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#179 - Jeremy Loenneke, Ph.D.: The science of blood flow restriction—benefits, uses, and what it teaches us about the relationship between muscle size and strength

Oct 11, 2021 1h 59m 24 insights
<p><span style="color: #000000;">Jeremy Loenneke has a Ph.D. in exercise physiology, a Master's in nutrition and exercise, and is currently the director of the Kevser Ermin Applied Physiology Laboratory at the University of Mississippi, where he focuses his research on skeletal muscle adaptations to exercise in combination with blood flow restriction (BFR). In this episode, Jeremy explains the science of BFR and the mechanisms by which BFR training can produce hypertrophy using low loads. Here, he reviews anatomy and terminology of muscle structure and discusses the evidence that increasing muscular strength may not be dependent on increasing muscle size. Additionally, Jeremy goes into depth on how one might take advantage of BFR training, including practical applications for athletes and average people, as well as the situations for which BFR training would be most advantageous.</span><span style="color: #333333;"><br /> <br /> We discuss:<br /></span></p> <ul> <li><span style="color: #333333;">Jeremy's interest in exercise and weightlifting and his scientific training [3:30];<br /></span></li> <li><span style="color: #333333;">The microstructure and physiology of muscle [8:00];<br /></span></li> <li><span style="color: #333333;">Definitions of fast-twitch and slow-twitch muscle fibers [12:45];<br /></span></li> <li><span style="color: #333333;">Comparison of strength vs. hypertrophy [21:30];<br /></span></li> <li><span style="color: #333333;">Blood flow restriction training and the origins of the Kaatsu system [28:30];<br /></span></li> <li><span style="color: #333333;">The details and metrics related to exercise under blood flow restriction [44:45];<br /></span></li> <li><span style="color: #333333;">Considerations when training with blood flow restriction: loading, pace, rest, and risks [53:00];<br /></span></li> <li><span style="color: #333333;">Blood flow restriction studies and the relationship between muscle size and muscle strength [1:04:15];<br /></span></li> <li><span style="color: #333333;">Evidence that increasing muscular strength is not dependent on increasing the size of the muscle [1:16:30];<br /></span></li> <li><span style="color: #333333;">Practical applications of blood flow restriction training for athletes and average people [1:27:30];<br /></span></li> <li><span style="color: #333333;">Situations in which blood flow restriction training is most advantageous [1:35:30];<br /></span></li> <li><span style="color: #333333;">The mechanisms by which blood flow restriction training can produce so much hypertrophy at such low loads [1:39:45];<br /></span></li> <li><span style="color: #333333;">Applications of "passive" blood flow restriction training [1:47:15];<br /></span></li> <li><span style="color: #333333;">What experiments would Jeremy do if he had unlimited resources? [1:51:45];<br /></span></li> <li><span style="color: #333333;">More.</span></li> </ul> <p>Learn more: https://peterattiamd.com/</p> <p>Show notes page for this episode: <a href="https://peterattiamd.com/JeremyLoenneke">https://peterattiamd.com/JeremyLoenneke</a> </p> <p>Subscribe to receive exclusive subscriber-only content: https://peterattiamd.com/subscribe/</p> <p>Sign up to receive Peter's email newsletter: https://peterattiamd.com/newsletter/</p> <p>Connect with Peter on Facebook | Twitter | Instagram.</p> <p> </p>
Actionable Insights

1. Use BFR for Efficient Hypertrophy

Blood flow restriction (BFR) training with low loads is a more efficient method for generating muscle hypertrophy compared to work-matched low-load training without BFR, often yielding better results with less total volume and time.

2. Progressive BFR Rehab Protocol

For rehabilitation, progress BFR usage from passive application (if unable to move) to low-intensity aerobic exercise, then to low-load resistance training, and finally to high-load exercise if appropriate, to maximize recovery and adaptation.

3. Restrict, Not Occlude, Blood Flow

When using blood flow restriction, ensure that blood flow is reduced but not completely occluded, as the goal is to always have some arterial flow into the limb for safety and efficacy.

