Not Resting Long Enough May Ruin Your Gains! 1 vs. 5 min Cut Post-Workout Increase in Protein Synthesis by 50% !

Not Resting Long Enough May Ruin Your Gains! 1 vs. 5 min Cut Post-Workout Increase in Protein Synthesis by 50% !

build muscle gains gainz hypertrophy inter-set rest muscle protein synthesis protein synthesis rest rest intervals

Rest is not a waste of time ;-)

You may remember Schoenfeld et al's 2015 study with the telling title "Longer inter-set rest periods enhance muscle strength and hypertrophy in resistance-trained men" (Schoenfeld. 2015) and Henselmann's and Schoenfeld's previous review of "The Effect of Inter-Set Rest Intervals on Resistance Exercise-Induced Muscle Hypertrophy" stating that "the literature does not support the hypothesis that training for muscle hypertrophy requires shorter rest intervals than training for strength development or that predetermined rest intervals are preferable to auto-regulated rest periods in this regard" (Henselmann. 2004).

Eventually, it can thus not be surprising that James McKendry and colleagues write in their latest paper that "short rest (1 min) between sets of moderate-intensity, high volume resistance exercise blunts the acute muscle anabolic response compared with a longer rest period (5 min), despite a superior circulating hormonal milieu," and conclude that their "data have important implications for the development of training regimens to maximize muscle hypertrophy" (McKendry).

Want to bump up the volume? Add bicarbonate as a pH-buffer to make that possible!

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What may be surprising, though, is the extent (see Figure 2) to which the post-exercise protein synthesis the researchers measured in young male subjects who habitually performed lower-limb resistance training at least once per week for ≥1 year prior to study enrollment and were deemed ‘recreationally trained’, when they had them do the same leg workout

• 4 sets of leg press and 4 sets of knee extension exercise at 75% of 1RM
• performed w/ a lifting-lowering cadence of ~1 sec in both concentric & eccentric phases, 
• without pause, until momentary muscular failure (i.e. 9-10 on the Borg CR-10 scale). 

with either five minutes or one minute of passive rest between sets and gave them 25g of whey protein isolate (MyProtein, Cheshire, UK) right after the workout to kickstart the protein synthesis.

Figure 1: Overview of the initial (Trial 1) and next morning procedures (Trial 2 | McKendry. 2016).

After having ingested the whey protein shake, the participants rested in both trials supine for 240 minutes. After those 4h, another muscle biopsy was obtained ~3cm proximal to the second biopsy to determine MPS rates over the ‘early’ phase (0-4 h) of post-exercise recovery. The data from this phase was complemented by data from a last, fourth muscle biopsy on the next morning and after consuming an identical protein shake after 10h of fasting (lunch and dinner on the day before were standardized, so that this would not mess with the results).

Figure 2: Protein synthetic (myofibrillar) and hormone response after working out with 1 vs. 5 min rest (McKendry. 2016).

Whether and to which extent the sign. difference in protein synthesis of which the scientists say that it is an 76% vs. 152% increase in the 0-4h time-window after the workout is related or even triggered by the significantly higher GH response in after the 5-min rest trial is questionable, but if you recall the seminal paper by West et al. (2012), you will certainly remember that GH and cortisol are the only hormones the levels of which after a workout show any correlation with muscle gains (see Figure 3).

Figure 3: Sign. associations between PWO hormone levels and lean mass, as well as fiber size increases (West. 2012).

With that being said, you may consider this odd, because usually the metabolically more demanding short-rest workout will yield greater GH increases (Kraemer. 1990; Goto. 2004; Bottaro. 2009) - this and the fact that the previously hinted at association exists, but the incline or, in other words, the effect on fiber size per unit increase in GH is low (too low to fully explain the 5-minute-advantage) suggest that there must be more to it than the small GH increase with 5 minutes vs. 1 minute rest.

Why do other studies not confirm this finding? I guess that depends on the study. An often-cited paper by Kraemer, et al. for example found 1 minute of rest to outperform 3 minutes hypertrophy-wise - probably because the 1-min rest protocol involved 3 sets of 8 exercises with a 10-RM load, while the 3 minute protocol involved "only" five sets of five exercises, performed with a 5-RM load, so that the two workouts were not volume equated and the study no comparison of workouts with different rest times, but rather one of hypertrophy vs. strength workouts.

