Frequently asked questions

BFR Science

Why does RockCuff use a non-pneumatic strap?

We found that a rigid, non-pneumatic strap was the only way to meet the needs of the marketplace.​While pneumatic straps are effective, every person we asked (and we asked hundreds) told us that while they liked the results obtained from BFR, the pneumatic products were too:​

  • Expensive
  • Difficult to Use
  • Time Consuming
  • Motion Limiting
  • Painful​
So we asked the same people "what would it take for you to adopt BFR as a recovery, rehabilitation, fitness, or performance solution." And they told us that it would need to be practical. It would need to have the following attributes:​
  • Safety
  • Comfort
  • Ease of Use
  • Affordability​
So after looking at the research, we determined that a rigid, non-elastic strap would be the only solution that would meet the needs.

Why is strap width important?

Comfort! Strap width, in theory, is directly related to the amount of pressure required to fully occlude venous flow. The amount of pressure required will determine the level of comfort you experience while using BFR. However, all straps ARE NOT created equal. Case studies, and vendors alike fail to take into account the "effective pressure area" produced by a cuff! Fact - Pneumatic Straps provide effective pressure over less than 50% of their measured width! A 4" pneumatic strap delivers just 2" of effective pressure. Fact - Elastic Straps/Bands provide effective pressure over less than 25% of the measured width! A 3" elastic strap delivers just .5" of effective pressure. Fact - RockCuff uses a rigid strap with a gel insert. Our 2" cuff provides 2" of effective pressure - similar to a 4" pneumatic cuff and 2x that of a 2" pneumatic cuff. Comfort - A 2" RockCuff strap and a 4" pneumatic strap require the same amount of pressure to fully occlude venous flow during a workout. However, a 2" pneumatic strap would require 2x to 3x the pressure while an elastic strap would require 5x the pressure. Delphi, the supplier of one pneumatic cuff, did some research and below is an illustration of what they found.

Do I need to measure my limb occlusion pressure (LOP)?

Short answer - NO LOP might be a good idea if your BFR strap can fully occlude (block) your arterial flow. However, RockCuff straps DO NOT fully occlude arterial flow in 99% of cases when properly used. Long answer - Measuring LOP gives you a number indicating the pressure at which you will fully occlude arterial flow (theoretically this is 20 mmHg above your systolic pressure). However, as you begin to exercise, your systolic pressure rises as much as 30 mmHg to 50 mmHg basically negating the value of the LOP you just determined. So here is where the clever science comes in. Some vendors have the personal applying BFR add a "personalization" number of say 30 mmHg to 50 mmHg to take this into account. As unscientific as that sounds, it is in fact unscientific. The personalization number is just a distillation of general observations. So how exact will be the outcome? Well 50 mmHg is about 50% of your normal systolic and pneumatic cuffs are about +/- 8% accurate, so there you go. It sounds impressive, but in the end, is not worth the time or effort, unless your BFR strap can put you into danger. So just for grins and giggles, lets say your personalization number should have been 35 mmHg and not 50 mmHg (you did not really try that hard on that day) and lets also say the cuff has not been calibrated, bled, or sized properly. Then that another 8% of say 150 mmHg or 12 mmHg off. In total, your "LOP" would be off by 15 mmHg + 12 mmHg or 27 mmHg from a theoretical calculation of say 150 mmHg. That's about 18% less (so they actually inflated the strap too tight) than their calculation and electronic monitoring equipment should be. Too complicated? I agree. Fatigue is the best measurement and just like monitoring your own heart rate, you can learn it in just a few minutes.

Is a pneumatic strap better than a rigid strap (like RockCuff)?

No. If you don't believe us, try it for yourself. Pneumatic straps are very ineffecient at applying pressure, try 50%!

  • First, you will pay more money like 2x
  • Second, it will be less comfortable requiring at least 2 x more pressure.
  • Third, it is difficult to put on and it will not be easy to adjust mid-exercise.
In our research, we found lots of examples of people with a bias (who does not have a bias)? Pneumatic equipment has digital numbers of dials to read. It seems "sciency" (we know, thats not a word so don't scold us. But leading experts boiled it down, one in particular, in his PhD thesis. What he said, and I paraphrase is "it does not matter how you apply pressure as long as you apply enough pressure." We agree. Frankly, we could not envision ourselves in a gym, staring at a dial (or trying to find it for that matter) and pumping a bulb to inflate the straps. So does an air pump with a cool app make it better? Depends, do you want to exercise, recover and get to it or do you want to carry your phone around. Seems to us that reaching over to release or increase pressure is easier than opening an app. For heavens sakes, the thing is just right there on you arm or leg! It's not like the cuff is 15 feet away and you are too lazy to walk over and make the adjustment! Plus, we like to swim. We have never used water wings in the pool and never intend to. The illustration below is from research done by Delphi. The illustration below shows the relative pressure required to generate venous occlusion compared to the width of the cuff. Below is an image of a test of the RockCuff non-pneumatic cuff. Below is a test of a 3" "Chambered Pneumatic" strap.

