Fast & Slow, Heavy & Light, Eccentric & Concentric: Do All These Fancy Training Variables Really Matter? Probably For Power. Not So Much for Size, Though.

Image 1: According to Sakamoto, 2011, EMG
activation during the bench press increases
with rep-speed & weight (pic from mylot.com)

"Go heavy or go home!" You probably have heard this advice time and again and, after all, two recent studies appear to suggest that, when all is set and done, ah... I mean all sets are done, the thing your muscles seem to care most about is workload. While the study by More et al. (Moore. 2011) does not tell us anything about the effectiveness of training with different rep speeds, it goes to show that concentric and eccentric training are similarly effective, when it comes to building sleeve bursting biceps. Sakamoto et al. (Sakamato. 2011), on the other hand, found that EMG activity of the pectoralis major increases with rep speed and (readers of the SuppVersity EMG Series know that already) weight. Now, before we jump to any preliminary conclusions, let's tackle the studies in some more detail...

The nine healthy, but previously not weight-training average Joes (mean age: 22yr; height: 1.75m; weight:78.3kg) from the Moore study (Moor. 2011) performed single arm biceps curls on a dynamometer twice per week. The volume increased from week one to week five from 2 to 6 sets and was cut back again in the last (ninth) week before the final testing session. Other than in similar studies on the effectiveness of eccentric vs. concentric training, the subjects did not perform their dynamometer curls either concentrically or eccentrically, but were instructed to perform concentric curls with one arm and eccentric curls with the other. Right and left arm had previously been randomly assigned to either the maximal lengthening (eccentric) or shortening (concentric) condition, so that limb dominance (n=5 dominant; n=4 non-dominant) was adequately counterbalanced. Moreover, the subjects had to perform ~40% more repetitions on the concentrically trained arm, to ensure total work was equal, or, put differently, to make up for the greater muscle force generation (+60% total work per repetition in eccentric vs. concentric) during eccentric dynamometer curls. Thusly, the participants performed the same 51.8MJ of work with each of their arms in the course of the 9-week training program.

Under these equalizing conditions, workoutput for both conditions rose similarly over the 9-week training program:

Total work per repetition increased from week 1 to week 9 for both LC and SC (main effect for time, P = 0.001) with no difference between conditions (time by condition interaction, P = 0.63). The average increase in work per repetition was similar between LC and SC (17.2 ± 6.3 vs. 22.1 ± 8.9%, respectively; P = 0.69). There were increases (at least P<0.05) in peak torque for all velocities tested (*8–20%) with no significant difference between conditions.

The scientists also found similar results for the muscle crossectional area (CSA), which had been "virtually identical (P = 0.99) before training" (48.5mm² vs. 48.4mm², for the ecc. and con. trained arm) and "increased similarly between conditions" (ecc. 6.5 ± 0.6% vs. con. 4.6 ± 0.4%, respectively; interaction, P = 0.37). What may initially sound like one of those statistically induced geeky underestimations of real world effects, i.e. calling 6.5% vs. 4.6% increases in muscle CSA "similar", turns out to be actually negligible if you calculate the respective absolute difference in CSA increase which is less than 1mm², or an area with the size of a pinhead.

Figure 1: Other than total work per repetition, the respective peak torque development did vary significantly (+8.9% vs. +13.5% for con vs. ecc) between the concentrically and the eccentrically trained arm (data adapted from Moor. 2011)

If, however, you plot the peak torque data from table 1 from the Moore study (I did that for you in figure 1), you will realize that, after all, there is more of a difference between the two training regimens than Moore and his colleagues dissertations would make you think. In fact, their assertion that "there was a main effect for condition for peak torque measured at 0.79 rad/s [slow concentric] in that LC [eccentrical training] was *8% greater than SC [concentric training]" is simply not consistent with the data they provide.

Note: A comment by "anoymous" (guys give me at least a pseudonym!) reminded me that in yesterday's hurry I forgot to mention a major caveat to the study. The latter is directly related to the unilateral training protocol which could potentially (or rather certainly) lead to cross-over effects from one arm (probably the eccentrically trained one) to the other. Similar effects have been observed in e.g. Adamson et al., 2008, where rate of force development and maximal isometric contraction (37% vs. 35%) in 10 adult females increased similarly in both arms, although the ladies had trained only one arm. It is yet notable that the 1RM increased almost exclusively in the trained arm and that the strength increases in the Adamson study occurred in the absence of muscular hypertrophy and are thus attributed by the authors to neurological addaptions of which obviously both arms benefited to a similar degree.

