Mechanical Effects of Exercise on Blood Flow. Arterial inflow to active skeletal muscle decreases during contractions and increases when the muscle relaxes. In contrast, the venous outflow increases during rhythmic contractions but decreases during muscle relaxation.

Contracting muscle consumes large amounts of oxygen to replenish ATP that is hydrolyzed during contraction; therefore, contracting muscle needs to be able to increase its blood flow and oxygen delivery to support its metabolic and contractile activities.

The goal of blood flow restriction training is to restrict venous return while still allowing arterial flow by strategically wrapping the topmost portion of your limbs. By restricting the veins and not the arteries, blood can keep pooling into a working muscle and it stays trapped there.

The purpose of this review is to examine the proposed mechanisms behind muscle damage and critically review the available BFR literature. The available evidence does not support the hypothesis that BFR in combination with low-intensity exercise increases the incidence of muscle damage.

The external forces the BFR creates can help improve bone density and its ability to regenerate after injury when used correctly. Rest assured blood flow restriction is safe when used properly. Initially, many patients are a little skeptical of the safety of BFR.

Blood flow restriction training uses higher metabolically demanding sets & reps with a much shorter rest period between (typically 30-45 seconds). Aim for 15-30 repetitions for 4 sets with only 30 seconds rest between each set. Concentrate as you squeeze out each rep and feel the movements working the muscles.

The bottom line. Current research suggests that occlusion, or BFR, training can be a safe and effective way of increasing muscle strength and size. As with the adoption of any new exercise, check with your doctor to see if BFR is appropriate for your level of health and physical abilities.

How Tight to Wrap. For both your upper and lower body, it is suggested that you wrap to 4-7 out of 10 in tightness; with 10 being as tight as possible. You shouldn’t feel any numbness or tingling once you’ve applied the strap.

As a result, using BFR during resistance training is said to not only increase strength but also boost muscle size, achieving the volume you’d expect from normal training of 12 weeks, in only four.

In theory, strength training with BFR can be done daily, however, this may not be the best long term strategy and training 1-2 times per day should only be done for shorter time periods of 1-3 weeks. BFR-RE is typically a single joint exercise modality for strength training.

BFR Causes Muscles to Work Harder Elastic BFR bands partially restrict the venous blood (oxygen deficient blood flowing from the limbs back to the heart) return. This makes the muscles work even harder to pump the blood back to the heart!

Studies have shown that people with chronic pain, who are recovering from surgery, or who have certain health conditions that reduce muscle mass can benefit from BFR training (2).

o We know that HGH increases with BFR, but we also experience increases in mTOR (mammalian target of rapamyacin). Think of mTOR as the precursor to additional protein synthesis. o You will experience 70% increase in the mTOR pathway following BFR. That’s 70% more work happening to improve your muscle protein synthesis!

Objective. Resistance exercise (RE) stimulates growth hormone (GH) secretion in a load-dependent manner, with heavier loads producing larger GH responses.

Overall, the literature suggests that BFR training is safer than traditional weight-training, which is performed with heavier loads. Some patients complain of a local discomfort due to the band digging into their skin as well as a general limb discomfort at higher levels of compression.

First, BFR can increase muscle growth, either as a standalone practice or in combination with heavy training. Second, because BFR causes very little muscle damage, it can be used during deloading periods to supplement as much as 60 percent of the high-intensity workload.

Blood flow restriction training can be used when the goal is to increase muscle hypertrophy and strength with an individual that is load compromised.

BFR can be used with resistance training, or with other modalities, including endurance activities such as walking and cycling. When combined with exercise (and even without it) BFR magnifies the metabolic stress of exercise.

Walking exercise with limb blood flow restriction (BFR) has been shown to increase muscular mass and strength even if it is performed at low exercise intensities. Peripheral systolic blood pressure (SBP) increased more substantially during walking with BFR (43 ± 5% vs. baseline) than without BFR (11 ± 4% vs. baseline).

Single-joint resistance training with blood flow restriction (BFR) results in significant increases in arm or leg muscle size and single-joint strength. These results suggest that BFR bench press training leads to significant increases in muscle size for upper arm and chest muscles and 1-RM strength.

Blood flow restriction therapy (BFRT) is an innovative training method for the development of muscle strength and hypertrophy in the athletic and clinical settings. Muscle weakness and atrophy are prevalent among musculoskeletal rehabilitation patients, causing delayed return to functional activity.

Patients who undergo joint replacement or knee, foot, ankle or shoulder surgery often experience faster recovery with blood flow restriction therapy. Our physical therapists also use blood flow restriction therapy to, among other things, help treat knee pain, tendinopathies, fractures and osteoporosis.

Blood flow restriction training can be helpful for individuals recovering from an injury or surgery (often to the lower extremities) who are unable to lift heavier weights or exercise at a higher intensity. It’s also beneficial for healthy individuals seeking additional strength gains.

BFR and blood clotting: Research from surgical tourniquet tells us that complete vascular occlusion can cause the formation of a thrombus (blood clot). The incidence rate of suffering a venous thrombosis during BFR training is 0.06%, and this number is lower than the general population figure.

For optimal results, resistance training should ideally be done 2-4 times per week. In theory, strength training with BFR can be done daily, however, this may not be the best long term strategy and training 1-2 times per day should only be done for shorter time periods of 1-3 weeks.

Question: How often should I perform Occlusion Training? Answer: It is recommended to perform 4-5 days per week but for more rapid muscle hypertrophy gains it may be more effective to do every day, at least for the first 2-3 weeks.