Unlocking Aerobic and Strength Gains with BFR Cycling

Welcome to BFR Radio, a podcast dedicated to all things blood flow restriction training. This podcast is proudly sponsored by the BFR.co, where if you want to buy your own BFR cuffs, access online BFR training programs. Increase your own BFR knowledge with the accredited BFR Dot Co course or you want more information about this type of training, this is your one place to go. And I'm your host, Dr. Chris Gavillio.

Welcome back to BFR Radio and to the second episode focusing on aerobic BFR exercise. In the last episode, we explored how low-intensity BFR walking led to improvements in VO2 Max in trained basketball athletes over just two weeks. For this week we're moving from the treadmill and onto the bike.

But before we dive into today's study, let's quickly revisit a previous episode where we looked at a study by the Oliviera and colleagues in 2016. In this short-term four-week training study, 37 recreational active participants were assigned to one of four groups. Low intensity cycling with BFR, low intensity cycling without BFR, a high intensity interval hit, and a combination alternating between the hit and the low intensity BFR. Each group trained three times per week on a stationary bike.

The protocol involved two sets of five to eight repetitions. Each repetition lasting two minutes, with one minute passive rest in between and five minutes of rest between sets. Why it was five to eight is is that over the four weeks they increased the number of repetitions per set. The low intensity group trained a steady state at thirty percent of the peak power output for the two minute rest.

The HIIT group, that high intensity training group on the other hand, for each two minute rep, completed a four stage descending interval, starting at one hundred and ten percent of their peak power max, decreasing every thirty seconds. to 105, 100, and 95%. The percentage decrease in power format was used for every repetition. Makes sense. It's pretty hard to hold that high peak power wattage, therefore decreasing it every thirty seconds will make it somewhat achievable.

With respect to the BFR cuffs in this study, they were placed on the thighs and inflated to one hundred and forty millimeters of mercury. in week one and progressing by twenty millimeters each week until they reached until they reached two hundred millimeters of mercury by week four. In total each session lasted around thirty to forty minutes. In the Compine Group, they alternated sets between the low intensity BFR protocol and the HIT non BFR protocol.

After four weeks all groups improve their lactate threshold. This is the point at which lactic acid begins to accumulate in the blood. However, only the BFR The HIT and the combined groups of the HIT and the BFR improve their VO2 max and maximal power output. Interestingly, only the BFR group improved isometric leg strength by 11%.

So in summary, BFR cycling at low intensity was the only method to produce gains in both aerobic capacity and leg strength, showing its unique value as a concurrent stimulus for endurance and muscular adaptation. Fast forward to twenty twenty two and we've got a much larger and more comprehensive study.

This one focuses on road cyclists, men aged 35 to 49, who were already cycling over 200 kilometers a week. Although the participants were a little older, there were a much larger number of participants. But more importantly, this group is more representative of an athletic population.

something which is very hard to get in any kind of training study. The article we're reviewing today is called Physiological Adaptations to High Intensity Interval Training Combined with BFR in Masters Road Cyclist. In the study, fifty of these athletes were split into three groups. The first was a continuous training group. This is the control

a high intensity interval training group and thirdly a high intensity interval training plus BFR group. Remembering in that previous study where they had that combination, very similar.

Breaking down the training each group performed. All three groups did their regular endurance based training, four sessions a week. Of these, two sessions were of 120 minutes in duration at 50 to 60% of their peak power output. And two sessions were seventy five minutes at sixty five to seventy percent peak power output. These were standard outdoor road rides for all of these cyclists. But the differentiating factor was what they did on the other two days per week.