As far as peak torques are concerned the available data (with reservations that the data the authors provide in table 1 of their paper is correct) would suggest that the peak torque increments in the concentrically trained arm for different repetition tempos were on average 4.6% greater than those for the eccentrically trained arm, or, in other words, the higher rep lower weight concentric training resulted in greater strength improvements than the higher weight, lower rep eccentric training, which is so contrary to what you see in similar studies that I would assume that the authors just got the captions wrong and the data in figure 1 would have been reversed, i.e. what now is red should be blue and what now is blue should be red... but who cares, anyway? Focus on getting a good contraction on both the con- and the eccentric phase of your curls, do the exercises described in the SuppVersity EMG series and grow ;-)!

Figure 2: The time [in s] to "speed failure" (i.e. not being able to complete another rep at the given tempo / slow: 5.6s; medium: 2.8s; fast: 1.9s) increases with increasing tempo and load expressed in % of 1 repetition max, 1RM (data adapted from Sakamato. 2011)

Fortunately, the Sakamato study does not contain similarly confusing results. In essence the study, which investigated muscle activations under varying speeds and intensities during bench press using surface electromyography (EMG) found that in the 13 weight-trained men (21.7 ± 3.6-year-old) who performed bench press until fatigue under five intensities (40–80% 1RM), and four speeds (slow 5.6-s/repetition, medium 2.8-s/repetition, fast 1.9-s/repetition, and ballistic maximum speed), found that ...

...faster conditions [...] produced a significant fall in amplitude during the final concentric phase compared to slower movements [while at the same time] after fatigue, EMG amplitude increased, with the speed effect being maintained. 

This means that in the rested state at the beginning of the training you still have the explosiveness to really "pump" the weight up and thus pump out more reps. On the othrt hand, maximum muscle stimulation does not occur before your pectoralis major brgins to fatigue later in the exercise session (cf. figure 3).

Figure 3: Normalized EMG activity at five time points for a given rep tempo / slow: 5.6s; medium: 2.8s; fast: 1.9s / in the rested and fatigued state (data adapted from Sakamato. 2011)

According to the EMG data in figure 3, it does make sense to start (after an appropriate warm up) with heavy and explosive sets / movements and to switch to medium weights and tempo later in a training session. But wait, isn't that exactly what generations of successful trainees have been doing already? Well, I guess this is then another case, where practical training experience beat exercise science by decades and thus further evidence that much more than in the case of nutrition & supplements most of the research that is put into specific exercise programs does little more than reproduce pieces of the knowledge that has accumulated in the heads of trainers and trainees all around the globe ever since the earliest days of physical culture.

Fast Paced High-Resistant Explosive Circuit Training Burns More Fat and Builds More Muscle Than Classical Weight Training. Trainees Dropped 1.5% Body Fat and Gained 3 Pounds of Lean Mass in 8 Weeks.

Figure 1: Outline of the HRC protocol
used by in the study.

The beneficial effects of fast-paced (indicating short / no rest periods between exercises) circuit training on fat loss have long been established. With the original intention being the addition of an aerobic component to traditional strength training routines, the loads (weights) that are usually used in these types of exercise regimens are often to low to elicit significant strength or muscle gains. This, however, was different in the study protocol Pedro E. Alcaraz and his collegues from Spain and Australia used in their most recent study (Alcarez. 2011).

Alcarez et al. recruited 33 healthy men, who "had been regularly performing resistance training (RT) in a gymnasium (e.g., ca. 6–12 repetitions per set, 3 sets per exercise, 2–4 d/week" (in other words recreational weight lifters) and assigned them to one of two training regimens:

• High resistance circuit training (HRC): 2x 3-6 circuits à three exercises with 5 minutes rest between circuit I and circuit II. There was a bi-weekly progression from 1 to 2 to 3 rounds on each of the two circuits. This means that in their 3 workouts per week (at least one rest-day in-between) the subjects performed 18-36 sets per workout of 6 repetitions at 85%-90% of their individual 1RM_max [1RM_max = maximal weight a person can perform a single repetition with adequate form with] with roughly 35 seconds 'rest' between exercises (this was the time it took them to move from one exercise to the next). Notwithstanding the high workload, each of these workouts took them only 55min-78min to complete.
• Traditional strength training (TS): For the same exercises that were used in circuit I and II in the HRC group (cf. figure 1), the subjects in the TS group performed 2x warm-up sets at 10 and 8 repetitions of the 6% max (1 minute rest in-between) followed by 3 sets of 6 repetitions at 85%-90% of their individual 1RM_max. Due to the one minute rest between individual sets, as well as the 5-minute pause in between exercises 1-3 and exercises 4-6, the supervised workouts of the TS group were on average 125min long.

