BFR: Low Intensity Exercise
This study actually reported decreases in skeletal muscle atrophy in the quadriceps from 20% to 9%! It seems that this is potentially due to cell swelling and/or tension and increased intermedullary pressure which mimics the weight bearing environment for the skeletal muscle and bones!
In the last article, we discussed what blood flow restriction, or BFR, actually involves, as well as touched on its safety.
Next, let’s look at skeletal muscle as well as atrophy so we can better understand why/when BFR could be useful.
Most people already know the role of skeletal muscles in movement. But what about skeletal muscle as an endocrine organ?
Here’s three points to consider:
1) skeletal muscle is the largest disposal site of blood glucose (which is that blood sugar that everyone is worrying about due to type II diabetes rates skyrocketing).
2) skeletal muscle helps with lipid oxidation, AKA breaking down or decreasing body fat.
3) skeletal muscle naturally increases resting metabolic rate (RMR). This means that increasing skeletal muscle mass directly correlates to amount of calories burned at rest (how’s that for a diet plan).
In summary, increasing skeletal muscle mass is key in not only building strength and resilience, but also in maintaining systemic wellness, which we are all about here at Refine PT and Performance.
But let’s talk about the opposite side of the spectrum. Atrophy. Atrophy is a loss or breakdown of skeletal muscle mass. This can be caused by multiple variables; however, we are going to focus on inactivity.
Here’s the hallmark response to inactivity:
1) Decreased quality and quantity of muscle mass. Research has shown that as little as 7 DAYS of bed rest could cause negative responses and jumpstart the atrophy process in muscle.
2) Impaired immune and cardiovascular function. The effects of inactivity are systemic.
3)There is preliminary evidence that fully resting tendons can actually have similar effects to overtraining tendons.
4) Decrease in insulin sensitivity. This creates increased blood glucose levels, which prompts further release of insulin, causing decreased insulin receptor sensitivity and further resistance- insert downhill spiral- with the collision course set for type 2 diabetes.
With that being said, is everyone who has to spend 7 days in a hospital bed destined for diabetes and a lifetime of weakness?
But I will warn that prolonged periods of bed rest significantly increase that risk (specifically in the aging population). The great news is that our bodies were created to be resilient, and with proper application of movement and exercise, we will generally respond very well! The key thing to note here is how paramount physical activity and skeletal muscle health are!
After surgery or with inactivity due to pain, atrophy is often seen. One of the best ways to combat this is, in order to keep muscle size, is with the use of BFR. A bigger muscle doesn’t necessarily mean a stronger muscle, but a bigger muscle does allow for more potential to be a stronger muscle.
So, now that we’ve covered the basics, as well as the importance of physical activity in strength development and prevention of atrophy, our next post will cover applications of blood flow restriction.
Stay tuned for more in this series in the coming days! If you’d like to find out more, or think you could potentially benefit from one-on-one physical therapy in the Daphne area, please don’t hesitate to contact us.
PT, DPT, OCS, CSCS, CF-L1
Owner Pathology Apparel
Blood flow restriction (BFR) involves the restriction of arterial blood flow into the muscle, while occluding or stopping the venous blood flow out of the muscle, which then creates pooling of the venous blood. With this pooling effect, blood flow restriction also causes oxygen deprivation in the muscles, enhancing metabolic stress, and encouraging muscle adaptation (strengthening) without the requirement of significant loading of the joints.
To put it more simply, you will be able to achieve targeted results with much lower loads and mechanical stress.
For instance, with traditional resistance training, the gold standard for achieving noticeable increases in muscle size lies around 70% of your one repetition max (1 RM). However, for some populations, high load exercises may not be appropriate or safe (think post-surgical achilles repair, or elderly patient recovering from a 2 week stent of pneumonia).
But isn’t that dangerous?
This technique appears to offer no greater health risk than training with high loads, while greatly reducing the mechanical stress to the joints. (Loenneke et al, 2011).
In fact, pooling of venous blood actually stimulates natural tissue plasminogen activator (TPA) to be released, which is the same derivative used for clot busting in hospitals for ischemic strokes. In this way, when applied correctly, BFR is safe and does not increase risk of clotting.
What is the mechanism or how does BFR accomplish the noted improvements?
That part is still largely theoretical. There are a few predominant theories at this time:
Cell Swelling (becoming less prominent)
It could be due to cell swelling (which trips a volume receptor of sorts, that then increases production of mTOR, which has been shown to be high following resistance training as well).
Oxygen deprivation (hypoxia) during BFR training leads to increased levels of lactate and free hydrogen in the muscle. The result is a decrease in pH, which encourages the production of growth hormone. Increased GH then stimulates increased levels of IGF-1 (insulin like growth factor), which supports muscle synthesis (increased production of HGH up to 290 fold- Takarada 2000).
Another theory proposes that improvement is elicited largely due to downstream affects of norepinephrine release (which prevents the decrease of protein synthesis usually seen with lack of activity).
Time Under Tension
There are yet other arguments for the fact that it’s still mainly about how much time the tendons/muscle units are under tension with BFR training as well.
The reality is that research is demonstrating positive responses to BFR that are not only beneficial, but safe. It likely involves multiple mechanisms working together.