Acute effect of different rest intervals between sets over the number of repetitions maximum (RM). Values expressed as RM (de Salles. 2009)

Conflicting results from other studies, e.g. Villanueva, et al. (2015) who found sign. greater muscle gains in with 1 vs. 4 minutes of rest, may be explained by differences in the study population (elderly in Villanueva, et al.) and/or the training protocol, which did not involve training to failure and thus probably didn't produce significant volume advantages for the 4-minute rest group. Eventually, volume appears to be, within sustainable limits, the most sign. determinant of the hypertrophy response to exercise, so if you do something to increase it (e.g. myoreps or real vs. volume- equated drop sets, etc.) you may still benefit. If you simply cut the rest, however, the volume suffers from not resting long enough (cf. table on the left) and this may affect your gains.

The existing differences in  anabolic signaling protein phosphorylation (e.g. p70S6KThr389, rpS6Ser240/244, 4EBP1Thr37/46, etc.) can likewise not serve as a mechanistic explanation. After all, these are the switches that trigger the growth. Saying they are responsible would be tantamount to saying that the light switch is the reason the light went out, when someone actually switched it off.

So, what is it that makes the difference? Well, in view of the results of previous studies that suggest that, ultimately, it's not hormones, not protein phosphorylation, but rather the total volume of weight that is lifted (at least unless that's so much that you do more harm than good) that determines the hypertrophy response to resistance training (Schoenfeld. 2013), we should look at a different study outcome: the total volume in kilograms (see Figure 4):

Figure 4: Set- and total volume when subjects trained with 1 vs. 5 minutes rest (McKendry. 2016).

That the sign. difference in volume on set 3 and 4, and the significant difference in total volume are actually the explanation, is obviously speculative, but at least for me it is the most likely explanation for a difference (see red box, as well).

The ineffectiveness of drop-sets in Fisher's recent study may in fact also have been a result of a lack of difference in training volume | more

Bottom line: Eventually, the study at hand only proves what we already knew - training volume is more important than metabolic stress when it comes to hypertrophy gains.

Any training regimen / modification that reduces the total volume of weight lifted may thus potentially compromise your gains... if the volume is in fact all that is to the effects of shortening rest times will obviously still have to be determined. As of now, volume is yet the best explanation for the differences or lack of differences and effects scientists observed in this and previous studies such as the recently discussed dropset study by Fisher et al. where the set-volume standardization may have blocked any sign. advantage of real-world (=add-on) dropsets | Discuss!.

References:

• Bottaro, Martim, et al. "Effects of rest duration between sets of resistance training on acute hormonal responses in trained women." Journal of science and medicine in sport 12.1 (2009): 73-78.
• de Salles, Belmiro Freitas, et al. "Rest interval between sets in strength training." Sports Medicine 39.9 (2009): 765-777.
• Goto, Kazushige, et al. "Muscular adaptations to combinations of high-and low-intensity resistance exercises." The Journal of Strength & Conditioning Research 18.4 (2004): 730-737.
• Henselmans, Menno, and Brad J. Schoenfeld. "The effect of inter-set rest intervals on resistance exercise-induced muscle hypertrophy." Sports Medicine 44.12 (2014): 1635-1643.
• Kraemer, WJ, Marchitelli, L, Gordon, SE, Harman, E, Dziados, JE, Mello, R, Frykman, P, McCurry, D, and Fleck, SJ. Hormonal and growth factor responses to high intensity resistance exercise protocols. J Appl Physiol 69: 1442-1450, 1990.
• Schoenfeld, Brad J. "Postexercise hypertrophic adaptations: a reexamination of the hormone hypothesis and its applicability to resistance training program design." The Journal of Strength & Conditioning Research 27.6 (2013): 1720-1730.
• Schoenfeld, Brad J., et al. "Longer inter-set rest periods enhance muscle strength and hypertrophy in resistance-trained men." Journal of strength and conditioning research/National Strength & Conditioning Association (2015).
• Villanueva, Matthew G., Christianne Joy Lane, and E. Todd Schroeder. "Short rest interval lengths between sets optimally enhance body composition and performance with 8 weeks of strength resistance training in older men." European journal of applied physiology 115.2 (2015): 295-308.
• 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.
• Willardson, Jeffrey M. "A Brief Review: How Much Rest between Sets?." Strength & Conditioning Journal 30.3 (2008): 44-50.

