic and diastolic blood pressures validated in a physiologic mathematical model.
Berger et al. (2001) How Does It Work? – Oscillatory blood pressure monitoring devices.
Beevers et al. (2001) ABC of hypertension Blood pressure measurement Part I -Sphygmomanometry: factors common to all techniques.
Clinical review.Croft & Cruickshank (1990) Blood pressure measurement in adults: large cuffs for all?
Jordanow et al. (2018) Comparison of oscillometric, Doppler and invasive blood pressure measurement in anesthetized goat.
Morais et al. (2016) – Upper limbs total occlusion pressure assessment- Doppler ultrasound reproducibility and determination of predictive variables.
Zachary et al. (2020) Limb Occlusion Pressure: A Method to Assess Changes in Systolic Blood Pressure.
Evin et al. (2020) Limb occlusion pressure for blood flow restricted exercise- variability and relations with participant characteristics.
Loenneke et al. (2014) Blood flow restriction in the upper and lower limbs is predicted by limb circumference and systolic blood pressure.
Masri et al. (2016) Technique for Measuring Limb Occlusion Pressure that Facilitates Personalized Tourniquet Systems- A Randomized Trial.
Hughes et al. (2017) Influence and reliability of lower-limb arterial occlusion pressure at different body positions.
Hughes & McEwen (2021) Investigation of clinically acceptable agreement between two methods of automatic measurement of limb occlusion pressure- a randomised trial.

📝A literature review (@msccerqueira et al. 2021) containing 29 original papers on cardiovascular adaptations to BFR training explores whether increasing pressure is warranted!?

❕️Blood Flow Restriction Pressure – absolute mmHg or % limb occlusion pressure (BFRP)

📌Introduction:
A major methodological concern in BFR training both from a practical and research perspective is how much BFRP is needed for optimal safety and effectiveness.

Cardiovascular adaptations to BFR and their possible relationship with BFRP are currently not well understood.

Subsequently, it is unknown if increased BFRP throughout a training intervention is needed for optimal outcomes!? Though many studies increase BFRP, it is unclear whether adjustments are warranted.

📍Methods:
Studies included assessments of chronic effects of BFR (>3 weeks of training) and outcomes that may influence BFRP.

Macro- and Microvascular Function & Adaptations to BFR:
BFR potentially increases vasodilatory capacity to reactive hyperemia reducing peripheral vascular resistance, stimulating capillarization, improving arterial compliance, less stiffness, and increasing arterial diameter.

Though, there is a rationale for decreasing BFRP based on vascular adaptations like reduced blood pressure.

❔️Is BFRP Adjusted in the Research? 35% (n =10) of the included studies adjusted BFRP during BFR training intervention with different rationales for BFRP adjustments: To achieve high levels of perceived effort, allow participants to adapt to the occlusion stimulus or impose progressive overload in muscles and circulation.

❔️Need for BFRP Adjustments?
When using fixed BFRP perceived effort and pain may decrease during the intervention period without impairing neuromuscular gains. unnecessary increases in BFRP may contribute to discomfort, impair adherence, and increase the risk of adverse events.

Conclusion:
Currently, no clear justification is provided in the literature for BFRP prescription during BFR exercises, and no specific recommendation can be identified if BFRP should be adjusted during a BFR training intervention.

Considering the possible lowering effect of BFR training on blood pressure, longitudinal studies directly measuring BFRP are needed to establish whether the effect is different in clinical populations.

Future studies should explore if changing BFRP makes BFR training safer and/or more comfortable with similar physiological adaptation!? And discover if there is a BFRP upper or lower threshold to induce cardiovascular adaptations.

Comments:
Anecdotical evidence can probably verify that starting with less BFRP seems to improve the likelihood of adherence to BFR Training. This highly relevant clinical concern has been elaborated by Rolnick et al. (2021).