Here are a few more notes to work through as we get prepare to discuss applications of BFR:
-BFR increases muscle protein synthesis in the elderly by up to 56% (Gundermann, 2012)
-Level of growth hormone was found to be elevated 10 minutes after activity, and remained elevated up to 40 minutes (Fujita, 2007)
-BFR has been found to increase collagen synthesis after as early as 2 weeks
-BFR decreases myostatin (which contributes to muscle protein breakdown) by up to 45%, which is comparable to high intensity training.
Summing it Up
In my clinical experience thus far with BFR, I’ve also noted decreased post-session or delayed onset muscle soreness despite a high RPE in the clinic (rate of perceived exertion) with all age groups, as well as significant reversal of functional decline in the aging adult population.
I don’t believe that any one specific training or rehab style fits into every case or with every client; however, this has been extremely beneficial in the clinic and with improving performance!
Stay tuned for more in this series in the coming days! If you’d like to find out more, or think you could potentially benefit from one-on-one physical therapy in the Daphne area, please feel free to contact us.
PT, DPT, OCS, CSCS, CF-L1
Owner Pathology Apparel
Did you know that falls are the leading cause of injury and injury death in individuals 65 years of age and older? Falls often lead to a decrease in functional ability, increased use of healthcare services, and an increase in patient anxiety. This anxiety and fear of falling again often causes these individuals to decrease their activity, resulting in impaired mobility and increased risk of morbidity and mortality due to being more sedentary (Berry and Miller, 2008).
This leads us to the question, what can we do as therapy professionals to reduce the risk of falls in the elderly population?
Older adults are the fastest growing segment of the US population. By 2060, the number of individuals 65 and older is expected to reach 98 million making up approximately 25% of the population; therefore, it is essential for us to understand and effectively dose exercise in this population in order to help them age well and decrease the risk of falls and fall-related injuries.
All too often, older adults are led to believe that they are fragile and weak, which causes them to avoid movement and more strenuous activities for fear of injuring themselves. Quite honestly, many healthcare professionals, including therapists, often believe and treat these individuals like they are incapable due to their age. This thought process is heavily flawed. Just because these individuals are older does not mean they are weaker. It is because of their age that movement and resistance training are even more critical. Each time an individual stands up from their recliner or gets up from the toilet, they are performing a squat. Every step they ascend to enter into their home is a step up. Every item they pick up off the floor is a deadlift. Every bag of groceries they carry into the home from the car is a type of carry.
So why are we not performing these exercises in the clinic?
When an older adult enters into a physical therapy clinic and the only exercises that they perform are things like straight leg raises, long arc quads, hip bridges, and banded hip abductions, we as therapy professionals are missing the boat. The exercises listed above are beneficial and have their place in the rehabilitation process; however, they should only be used as a stepping-stone to help older adults improve their ability to perform more functional tasks and to increase independence. Our interventions have to extend beyond the TheraBand and ankle weight and transition into more functional activities as the patient progresses.
Resistance training in older adults has been shown to improve blood pressure, mobility, muscle mass, strength, immune system function, blood glucose, and lipid profiles. All of which combat age-related chronic diseases that often are impacting the older adult population (Mcleod, et al. 2019).
A study performed in Australia assessed the effects of an 8-month long high-intensity resistance and impact (HiRIT) program in postmenopausal women older than 58 years of age that had low bone mass. Exercises performed throughout the study were deadlifts, back squats, overhead press, and jumping chin-ups with drop landings. The study found that the HiRIT program was superior to other lower-impact programs for enhancing bone mass at clinically relevant sites, as well as improving functional performance that impacts risk of falls (Watson, et al. 2019). Often this population avoids higher impact activities for fear that they will actually increase their risk of injury, but have we stopped to ask ourselves what the risk is if we don’t appropriately load this population?
There is greater risk of injury and functional decline from underdosing this population compared to the perceived possibility of injury from performing exercises such as squats and deadlifts that actually correlate more with tasks that are required of our older adult patients day in and day out.
If we aren’t preparing our older adults to handle the demands that are placed on them each day, we are doing them a disservice. In a healthcare system that is consistently producing fear of movement in the older adult population, I want to challenge us all to not give into this flawed system but to empower our older adults to stay active, pick up a kettlebell, dumbbell, or barbell, and take control of their health.
Makayla Palmer, PT, DPT
Refine PT and Performance
Berry, S. D., & Miller, R. R. (2008). Falls: epidemiology, pathophysiology, and relationship to fracture. Current osteoporosis reports, 6(4), 149“154. https://doi.org/10.1007/s11914-008-0026-4
Mcleod, J. C., Stokes, T., & Phillips, S. M. (2019). Resistance Exercise Training as a Primary Countermeasure to Age-Related Chronic Disease. Frontiers in physiology, 10, 645. https://doi.org/10.3389/fphys.2019.00645
Watson, S., Weeks, B., Weis, L., Harding, A., Horan, S., & Beck, B. (2019). Highintensity resistance and impact training improves bone mineral density and physical function in postmenopausal women with osteopenia and osteoporosis: The liftmor randomized controlled trial. Journal of Bone and Mineral Research, 34(3), 572-572. doi:10.1002/jbmr.3659
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