Resting 3 vs. 1 Min. Between Sets Pays Off: Greater Size + Strength Gains - Probably Mediated by 15% Higher Volume

Resting 3 vs. 1 Min. Between Sets Pays Off: Greater Size + Strength Gains - Probably Mediated by 15% Higher Volume

build muscle build strength hypertrophy rest rest intervals rest periods rest times

Resting long enough to maximize your training volume could be the key to success, i.e. strength and size gains.

If you have been following the various affords to ascribe differences in strength and, even more so, size-increases to a specific training variable, you will remember that the only promising parameters that appear to be supported by more than the literal "outlier study" are training load and volume.

Of these, the former is pretty much uncontested. The latter, however, is still questioned by a camp of inconvincible skep- tics, who simply ignore the fact that there's ample evidence that "[h]igher-volume, multiple-set protocols have consistent- ly proven superior over single set protocols with respect to increased muscle hypertrophy" (Schoenfeld. 2010).

It would be interesting to see if rest periods should also be periodized!

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What still isn't clear, though, is the role of other training parameters, such as the time you take to recover between multiple sets and exercises aka the "rest intervals". As Schoenfeld et al. point out in the introduction to their most recent study, "several studies have investigated the effects of varying rest interval length on muscular adaptations," (Schoenfeld. 2015) albeit with contradictory results: While Ahtiainen et al (2005) were unable to find a significant inter-group size or strength difference in well-trained subjects (6.6 +/- 2.8 years of continuous strength training) who rested 2 minutes compared to those who rested only 5 minute in response to their 21-week training intervention, Buresh et al (2005) reported more recently that significantly greater size increases of the arms and a trend for greater muscle hypertrophy in the legs in young, albeit untrained subjects who rested for 2.5 minutes instead of just one.

Figure 1: Previous studies found "conflicting" evidence. While Ahtiainen et al. found no effects of 2 vs. 5 minutes in trained, Buresh et al. found effects of 2 vs. 1 minutes rest in untrained subjects. With different subjects, different workouts and most importantly different rest times that were compared it is yet not exactly right to say that the studies contradict each other.

Now, obviously, the ostensible "contradiction" I alluded to in the previous paragraph does eventually not exist. With trained vs. untrained subjects, different workout protocols and most importantly different rest intervals (1 vs. 2 minutes and 2 vs. 5 minutes) the studies by Ahtiainen and Buresh cannot really contradict each other. The same must be said of an even more recent study by Villanueva et al. (2014) the surprising findings of which, i.e. "longer rest periods compromise the gains of older trainees", I've discussed last year, already.

What about the lack of different increases in strength endurance? I have to admit that I do not discuss this finding of the study in detail. While one would expect that shorter rest intervals would produce greater strength endurance adaptations, the researchers observed the opposite, an - albeit non-significantly larger increase in strength endurance in the 3-minute-rest group that correlated with the increase in 1RM strength. Further studies will have to show what the underlying mechanism of this counter-intuitive observation is and whether it may be muscle specific, i.e. occur only in the upper, but not in the lower body.

Eventually, however, this does not change that there is, as Schoenfeld et al. write that "a need for more research to provide greater clarity on the topic" (Schoenfeld. 2015). A "clarity" Schoenfeld et al. sought to find with a study that "used current rest interval recommendations for hypertrophy and strength of 1 versus 3 minutes, respectively, and employed validated measures to directly assess site-specific changes in muscle thickness" (ibid). In that, the researchers speculated that ...

"[c]onsistent with generally accepted guidelines on the topic (Willardson. 2006), we hypothesized that short rest intervals would produce greater increases in muscle growth and local muscle endurance while long rest intervals would result in superior strength increases" (Schoenfeld. 2015).

