Finally, the 1st Blood-Flow Restriction + Classic Training Periodization Study is There and the Gains are Impressive

Finally, the 1st Blood-Flow Restriction + Classic Training Periodization Study is There and the Gains are Impressive

BFR blood flow-restriction build muscle build strength periodization

No, the study did not use a simple rope or band to restrict blood flow. Instead an automated system was used that kept the pressure at stable 100mmHg.

As a SuppVersity reader you know that blood flow restricted training is - at best - as effective as regular resistance training and can thus only be recommended as an adjunct to your regular training (efficacy unproven) or replacement for injured athletes. With a recent thesis by Daniel Cortobius and Niklas Westblad from the Swedish School of Sports and Science, the former use gets scientific backup.

The aim of the bachelor students' study was to investigate how a periodized combination of classic resistance and blood flow restricted resistance exercise (BFRE) compares to regular training when it comes to increase in quadriceps muscle growth and strength.

You can learn more about BFR and Hypoxia Training at the SuppVersity

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Strength ⇧ | Size ⇩ w/ BFR

Training & Living in Hypoxia

Now as great as this sounds, the study has several important weaknesses (few, though, considering the fact that this is undergrad research) due to which it should be considered a "proof of concept", not a "classic + BFR is better than classic alone" study:

• untrained subjects - 10 males and 10 female (4 dropouts), to be specific, 
• no dietary standardization (only a 21g vegetable protein shake after workouts),
• unilateral (=one leg only) resistance training for the legs, only, and 
• the lack of a non-BFR periodized control group 

Without control group, it should be quite obvious that the magnitude of the results of the strength and ultrasound tests Cortobius & Westblad performed before and after the subjects trained for 10 weeks must be interpreted with utmost caution.

BRF After Each Set? More!

What did the workouts look like? "After two familiarization sessions subjects performed three sessions per week in leg press and leg extension, except for week 4 and 8 were subjects performed five BFRE training sessions Monday to Friday" (Cortobius. 2016)." During the weeks, the subjects did three sets with 70-75%, 63-67,5% (90% of Monday) and 80-85% of their individual 1RM for 10-12, 10-12 and 5-7 reps on Monday, Wednesday and Friday of weeks 1-3 and 5-7. During the classic training weeks 9-10, they did 2-3 sets of 10-12 reps at 70-75% on Monday, 1 set of 10-12 reps at 63-67,5% (90% of Monday) on Wednesday and 2-3 sets of 5-7 reps at 80-85% on Friday.

During the BFR weeks, subjects exercised every day, but switched back and forth between leg extensions and presses with the former being done on Monday, Wednesday and Friday, and the latter being performed only on Tuesday and Thursday. Both exercises were performed wearing an automated cuff that was set to regulate the pressure at 100mmHg during the workouts. The BFR workouts, itself, consisted of four sets of unilaterally leg press or leg extension the subjects did at a set pace of 60 BPM and 50 BPM for the extensions and press, respectively. As usual, the intensity was reduced for the BFR weeks: 20 % of 1RM in leg extension and 30 % of 1RM in the leg press. With the short rest of thirty seconds after the first set of 30 reps, the 2nd set of 10 reps and the third and fourth set, during which the subjects performed to concentric failure, the BFR workouts were yet still pretty intense. 

This does not refute the authors' conclusion that their findings, namely a significant increase of vastus lateralis muscle thickness by 15,1 % ± 7,6 (p ≤ 0,01 | no difference between genders), as well as leg press 1.RM by 59,1 % ± 27,4 (p ≤ 0,01), and leg extension 1RM by 19,8 % ± 13,1 (p ≤ 0,01), suggest superior effects of periodized BFR + regular training on muscle growth in comparison with most other strength training studies.

Figure 1: Size (left) and strength (right) gains over the 10-week study period / no sign. sex-differences (Cortobius. 2016).

