The price you'll have to pay for theses strength increases is a reduced increase in muscle size that's particularly pronounced for the pectoralis major (the large chest muscle), where doing those three extra-sets leads - irrespective of whether you're "all cuffed up" or not - to a reduction(!) in muscle size (as measured by chest circumference).
Obviously we cannot explain the catabolic effects,....
... by taking a look at the results of another recently published study on blood flow restriction. What the results Eonho Kim et al. present in their most recent paper in the Journal of Sports Science and Medicine could tell us, though, is whether the positive effects on strength development are mediated by BFR-induced changes in the expression of "anabolic" hormones.
Important note: The previously reported negative effects on muscle size are negative effects that ar brought about by the "pump sets" at the end of the workout - they are not negative effects of BFR.As the scientists from the University of Oklahoma point out, the purpose of their study was to determine whether there was an acute hormone response to exercise differed between low intensity blood flow restricted resistance exercise and traditional high-intensity resistance exercise in college-aged women.
|Suggested: "Anabolic Workouts Revisited: Testosterone, GH, Prolac- tin & Co - Effects of Workout Type, Volume & Density" | more|
The allegedly catabolic stress hormone, of which most people forget that it is eventually a glucocorticoid and allows you to train without having to have a glucose infusion at hand, is the only hormone with significant (p = 0.03) positive correlations (r = 0.29) with the strength gains of the 56 young men who participated in the 2012 study by West & Phllips (West. 2012).
What about the cuffed up ladies in the study at hand, then?
If we assume that (a) the acute post-workout increase in cortisol is actually an indicator of chronic strength increases and (b) that this is the same for men and women, we should see higher glucocorticoid levels in the 13 healthy women (aged 18-25 yrs), who participated in the Kim study, when they trained with cuffs, then we do, when they train without cuffs.
|Figure 1: Relative changes (pre vs. post) in lactate, growth hormone, hematocrit and cortisol in response to leg presses and leg extensions with (1x30, 2x15 @20% 1RM) and without (3x10 @80% 1RM) blood flow restriction (Kim. 2014)|Don't forget to read more about the "anti-size" effects of BFR" | more
- high intensity leg presses and extensions
for 3x 10 @ 80% 1RM, or
- BFR leg presses + extension
for 1x30, 2x15 @ 20% 1RM with
- 1 minute rest between sets and exercises.
- Abe, Takashi, Charles F. Kearns, and Yoshiaki Sato. "Muscle size and strength are increased following walk training with restricted venous blood flow from the leg muscle, Kaatsu-walk training." Journal of Applied Physiology 100.5 (2006): 1460-1466.
- Fragala, Maren S., et al. "Glucocorticoid receptor expression on human B cells in response to acute heavy resistance exercise." Neuroimmunomodulation 18.3 (2011): 156-164.
- Kim, Eonho, et al. "Hormone Responses to an Acute Bout of Low Intensity Blood Flow Restricted Resistance Exercise in College-Aged Females." Journal of Sports Science and Medicine 12 (2013): 91-96.
- West, Daniel WD, and Stuart M. Phillips. "Associations of exercise-induced hormone profiles and gains in strength and hypertrophy in a large cohort after weight training." European journal of applied physiology 112.7 (2012): 2693-2702.
- Yasuda, T., et al. "Electromyographic responses of arm and chest muscle during bench press exercise with and without KAATSU." International Journal of KAATSU Training Research 2.1 (2006): 15-18.