Physical Therapy

Blood Flow Therapy: Effective Physical Therapy for Knee Pain

Published August 16, 2021
By Health Loft

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Blood Flow Therapy: Effective Physical Therapy for Knee Pain

Knee pain can be caused by a plethora of reasons. However, as we age osteoarthritis (OA) can become a root cause of knee pain.  Many people with OA will ultimately require a knee replacement, but there is often a lot we can do before that to manage the pain and get back to the activities we enjoy. Strengthening of the hip, thigh and core is often recommended to provide better support to the knee joint and to relieve pain. However, what if the exercises meant to strengthen your knee, make the pain worse? Well, blood flow restriction training can be a powerful tool to strengthen the muscles around your knee without further exacerbating the pain, not only for knee OA but many other causes of knee pain as well. 

What is BFR training?

Blood flow-restriction (BFR) training is a method of physical therapy for knee pain in which a blood pressure cuff or wrap is placed around either the upper or lower limb during resisted exercise, allowing for better enhancements in muscle strength and size while using a lower training load. It has been found to be beneficial in both rehab settings and the gym setting. 

How does BFR training work?

BFR provides greater strength and muscle mass increases from lower loads, likely through addressing the two mechanisms in which muscles grow – increasing muscle protein synthesis and decreasing muscle protein breakdown. 

Normally, loads greater than 65% of your one rep max are needed for muscle improvements, but BFR physical therapy stretches for knee pain utilize loads as low as 20% to cause similar muscle growth. These lower loads produce less muscle damage, allowing for quicker recovery.

In addition to decreased muscle protein breakdown, BFR additionally increases muscle protein creation, further increasing muscle growth following training. Health scientists have not reached a consensus on why this occurs but many believe that BFR increases hormone concentration to create more fast-twitch muscle fibers than slow twitch fibers1-3

BFR for All Athletes 

In traditional methods, a blood pressure cuff will be inflated until blood flow towards the heart  is prevented but blood flow away from the heart is maintained. The cuff should only be placed on the upper thigh or upper arm to prevent damage to nerves close to the skin, especially if the cuff is over inflated. The cuff should be inflated to 80% of limb occlusion pressure. If a wrap is used, it is recommended that a pressure of 6-7/10 be used4 

In physical therapy for knee pain, the typical training regimen recommended for blood flow restriction training is the 30/15/15/15 method. This breaks down into 75 reps over 4 sets with 30-60 seconds of rest in between. Start with  20% of your max weight slowly increase if all 75 reps are achieved. 

Set 1: 30 reps
Rest 30s
Set 2: 15 reps
Rest 30s
Set 3: 15 reps
Rest 30s
Set 4: 15 reps

Ideally the pressure of the cuff should be maintained throughout the rest periods if possible. If the pressure is unable to be sustained, it can be partially released and then reinflated prior to the next set. Typical exercises prescribed include leg presses, deadlifts and lunges. 

For those utilizing BFR post-operatively and are in the initial stages of rehab or are not cleared for full weight bearing yet, minimal to no resistance should be utilized. Shorter rest periods (~15s) in between sets is appropriate when no weight is added. 

Benefits of BFR physical therapy for knee pain:

Research has found that BFR training paired with resistance training results in greater strength and muscle mass increases than resistance training alone. Previous studies have found an increase in muscle strength by 10-20% over a 4-6 week period1. This held true in a study looking at patients with osteoarthritis, who in addition to improved strength and mass, reported improved function and decreased pain following a BFT knee pain physical therapy course6

For patients with more generalized knee pain, there was a 93% greater reduction in pain than a group that performed standard high resistance strength training7 BFR training allows for a significant reduction in pain by not further aggravating the knee with high loads while allowing strengthening for long-term improvements. 

BFR After Surgery

BFR training can be a powerful tool following knee surgery due to its ability to greatly increase both strength and muscle mass while using light resistance. Muscle atrophy and weakness is a common side effect of most knee surgeries. Regaining strength of the thigh musculature is important for a successful surgical outcome and prevention of future injury to the knee joint. BFR physical therapy for knee pain after surgery resulted in greater thigh muscle strength, muscle mass increase and better overall recovery than a normal therapy group 8 

BFR training is a safe and effective tool that can be utilized under normal training circumstances but also in the rehab setting for both knee pain and post-operatively. It has been consistently shown to result in not only better strength and muscle mass increases than normal training methods but also found to reduce pain. 

For an individualized plan of physical therapy for knee pain to help you with your injury, consult with one of our Health Loft physical therapists in Chicago (virtually via our telehealth platform or in person) by calling us at (312) 374-5399 or by scheduling an appointment online. Remember to also check out our Facebook, Instagram, and Twitter pages for more articles on nutrition, physical therapy, and exercise!


Written By Rachel Horton
Edited by Alexander Franz
Reviewed by James Caginalp PT, DPT, CSCS, CES, PES


  1. Hwang, Paul S.; Willoughby, Darryn S. Mechanisms Behind Blood Flow–Restricted Training and its Effect Toward Muscle Growth, The Journal of Strength & Conditioning Research: July 2019 – Volume 33 – Issue – p S167-S179 doi: 10.1519/JSC.0000000000002384
  2. Loenneke, J. P., Abe, T., Wilson, J. M., Ugrinowitsch, C., & Bemben, M. G. (2012). Blood flow restriction: how does it work?. Frontiers in physiology3, 392. https://doi.org/10.3389/fphys.2012.00392
  3. Loenneke J. P., Wilson J. M., Marin P. J., Zourdos M. C., Bemben M. G. (2012b). Low intensity blood flow restriction training: a meta-analysisEur. J. Appl. Physiol. 112, 1849–185910.1007/s00421-012-2312-1
  4. Lowery RP, Joy JM, Loenneke JP, de Souza EO, Machado M, Dudeck JE, Wilson JM. Practical blood flow restriction training increases muscle hypertrophy during a periodized resistance training programme. Clinical physiology and functional imaging. 2014 Jul;34(4):317-21.
  5. DePhillipo, N. N., Kennedy, M. I., Aman, Z. S., Bernhardson, A. S., O’Brien, L., & LaPrade, R. F. (2018). Blood Flow Restriction Therapy After Knee Surgery: Indications, Safety Considerations, and Postoperative Protocol. Arthroscopy techniques7(10), e1037–e1043. https://doi.org/10.1016/j.eats.2018.06.010
  6. Ferraz, R. B., Gualano, B., Rodrigues, R., Kurimori, C. O., Fuller, R., Lima, F. R., DE Sá-Pinto, A. L., & Roschel, H. (2018). Benefits of Resistance Training with Blood Flow Restriction in Knee Osteoarthritis. Medicine and science in sports and exercise50(5), 897–905. https://doi.org/10.1249/MSS.0000000000001530
  7. Giles, L., Webster, K., Mcclelland, J., & Cook, J. (2017). Quadriceps strengthening with and without blood-flow restriction in the treatment of patellofemoral pain – A double blind randomised trial. Journal of Science and Medicine in Sport20. doi: 10.1016/j.jsams.2017.01.081
  8. Tennent, D. J., Hylden, C. M., Johnson, A. E., Burns, T. C., Wilken, J. M., & Owens, J. G. (2017). Blood Flow Restriction Training After Knee Arthroscopy. Clinical Journal of Sport Medicine27(3), 245–252. doi: 10.1097/jsm.0000000000000377

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