One specifically important and oftentimes under-appreciated parameter, both groups had in common, was the lifting tempo:

The eccentric phase of each exercise was performed for approximately 3 seconds, whereas the concentric phase was performed at maximum velocity. This sequence was standardized in the first training week and eccentric phase duration was regularly timed as feedback for the subjects.

In that, what the subjects did was fundamentally different from what I am (unfortunately) forced to look at day in and day out in my gym: people just moving weights instead of training muscles for strength or hypertrophy. With an emphasis on the explosiveness of the concentric part (where push / pulling the weight) of the movement and an accentuation of the deceleration in the course of the 3 second eccentric part (where lowering of the weight) of the exercise, you do just that - you train your muscle for strength and hypertrophy. The data in figure 2 underlines that this strategy works, regardless of whether you stick to the classical strength training protocol with longer rest periods (TS) or if you innovate your training by integrating some explosive strength circles.

Figure 2: Bench press concentric peak power [in W] increase measured for different loads (45%, 60% and 80% of 1RM_max) after 8 weeks on a traditional or a high resistance circuit training program (data adapted from Alcarez. 2011)

Obviously the classical strength training, where the three sets of bench presses were performed one after another and with more than adequate rest of 3 minutes produced greater increases in peak bench press performance with the most significant advantages for the traditional training routine (TS) in the range of 60% of the individual one-repetition maximum (1RM_max). So, if you are all about strength and can afford to invest 120 minutes three times à week into your training and like what you have been doing, you can stick to what worked for generations of lifters. If, however, you still don't have your summer-six-pack ready, have only 60 minutes to train, or - as almost 90% of the gym-goers claim - "just want to look good naked", or even just try something new, you should give the explosive strength circuits a try.

Figure 3: Changes in fat and lean body mass [in kg] after 8 weeks on a traditional vs. a high resistance circuit strength training protocol (data adapted from Alcarez. 2011)

Although the advantages of high resistance circuit training over traditional strength training in terms of on body composition (cf. figure 3) appear to be less significant than those TS has over HRC in the strength department (cf. figure 2), the significance of the data must be relativized in view of the large standard deviations which are as high as ~70%-110% of the improvements of both strength and body composition.

Note: I think I do not have to tell you, the educated readership of the SuppVersity, that it goes without saying that it is very likely (yet still warrants scientific validation) that high resistance circuit training will also produce better results in terms of body (re-)composition (less fat, more muscle) than cardio training (cf. Exercise! Beneficial Effects of Resistance Training on Variables of General Health) or dieting (cf. Calorie Restriction vs. Exercise for Optimal Body Composition?), alone.

Consequently, the conclusions of the authors, that the gains in strength and body composition in the HCR group "are identical to those obtained with traditional, heavy strength training" is spot on: In the end, it is probably all about your personal training-philosophy, -style and -preference what will work better for you as an individual. One thing you should keep in mind though is to explode on the way up and slow down on the way down; or, in other words, Add high resistance circuit training to your repertoire, if you will, but don't forget: Train the muscle, don't just move the weight!

Leucine & HMB - Similar, Yet Different. BCAA, B6 & NAFLD - It's About Ratios. Eccentrics, Mitochondria & GLUT-4 - No Pain, No Fat Gain. Fiber & Diabesity - Useful, But Not Magic.

"Potatoes" have the "pot-" from "potassium" not just in their name, they also got plenty of it in them. A medium sized potato (147g) contains 926mg of highly bioavailable potassium and covers ~26% of your daily requirements... and no, normal potatoes are not pro-diabetic unless you over-process them (learn more in the Potato Manifesto)

5.93 mm and 3.7 millimeters those are the SuppVersity Figures of the Week and the average heights by which the systolic and diastolic blood pressure of dropped in 21 controlled trials in the course of which the subjects simply increased their daily potassium intake (Aburto. 2013). Results like these, which were published in the latest issue of the British Medical Journal rarely make it to the mainstream news and if they do than just as a marginal note to the paradigmatically blinded message that we all had to dramatically reduce our salt intakes if we did not want to end up in the emergency room.

Now, aside from the fact that Maillott et al. have demonstrated only recently, that "the 2010 Dietary Guidelines for sodium were incompatible with potassium guidelines and with nutritionally adequate diets, even after reducing the sodium content of all US foods by 10%" (Mailott. 2013), both a dramatic reduction in salt and significant increase in potassium intake could be achieved if people simply stopped eating convenient, but blatant and thus salt- and sugar-laden products of the food industry and bought fresh products instead.

