Strength and Size Gains from Blood Flow Restriction

When we perform resistance training, we have a lot of options available to us. And I'm not talking about exercise choice or which tool to use.

Instead I'm referring to how many reps we perform, how many sets we do, what tempo we use and how long our rest breaks will be.  

From the table below we can see how the various rep ranges are representative of a percentage of our one rep maximum. For example, when we perform between 6 and 8  reps of an exercise, this will be close to 75-85% of the weight we could lift once.

So if we wanted to get bigger, or stronger, we can see that loads of at least 60%, and probably closer to 70% of 1 RM would be required.

A new training technique, blood flow restriction or BFR, appears to be changing that.

A Finish study had 23 soccer players, average age of 18 years, take part in a study comparing high intensity resistance exercise and low intensity resistance exercise with blood flow restriction.

The experiment ran for 6 weeks with 2 training sessions per week. The high intensity group did 4 sets of 12 reps at 80% of their 1 rep max. The one rep max was determined for each subject at the beginning of the study. Subjects took two minutes rest between sets. 

The experimental group did 4 sets at 30% of their one rep max with sets of 30 reps, 15 reps, 15 reps and 15 reps. 30 seconds rest was taken between sets. For the blood flow restriction, a cuff was placed around the legs and the pressure was set at 130-150 mm Hg. 

Leg exercises such as leg extension and leg flexion were performed, with particular consideration given to the impact this had on the quads, hamstrings, rectis femoris and vastus lateralis.

What they found is the the blood flow restriction group got stronger and bigger compared to the group that performed traditional high intensity resistance exercise.

This is interesting for a couple of reasons:

1. Traditionally we have understood that size and strength gains required loads of at least 75%. This study employed less than half of that at 30% and were able to see the soccer players develop bigger and stronger legs.

2. BFR out-performed high intensity strength training as seen in the table below. I have high-lighted in yellow the pre and post strength gains realized by the BFR group, and these results were better than those not using BFR.

Going forward it is important to keep a few points in mind:

* this experiment included only teenage male soccer players

* the experiment lasted 6 weeks

* the experiment only looked as strength and size gains for the lower body

If you experiment with BFR, keep the resistance low i.e. less than 40%, and start lower with the amount of blood flow resistance. Typically less resistance is applied to the upper limbs compared to the lower. Total reps are typically about 75 and BFR may be used as a finisher after working a particular set of muscles.

Reference

Korkmaz, E., Dönmez, G., Uzuner, K., Babayeva, N., Torgutalp, Ş. Ş., & Özçakar, L. (2020). Effects of Blood Flow Restriction Training on Muscle Strength and Architecture. Journal of strength and conditioning research.