Without a group that trained without cuffs in weeks 4 and 8, too, however, the attribute "superior" is yet practically meaningless. Different subjects, probably different nutrition, different exercises, ... a direct comparison between one study and another is never really valid, even if Cortobius and Westblad are right to point out that that the effects they observed in their study are "much greater than the mean increase of 0.11 % per day reported in a large meta-analysis (Wernbom, Augustsson & Thomeé 2007)" (Cortobius. 2016) - without a control group that trained regularly or simply with slightly higher intensity, but similarly high reps to failure daily during weeks 4 and 8, we have no valid benchmark for the results of the study at hand (so let's hope there's a follow up before the authors' master thesis ;-).

BFT Preconditioning no Better Than Placebo, Study Shows | more

Bottom line: As happy as I am that this study has finally been conducted (you may remember from previous SuppVersity articles on blood flow restriction that I've argued in favor of periodization to use BFR more effectively), there's no way to tell whether BFR + classic training produces greater gains than classic training alone based on the study at hand.

Therefore, we can only hope that a follow-up study with a 1:1 comparison of periodized BFR and unperiodized regular resistance training will be done to finally answer the question, whether the two weeks of training with cuffs actually promoted additional size and/or strength gains (in my dreams, that study would be done with a full body or at least a complete leg workout in trained individuals, obviously ;-) | Comment!

References:

• Cortobius, Daniel, and Niklas Westblad. "Optimizing strength training for hypertrophy: A periodization of classic resistance training and blood-flow restriction training." (2016).
• Wernbom, Mathias, Jesper Augustsson, and Roland Thomeé. "The influence of frequency, intensity, volume and mode of strength training on whole muscle cross-sectional area in humans." Sports medicine 37.3 (2007): 225-264.

BFR Preconditioning Not Better Than Placebo? Long Rest Periods For Sustained Testosterone Increase? Train One Leg, Grow Both? - Resistance Training Update October '14

BFR Preconditioning Not Better Than Placebo? Long Rest Periods For Sustained Testosterone Increase? Train One Leg, Grow Both? - Resistance Training Update October '14

BFR blood flow-restriction build muscle build strength cross-education multi-set training on short notice resistance training rest times single-joint exercises single-set training unilateral training

Single-legged leg presses that make both legs stronger are only one of many topics, today.

Time for an update on the latest resistance training research - just the interesting stuff, obviously ;-) What exactly? Well, let's see: We'll take a look at how long rest periods sustain the exercise induced. Then, we'll dive right into a placebo-controlled study on blood flow restriction as a means of preconditioning before resistance training, only to top things off with a study that found that training your dominant leg will also increase the leg press strength of the untrained, non-dominant limb.

Ah, and since there was some space left in the bottom line, we will acknowledge that AM vs. PM training have identical effects on power, force and hormonal response in young men and pretend to be surprised that a three-set upper-body workout is much more energetically demanding than its one-set analog. All in all, a very balanced update on the latest resistance training research, I'd say.

Read more about exercise-related studies at the SuppVersity

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• Long rest periods prolong testosterone response to bench press exercise -- From various previous SuppVersity articles you know that resistance training triggers an acute increase in testosterone. That this increase may depend on the rest between sets, though, is news. News from a recent article in the Journal of Strength and Conditioning Research.
  
  The purpose of the study was to examine the influence of rest period duration (1 vs. 3-minute between sets) on acute hormone responses to a high intensity and equal volume bench press workout (5x3 sets at 85% of the 1RM, to be specific).
  

  

  Figure 1: Mean (left) and individual (right) free testosterone levels before and after performing bench presses with 1 min or 3 min rest (Scudese. 2015).