Leucine and HMB both work, but they work via different pathways / mechanisms.

If you want to learn more about the usefulness of HMB, check I suggest take (another) look at my article about the results of a 2012 dissertation (read more)! And in case you feel you need to learn more, browse the SuppVersity archive for the key-words leucine and HMB and educate yourself.

(Wilkinson. 2013) A group of researchers from the UK and Canada has recently found that "leucine (Leu) possesses the most marked anabolic characteristics in acting as a trigger element for the initiation of protein synthesis". In that it is even superior to its best-known metabolite β-hydroxy-β-methylbutyrate (HMB), which has a 40% less pronounced stimulatory effect on protein synthesis (110% leucine; 70% HMB; after oral supplementation).

The reason it may still have merit to supplement with (additional?) HMB is its non-insulin depended effects on skeletal muscle breakdown (-57%), which would up the rate of protein retention, i.e. the difference of protein synthesis (70%) and protein breakdown (-57%) to 127% and should thus result in superior net gains in skeletal muscle protein compared to pure leucine.

Bottom line: Whether you actually "need" HMB, is a whole different question, though. After all studies comparing a simple 30g whey protein shake and an HMB supplement are missing and whether the addition of HMB to the whey would yield benefits is questionable. Doing just that with leucine has, after all, already been shown not to yield any additional benefits.

Fatty liver from 50%+ of the currently available dietary supplements? 

(Kaimoto. 2013) If we go by the results of a soon-to-be-published rodent study from Japan the chronic consumption of BCAA containing supplements could in fact result in an increased hepatic lipid and cholesterol deposition and would thus pave the way to non-alcoholic fatty liver disease (Kaimoto. 2013).

Figure 1: Changes in body composition & organ weight, serum and liver measures after 21 days on BCAA (BCAA(+)) and/or pyridoxin (B6(+)) enriched diets (Kaimoto. 2013)

If you take a look at the data in figure 1, you will yet also realize that the triglyceride and cholesterol deposition in the liver the scientists observed, when the rats were fed with a show that contained comparatively low supplemental amounts of 2%, 1.5% and 1.25% leucine, valine and isoleucine and thus the human equivalent of ~3-4g of BCAAs, was ameliorated when the diet contained sufficient amounts of vitamin B6 aka pyridoxin. Since the corresponding human equivalent dosages for B6 were ~3-4x higher than the RDA of 1.3mg/day but still way below the amount of B6 almost every currently available BCAA supplement contains, you probably don't have to worry about fatty liver or a shrinking thymus and compromised immune system.

Tired, exhausted, had to cut your workout short today? Is it the flu, or just too much BCAAs?

As a seasoned SuppVersity reader you will however be aware that the hailed anti.catabolic muscle builder is by no means free of nasty side effects, when consumed in excess - suggested reads:

• High Dose BCAA Supplementation Can Inhibit Serotonin Metabolism & Cause Anxiety (read more)
• Chronic High Dose BCAA Supplementation Reduces Endurance Performance by 43% Plus: How Ammonia, Glutamine, Arginine & Low Carbing Could be Involved (read more)

If you want to know more about the established benefits of leucine, valine and isoleucine, I suggest you simply go through the archives and pick whatever yo are interested in.

Bottom line: The latest BCAA news don't negate their established ergogenic effects, but they do support the notion that the "more is more" and "better take them with every meal" principles are not worth following - even if you get your BCAAs for free, by the way.

More dietary fibre lovin' ... but rightly so?  

(Dall'Alba. 2013) A recent study from the Universidade Federal do Rio Grande do Sul in Brazil confirms that the consumption of additional 10g of soluble dietary fiber (/-re) in the form of partially hydrolysed guar gum can have beneficial effects on some of the markers of metabolic syndrome.

Figure 2: Relative changes compared to baseline in 44 patients with type 2 diabetes (males 38·6 %, mean age 62 years, diabetes duration 14.2y) after 4 and 6 weeks on diets w/ or w/out 10g of additional guar gum (Dall'Alba. 2013)

The results of the study (figure 1) do yet also show that the benefits are modest at best. Even the statistically highly significant increase in HDL after 6 weeks on the guar gum diet is not necessarily physiologically relevant and if it was not for the higher baseline energy intake in the supplementation group, and the greater reduction in HbA1c (indicating a better blood glucose stability), you could even argue that the addition of the 10g/day of dietary fiber was totally useless (suggested read: previous articles about fiber).