4. Determine Individual Occlusive Pressure

Before applying BFR, measure your arterial occlusion pressure (AOP) using a handheld Doppler probe to find the lowest pressure at which there is no blood flow, then use a percentage of that pressure for training to ensure appropriate restriction.

5. Moderate BFR Pressure for Growth

For muscle adaptations (size and strength), aim for approximately 40% of your arterial occlusion pressure (AOP), as it provides similar benefits to higher pressures (80-90% AOP) with significantly less discomfort.

6. Train with Low Loads in BFR

Utilize very low loads, typically around 20-30% of your one-repetition maximum (1RM), when performing blood flow restriction exercise to leverage its primary utility and achieve desired adaptations.

7. Gauge BFR Tightness by Reps

When using BFR with low loads (e.g., 20-30% 1RM), aim for around 30 repetitions on the first set and 15 on subsequent sets; if you cannot achieve these targets, the load is too high or the wraps are too tight.

8. Adjust BFR if Painful

If you experience pain before starting BFR exercise, your wraps are likely too tight and should be loosened to prevent excessive discomfort and potential issues.

9. Start BFR with One Exercise

When first incorporating resistance training with BFR, limit continuous cuff application to one exercise (around 7-10 minutes) to allow your body to adapt to the sensation and demands.

10. Limit BFR to Minutes

Remember that BFR involves restricting blood flow for minutes, not hours, which is a key factor in maintaining its safety profile.

11. BFR is Generally Safe

Blood flow restriction training has a safety profile comparable to traditional high-load exercise, as it does not appear to increase the risk of blood clots or muscle damage, and blood pressure responses are similar or lower than heavy lifting.

12. Prioritize Heavy Lifting for Strength

If your primary goal is to maximize strength in a specific lift, consistently training at or close to your one-repetition maximum (1RM) with heavy weights is the most effective method.

13. Avoid BFR with High Loads

Do not combine blood flow restriction with high load training, as it does not provide additional benefits beyond what high load exercise already offers and is likely a maximal stimulus on its own.

14. Metabolite Pooling Drives BFR Growth

BFR traps metabolites (like lactate), which augments muscle activation and induces fatigue, thereby recruiting more muscle fibers for a sufficient duration to stimulate muscle growth.

15. Supersetting with BFR is Effective

Supersetting can be effective with BFR, particularly when working a muscle not directly under restriction (e.g., chest exercises with BFR on arms), as the distal muscles fatigue and the chest picks up the load.

16. BFR for Training Variety

Implement BFR as a versatile tool on days when you lack focus or feel unable to lift heavy, as it allows for effective training with light weights and provides variety to your routine.

17. Account for BFR Cuff Size

Be aware that cuff size significantly impacts the pressure needed for occlusion; wider cuffs require lower pressure, so always measure AOP with the specific cuff you plan to use.

18. Maintain Controlled BFR Pace

When performing BFR exercises, use a controlled pace, such as one second for the concentric phase and one second for the eccentric phase, as speed does not significantly impact growth.

19. Use Short BFR Rest Periods

For resistance exercise with BFR, a standard rest period of approximately 30 seconds between sets is generally used to maintain metabolic stress.

20. Passive BFR Slows Muscle Loss

For individuals who cannot exercise (e.g., post-surgery), passive BFR (applying and deflating cuffs without exercise) may help slow down muscle loss, though more large-scale studies are needed.

21. BFR for Low-Intensity Aerobics

For low-intensity aerobic exercise, BFR cuffs can be kept on for 30-40 minutes, as the lower intensity makes it less discomforting and potentially beneficial for adaptation.

22. Higher BFR for Vascular Changes

Preliminary data suggests that achieving vascular changes, such as improvements in limb blood flow or conductance, might require higher BFR pressures (e.g., 80-90% AOP) compared to muscle adaptation.

23. Caution with Complex BFR Lifts

While multi-joint movements like squats or bench press can be done with BFR using lightweight, isolation movements are generally preferred for safety and targeted growth, to avoid altering mechanics and increasing injury risk.

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