  To this ends, Scudese et al. (2015) recruited ten resistance trained men (25.2 +/- 5.6 years; 78.2 +/- 5.7 kg; 176.7 +/- 5.4 cm; bench press relative strength: 1.3 +/- 0.1 kg/kg of body mass) and had them perform two bench press workouts separated by one week. Each workout consisted of 5 sets of 3 repetitions performed at 85% of 1-repetition maximum, with either 1 or 3-minute rest between sets. The rates of perceived exertion and serum levels of growth hormone (GH), cortisol, free and total testosterone were sampled at three different timepoints right (PRE), right after (T0) before, 15 (T15) and 30 (T30) minutes after. The results were as follows:
  • For total testosterone, both rest lengths enhanced all post-exercise verifications (T0, T15 and T30) compared to PRE, with 1-minute showing decreases on T15 and T30 compared to T0.
  • For free testosterone, both 1 and 3-minute rest protocols triggered augmentations on distinct post-exercise moments (T0 and T15 for 1-minute; T15 and T30 for 3-minute) compared to PRE.
  • Since the the cortisol values did not change throughout any post-exercise verification for either rests, the total testosterone/cortisol ratio was significantly elevated for both rests in all post-exercise moments compared to PRE.
    The growth hormone values did not change for both rest lengths.
  Now, that's exciting, right? The free testosterone levels kept increasing... well, not exactly. If you look at the data in Figure 1 right, you will notice interpersonal differences that suggest that the elevation would not have lasted for much more than those 15 extra-minutes .
  
  What's of significantly greater importance for the interpretation of the study results is yet a study by West et al. (2012) who observed that the testosterone response (both free and total) to resistance training is not associated with either strength or size gains. So what? It is very likely that the results of the study at hand are of zero practical relevance for your gains (strength- and sizewise, as West's study indicates).
• Blood flow restriction before strength training? It works - just as well as placebo! -- You will probably remember my recent article about the benefits of using blood flow restricting cuffs before a sprint workout, right (click here if not)? With the publication of the results of Moacir et al.'s (2015) latest study, we do now know that similar benefits will be seen with subsequent resistance training, too.

  

  The study at hand should make you question the results of the previously discussed study which did not have a placebo group | learn more

  "Thirteen men participated in a randomized crossover design that involved 3 separate sessions (ischemic preconditioning, placebo and control). A 12-RM load for the leg extension exercise was assessed through test and retest sessions prior to the first experimental session. The IPC session consisted of 4 cycles of 5 minutes occlusion at 220 mmHg of pressure alternated with 5 minutes of reperfusion at 0 mmHg for a total of 40 minutes. The PLACEBO session consisted of 4 cycles of 5 minutes of cuff administration at 20 mmHg of pressure alternated with 5 minutes of pseudo-reperfusion at 0 mmHg for a total of 40 minutes. 

  The occlusion and reperfusion phases were conducted alternately between the thighs, with subjects remaining seated. No ischemic pressure was applied during the control (CON) session and subjects sat passively for 40 minutes. Eight minutes following IPC, PLACEBO or CON, subjects performed three repetition maximum sets of the leg extension (2min rest between sets) with the pre-determined 12-RM load. Four minutes following the third set for each condition, blood lactate was assessed" (Moacir. 2015)

  When the researchers analyzed the results, they found that for the first set, the number of repetitions significantly increased for both the IPC (13.08 +/- 2.11; p = 0.0036) and PLACEBO (13.15 +/- 0.88; p = 0.0016) conditions, but not the CON (11.88 +/- 1.07; p > 0.99) condition.
  

  

  Figure 2: Significant increases in the number of reps (left) were observed for both the placebo and IPC group. The fatique index (right) did not differ between treatments, but the large inter-individual variety in the IPC group clearly suggests that BFR as a means of preconditioning ain't for everyone (Moacir. 2015).

  Similarly, the IPC and PLACEBO conditions resulted in significantly greater repetitions versus the CON condition on the 1st set (p=0.015; p=0.007) and 2nd set (p=0.011; p=0.019), but not the 3rd set (p=0.68; p>0.99). No significant difference (p=0.465) was found in the fatigue index and lactate concentration between conditions.
  