Bottom line: While dietary fiber has its merit. It's not much different from veggies. If you just add it / them on top of you junkfood diet, the effects you can expect are modest - if not non-existent.

Eccentric exercise it's not all productive that induces damage

More reasons for a GLUT-4 boosting EAA smoothie post workout (learn why)

(Magalhães. 2013) According to a study that has been published ahead of print in the online version of the Journal of Applied of Physiology, eccentric exercise (downhill running) did not jst lead to highly significantly increases in plasma creatine kinase activity, myoglobin and interleukin-6 content of the muscle of 12-week old mice, it also impaired state 3 and respiratory control ratio of the mitochondria and increased their susceptibility to mitochondrial permeability transition pore (MPTP) which can lead to cell sqelling and eventually cell death. Accordingly, Mangalhães et al. observed an increase in cell swelling amplitude, lower time to maximal swelling velocity, and calcium release immediately after the end of exercise annd conclude that

"prolonged EE [eccentric exercise] transiently impaired mice skeletal muscle mitochondrial function and increased susceptibility to calcium-induced MPTP opening"

Now you can certainly argue that this is the necessary training effect your cells need in order to adapt, in view of previous findings from human studies (just randomly selected examples, here)...

• 

  Figure 3: Glycogen snythase  (in mmol/mg protein per min) 4h after postexercise (10 x 10 eccentric or concentric isokinetic leg extensions after previous glucose depleting cycling exercise) carbohydrate feeding depening on G6Pase levels (Doyle. 1993)

  -37% reduction in insulin-mediated glucose disposal rate in 6 healthy, but untrained men after 30min downhill running (Kirwan. 1992)
• -11% reduced glucose uptake and glucose necessary to maintain euglycemia during maximal insulin stimulation, as well as -39% lower basal = non-insulin triggered GLUT-4 expression and in seven healthy subjects even 48h after one-legged eccentric exercise (Asp. 1996)
• significantly reduced glycogen synthase after eccentric vs. concentric training in ten moderately trained subjects after 10 sets of 10 repetitions of either concentric or eccentric contractions in opposite legs and the ingestion of 0.4g carbohydrate/kg body wt every 15min (Doyle. 1993; see figure 3).

... you should yet reconsider to which extend the "no pain no gain" principle is going to yield the healthy lean mass and performance gains you are probably looking for.

Bottom line: While the broscientific wisdom "You won't grow, if you're training like a puss'!" may have its limited merit, the equation "maximal damage = maximal growth" many of the bros derive from this supposition is not just unsustainable and counterproductive, but potentially unhealthy and fattening.... How's that? Just imagine bulking while you are constantly insulin resistant for daily eccentric exercise.

---

Aside from the obligatory Facebook news that's it for today's installment of On Short Notice!  So once, you've checked out the following news over @ www.facebook.com/SuppVersity ...

Aside from coffee and nutrition in general, vitamin A is another potential regulator of the peripheral  (non-light regulated) circadian clock - especially in the liver (learn more)

• Some light exercise can shed some heavy fat -- Weight loss success of healthy, but sedentary women demonstrates: as long as you are not fixated on what the scale says you will be surprised by how powerful even moderate physical activity is (read more) 

• Treating type I diabetes with GABA -- In a 2011 rodent study the administration of the amino acid and neurotransmitter helped repair damaged pancreatic beta cells (read more)

• Undereating + (over-)training is the most effective endocrine disruptor -- At least among natural stressors, the aforementioned combination is far "superior" to regular stress (read more)

• Don't forget about vitamin A -- Scientists identify the mechanism behind the anti-Alzheimer's effect of retinoic acid (read more).

...it's high time to get your behind off the couch or computer chair and enjoy a well-deserved active and social, yet regenerative weekend.

References:

