Safety Testing - Arterial Occlusion
We're concerned about safety, so we take every reasonable precaution to protect our users. As part of that effort, we tested our cuffs using advanced color doppler administered by a trained technician with more than 22 years of experience and a Vivid Q Doppler with Cardiac/OB/Vascular Package.
The Doppler test was done to show us at what pressure total arterial occlusion would occur. Total arterial occlusion is a state that you want to avoid at all costs with BFR Training because going there can be not only ineffective (reduces muscle size) but also very dangerous, think tourniquet!
The results as you can see from the video below is that at 5x the recommended highest tightness, our cuff did not occlude. In fact, we tightened it to the maximum (very uncomfortable according to our subject), and we still had not fully occluded arterial flow.
Ask any other vendor for the results of their tests! We doubt that they have them since they know that under normal or even extreme conditions their cuffs occlude. That is why they actively monitor with electronics or require a trained therapist to advise you in real time.
Another suggestion by our expert technician - 1) Hydrate before use and 2) Avoid caffeine within 60 minutes of using the cuffs. Check out the study here.
Our surgeon advisor Dr. Lonnie Paulos, a renown orthopedic surgeon, researcher, inventor, lecturer, and the first sports medicine fellow suggests that everyone should take low dose aspirin (81 mg) daily for both general health and as an added measure to optimize blood flow.
The tests below were done with our 6cm (2.25 inch) Cuff.
200 mm Hg 1,000 mm Hg
Oh, and as long as we were paying for the doppler technician we tested additional cuffs and cuff types, the results:
Multi-Chambered Pneumatic Cuff - Fully occluded at about 600 mm Hg! When we saw this, we backed off the pressure to 250 mmHg, still occluded, then backed further to 150 mm Hg and got the arterial flow back. Needless to say, when using this type of cuff at higher pressures during exercises, you want to be sure not to test this limit as muscle compression can add 200 mm Hg to the cuff reading. These readings are higher than a typical cuff because of the effective width of the compression pressure face.
Regular Pneumatic Surgical Cuff - Fully occluded on our subjects around 110 mm Hg to 130 mmHg. Concerning to us was when we backed off the pressure to a recommended 50% of Limb Occlusion Pressure (LOP) for BFR Training, we did not see much reduction in the venous flow. We will do a few more studies on this.
Safety Testing - Skin Safe
A few years back, a famous fitness wearable had issues with skin reacting to the metal in their wrist band. We chose to use a "Skin Safe" material for our "cuff to skin" cushion interface. The material is independently certified OECD TG 439 and ISO 10993-10.
Safety Testing - Pressure Testing
We designed RockCuff to apply pressure evenly over the surface of the cushion.
You probably did not know this, but pneumatic cuffs (air bladder) do not apply pressure evenly. That's because they are air bladders. When inflated, they tend to bulge in the middle, and that is where they apply the most pressure. The result is that a 4" pneumatic cuff delivers maximum pressure over a smaller area, about 2". The image below is from a study done in 2009. Don't believe us? Take off your cuff and pump it up to see for yourself.
Your 5" Cuff may be a 2.5" Cuff - We are currently testing the effective areas of a wide variety of cuffs. So come back to see the results. Until then, enjoy the image below which was provided for a 6" surgical cuff. Areas in red are the areas of highest pressure. As you can see, the effective area of maximum pressure is much smaller than the actual width of the cuff. By the way, the narrow red indicators are "pinch" points. One cuff manufacturer recommends that you wear a "sleeve" between the skin and cuff to minimize these since they can be painful.