As you will know if you didn't miss the headline of this SuppVersity article, this hypothesis was only partly validated. The data in Figure 2 confirms that the subjects, "experienced lifters (defined as consistently lifting weights for a minimum of 6 months and a back squat / body weight ratio ≥ 1.0)" (Schoenfeld. 2015), gained significantly more strength, when they rested 3 versus just 1 minute between the 3 sets of their three weekly workouts (Figure 2 does also tell you that the strength endurance increases were identical in both groups).

Figure 2: Changes in markers of strength and strength endurance; * denotes significant pre- vs. post difference, # denotes significant inter-group difference (here in favor of long(er) rest periods | Schoenfeld. 2015).

What was Schoenfeld et al. did not find, however, were increased size gains in the short-rest period group whose 24 workouts that were performed on non-consecutive days over the course of the 8-week study period, were otherwise identical with those of the long-rest period group and comprised a total of 7 exercises for all major body parts, namely...

• three leg exercises, i.e. barbell back squats, plate-loaded leg presses, and plate-loaded leg extensions), 
• two exercises for the anterior torso muscles, i.e. flat barbell presses and seated barbell military presses, and 
• two exercises for the posterior torso muscles, i.e. wide-grip plate-loaded lateral pulldowns, and plate-loaded seated cable rows

This is a highly significant result even for you who is - according to an older SuppVersity Poll - probably training according to a split regimen, albeit most likely with very similar exercises. What may be different from the some, but obviously *smile* not your workout though, is that the supervision by members of the research team ensured that the subjects stuck to the prescribed cadence of 1 second for the concentric and "approximately 2 seconds" (ibid.) for the eccentric part of every the exercise. This as well as the imperative progression to higher weights, whence the prescribed number of 8-12 reps per set could be performed is unfortunately overlooked by many recreational trainees - with disappointing consequences in the form of inferior or even no size and strength gains, by the way... but I am digressing, let's rather take a look at the already mentioned, unexpectedly superior strength size gains in the long(er) rest interval group (Figure 3).

Figure 3: Changes in muscle thickness and corresponding effect sizes; * denotes significant pre- vs. post-changes, # denotes significant inter-group differences; overall it is obvious that there's a long(er) rest advantage (Schoenfeld. 2015).

As the single "#" in Figure 3 tells you, the inter-group differences and thus the advantage of the long(er) rest intervals was statistically significant only for the quads, though. If we also take into account the lack of statistically significant effects on the sleeve sizes (biceps and triceps) in the short rest interval group, as well as the obvious differences in effect sizes (Figure 3, right), there's yet little doubt that the hypothesis that shorter rest intervals yield greater size increases must be considered falsified - at least under the given experimental conditions (trained subjects, three full-body workouts per week, standard hypertrophy set and rep-ranges, etc.).

So what's the verdict, then? At first sight it would appear as if the study at hand would totally refute the idea that shorter rest intervals, or I should clarify, rest intervals that are as short as 60s (*) should have a place in your training regimen altogether (*Schoenfeld, et al. rightly point out that Ahtiainen's result suggest that even 120s could have been enough time to rest - it is thus important to give precise recommendations for rest intervals, not something as arbitrary "short" vs. "long"). We should not forget, though, that even a thoroughly conducted study like the one at hand has its limits and definite conclusions should not be drawn hastily based on a single study result - even if it is, as in this case, corroborated by the results of Buresh et al (2009).

Figure 4: The total training volume in the long(er) rest period group (3 vs. 1 minutes of rest) was on average 15% higher. Due to the relatively high inter-individual differences and the relatively low number of participants (N=21) a statistically significant correlation between the weight lifted per week (total volume in kg as in the figure) and the surprisingly superior gains in the 3-min-rest group could not be established (based on Schoenfeld. 2015).

With that being said, a secondary outcome of the study provides a reasonable explanation for why both, the strength and the size gains benefited from long(er) rest intervals: The total training volume I've plotted in Figure 4. As Schoenfeld et al. point out, the latter has previously been suspected to mediate the effects of inter-set rest on strength and hypertrophy on total training volume and strength (Henselmans. 2014). A correlation between the visible differences in training load (see Figure 4) and the magnitude of training adaptations, however, could not be found in the study at hand. As the authors highlight, the reason for this lack of statistical significant correlations may yet be a simple lack of statistical power, so that one "cannot rule out the possibility that the greater training load achieved by the longer rest period group was responsible for the greater training adaptations" (Schoenfeld. 2015 | Buresh et al. found such an effect for the upper, yet not for the lower body).

