Saturday, February 1, 2014

Strength ⇧ | Size ⇩ - After 7 Weeks With Three Additional Sets of Blood Flow Restricted High Rep + Low Intensity Squats & Bench Presses in Well-Trained Athletes

Strength and size don't always go hand in hand... and BFR training appears to be better suited for strength than size gains.
"A Seven-week Practical Blood Flow Restriction Program on Well-trained Collegiate Athletes", this does not just sound awesome, this is awesome, because it is the title of a soon-to-be-published paper in the Journal of Strength and Conditioning Research. Conducted by researchers from the Emporia University and the University of Kansas, the corresponding seven week trial that involved 62 participants is yet not the first study to examine the effects of blood flow restriction (BFR) used in conjunction with a traditional weight training program on measures of muscular strength and size in athletes (collegiate American football players).

The protocol used in this investigation was modeled after a practical BFR study conducted by Yamanaka et al. (2002) - a 4-week study with 32, instead of 62 National Collegiate Athletic Association Division IA football players as subjects, which already found "improved muscular hypertrophy and muscular strength" (Yamanaka. 2002) in response to a twice-a-week lower body vs. upper body workout (Mo, Tue - Thur, Fri):
Table 1: Overview of the the 2-day upper / lower body split the subjects in the study performed (Luebbers. 2014)
The experiment took place during the team's off-season, as a part of their strength and conditioning program and the scientists speculated that they would see similar increases in strength and size gains as Yamanaka et al. in those athletes who did the additional 3 sets with cuffs .

Four, not just two groups - that's an important difference

To investigate if it's not the blood flow restriction, but simply the addition of 3 sets of high rep (1x30, 2x20), low intensity (20% or 1RM) bench presses and squats (see Table 1) to the end of the workout that yields the performance benefits, the scientists randomized their initial 72 study participants to four, not just two groups, that performed different combinations of
  • "Resting Done Right: Passive Rest or Active Recovery to Get the Most Out Of Your Workouts?" | more
    traditional high intensity training (H) - all the exercises in Table 1 except for the orange bonus at the bottom
  • modified medium intensity training (M) identical to (H) but without the high intensity squats and bench presses at the beginning of the workout
  • supplemental 20% 1RM Lifting Protocol (S) additional high rep, low intensity bench presses and squats, but without blood flow restriction
  • supplemental BFR restricted training (R) additional high rep, low intensity bench presses and squats, but without blood flow restriction
You can see the result in Table 2. Eventually, the the letter-combinations in the "group" column do yet already give away what the participants in the individual groups are doing. Right?
Table 2: Overview of the different groups in the study (Luebbers. 2014)
It goes without saying, that the "H/S/R" group is the one we are most interested in. It is, after all, the group, in which the participants did the blood flow restriction training as an adjunct to a "full" high intensity workout program.
Figure 1: Relative changes in lean mass and strength over the 7-week study period (Luebbers. 2014)
Well, I am not sure if you feel the same, but if I take a look at the data in Figure 1, I am kind of disappointed. Ok, if you want to boast of being a "master squatter", it's probably worth to bandage yourself up at the end of every workout, if you want to get bigger, on the other hand, you better refrain from any type of additional high rep + low intensity exercises towards the end of your workout - irrespective of whether or not you're planning to to them with cuffs.
The study at hand does not refute that BFR training could be a valuable way to make progress in size and strength if you can't train intensely, because of injuries or whatever | learn more
Bottom line: While blood flow restriction appears to be a worthwhile addition to a high intensity strength training regimen that's designed to deliver maximal strength increases it blunts the corresponding increases in muscle size.

In the case of the pectoralis major, the additional three sets of high rep (1x 30, 2x 20 reps) work even led to a measurable, albeit statistically non-significant decrease in chest circumference. If your main goal is muscle size, not strength, the results of the study at hand would clearly suggest that you better stay away from both blood flow restriction and additional low intensity, high rep work (aka pump sets) at the end of the workout.
  • Luebecke et al. "The Effects of a Seven-week Practical Blood Flow Restriction Program on Well-trained Collegiate Athletes." Journal of Strength and Conditioning Research Publish Ahead of Print. DOI: 10.1519/JSC.0000000000000385
  • Yamanaka, Tetsuo, Richard S. Farley, and Jennifer L. Caputo. "Occlusion training increases muscular strength in division Ia football players." The Journal of Strength & Conditioning Research 26.9 (2012): 2523-2529.