Worth noting is the common and warranted individual approach to general training dosage that inherently also applies to BFRP. Folks which either are experienced with resistance-type exercise or just being highly motivated may start with higher BFRP (60-80% LOP) as Ratings of Perceived Effort or pain might not be a relevant barrier. On the other hand, less experienced individuals or fragile elderly might benefit from starting with less BFRP (40-50% LOP).

Another important perspective is the other relevant parameters of progression in BFR Training. In both clinical practices and effect studies, if the resistance/load is progressed accordingly throughout the intervention period, alteration of BFRP is probably not warranted above the common threshold of ~50% LOP.

Future research could feature a 3-group design with the following effect parameters: Constant BFRP VS Increasing BFRP VS Decreasing BFRP.

Muscle strength/hypertrophy & Changes in central and/or peripheral cardio vasculature & Adherence as either drop-out/self-reporting acceptability of the intervention

Primary Source: Cerqueira et al. (2021) Blood Flow Restriction Training – To Adjust or Not Adjust the Cuff Pressure Over an Intervention Period.

Secondary Source: Rolnick et al. (2021) Perceived Barriers to Blood Flow Restriction Training.

Presenting the V3.1’s as the redesigned Contoured Leg Cuffs & the swiftly attached Arm Cuffs both designed for Blood Flow Restriction Training (BFR Training).

Yet again this is old news, as this was officially released last week (Check our Instagram story highlights here, but on this blog post, we collect and present this literally.

Beware of copy-🐈‍⬛”s from the blog post from 01 February 2022 concerning the V2.1 cuffs, ⚠️Nerd-Alerts⚠️ & the expected high LIX as usual as we run through the Nuts & Bolts:

🔩Updates concerning Arm & Leg Cuffs V3.1⚠️: 🐈‍⬛” The backside material is the same as the V2.1 which is a thicker TPU coated nylon material that prevents movement of the cuff during exercises with near-infinite durability.
🐈‍⬛” The Cu-logo rubber patches are mostly for the looks, but if you get your hands on these You will soon discover it simply makes attachment and particularly detachment of the cuffs more intuitive.

🔩Improvements for the Arm Cuff 3.1⚠️: The asymmetrical placement of hook & loop velcro enables the cuff to fit a larger range of arm sizes. Specified as applicable for arm sizes 20->50cm

🔩Improvements for the Leg Cuff 3.1⚠️:

🐈‍⬛” After testing several prototypes and researching on mechanical properties of different materials, we believe to have discovered a core material and thickness with an excellent blend of both stability, pliability & improved tensility. This flexible material seems to be the perfect match for occlusion training as this decreases pressure fluctuations during muscle contractions.

🐈‍⬛” Subjective comfort is also of huge importance in BFR Training as this type of training is inherently unpleasant in itself. In hand the Leg Cuff V3.1 simply feels more robust but also a bit softer to the touch compared to similar devices. This is definitely noticeable during your occlusion training sessions with the Leg Cuffs V3’s.

🐈‍⬛” The air-plug has been further reinforced by an external rubber patch with the black protruding logo. Applicable for sizes 45->85cm as both straight and tapered thighs adjusted by the placement of the hook velcro strap as shown.

Please let us know by email or write a review at trustpilot.com/review/fitcuffs.com of what you think of the V3s & if You see any benefit of the redesigned V3.1s!?

It seems that BFR prehab training can improve outcomes for Total Knee Arthroplasty (TKA).

📄A relatively new pilot study exploring the possible effect of BFR Training before TKA (prehab). I.e., can BFR used only pre TKA attenuate atrophy and improve function post-TKA!?

➡️Introduction: It is important in TKA’s to mitigate the decline in strength, muscle mass, and functioning. Though, conventional resistance training (RT) is often not well tolerated preoperatively and prohibited in the acute to sub-acute phase post-op.

🔳Aim: Explore the feasibility and acceptability of BFR Training in the preoperative period for patients awaiting TKA.