Personally, I tend to believe that, with a higher number of subjects, a correlation between the total training volume that was on average 15% higher in the 3 vs. 1 minute rest group could have been established. This, in turn, would support the notion that long(er) rest periods - maybe, as Schoenfeld et al. suggest based on the data from Ahtiainen's study, at least 120s - are necessary to maximize the total training volume and thus the overall = strength and hypertrophy response to workouts. Whether that is true for all types of workouts (e.g. split- vs. full-body), all subject groups (e.g. people who are used to short rest periods vs. those who are not) as well as special athletic requirements (e.g. power vs. strength & hypertrophy) will have to be determined in future studies, however | Comment on Facebook!

References:

• Ahtiainen, Juha P., et al. "Short vs. long rest period between the sets in hypertrophic resistance training: influence on muscle strength, size, and hormonal adaptations in trained men." The Journal of Strength & Conditioning Research 19.3 (2005): 572-582.
• Buresh, Robert, Kris Berg, and Jeffrey French. "The effect of resistive exercise rest interval on hormonal response, strength, and hypertrophy with training." The Journal of Strength & Conditioning Research 23.1 (2009): 62-71.
• Henselmans, Menno, and Brad J. Schoenfeld. "The Effect of Inter-Set Rest Intervals on Resistance Exercise-Induced Muscle Hypertrophy." Sports Medicine 44.12 (2014): 1635-1643.
• Schoenfeld, Brad J. "The mechanisms of muscle hypertrophy and their application to resistance training." The Journal of Strength & Conditioning Research 24.10 (2010): 2857-2872.
• Schoenfeld, et al. "Longer inter-set rest periods enhance muscle strength and hypertrophy in resistance trained men." Journal of Strength and Conditioning Research (2015): Publish Ahead of Print.
• Villanueva, Matthew G., Christianne Joy Lane, and E. Todd Schroeder. "Short rest interval lengths between sets optimally enhance body composition and performance with 8 weeks of strength resistance training in older men." European journal of applied physiology (2014): 1-14.
• Willardson, Jeffrey M. "A brief review: factors affecting the length of the rest interval between resistance exercise sets." The Journal of Strength & Conditioning Research 20.4 (2006): 978-984.

GYM-Science Update: Bands Aid W/ Deadlifts? 16x1 or 4x4 for HIIT? Kettlebell HIIT Workout Better Than HIIT-Cycling?

GYM-Science Update: Bands Aid W/ Deadlifts? 16x1 or 4x4 for HIIT? Kettlebell HIIT Workout Better Than HIIT-Cycling?

bands cycling deadlift high intensity HIIT interval training intervals kettlebells lose fat on short notice performance rest intervals workout routines workouts

Deadlifts w/ bands as they were done in the Galpin study (original photo from Galpin's 2015 study | see below).

Time for a news-quickie with the latest science to use at the gym - either for your workouts or just to impress the bros with your knowledge. I mean, who else reads and understands all the latest papers in the #1 strength and conditional journal on earth? Well, you do... ok, you read my laymen summaries, but your bros don't have to know that, do they?

Ok, that's enough of the pseudo-comedian warm-up, let's deadlift the first scientific paper... oh,yeah: Actually the paper is about deadlifting, deadlifting with resistance bands as it is shown in the photo on the right, where a subject performs the deadlift on a force plate.

Read more about exercise-related studies at the SuppVersity

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• Deadlift with bands for power and speed - Galpin et al. (2015) investigated how using bands while deadlifting at different loads, namely 60 and 85% of one's individual 1RM, i.e. the maximal weight you can lift for exactly one perfect rep, would influence the power and velocity at which twelve trained men (age: 24.08 ± 2.35 years, height: 175.94 ± 5.38 cm, mass: 85.58 ± 12.49 kg) with deadlift 1 repetition maxima (1RM) of 188.64 ± 16.13 kg pulled the weight off the floor.
  
