Written by Josiah Ayling
Occlusion training or Blood flow restriction training (BFRT) is being used more and more by physiotherapists, exercise physiologist or other trained allied health professionals to assist with improving muscle hypertrophy in a range of general and clinical populations. It works by using compression at the proximal limb to limit blood flow out of the muscle. Research has shown BFRT to increase muscular strength and hypertrophy using loads less than half of what is recommended by the ACSM for general hypertrophy training (60% of 1RM). It is proposed that occlusion training works by altering the traditional ratio of mechanical loading and metabolic stress to give similar outcomes without high mechanical loads – perfect in a rehab setting. How does it work:
When to use BFRT:
- The occlusion cuff compression limits venous return (blood flow out of the muscle) causing venous pooling. Be careful to not elicit full arterial restriction (don’t wrap too tight).
- This causes greater metabolic stress via elevated blood lactate levels which leads to increase growth hormone and IGF-1 (anabolic protein)
- Studies have shown BFRT elicits increased fast-twitch fibre recruitment
- BFRT has also shown to increase; cell swelling and protein synthesis
More recent research suggests the use of BFRT to be useful to elicit improvements to quad/hamstring and lower limb strength, power and total workload in the rehabilitation of osteoarthritic knee pain, post-op ACL-reconstruction, osteochondral fractures and other lower limb pathologies in which heavy lifting (>60% 1RM) may be contraindicated. BFRT may be contra-indicated if you have deep vein thrombosis, varicose veins, high blood pressure, history of stroke or cardiac disease or during pregnancy. Always consult your accredited Exercise Physiologist before starting BFRT to ensure this is appropriate for you. How to implement BFRT:
The use of a Sports Rehab tourniquet is best practice for BFRT this is due to its ability to objectively measure the amount of pressure being applied. As discussed above the goal of occlusion training is to restrict venous return rather than occlude blood flow to the limb. For this reason, it is advised that pressure of 90-120mmHg is optimal. Once the compression has been applied the prescription of appropriate exercises at a specific rep & set range needs to be determined. The following figure gives an outline as towards appropriate load, reps, sets and frequency.