Blood Flow Restriction Training and Rehab Outcomes

Introduction:

The office of analysis and epidemiology at the United States center for disease control reported an average annual estimate of 8.6 million sports- and recreation-related injury episodes between the years 2011-2014.6 Further analysis concluded that 46% of those 8.6 million annual injuries included the lower extremity.6 As with any injury, rehabilitation is a vital stage in the process of restoring a patient’s state of health after incurring an injury to their lower extremity or suffering from any sort of chronic lower-limb pathology.

Many health care professionals such as physical therapists and athletic trainers are particularly concerned with implementing new methods or modalities into their practice in order to help their patients obtain the best possible results. In patients recovering from lower extremity injuries, the best possible result at the end of a rehabilitation program would be increased function, strength, and muscular hypertrophy along with decreased pain felt in the associated structures.

For years now, sports medicine and exercise professionals have accepted the notion that traditional heavy-load resistance training with loads > 70% of an individual’s 1-repitition maximum can induce significant improvements in both muscular strength and hypertrophy.

However, this type of exercise can be contraindicated for patients undergoing lower extremity injury rehabilitation. Recent research suggests that low-load resistance training, in conjunction with blood flow restriction, may elicit similar if not more desirable effects on function, strength, muscular hypertrophy, and pain modulation. For this reason, the clinical use and effectiveness of blood flow restriction training warrants further investigation.

Methods:

The following searches were conducted using databases found on the NSU Alvin Sherman Library website that pertained to the disciplines of Athletic training, Physical Therapy, Orthopedic Surgery, and Exercise Science.

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My primary goal in the early stages of my research was to find studies (preferably randomized controlled trials) that would demonstrate the clinical relevance of blood flow restriction therapy rather than just its’ relationship to muscular development. Therefore, three initial searches were conducted using key terms such as “blood flow restriction”, “training”, “therapy”, “lower extremity”, “injury”, and “rehabilitation”.

I then narrowed down the articles that I decided I would use by simply excluding the ones that were either targeted towards a different population, demonstrating physiological adaptations that I was not concerned with, or did not meet the level of evidence that was required. Medline (via EBSCOhost) produced 58 results; 4 sources were used. SPORTDiscus with full text (via EBSCOhost produced 308 results; 1 source was used. PubMed produced 206 results; 2 sources were used. Finally, I gathered 2 more resources after reviewing the references listed in a met-analysis titled “Blood flow restriction in a clinical musculoskeletal rehabilitation: a systematic review and meta-analysis”.

Discussion:

With the question of “Does blood flow restriction training increase the rate of rehabilitation in healthy adults with lower extremity pathologies and/or musculoskeletal injuries?” in mind, I chose two studies3,5 as my primary resources to help me find the answers I was looking for.

The first study5 was a randomized controlled trial where 28 lower-limb injured adults were randomly allocated into a conventional resistance training (RT) or low-load blood flow restriction (LL-BFR) training group. Participants in the LL-BFR group performed knee extensions and leg presses for 4 sets of 30, 15, 15, and 15 at 30% 1-RM combined with BFR inflated to 60% LOP. Training was performed twice per Monday through Thursday and once on Friday Morning. Participants in the High- Load RT group performed 4 sets of 6-8 of the deadlift, back squat, and lunges 3 times per week at a load which reflected their best effort while limiting pain during the session.

Quadriceps and total thigh muscle CSA and volume, 5-RM leg press, 5-RM knee extension, isometric hip extension, Y-balance test, multistage locomotion test, and pain was assessed before and after completion of 3-week rehabilitation program. There were no significant differences between groups for any outcome measure post-intervention. Both groups showed significant improvements in mean scores for muscle CSA/volume and 5-RM leg press/knee extension. LL-BFR group demonstrated significant improvements in the Y-balance test and MSLT test while pain measures decreased over the course of the 3-week program. This study demonstrates that LL-BFR allows patients to make improvements in strength, hypertrophy, pain, and function that are comparable to improvements made when utilizing traditional heavy-load RT which would be contraindicated for patients with significant functional deficits.