  The results of the study show that there were significant peak (yet not relative) power changes irrespective of whether only 15% of the total resistance (group B1) or 35% of the total resistance (group B1) came from the bands (vs. the actual weight).
  

  

  Figure 1: Relative changes in power and bar velocity (compared to training w/out bands = control); * denotes sign. difference to control, ** denotes significant difference to control and light bands (Galpin. 2015)

  The effect became even more pronounced and extended from peak to average power, when the subjects used the heavier (85% 1RM) weights. In this condition using bands lead to greater peak and relative power production and lowered the velocity significantly compared to the control condition in which the subjects lifted at the same total level of resistance, albeit without bands (all values in Figure 1 are relative differences).
  
  For trainees the data in Figure 1 could be highly relevant, because it indicates that heavy bands should be used, when "prescribing the deadlift for speed or power, but not maximal force" (Galpin. 2015). If that's not you, i.e. you're not training for speed and power, but e.g. for size, future long(er)-term studies will have to show whether using bands makes a difference with respect to this study training goal.
• Interval length, can you really pick whichever suits your best? Even though a recent study by Wesley Tucker et al. (2015) shows that the rate of perceived exertion, as well as the mean heart rate of 14 recreationally active and thus not exactly jacked males who participated in their latest study were identical on 4x4 and 16x1 high intensity interval protocols (i.e. 4 intervals à 4 minutes vs. 16 intervals a 1 minute | see Figure 2), seasoned SuppVersity readers will probably remember that previous studies showed highly relevant differences in the long(er) term effects which obviously cannot be measured in an acute phase study like the one at hand.
  

  

  Figure 2: Illustration of the two HIIT protocols, incl. warm-up and cool down on cycle ergometers. White boxes are intervals during which the subjects were supposed to exercise at 90% of their peak heart rate (during the 16x1 protocol this was not achieved by all study participants in the latter intervals, though | Tucker. 2015).

  To be more specific, previous studies on high intensity interval training suggested that athletes who want to increase their VO2 max benefit more from fewer longer intervals, while "Mr. and Mrs. Average" could be better off improving their body composition and metabolic rate with a higher number of short intervals (even as short as 15 seconds in the Tabata protocol). Against that background and in order to explain or contradict the previous findings, it may be worth to consider other study outcomes in Tucker et al. (2015). Study outcomes which did differ. The total energy expenditure, for example, was 19% higher during the 16x1 protocol (p < 0.001) which is in line with the previously referenced recommendation of short intervals for people who are trying to lose weight.
  

  

  Figure 3: VO2, heart rate, and energy expenditure during the two HIIT protocols (watch the units! I converted them to be able to put all data into the same graph | Tucker. 2015).

  The VO2 uptake, as well as the maximal heart rates, which could be of interest for endurance athletes, on the other hand, were higher in the 4x4 protocol - a finding that would likewise support the previously voiced recommendation that (endurance) athletes should torture themselves with long(er) intervals to trigger further adaptations in VO2max and heart rate at a given power output.
  
  Overall, the study at hand will thus not revolutionize your training, but if you haven't read the previous SuppVersity articles, you may still have gotten some new insights into how you may want to adapt your HIIT training in the future.
• Kettlebell or cycle ergometer? Which do you chose for your HIIT sessions? I've written about kettlebell swings as muscle builders before and I've also hinted at the possibility of using the "bells" for your HIIT workouts. Now, a recent study by Williams and Kraemer shows that

  "[kettlebell high intensity interval training aka] KB-HIIT may [even] be more attractive and sustainable than [sprint interval cycling aka] SIC and can be effective in stimulating cardiorespiratory and metabolic responses that could improve health and aerobic performance" (Williams. 2015).

  The purpose of the study was - you probably already guessed it - to determine the effectiveness of a novel exercise protocol we developed for kettlebell high-intensity interval training (KB-HIIT) in comparison to the classic, standard sprint interval cycling (SIC) exercise protocol most people associate with equipment-based HIIT sessions. To this ends, the researchers from the Southeastern Louisiana University had eight "very active" young men (mean age 21.5 years; body fat 18.52 +/-3.04%, fat free mass 67.44 kg of a total weight of 82.95 kg) complete two 12-minute sessions of KB-HIIT and SIC in a counterbalanced fashion.