🔩Methods: Patients undergoing TKA were randomized to either BFR exercise for 4 weeks before surgery vs standard care (no exercise).
BFR group: 2/weekly as 2 sets of each exercise to volitional failure: leg press, leg extension, leg curl, and calf raise at 30% 1RM.

Pressure (mmHg) set as: 0.5(SBP) + 2(thigh circumference) + 5.

📐Outcomes: Baseline; 4 to 5 weeks preoperatively and follow-up; 2 weeks postoperatively.

📌Physical function – Short Physical 📌Performance Battery (SPPB). 📌6-Minute Walk Test (6MWT). 📌Leg strength (peak torque). 📌Numerical Pain Score (NPS).

📏Secondary outcomes:

📌Patient acceptability as the rating of exertion (Borg CR10)
🤷🏽‍♂️Patients’ ratings of “pleasantness” of exercise 0-100!?

📊Results: BFR group: less decline in SPPB following surgery (-2.2,) VS No-BFR (-4.8). No differences for the 6MWT, peak torque, and NPS.
No complications and full compliance were observed as a proxy for the feasibility and acceptability of BFR.

Discussion:
The study was not powered (few participants and small expected outcome difference) for statistical comparison of the 2 groups. It can also be speculated that the volume load was underdosed as 2/weekly with 4 different exercises but only 2 sets of each, as the body of evidence seems to favor 3-4 sets of each exercise. And importantly, it would be of higher clinical relevance comparing BFR vs similar exercises without BFR.

It seems obvious that muscle strength and size for the postoperative phase (rehab) is of greater importance than BFR used only as prehab because of the expected “return to the mean”. So, it would be interesting to explore if BFR-prehab can accelerate functioning when also used as rehab!?

Either way, stay tuned for the results of an ongoing study with about 150 participants on BFR Training vs Standard PT After Total Knee Arthroplasty

Primary Source: Przkora et al. (2021) Blood flow restriction exercise to attenuate postoperative loss of function after total knee replacement: a randomized pilot study.

Secondary Source: BFRT vs Standard PT After Total Knee Arthroplasty (BFRT-TKA) – Only protocol ATM: clinicaltrials.gov/ct2/show/NCT04366336
Wengle et al. (2021) The Effects of Blood Flow Restriction in Patients Undergoing Knee Surgery: A Systematic Review and Meta-analysis.

After valuable user feedback, development and prototype testing, we can proudly present the polished version of the straight arm & leg cuffs the V2.1 cuffs!

For some of you this might be old news, as this was officially released last week, but in this post, we dig a bit deeper and present what the new cuffs have on offer.

Some of the changes are mostly of what we find “cosmetic”, but others are designated improvements of functionality and durability.

Below we run through ⚙️&🔩. So please beware of the ⚠️Nerd-Alert ⚠️.

🔩Updates concerning Arm & Leg Cuffs V2.1:
The backside material has undergone a major update. That is a new thicker TPU coated nylon which inhibit sliding of the cuff during exercise and seems to be extremely durable with almost infinite longevity.

The Cu-logo rubber patches are mostly for the looks, but if you get your hands on these You will soon discover it simply makes attachment and particularly detachment of the cuffs more intuitive.

🔩Exclusive improvement for the Leg Cuff V2.1:
To decrease pressure fluctuations during muscle contractions, we have implemented a more flexible internal core material. After testing several prototypes and researching on mechanical properties of different materials, we believe to have discovered a core material and thickness with an excellent blend of both stability, pliability and tensility.

In hand the Leg Cuff V2.1 simply feels more robust but also a bit softer to the touch.

The air-plug has been further reinforced by an external rubber patch with the black protruding logo.

Please let us know at info@fitcuffs.com what you think of this new design and do not hesitate if you have any suggestions for further improvements!?

A recent review by Queiros et al. has explored how different restriction pressures measured as % Limb Occlusion Pressure / Arterial Occlusion Pressure (LOP) effects fatigue.

