Occlusion training refers to blood flow restriction (BFR) to small muscle groups like the biceps and triceps, then using single-joint resistance training with 20% of a 1 rep max. The results produced up to a 300% greater increase in strength and up to an 800% greater increase in muscle thickness, over the subjects who used traditional strength training methods.
The initial reported study had noted great results for BFR exercise in small muscle groups using single-joint exercises. For example they measured the results of occlusion training on the biceps after 2 weeks of biceps curls.
At Project Swole, we are more interested in the results on large muscle groups using multi-joint exercises, such as the bench press, squat, or deadlift.
So today’s question remains: does occlusion training increase the strength and size of large muscle groups during multi-joint exercises, when blood flow is restricted from the extremities?
In a recent study by the Department of Human and Engineered Environmental Studies at The University of Tokyo, researchers studied a group of college students by restricting the blood flow to their upper arms (biceps and triceps), and asking them to perform a bench press workout.
The Bench Press Workout
- Flat Barbell Bench Press
- 4 sets for 75 total reps
- using 30% of one rep max (1rm)
- workouts were performed twice per day
- 6 days per week
- for 2 weeks
Strength: Muscle thickness for triceps and pectoralis major were both taken before and after training, and a bench press 1rm and serum anabolic hormones were measured. After two weeks of training, the subjects displayed a significant increase of 6% in 1rm bench press strength in the BFR group, but not in the control group, who lost 2% of their strength.
Size: Triceps and pectoralis muscle thickness increased for BFR subjects by 8% and 16% respectively. The control group lost 1% of their triceps mass and gained only 2% in the pecs.
These results suggest that occlusion training for the bench press leads to significant increases in muscle size and strength for the upper arm and chest muscles. We can only assume this would be true for the back and biceps when rowing or performing pull-ups; and for the quads, hamstrings, and calves when squatting or lunging. Deadlifts are a little different I think.
As before, there was no change in the baseline concentrations of anabolic hormones for either group.
Clearly we can use Kaatsu or occlusion training to increase both muscle size and muscle strength. I still think there are many disadvantages of training this way, despite the wondrous results reported by this study.
There are a million questions still unanswered about BFR training:
- What about the neurological adaptations forced by moving heavy loads?
- What about speed and power?
- What about endurance and stamina?
- What about the long term side effects of restricted blood flow in the extremities?
- How long would it take to lose those gains with reduced training frequency?
I’m still not going to recommend any Project Swole readers base their workout routines around this theory. What if someone added occlusion training to their routine for 2 months, for just one muscle group, while continuing to follow a regular workout routine designed to gain muscle, like Werewolf Training for example?
I would love to see someone do that and report their results. However, please do not attempt occlusion training if you have any medical issues related to any organs, blood conditions, high blood pressure, or really anything out of the ordinary. Definitely check with your doctor before trying anything new if you have any concerns.