• Aburto NJ, Hanson S, Gutierrez H, Hooper L, Elliott P, Cappuccio FP. Effect of increased potassium intake on cardiovascular risk factors and disease: Systematic review and meta-analyses. BMJ 2013;346:f1378.
• Asp S, Daugaard JR, Kristiansen S, Kiens B, Richter EA. Eccentric exercise decreases maximal insulin action in humans: muscle and systemic effects. J Physiol. 1996 Aug 1;494 ( Pt 3):891-8.
• Dall'Alba V, Silva FM, Antonio JP, Steemburgo T, Royer CP, Almeida JC, Gross JL, Azevedo MJ. Improvement of the metabolic syndrome profile by soluble fibre – guar gum – in patients with type 2 diabetes: a randomised clinical trial. British Journal of Nutrition. April 2013. [Epub ahead of print]
• oyle JA, Sherman WM, Strauss RL. Effects of eccentric and concentric exercise on muscle glycogen replenishment. J Appl Physiol. 1993 Apr;74(4):1848-55.
• Kaimoto T, Shibuya M, Nishikawa K, Maeda H. High Incidence of Lipid Deposition in the Liver of Rats Fed a Diet Supplemented with Branched-Chain Amino Acids under Vitamin B6 Deficiency. J Nutr Sci Vitaminol (Tokyo). 2013;59(1):73-8.
• Kirwan JP, Hickner RC, Yarasheski KE, Kohrt WM, Wiethop BV, Holloszy JO. Eccentric exercise induces transient insulin resistance in healthy individuals. J Appl Physiol. 1992 Jun;72(6):2197-202.
• Magalhães J, Fraga M, Lumini-Oliveira J, Gonçalves I, Costa M, Ferreira R, Oliveira PJ, Ascensãoa A. Eccentric exercise transiently affects mice skeletal muscle mitochondrial function. Applied Physiology, Nutrition, and Metabolism, 10.1139/apnm-2012-0226. 
• Maillot M, Monsivais P, Drewnowski A. Food pattern modeling shows that the 2010 Dietary Guidelines for sodium and potassium cannot be met simultaneously. Nutr Res. 2013 Mar;33(3):188-94.
• Wilkinson DJ, Hossain T, Hill DS, Phillips BE, Crossland H, Williams J, Loughna P, Churchward-Venne TA, Breen L, Phillips SM, Etheridge T, Rathmacher JA, Smith K, Szewczyk NJ, Atherton PJ. Effects of Leucine and its metabolite, β-hydroxy-β-methylbutyrate (HMB) on human skeletal muscle protein metabolism. J Physiol. 2013 Apr 3. 

Exercise Research Quickie: HIIT vs. Steady State, More on the Hormonal Response. Light Training, High TUTs & Peak Contractions - Not Just for The Elderly. Train Your Left, Grow Your Right Leg - Contralateral Training Effects

The role of the innervations between our muscles as well as to our brain is often overlooked, when we are talking about size gains. The image shows stained nerve fascicles from the Song study, which brings this wiring back onto the radar.

I know that we have had the short news on Saturday only and that there are of course tons of short news on Facebook everyday, but the studies I am going to present you in this exercise research quickie were so in-between (meaning not really worth a full post, but still way too good to be wasted on facebook) that I decided to devote a post of its own to the research on the hormonal effects of interval vs. steady state training by Hackney et al. (Hackney. 2012b), the impressive and certainly not totally irrelevant effects of slow movement, low-intensity resistance training in the elderly Watanabe et al. describe in their latest paper and the surprising muscle building (Watanabe. 2013) and growth priming carry over effects Song et al. observed in response to unilateral electrical muscle stimulation (Song. 2012).

Although, the latter post is pretty theoretical I hope that all of you will find something that enlightens, amuses or entertains them in this "threesome" ;-)

More T, more DHT, more cortisol - that's the HIIT vs. LISS formula

(Hackney. 2012b) -- In fact the results of two subsequently published papers by Hackney et al. would suggest that it's about as easy. Work out hard and fast and see greater increases in testosterone levels, but also testosterone turnover (into DHT via 5-alpha reductase), but don't forget that aside from these (questionable) anabolic benefits, your thyroid hormone levels are going to take a dive (as reported previously), as well.

Figure 1: Comparison of the hormonal responses measured in the plyometrics (left) and the HIIT vs. LISS (right) study (based on Ozen. 2012 and Hackney. 2012)

The figure above is actually from a post where I discussed this before, so if you cannot remember all the details, briefly go back before you take a look at the summary of results of the more recent study by Hackney.

"Dihydrotestosterone (DHT) - Bigger, Stronger, Faster or just Balder, Fatter and Unhealthier?" That's the question I asked in one of the installments of the Intermittent thoughts on building muscle. A post I would highly suggest you read, by the way ;-)

In this 2nd paper that was published right before Christmas in the Journal of Endocrinological Investigations the researchers were able to show that repeated periods of 90-sec treadmill running at 100-110% maximal oxygen uptake (VO2max) and 90-sec active recovery at 40% VO2max for 42-47 min (which is obviously pretty long!) caused  just a significantly more pronounced increase not just in free testosterone, but also in its conversion to testosterone's big brother DHT (as indicated by statistically higher levels of the 5α-reductase marker 3-α Diol G at 12POST HIIT vs. LISS). This is interesting, as dihydrotestosterone (DHT) which is often falsely associated only with hair loss, prostate cancer and even obesity, does also play an important role in strength development (click here to learn more) and appears to do it's magic via the MAPK receptor. Now, MAPK in turn can activate PGC-alpha and that the latter is way more than just the endurance / mitochondria builder it was long thought to be is something you should still remember from the post on the"The IGF-1 Promoting, Myostatin Reducing, Muscle Building Effects of PGC-1 α-4" (read more).