📍Background:
Considering the association between metabolite induced fatigue with muscle hypertrophy, some authors have investigated how manipulating BFR pressures during exercise can exert an effect on the level of acute fatigue i.g., Maximum Voluntary Contraction (MVC) or electromyography (EMG).

The data from the original studies are divergent, but it seems that very low-load resistance exercise performed with higher pressures evokes higher levels of acute fatigue and overall training effect known as the pressure-load continuum.

📍Aim:
Systematically review and pooling of available data on neuromuscular and metabolic responses at Low-Load BFR resistance exercise (LL-BFR) with different pressures (% of LOP/AOP).

The effects of different restriction pressures on neuromuscular responses can assist trainers and physical therapists in more appropriate and safer prescriptions.

📍Main Outcomes:
1. Maximum Voluntary Contraction (MVC)

2. Surface Electromyography (EMG)

1. MVC:
40% vs. 60% LOP – No difference.

30% of 1 RM: 40-50% vs. 80-90% LOP – No difference.

15-20% 1 RM: 40-50% vs. 80-90% LOP – Favor of High Pressure.

40-80% LOP vs. No-BFR (Free Flow) – Favor of BFR.

2. EMG:

“Not failure protocols”: 40% vs. 60% or 80% LOP – Favors Higher Pressure.

“Failure protocols”: 40% vs 80% LOP – Favors Less Pressure

Low-load 40-80% LOP vs. Low-Load No-BFR – No difference.

Low-load 40-80% LOP vs. High-Load No-BFR – Favors High-Load.

📌Conclusion

Not surprisingly, low-load resistance exercise with (40-90% LOP) BFR pressure induces more fatigue than No-BFR low-load.

For very low-load (15–20% 1RM) higher pressure (about 80% LOP) can increase the magnitude of fatigue and are thereby recommended. On the other hand, it seems that higher pressures (≥80%) with loads of 20-40% 1 RM should not be performed to failure but instead use a pre-defined repetition schemes e.g., 30x15x15x15 reps.



📄Primary Source:
Queiros et al. (2021) Myoelectric Activity and Fatigue in Low-Load Resistance Exercise With Different Pressure of Blood Flow Restriction- A Systematic Review and Meta-Analysis

As a related topic, the potential of BFR combined with “functional” training has been discussed in an opinion article from Da Silva-Grigoletto et al. (2020).

The authors deliberate on the possible integration of functional resistance training with BFR which may maximize the effects of conventional training.

To our knowledge no articles has yet to explore or discuss the potential use of BFR in combination with typical dynamic stability exercises for the shoulder!?
Though, the rational is perhaps not too farfetched!?

Various sports and simple ADL requires relative amounts of shoulder stability i.e. inter-individual task demand. So, by improving dynamic stability through various exercises, you will likely prevent and treat injuries or pain associated with these.

BFR in combinations with low-load resistance training seems to be both time and load effective with respect to the current body of evidence:

Any conventional shoulder exercise can be combined with BFR training, just mind that training involving dynamic biceps or triceps contractions would probably benefit the most from BFR.

BFR training for the upper body is most effective when conducted with high reps (15-30 or failure), low load (20-40% of 1RM) and short rest periods (30-60 s). It is recommended to only do 2-4 different exercises relative to your experience.

On the other hand, dynamic stability exercises for the shoulder stresses various physical systems, especially coordination and muscle endurance. The rationale underlying multi-system adaptations with dynamic stability exercises, can be explained by the manipulation of exercise complexity (variations in stability, movement velocities etc.), load or simply time under tension.

In the present video, the last 2 exercises can be categorized as “dynamic stability” drills (00:37 →), So these are intrinsically not well-suited for the standard BFR Training protocol. But by matching time under tension for conventional BFR training, it seems appropriate to extrapolate this as 30-90 s. active exercise relative to the difficulty of the task, followed by the standard inter-set rest period.

The rational for doing BFR combined with dynamic stability drills is the same as for low-load BFR resistance training. A tool to increase the internal training load with less extrinsic load while also being time saving.