The continuous group, the control group, did another seventy-five minutes of continuous cycling at sixty-five to seventy percent of their peak power output. The high intensity interval training group performed four four minute intervals at eighty percent peak power output with two minutes active recovery at thirty percent peak power output. And thirdly, the BFR and high-intensity interval training group. They performed the same interval format, that's four four-minute intervals.

except that the second and the fourth intervals were reduced to sixty percent of peak power output, and BFR cuffs were worn on both sides. In these sessions, they maintained an RPM of eighty five to ninety. For the BFR they used an eleven centimeter wide cuff and inflated the cuff to thirty percent of arterial occlusion pressure. The authors said that thirty percent of arterial occlusion was chosen for the BFR exercise.

as thirty to forty percent of arterial occlusion pressure was somewhat similar, and some cyclists expressed discomfort at forty percent, but not at thirty percent of arterial occlusion pressure performed in a previous pilot study work. This is a really interesting point. I personally advocate dropping BFR pressure by approximately 20 to 40 millimeters Mercury from the usual resistance training pressure, as holding the higher pressures during aerobic exercise becomes extremely difficult.

Well, similar to the cyclists in the study, I find holding higher BFR pressures during aerobic exercise uncomfortable, affecting the ability to finish the session. Before we go through the results, let me clarify some of the terms that we'll go through. Firstly, VO2 Max, potentially familiar for all of you, this is the maximal amount of oxygen the body can use during exercise. It's a gold standard measure of aerobic fitness.

Next is ventilatory threshold. This is the point during exercise when breathing starts to become more rapid. It's a marker of how efficiently your body handles increasing intensity. Stroke volume, the amount of blood the heart pumps out with each beat. Bigger stroke volume equals more oxygen to the muscles. Cardiac output, the total volume of blood the heart pumps in a minute. It's stroke volume multiplied by heart rate.

Vascular function. This is measured using flow-mediated dilation. And this assesses how well you'll dilate. And this is an important indicator of heart and vessel health. And then there's muscle oxygen saturation. This is measured with a tissue saturation index or a TSI. Lower values during exercise means that the muscles is extracting more oxygen, which is generally a good adaptation in trade muscles.

And here's what they found over the twelve weeks. Firstly, VO2 Max. They improved in all the three groups, with the control group increasing by two millimeters per kilogram per minute. The hit group improved by three point nine and the BFR and high intensity interval group by four point three milliliters per kilogram per minute.

That's an increase of about 3.5% for the control group and over 7% for both the HIT and the combined BFR and HIT interval training session. Solid improvements, especially for trained cyclists. The BFR interval training group had a significantly greater increase in absolute VO2 max compared to the control group. Stroke volume increased by five milliliters in the control group, six milliliters in the hit group, and four in the combined BFR and interval group.

Cadiact output increased by approximately one point one to one point three liters per minute across all groups. Ventilatory threshold rose in all groups, meaning the cyclists could exercise harder before fatigue kicked in. and only the BFR interval group showed a statistically significant increase in arterial venous oxygen difference. Going from 20.5 to 21.4, showing that the athlete's muscles became better at extracting oxygen.

These cardiovascular improvements translated into better forty eight kilometer time trial performance. And the bear farm. and interval and the hit groups improve significantly more than the control groups. with time trial decreasing by two point four percent in the combined BFR and interval group, and average power output increasing by six point eight percent.

The researchers also assessed muscle size and strength adaptations, looking at things like lean mass, muscle cross-sectional area, and torque output during knee movement. Here's where the BFR group really stands out. Only the BFR group showed increases in total lean mass with an increase of 1 kilogram and leg lean mass with a gain of 0.4 kilograms.

MRI and ultrasound assessments showed significant increases in quadriceps and hamstring cross sectional area and vasus lateralis thickness in only that BFR training group. in trained cyclists that do a really high aerobic volume, which means that it's quite hard to put on any kind of muscle, these are meaningful gains. Knee extension strength improved by 6.4%. And all three groups improved knee flexion strength. But the BFR group had the greatest peak torque increase of 14.8%.

So BFR cycling not only improved endurance, it also significantly increased leg muscle size and strength, especially for the quads and the hamstrings. If we look at vascular and muscle oxygenation responses, in this part of the study, the researchers looked at changes in blood vessel function and how well the muscles used oxygen during exercise. I mentioned something about this flow mediated dilation or F M D.