Bottom line: It is becoming more and more clear that HIIT is in fact somewhat of a chimera that shares beneficial and detrimental effects of both classic cardio and classic strength training with mammoth sessions like the one performed in the studies at hand triggering similar hormonal cascades that will - despite probably causing beneficial adaptations - simply require longer rest times than a classic LISS regimen.

A  note of caution: Both these studies point to the highly questionable "value" of taking a bunch of people letting them do whatever type of training once, measure some stuff of which you do only have a very rough idea of what it's actually doing and then have a bunch of morons like myself try to come up with "practical implications"

So if you do HIIT, stick to the principles "short and hard" (I would never suggest doing the >40min interval sessions for anyone whose primary goal is to be healthy and look good naked, by the way; add a walk on the treadmill if you want to train longer like on a combined HIIT + LISS cardio only day. But most importantly don't forget to enjoy your well-deserved, highly productive off-time and remember that it's during those hours, when all the hard work is paying off... ah I almost forgot, this is a tried and proven way that happens to be confirmed by studies like Hackney's and not vice versa.

 Light training, high TUTs and peak contractions - not just for the elderly?!

You cannot only implement"light" training into your established routine (see last paragraph), but should also think of the often forgotten benefits of periodization, detraining & co (learn more), as well as times, when you may be injured or otherwise disabled and cannot lift heavy.

(Watanabe. 2013) -- It may sound like a study for the elderly, but just as the best-agers among the SuppVersity readers can learn something from studies done in the the younger fellows, the younger weightlifters may well get some intriguing insights from studies with older participants - studies like the one by Watanabe et al., for example.

When the researchers from the Department of Life Sciences at the University of Tokyo compared the hypertrophy and strength gains of two exercise regimen using a low resistance of 50% of the personal 1-RM max of their 59-76yr old subjects, the scientists found that slow movements with tonic force generation were superior to the regular 1s concentric vs. 1s eccentric reps I guess most of you will be employing in their training routines.

The subjects who had been randomized to the LST group and performed their reps with a 3s concentric, a 3s eccentric and phase and most importantly a peak contraction in-between did gain a similar amounts of strength as those subjects who performed the standard protocol for 10 weeks (the 12-week study had a 2-week familiarization phase), but contrary to they did also record statistically significant increases in muscle size.

Alternative exercises on which peak contractions work well, are the fly (preferably on a machine or using cables), the lat pulldown, cable crunches, all sorts of triceps extensions, the scott curl (where you would do them midrange), every form of calf raises. Always remember, though: A peak contraction is never done in the full stretch position, but always either midrange or as the name implies at the peak of the contraction, before the eccentric phase begins.

So what does that mean? Certainly not that all of you should stop lifting heavy weights, because 50% 1-RM was enough if not superior to the regular 70-90% that are recommended in most serious training regimen. Rather, these results should remind young and old trainees alike of keeping an eye on your form and making sure that you stimulate the muscle and don't just move whatever weight from place A to place B.

That said, try to incorporate peak contractions with every rep on the auxilliary movements of your next workout. Start your leg workout with regular squats, for example, 5x5 TUT 101 (meaning 1s eccentric, 0s rest at the bottom, 1s concentric), but instead of the 4x10 leg extensions you would usually do for your quads, you lower the weight somewhat and do them with a slower rep-speed (somewhere in between 1-3s) and a peak contraction (meaning you really squeeze the muscle in a position, where your knees are almost locked out). Done right, this is going to give the word DOMS (=deep onset muscle soreness) a whole new meaning + you will have to reduce your weights, anyways.

Train your left leg and your right one will grow as well

(Song. 2012) -- Do our bodies know something about aesthetics? Well, if that were the case, the legs of some of the gymbros who "don't train legs, because [they] play soccer" shouldn't look the way they do... but I am digressing here. According to the study by Yafeng Song et al. have just published in the open access journal Plos ONE, there appears to be a certain carry-over effect - at least if the growth stimulus is chronic and profound.