  

  Figure 4: Overview of the KB-HIIT workout (my illustration).

  "In the KB-HITT session [exercises see Figure 4, mean weight depending on exercise and subject 10-22 kg], 3 circuits of 4 exercises were performed using a Tabata regimen.

  
  

  In the SIC session, three 30-second sprints were performed, with 4 minutes of recovery in between the first 2 sprints and 2.5 minutes of recovery after the last sprint" (Williams. 2015)

  The study's within-subjects' design over multiple time points allowed Williams and Kraemer to compare the oxygen consumption, the respiratory exchange ratio (RER, a marker of the ratio of fat to carbohydrates that is used as fuel during the workout), the tidal volume (TV, the volume of air that is inspired or expired in a single breath during regular breathing), the breathing frequency (f), the subject's minute ventilation (VE), caloric expenditure rate (kcal/min), and their heart rate (HR) on an individual basis between the exercise protocols. In conjunction with the total caloric expenditure which was likewise measured / calculated and compared. The total amount of data the authors collected was thus quite large.
  

  

  Figure 5: Mean total energy expenditure in kcal during the KB and SIC sessions (Williams. 2015)

  Significant inter-group differences were found for VO2, RER, TV and total energy expenditure, with VO2 and total energy expenditure being higher and TV and RER being lower in the KB-HIIT compared with the cycle ergometer HIIT protocol. For f, VE, the energy expenditure per minute and the heart rate, there were no general inter-group differences, but "only" significant group × time interactions. Practically speaking, this means that they changed differently over the course of the whole protocol and are thus maybe relevant for certain athletes, yet not for the general public.
  
  Overall, the William's and Kraemer's study does therefore support the notion that doing kettlebell HIIT workouts is probably at least on par with the classic cycling HIIT sessions. In view of the increased total caloric expenditure and the lower RER, which signifies a significantly higher fat oxidation during the workout, it is even possible that KB-HIIT would be the better choice for dieters than doing HIIT on a cycle ergometer. Since there is no direct link between fat oxidation and/or energy expenditure during workouts and fat loss, however, long(er)-term studies are necessary to find out whether doing KB-HIIT is in fact more than a equivalent and for many of you maybe funnier alternative to doing HIIT on a cycle ergometer. 

Block Periodization - Training revolution or simple trick? This is what we have to ask ourselves in view of the results of a previously discussed study from 2014 | Read the full SV-Classic article here!

Bottom line: That's it for today; so I suggest you take what you learned, pack it in your gymbag and go and impress your bros at the gym ;-) I am just kiddin'... actually I hope that you can really use some of the information in today's installment of the SuppVersity Short News to make your workouts more productive, more enjoyable and/or simply more versatile.

Personally, I will probably give the KB-HIIT workout a try,... and that even though I expect it to be much harder than cycling which is something I am already used to. But hey, isn't that what training is all about? You have to challenge your body - even if that means conquering your weaker self.

I mean, we all know that as soon as you are staying within the cozy comfort zone of doing the same exercises with the same weights workout after workout your progress will stall; and unless you are one of those people who hit the gym to be able to talk to their athletic friends, that's certainly nothing you should aim for | Comment on Facebook!

References:

• Galpin, AJ, Malyszek, KK, Davis, KA, Record, SM, Brown, LE, Coburn, JW, Harmon, RA, Steele, JM, and Manolovitz, AD. Acute effects of elastic bands on kinetic characteristics during the deadlift at moderate and heavy loads. J Strength Cond Res 29(12): 3271–3278, 2015
• Tucker, WJ, Sawyer, BJ, Jarrett, CL, Bhammar, DM, and Gaesser, GA. Physiological responses to high-intensity interval exercise differing in interval duration. J Strength Cond Res 29(12): 3326–3335, 2015
• Williams, BM and Kraemer, RR. Comparison of cardiorespiratory and metabolic responses in kettlebell high-intensity interval training versus sprint interval cycling. J Strength Cond Res 29(12): 3317–3325, 2015