This is a test that looks at how well your blood vessels expand when blood flow increases. It's an important sign of vascular health and better flow mediadilation means your arteries are more flexible and responsive. which lowers your risk of cardiovascular issues and supports overall endurance. Now here's the interesting part. Only the BFR group showed a significant change in muscle oxygen saturation. It's measured by what's called a tissue saturation index, or TSI.

With the BFR group, TSI dropped by 4.8%, which means that the muscles were pulling out more oxygen from the blood during exercise. This tells us that their muscles were working harder and had become more efficient at using oxygen. Why does that matter? Because better oxygen extraction helps with endurance and may contribute to the increases in muscle size and strength that was mentioned earlier.

Overall, it means that the body is using its fuel systems more efficiently. A huge plus for performance. Now let's look at performance. The researchers looked at how each training method influenced cycling specific performance outcomes, such as a forty kilometer time trial. average power output, and how long the cyclists could sustain a very high intensity effort. All three groups improved their forty kilometer time trial times over to the twelve week period.

The control group improved by two point three percent, the high intensity group by four point five, and the BFR group by five point one percent. When looking at average power output during the trime trial, the hit group improved 5.5%, and the BFR group improved the most 6.8%. in a high intensity fatigue test at 150% of the athlete's peak power output. Time to fatigue increased by 22% in the high intensity interval training group and 31% in the combined BFR group.

And total work capacity during this fatigue test also improved significantly. 19% in the HIT group and 25% in the BFR high intensity combined group. These performance gains were strongly linked to increases in VO2 max and leg strain. while the BFR Interval Training Group consistently showed the largest improvement across all markets.

These performance gains were significantly correlated with increases in VO2 max and leg muscle strength, again strongest in the combined BFR high intensity interval training group.

So what can we take away from this? If you're a coach, athlete, or master's level cyclist, there's something there for all of Overall, adding just two BFR cycling sessions per week to your existing endurance training can yield simultaneous gains in aerobic fitness, muscular strength, and performance.

The sessions are pretty straightforward. Perform full Four minute intervals set one and three are high intensity at eighty percent of peak power output without BFR and sets two and four at sixty percent of peak power output whilst wearing the BFR cut. For the BFR, wear them on your thighs and inflate them to thirty percent of measured limb occlusion pressure. I feel that this is a very achievable pressure to hold for four minutes.

For all sets, maintain a cadence of 85 to 90 RPM. Remember to also include a warm up prior to start of your first working set. This next bit is my own opinion, but something else to consider to potentially improve the performance outcome of this session is to do the following. Prior to the start of the session, perform a BFR warm-up protocol. Forty seconds of inflation, twenty seconds of deflation, three to four sets of increasing pressure.

Then for your first few minutes of the warm-up on the bike, consider riding with the cuffs inflated. As the intensity increases during the warm-up leading into the first set, decrease the pressure or just take them off. Ensure to warm up appropriately and spend some time approaching the 80% intensity before your first set.

Then, after you finish your session, decrease the cuff pressure and spend another few minutes cycling during your cooldown. Add in some quad, hip flexor, and glute stretches as well. You get more bang for your buck, strength and endurance improvements in the same session. That's rare, especially in trained athletes.

In summary, this study highlights that BFR cycling isn't just a rehab tool. It's a performance tool. It's safe. It's effective. And it might just be one of the most efficient ways to train, especially for masters or aging athletes looking to optimize adaptations without overloading their joints or nervous system. For elite athletes looking to maximize their lower intensity or additional sessions.

And that's all for this episode. If you have any questions related to this, you can get in touch with me through my website, which is thebr.co, or my socials at thebr.co. You can also purchase your own BFR cusp from our website and you can find it at www.thebr.co.

And lastly, before I go, a couple of favors from me to you. If you know of someone who would benefit from this episode, please share it. And if you're enjoying the podcast, please give it a rating on iTunes. Thanks for listening and remember to keep the pump.