Any thoughts on using BFR with “functional” resistance training or dynamic stability drills to enhance adaptations, please let us know!? info@fitcuffs.com or IG at @fitcuffs

Thanks to @kostasrotziokos for the brilliant video material!

Source:
Da Silva-Grigoletto et al. (2020) Functional Training and Blood Flow Restriction: A Perspective View on the Integration of Techniques.

FYI – When doing upper Body BFR, keep in mind that the the cuffs are always attached at the top of the upper arm, just below the armpit.❗

In a previous blog post from August 05, intermittent BFR (deflating the pressure in the inter-set rest period) was mentioned to mitigate or at least attenuate perceptual responses to BFR.

The actual effect of intermittent BFR (iBFR) vs Continuous BFR (cBFR) has recently been investigated in a review by Sinclair et al.

The present paper was conducted to decipher whether iBFR improves tolerance, without compromising strength, as iBFR VS cBFR on outcomes of exercise tolerance or strength.

Materials and Methods: Only RCT’s were included in this review. The primary outcomes of interest were those describing tolerance to BFR during exercise:
• Rating of perceived exertion (RPE)
• Pain
• Discomfort
• Delayed onset muscle soreness (DOMS)
• Objective reporting of adherence rates and adverse events, with the appropriate reasons provided.
• Qualitative reporting of experiences and preferences.

Secondary outcomes:
Change in muscle strength.

Search strategy: Preferred reporting system for systematic reviews and meta-analyses (PRISMA) statement. Data analysis: Cochrane risk of bias tool for randomized trials e.g., randomization and allocation processes, blinding of participants, investigators and outcome assessors, and reporting of outcomes. Excluded studies whose methodology created a disparity in tourniquet pressure across groups, i.e., confounding variable.

Results:
186 studies were selected, but only 9 RCT’s were included published between 2013-2019, 7 were cross-over by design.
The iBFR groups of all studies had their cuffs deflated in the inter-set rest periods. All but one study deflated the cuffs during the rest periods between exercises for both iBFR and cBFR.

Primary outcome:
There was no significant difference in RPE between BFR training methods, however, the effect estimate shifted towards the use of iBFR.

Secondary outcome:
No significant strength difference between BFR groups.

Discussion:
It seems iBFR may be better tolerated than cBFR. The overall difference in the meta-analysis however did not show significant variance. Additionally, there is limited evidence to suggest that comparable gains in strength can be expected.

Conclusion:
Deflating the cuffs risks attenuating the metabolic stress and thus the mechanism by which BFR exerts its effects on hypertrophy and strength. It is recommended that further research in this area focus on other means to improve tolerance to exercise.

Primary Source: Sinclair et al. (2021) Tolerance to Intermittent vs. Continuous Blood Flow Restriction Training: A Meta-Analysis.

In this blog post we present the results from a BFR-futsal RCT conducted on 12 elite futsal players:

Aim: The effect of 3 weeks of BFR-Futsal on performance, strength and hormone levels.

Method: 12 players, 6 BFR-players vs. 6 No-BFR. 10 sessions as small sided games 3 vs. 3, 3 min futsal followed by 2 min rest for 4-8 intervals. BFR group had cuffs inflated to 110% of leg systolic blood pressure and further increased by 10% after every two completed sessions. Intensity 80–100 % HRmax in both groups.

Results: BFR-group had significantly greater improvements in peak torque knee extension (30.9 ± 8.0% vs. 14.9 ± 7.5%), flexion (23.8 ± 8.4% vs. 8.1 ± 5.7%), favorable serum concentration of myostatin and a trend for a greater improvement in a Futsal Special Performance Test. Though, Ratings of Perceived Exertion were higher in the BFR-group: (13–14 Borg) vs. (15-17 Borg).

Conclusion: The study combined futsal training with BFR and showed that the addition of BFR was superior to normal futsal training. The addition of BFR to futsal practice can enhance muscle activation, strength and hormonal responses. But please consider several limitations, e.g. sample size was fairly small.