  As the researchers point out, their results "indicate that IPC and PLACEBO ischemic preconditioning may have small beneficial effects on repetition performance over a CON condition" (Moacir. 2015). It is thus not completely logical that they suggest "that ischemic pre-conditioning might be practiced gradually to assess tolerance and potential enhancements to exercise performance" (ibid.). What? Oh, you think your clients would notice that their blood flow is not actually impaired and the placebo effect would be lost? Right, now I understand why you should keep using it. Unfortunately that does not exclude that it is still a placebo effect which seems not unlikely in view of the larg(er) inter-individual differences in the IPC vs. any other group. Further studies are necessary... obviously!
• Train your right leg, and your left leg will become stronger, too - on leg presses, at least -- What sounds like a joke (or magic) is actually science. Science that is going to be presented in an article in a future edition of the Journal of Strength and Conditioning Research; and more precisely from a study that assessed the cross education of strength and changes in the underlying mechanisms (muscle size, activation, and hormonal response) following a 4-week unilateral resistance training (URT) program.
  
  In said study by Beyer et al. (2015), a group of nine untrained men completed a 4-week URT program on the dominant leg (DOM), while cross education was measured in the non-dominant leg (NON); and were compared to a control group (n=8, CON).

  "Unilateral isometric force (PKF), leg press (LP) and leg extension (LE) strength, muscle size (via ultrasonography) and activation (via electromyography) of the rectus femoris and vastus lateralis, and the hormonal response (testosterone, growth hormone, insulin, and insulin-like growth factor-1) were tested pre- and post-training" (Beyer. 2015).

  In all strength and size related measures, the trained group improved significantly better than CON. Significant group x time effects for PKF, LP, LE, and muscle size were observed only in the dominant leg (DOM), the non-dominant (NON = untrained leg), on the other hand, the scientist observed not just a trend, but rather an actual and statistically significant increase in leg press strength.
  

  

  Figure 3: Relative leg press and leg extension strength relative to body weight; the values above the post-bars indicate the relative difference between post and pre-test (2015).

  Whether that's related to the acute hormonal response to URT, the scientists observed, is more than questionable, after all the strength increase in the non-dominant leg didn't just occur in the absence of "detectable changes in muscle size, activation (EMG), or the acute hormonal response" it did also occur only during leg presses - if it was the result of any of the aforementioned factors one would expect to see at least something like a trend for leg extensions, as well.
  
  Against that background it should also be clear that you must not neglect one leg or arm when you train in the definitely false hope it would grow and the almost certainly false hope it would get stronger as you train your "favorite" limb. 

There's more: In view of the fact that the bottom lines to the individuals studies discussed in SuppVersity Research Overviews are always provided at the end of the respective item, I have room for mentioning two other interesting results at least briefly.

Figure 4: Energetic demands of 5x3 vs. 5x1 set upper body workout in men and women. Needless to say that the inter-group difference between 3 vs. 1 sets and the inter-group difference between men and women (not shown) were significant (Mookerjay. 2015).

Firstly, Hatfield et al.'s study of the "Effects of circadian rhythm on power, force, and hormonal response in young men" that indicates that "high force and power exercises utilizing  bench press-throws or jump squats may be performed any time of day without detrimental decreases in acute performance" (Hatfield. 2015). And secondly, Mookerjay et al.'s "[c]omparison of energy expenditure during single vs. multiple-set resistance exercise" (Mookerjay. 2015) that yielded a very obvious result which was that the multi-set protocols yield greater metabolic and cardiovascular demands than single set protocols when the number of exercises performed are the same (see Figure 4). In the study 5 upper-body exercises of either 1 or 3 sets per exercise performed in random order the gross and net energy expenditure was determined for the workout + 5 minutes of recovery. You can see the exact data in Figure 4, in case you're interested | Comment on Facebook!

References:

• Beyer, et al. "Short-Term Unilateral Resistance Training Results in Cross Education of Strength without Changes in Muscle Size, Activation, or Endocrine Response." Journal of Strength and Conditioning Research (2015): Ahead of print.
• Hatfield, et al. "Effects of circadian rhythm on power, force, and hormonal response in young men." Journal of Strength and Conditioning Research (2015): Ahead of print.
• Moacir, et al. "Ischemic preconditioning and placebo intervention improves resistance exercise performance." Journal of Strength and Conditioning Research (2015): Ahead of print.
• Scudese et al. "Long rest interval promotes durable testosterone responses in high intensity bench press." Journal of Strength and Conditioning Research (2015): Ahead of print.
• 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.