Occlusion training causes greater muscle cell swelling.
The recent excitement over the last few years has led to a surge in the number of bodybuilders using tourniquet or occlusive training to get better pumps in the gyms. Occlusive training, or blood flow restriction (BFR) training, involves wrapping a device or band around the muscle which restricts blood flow while lifting very lightweight. Many lifters have commented on the intense muscle pumps they have received from wrapping an occlusive device around the muscle. Additionally, the lifters will often experience a much higher metabolic response and much greater pain while using blood flow restriction training. Despite the greater pain levels while using BFR training, the exciting aspect of occlusion training is that despite very lightweights being used, similar increases in muscle mass have been documented as those lifting heavier weights (80 percent of a 1-RM). This makes BFR training applicable for people who cannot withstand the high-intensities of traditional resistance exercise, such as those recovering from injury/disease, the elderly, and even athletes, as part of their traditional training programs.
All of the physiological mechanisms involved in the positive adaptations associated with BFR training are not completely understood, but it has been speculated that increases in muscle acute and chronic increases in:
– Increased in anabolic hormones secretion such as GH, IGF-1, and testosterone.
– Increased motor unit recruitment, especially Type II fibers
– Muscle or cell swelling
– Inhibition of myostatin gene expression
– Activation of anabolic molecular pathways such as mTOR.
Cell swelling is one of the most interesting hypotheses based around occlusion training. Cell swelling is the result of increased intracellular fluid accumulation which can contribute to increases in muscle protein synthesis and muscle growth. Previous studies have documented increased cellular swelling after BFR training; however no research studies have compared high intensity resistance exercise to blood flow restriction training and its effect on cellular swelling.
Researchers wanted to compare muscle swelling following an:
– Acute bout of low-intensity (20 percent 1RM) resistance exercise with BFR in comparison, OR
– A traditional high-intensity (80 %1RM) resistance exercise with no BFR.
The heavy load workout involved three sets of 8-10 reps at 80 percent of 1RM on the leg press, knee extension, and leg curl machines, with two minutes of rest between sets and exercises. The light load and BFR workout involved one set of 30 reps, followed by three sets of 15 reps at 20 percent of 1RM on the same exercises, with 30 seconds of rest between sets and exercises, using a BFR pressure of 160mmHg and without removing the cuffs between sets.
At the end of the study, muscle swelling immediately post-workout was greater when performing strength training with a light load (20 percent of 1RM) in combination with blood flow restriction (BFR) and short rests, compared to when using a heavy load (80 percent of 1RM) without BFR and with moderate rest, but this effect is very short-lived. BFR training with a lightweight caused a greater increase in quadriceps muscle thickness immediately post-workout than heavy load training, and caused an increase in hamstrings muscle thickness immediately post-workout, while heavy load training did not. BFR training increased thigh muscle cross sectional area up to 75 minutes post-workout, but heavy load training only elevated thigh muscle cross sectional area up to 15 minutes post exercise. This suggests that muscle cell swelling could be an important contributor to hypertrophy. Cell swelling after BFR training lasts up to 75 minutes post-workout. Many bodybuilders have commented on the intense muscle pumps with blood flow restriction training, so its good to know that science backs up these findings.
Freitas EDS, Poole C, Miller RM, Heishman AD, Kaur J, Bemben DA, Bemben M. Time Course Change in Muscle Swelling: High-Intensity vs. Blood Flow Restriction Exercise. Int J Sports Med. 2017 Nov;38(13):1009-1016.
Loenneke, J. P., Fahs, C. A., Rossow, L. M., Abe, T., & Bemben, M. G. The anabolic benefits of venous blood flow restriction training may be induced by muscle cell swelling. Medical Hypotheses, 2012, 78(1), 151-154.
Loenneke, J. P., Kim, D., Fahs, C. A., Thiebaud, R. S., Abe, T., Larson, R. D., & Bemben, M. G. The influence of exercise load with and without different levels of blood flow restriction on acute changes in muscle thickness and lactate. Clinical Physiology and Functional Imaging. 2016