The second study3 was described as a repeated cross-sectional design study in which 30 male patients who had previously consulted a sports medicine physician in a primary-care setting with complaints of AKP were recruited. The participants performed 4 sets of low-load knee extensions (2 second concentric, 2 second eccentric, paced by a metronome) with a BFR cuff applied at 80% LOP. Loading for the exercise was dependent on the patient’s reported pain on a scale of 1-10 such that the patient reported a maximum of 4/10. The first set was performed to failure which, in this study, was defined as the inability to follow the pace of the metronome or inability to fully extend the knee joint.

The following sets consisted of 15 repetitions with 30 seconds of rest in between sets. Pain during the shallow single-leg squat, deep single-leg squat, and 20-cm step down was assessed on a scale of 1-10 immediately after BFR application and then again after a 45-minute physical therapy session. Significant pain relief (> 40% pain change) during all three functional tests was seen immediately following completion of the BFR protocol outlined above. Percentage reduction of median values for pain following the deep single-leg squat at post-BFR and post-PT session were 64.3% 57.1%, respectively. This study demonstrates that a single bout of BFR-exercise can induce hypoalgaesia in patients with AKP, and thus allow painless application of therapeutic exercise for at least 45 minutes.

So what factor:

Blood flow restriction training may have several therapeutic effects when rehabbing a lower extremity injury. Surprisingly, evidence suggests that even bouts of lower-limb blood flow restriction without exercise has been shown to have the potential to modulate pain and prevent muscular dysfunction due to chronic unloading or immobilization.1,4 Perhaps the best clinical use for low-load blood flow restriction training would be in a rehabilitation protocol where traditional heavy-load resistance training is contraindicated. In this case, blood flow restriction training would allow higher intensity exercise5 that would otherwise be painful3 therefore increasing the rate of rehabilitation.

References

1. Giles L, Webster K, Mcclelland J, Cook J. 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 Sport. 2017;20. doi:10.1016/j.jsams.2017.01.081.

2. Hughes L, Paton B, Rosenblatt B, Gissane C, Patterson SD. Blood flow restriction training in clinical musculoskeletal rehabilitation: a systematic review and meta-analysis. British Journal of Sports Medicine. 2017;51(13):1003-1011. doi:10.1136/bjsports-2016-097071.

3. Korakakis V, Whiteley R, Epameinontidis K. Blood Flow Restriction induces hypoalgesia in recreationally active adult male anterior knee pain patients allowing therapeutic exercise loading. Physical Therapy in Sport. 2018;32:235-243. doi:10.1016/j.ptsp.2018.05.021.

4. Kubota A, Sakuraba K, Sawaki K, Sumide T, Tamura Y. Prevention of Disuse Muscular Weakness by Restriction of Blood Flow. Medicine & Science in Sports & Exercise. 2008;40(3):529-534. doi:10.1249/mss.0b013e31815ddac6.

5. Ladlow P, Coppack RJ, Dharm-Datta S, et al. Low-Load Resistance Training With Blood Flow Restriction Improves Clinical Outcomes in Musculoskeletal Rehabilitation: A Single-Blind Randomized Controlled Trial. Frontiers in Physiology. 2018;9. doi:10.3389/fphys.2018.01269.

6. Sheu Y. Sports and recreation related injury episodes in the US population, 1997-99. National Health Statistics Reports. 2016;99:1-4. doi:10.1136/ip.9.2.117.

7. Takarada Y, Takazawa H, Ishii N. Applications of vascular occlusion diminish disuse atrophy of knee extensor muscles. Medicine and Science in Sports and Exercise. 2000;32(12):2035-2039. doi:10.1097/00005768-200012000-00011.

8. Tennent DJ, Hylden CM, Johnson AE, Burns TC, Wilken JM, Owens JG. Blood Flow Restriction Training After Knee Arthroscopy. Clinical Journal of Sport Medicine. 2017;27(3):245-252. doi:10.1097/jsm.0000000000000377.

9. Yow BG, Tennent DJ, Dowd TC, Loenneke JP, Owens JG. Blood Flow Restriction Training After Achilles Tendon Rupture. The Journal of Foot and Ankle Surgery. 2018;57(3):635-638. doi:10.1053/j.jfas.2017.11.008.