Our recommendation regarding augmentation of functional BFR Training to team sports like futsal: Be cautious if you apply BFR in situations with near maximal effort such as jumping, acceleration and change of directions, as these types of movements are associated with peak muscle forces comparable to heavy lifting. And not least, the risk of adverse events in relation to contusions on blood flow restricted limbs, which is obviously not appealing.
The inclusion of BFR in futsal or similar sports is twofold. As shown in the current study the potential performance enhancement is obvious and for rehab and return to play this seems relevant. Regarding the high exercise intensity, olieveira et al. showed that Low-intensity BFR-interval running had similar benefit compared to high-intensity BFR.

Source:
Amani et al. (2019) BFR During Futsal Training Increases Muscle Activation and Strength.
Oliveira et al. (2016) Short-term BFR interval training improves both aerobic fitness and Strength.

In this post we present the outstanding results from a BFR-running RCT conducted on physically active women.

The study combined interval running with BFR and showed that training intensity and pressure are important for aerobic, anaerobic, and muscular performance!

Purpose: Comparison of different BFR stimuli and exercise intensities on aerobic, anaerobic, and muscle strength in 4 different groups, as a dose response study.

A 4-week intervention period consisted of 3d/week, 10 sets for each session as 2 min running on a treadmill with BFR interspersed by 1 min of recovery without BFR. The pressure was estimated from thigh circumference.

The four groups: (IP-CE): Increasing Pressure with Constant Exercise intensity. (CPP-IE): Constant Partial Pressure with increasing Exercise intensity. (IP-IE) Increasing pressure with increasing exercise intensity. (CCP-IE): Constant Complete occlusion with increasing exercise intensity.

The study demonstrated improvements in all aerobic and anaerobic variables in all 4 groups, with a trend for greater gains for all parameters in response to progressing intensity and high BFR stimuli.

The CCP-IE (complete occlusion) group had a trend for the greatest overall effect (Vo2max Ꙟ 14.8%). – Though, it might be contrary for safety and could hypnotically lead to adverse events. Nevertheless, this is not the first study that shows a higher BFR stimuli is superior and this was also conducted on a young population + a trend for higher Ratings of Perceived Exertion (RPE) in the CCP-IE group.

Conclusion of the study: Interval based BFR-running with higher BFR stimuli and progressive intensity is superior for overall effectiveness.

We do not recommend complete occlusion (100% Limb Occlusion Pressure) / 100% AOP for the general public, but it is common practice that you either progress effective running time or pace.

Another discovery is that circumference seems to be a legit way to set the pressure, while using Fit Cuffs, we recommend that you use Fit Cuffs Training App – training.fitcuffs.com

Source: Amani et al. (2019) Effects of Blood Flow Restriction and Exercise Intensity on Aerobic, Anaerobic, and Muscle Strength Adaptations in Physically.

This recreational athlete (true ⚽️) experienced pain with squatting, sumo deadlifts and similar type of exercises, with symptoms originating profound (deep) within the groin.

Subsequently, special tests were positive for both FABER (hip Flexion-ABduction-External Rotation & FADIR (hip Flexion-ADduction-Internal-Rotation).

As both history and tests indicated intra-articular irritation e.g., overuse injury of the labrum of the hip, reminiscent of Internal Hip Impingement aka Femoroacetabular Impingement (FAI). Even though, FAI can further be classified relative to structural characteristics of the hip as either CAM, PINCER or both, a pragmatic approach without further specification by MR is often sufficient for positive rehab outcomes.

For most types of overuse injuries with or without any underlying mechanical morphology, 100% bullet proof diagnostics, isn’t necessary to achieve relief while maintaining or improving physical function. In this case, simply doing too much of specific exercises too soon had initiated the symptoms and if not managed properly would most likely exacerbate.

First line care for this athlete would be working around pain in a progressively manner and other passive modalities as hip mobilization techniques being secondary, to support performing at the upper best. So, whenever appropriate relative to the severity of the injury aiming for non-time-loss management e.g., missing no playing time.

