BFR: The bridge
(From Low-load Resistance Training with BFR to High loads Without BFR)
Last post we discussed the benefits of the application of BFR training to low intensity endurance exercise, namely walking (and stationary cycling). The third rung in the ladder to full functional tolerance after injury or bed rest is the progression to resistance training. It is recommended that as resistance training is tolerated, BFR with endurance training is slowly phased out and replaced with resistance training.
It has been shown that training at 20-50% of your 1 repetition maximum (1RM) with blood flow restriction in various populations provided similar results to 50-80% of 1 RM without BFR (Takarada et al, Karabulet et al).
This difference in loading requirements can be extremely important because often, 70% and greater of 1RM will not be tolerated in post-injury or aging populations (although it is a goal to reach this point). This allows for the use of lighter loading to achieve a similar musculoskeletal response to heavier loading, without the joint stress or risk of injury.
There are various recommendations for dosing BFR with submaximal loads. A generally accepted sets/rep scheme that’s recommended is the following:
75 repetitions total
I have found that initially, a volume of 75 repetitions might not be tolerated in those that have been de-conditioned, even at lighter loads. In these cases, it can be helpful to work up to that range over time. Each client/patient is different and needs to be approached specifically. 3-4 sets to failure have also been used as well, but generally are more uncomfortable for the patient/client. Clinically, I prefer to shift towards heavier loading with BFR, with a progression to traditional loading as soon as it can be achieved safely, or without significant discomfort.
One example of a generalized progression would be something like the following:
-Application of BFR with submaximal loading 3x’s per week at 50 total reps per exercise
-Progression to 75 total reps per research-based protocol
-Increased resistance within the 75 rep scheme
-Addition of sets to failure OR addition of 1 day of increased loading without BFR to begin transition to traditional loading
-Primary utilization of heavier loading with less utilization of BFR (2:1).
-Full transition to classic progressive loading
This is just one example and I’m trying to steer clear of being too specific here because it really does depend on the individual, their exercise capacity, and an array of other factors.
One thing I would like to stress here is that higher load training is the long-term goal. It drives positive musculoskeletal adaptations and encourages improved overall function and wellness, not to mention confidence and resilience with daily tasks. Also, increased loading is paramount to address tendon stiffness and tolerance to further stress (aka real world requirements). I do not think that BFR training replaces traditional strength training methods, but I do believe it’s a tremendous tool for modifying and progressing exercise and tissue tolerance depending on the circumstances both aside from and in conjunction with heavier loading.
So far, there are a few proposed mechanisms for how low-resistance training with applied BFR achieves comparable results. Generally, it stimulates the process of protein synthesis through a cascade of events. The reduced oxygen environment with metabolic accumulation leads to further recruitment of type 2 muscle fibers as well as increased hydrogen accumulation, which makes the muscle more acidic and encourages the production of growth hormone. Also, there are increases in both mTOR and MAPK signaling (involved in protein synthesis), and inhibition of the production of myostatin (which is known to decrease protein synthesis). It also achieves the cell swelling that has been previously mentioned in recent posts with cuff application during bed rest and endurance training. Lastly, the protocol involves large amounts of time under tension, which has been shown to help with improving tendon load tolerance.
Ultimately, the progression that we’ve seen up to this point includes the initiation of BFR applied during bed rest and then in coordination with return to endurance exercise. As further loading is tolerated, BFR can be applied to low-load resistance training, with progression to further volume and then eventually further mechanical loading without BFR or some combination of both options.
BFR is certainly a useful tool, and has been one that I’ve used across various populations in post-operative cases, to combat generalized deconditioning, and even in cases of severe arthritic pain that had limited weight bearing tolerance. It has been an invaluable tool, and I look forward to further advances and applications.
Stay tuned for more in this series. 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