Where are BFR straps placed and why?

Cuff are placed at the top of the arm, above the bicep, and at the top of the leg, above the thigh. As you can see in the illustrations below, this is where the artery, vein, and nerve are located and offers the best placement to deliver results. Do not install cuffs, no matter what images you see online, directly on the bicep, below the elbow, or below the knee. There is no study data on those placements and in fact, placement there could be harmful. Remember, the cuffs produce a systemic and physiological result that IS NOT localized to the muscle. BFR is not a musculoskeletal device. Proper placement is shown in the image below. Below are some examples of improper placement or straps that are too wide or too narrow.

Does BFR work? - Study by Dr. Frank Noyse, MD

Check out this study from Frank Noyse, MD, Orthopedic Surgeon.

RockCuff Use

How do you clean RockCuff straps?

Cleaning is simple. You can clean your straps in the sink using warm water and a little detergent or soap. Same with the gels. If you want, throw them into the washing machine with warm water. Let them drip dry. Or maybe you just want to go swimming with them on! Thats fine, they won't act like "water wings" since they do not use air like pneumatic cuffs.

How tight do my RockCuff straps need to be?

Research shows that arterial occlusion between 30% and 70% will deliver the same results. To adjust your RockCuff straps:

  • Lift the tab and pull the strap all the way out.
  • Close the tab and rotate the dial clockwise - set the marker to "0"
  • Thread the strap up the arm and above the bicep - pull the strap so it is snug.
  • Rotate the dial as follows for the upper body:
  • For a small limb - 8" to 12" - 3/4 of one full turn (18 clicks)
  • For a medium limb - 12" to 16" - 1 full turn (26 clicks)
  • For a large limb - 16" to 20" - 1 full rotation + 10 clicks
Verify no numbness or tingling in the arm. Check for capillary refill by pressing the tip of your finger until it loses color, then release, color should return in less than 5 seconds. The key is that during exercise routines, you want to completely fatigue the limb. If you do not, adjust the dial tighter by rotating 8 full clicks. If you fatigue too early, lift the tab, flex, and let the dial "de rotate". DO NOT rotate the dial counter-clockwise. Over the first two to three uses, you will be able to "dial in" your tightness and "fell" when it is right.

A BFR "expert" told me that straps that do not fully occlude arterial flow will not work!

Your "expert" is really no expert! If you think about it, the claim is actually silly if you think about it since to achieve the full effect of BFR, you should never fully occlude arterial flow. We think that they are actually trying to justify selling a BFR strap that could be potentially dangerous by fully occluding arterial flow. If they explain that "unless I know your limb occlusion pressure, i cannot acurately set your BFR cuffs, then again, they are wrong. Studies show that occlusion rates between 30% and 70% actually deliver similar or the same results. Here is a test we did with a digital thermal camera to prove the effects of partial occlusion. The image on the left, is the limb that did not have a cuff, the image on the right, had a RockCuff. The subject did 30 repetitions then 15, 15, 15 with a 10 pound weight. THe results? Fatigue on the right side and none on the left. You cannot ignore the venous engagement (see the heat signature?) on the right side.

The lace in my cuff has broken!

First of all, don't worry, if this happens, contact us and we will replace your broken cuff. Lace breaking or pulling out the of the dial happens about 1% of the time. The most common issue is that you have not "pre-loaded" the dial putting too much stress on the lace. To avoid this do the following before use. 1. Lift the tab and pull the strap all the way out of the cuff 2. Close the tab and rotate the dial 3/4 to 1 full turn 3. Than apply the strap This will take a lot of tension off of the lace. A second most common problem is that many people overtighten their straps thinking that the more they tighten, the more effective they are. This is wrong. Tighten as follows: 1. Pre-prep the strap as above 2. Put the strap on snug pulling the velcro strap through the ring and secure with the "brillo" pad. 3. Rotate the dial to create pressure as follows based on your arm circumference:

  • 8" to 12" - 3/4 turn to 1 full turn
  • 12" to 16" - 1 full turn to 1.25 turns
  • 16" to 20" - 1.25 to 1.5 full turns.
Adjust tightness +/- based on your level of fatigue.


Can I use more than one strap at a time?

Yes! During functional or compound exercises, you can activate more fatigue buy using both upper and lower body straps at the same time! Try a "Bear Crawl". You will never be so tired! Remember limit the time cuffs are tight to less than 25 minutes.