Both general and joint specific warm-ups, wasn’t relieving pain as conventional wide knee squats and similar movements where still tricky, so other strategies were explored.

The immediate objective was to determine the least affected squatting pattern and as often seen with these types of hip problems, limiting hip abduction, deep hip flexion and external rotation of the femur seemed most comfortable.

So, as displayed in the video with the smith-machine squats was selected because the fixed bar paths enable You to place the feed in front of the axial load, mitigating the deep of part of the ROM (hip flexion) without deviating to far from conventional squatting. Secondly, by applying a narrow stance hip abduction and hip external rotation are also limited.

Thirdly, using low-load the compressive forces within the hip is further eased. And by applying Blood Flow Restriction the effective rep range is reached sooner and volume load is simply less compared with conventional low-load training.

Source:
Luebbers et al. (2014) The Effects of a 7-Week Practical Blood Flow Restriction Program on Well-Trained Collegiate Athletes.

Abe et al. (2005) Eight days KAATSU-resistance training improved sprint but not jump performance in collegiate male track and field athletes.

Cook et al. (2014) Improving strength and power in trained athletes with 3 weeks of occlusion training.

Neto et al. (2014) Effects of high-intensity blood flow restriction exercise on muscle fatigue

Scott et al. (2017) The effects of supplementary low-load blood flow restriction training on morphological and performance-based adaptations in team sport athletes.

In this follow-up post we present the findings from a recent editorial concerning Blood Flow Restriction.

Introduction:

Numerous research papers have shown its effectiveness using light loads/intensities in the elderly, impaired to high performance athletes. More recent data shows promising results with novel application such as whole-body vibration techniques and neuromuscular electrical stimulation.

Safety:

Though, current guideline exits e.g., Patterson et al. 2019, more research is warranted for long term effects consistent use of BFR!?

Though, recent research has explored the safety aspect of longer term (1 month) of consistent low-load BFR resistance training on parameters of cardiovascular health. It seems that general blood pressure, mean arterial pressure and systemic vascular resistance are unaltered at rest during and after the intervention period. The authors also discovered that BFR Training were hypotensive (reduced blood pressure) during handgrip exercise, thereby suggesting a hypotensive effect

The authors also discovered that the metaboreflex following BFR – the proposed effect of low oxygen delivery to muscles and metabolites accumulation stimulating skeletal muscle afferents and thereby increased blood pressure, were not present after the training period.

Efficacy:

A recent systematic review with data from 13 original papers investigated whether exercise interventions utilizing BFR were able to improve various objective measures of physical function relevant for active daily living (ADL) in the elderly.

The authors discovered increased performance on tests like:

30 s sit-to-stand
Timed up and go
Walking speed
Balance and Stepping tests

Conclusion:

BFR appear safe and effective for muscle hypertrophy, aerobic capacity and strength comparable to conventional exercise, but the precise mechanisms and optimal protocols still require additional exploration!? But considering the current research, it seems that many modes and different protocols can be applied to positively affect health and performance across various populations.

Primary Source:
Patterson, Burr, Warmington (2021) Editorial: Blood Flow Restriction: Rehabilitation to Performance

Secondary Source:
Clarkson et al. (2019) Chronic Blood Flow Restriction Exercise Improves Objective Physical Function: A Systematic Review

A relatively new editorial from Patterson et al., elaborates on the current utility of BFR in various populations extracted from 18 original research, 1 systematic review, 1 review and 1 opinion papers.

Introduction:
BFR training has demonstrated efficacy when using light-loads/intensities (20–30% 1RM / 40-60% VO2 Max), generating supporting evidence for BFR resistance training and aerobic exercise, but also passively i.e., Ischemic Preconditioning (IPC).
Despite a growing body of evidence in support of beneficial outcomes as well as functional performance benefits, there is no absolute consensus for the application of different BFR modes or protocols.

Acute Responses of BFR:
There seems to exists a progressive response to increasing applied restriction pressure with a minimum “threshold” of ~60% Limb Occlusion Pressure (LOP) when using very low-load BFR resistance training (20% 1RM), for long-term training adaptations.
Compared with both high- and low load resistance training, the vascular stress is greater with BFR relative to the amount of muscle mass used such as multi- vs single joint exercises. That is why caution be exerted when prescribing BFR to certain at-risk populations and more research are needed to explore the long-term hemodynamic and vascular effects of BFR

Adaptations to Training with BFR:
While mechanical tension and metabolic stress seem to share the variance of the muscle hypertrophy response in high-load training, the metabolic stress seems to be the main mechanism responsible for muscle hypertrophy in BFR Training. Though, it seems that BFR training increases long-term muscle protein turnover to a similar degree compared to high-load training. Collectively, the literature support the clinical value of BFR for populations in whom exercise with high loading is untenable.

Ischemic Preconditioning:
Performance capacity may be mediated through altering exercise-induced blood flow and/or vascular function. Considering the current literature, future studies should test the clinically relevance of shorter protocols 12min (2 × 2–3min occlusion/reperfusion)!?

Primary source: Patterson et al. (2021) Editorial: Blood Flow Restriction Rehabilitation to Performance

Ratings of Perceived Exertion (RPE), general discomfort, or pain likely constitute a barrier to BFR. So, by reducing the magnitude of perceptual demands You will increase the likelihood of long-term compliance to BFR.

Considering cuff width is imperative as wider cuffs are associated with higher (RPE) than narrow cuffs with the same absolute pressure being applied. This will also proportionally influence the occlusion pressure necessary to reduce blood flow.

We advise for initially lower pressure as upper body at least 30% Limb Occlusion Pressure (LOP) and Lower body at least 40% LOP. So, by lowering the pressure relative to the individual You can influence perceptual responses and thereby maximize tolerance and compliance.

Though, it seems that at least 50% LOP is the threshold for any real benefit of applying BFR, so mind that less pressure should only be applied in a brief familiarization period (1-2 week).

Low relative pressure can also be combined with intermittent BFR, which can either be cuff deflation in-between exercises or even more gentle by deflation during the inter-set rest period. This can be a great method to let people have a tempered introduction to BFR for people experiencing unacceptable discomfort when applying continuous pressure.

Though, intermittent BFR can mitigate discomfort, its effectiveness vs continues BFR is currently not well explored.

Avoid failure training initially as it seems not to provide superior benefits for muscle mass and strength when unaccustomed to BFR.

Loads. Initially about 20% of 1RM, but progressed thoroughly.

For some individuals it can be favorable to introduce BFR passively, simply inflating the cuff to sub occlusion pressures for brief intervals letting the person experience BFR in the absence of exercise.

Summarized:

1 Pressure. 30%-80% LOP

2. Avoid failure training.

3. (Passive BFR) or Intermittent BFR progressed to Continues BFR

4. Initially not more than 25 reps for 3-4 sets of 1-2 exercises.

5. Load of not more than 20% of 1RM

6. Communication. Is it acceptable? Simply ask the client during exercise, but also inform about the importance of high RPE during BFR exercise to elicit adaptations long-term.

Primary source: Nicholas Rolnick, Kyle Kimbrell, Mikhail Santos Cerqueira, Ben Weatherford and Christopher Brandner (2021): Perceived Barriers to Blood Flow Restriction Training

Secondary Source: Hughes et al. (2017) Blood flow restriction training in clinical musculoskeletal rehabilitation: a systematic review and meta-analysis
Hughes et al. (2020) Blood flow restriction exercise position stand: considerations of methodology, application, and safety
Hughes et al. (2019) Examination of the comfort and pain experienced with blood flow restriction training during post-surgery rehabilitation of anterior cruciate ligament reconstruction patients
Spitz et al. (2020) Blood flow restricted exercise and discomfort: a review