To achieve the latter, i.e. a chronic and profound training stimulus, the researchers from the Umea University in Sweden exposed the soleus and gatrocnemius muscles of rabbits to a 6-week electrical muscle stimulation + exercise protocol and measured muscle changes and inflammation on weeks 1, 3 and 6 of the study. Now, the clue of the study was that the unilateral "exercise" was actually mechanically and electrically enforced, so to say:

"The movements are produced by a pneumatic piston, in which the range of motion can be controlled. The range of movement was set to 9.5 cm, given a range of motion in the ankle of 55–65u of which 20–25u was dorsiflexion and 35–40u was plantarflexion. The right leg was attached to the piston and the pelvis/hip region was strapped down to restrict the motion in the left non-exercised leg. The left leg was unattached. During the plantar flexion of the right leg, an active contraction was induced by electrical muscle stimulation via surface electrodes placed 2 cm apart over the right triceps surae muscle. The stimulation was synchronized with the plantar flexion movement of the piston by a microswitch, which trigged the stimulator unit".

I will spare you the further details... just think of a modern rabbit torture machine that was designed to "work the rabbits right extremities out". As you would expect from any good torture machine this device brought about a significant amount of tissue damage and a corresponding increase in the number of necrotic fibers.

Figure 2: Variability in fiber size, fibers with internal nuclei, inflammation in soleus (left) and gastrocnemius muscle (right) in response to the exercise + electrostimulation program. Mind the similar responses in the exercised (E) and the non-exercised (NE) limb (Song. 2012)

Now what's surprising though is the fact that despite the local damage, the inflammation had a systemic component, which happened to be more pronounced in the untrained soleus vs. gastrocnemius muscle (slow vs. fast twitch, by the way).

Against that background it is still only a little less surprising that the variability in fiber size, the number of fibers with internal nuclei (=sign of restructuring process, cf. "The Skeletal Muscle Hypertrophy 101") and even the fiber splitting were virtually identical. After all, this would mean that systemic parameters do matter. But haven't we just discarded this notion yet another time in the first of the items in today's exercise research quickie? Yes we have, but in that case we were talking about the usual subjects, the "anabolic" and "catabolic" hormones, Song et al. on the other hand speculate that

"[t]he collateral muscle changes and inflammation after unilateral EMS/E observed in this study may be caused by [a] neuronal mechanism. Since there is some evidence for a commissural system in the spinal cord that mediates transmedian signaling with a fairly precise bilateral representation, nerve signals from the trained side may pass over to the contralateral muscles through commisural inter-neurons. If this is the case, unilateral injury caused by EMS/E may cause a cross-transfer up-regulation of neuropeptides that can be involved in the inflammatory response in the contralateral muscles." (Song. 2012)

The researchers indicate that their current, as well as previous results from their laboratory would support this hypothesis and that any systemic or circulatory effects must actually be excluded, because these would not have occurred only focally, but generally within all muscles. They also point towards previous studies in which the signalling between contralateral and ipsilateral limb was blocked and the observed cotralateral responses were abolished.

So what's the point? I will openly admit that the practical relevance of these results (esp. for you as a hopefully healthy trainee) is as of now still very questionable, but the fact alone that it brings the nervous system back on the "scientific" radar was certainly worth including it in this "threesome" - don't you think so? No, well... maybe you like the scientists own rational who argue that the findings are (a) important in the context of a wide range of musculoskeletal and neuromuscular disorders and (b) relevant for each and every unilateral exercise experiment, where the contraleteral limb is used as a control - and you know there are plenty of them!

References:

• Hackney AC, Kallman A, Hosick KP, Rubin DA, Battaglini CL. Thyroid hormonal responses to intensive interval versus steady-state endurance exercise sessions. Hormones (Athens). 2012a Jan-Mar;11(1):54-60.
• Hackney AC, Hosick KP, Myer A, Rubin DA, Battaglini CL. Testosterone responses to intensive interval versus steady-state endurance exercise. J Endocrinol Invest. 2012b Dec;35(11):947-50.
• Ozen, SV. Reproductive hormones and cortisol responses to plyometric training in males. Biol Sport.2012; 29 (3).
• Song Y, Forsgren S, Yu J, Lorentzon R, Stål PS. Effects on contralateral muscles after unilateral electrical muscle stimulation and exercise. PLoS One. 2012;7(12):e52230.
• Watanabe Y, Tanimoto M, Ohgane A, Sanada K, Miyachi M, Ishii N. Increased muscle size and strength from slow-movement, low-intensity resistance exercise and tonic force generation. J Aging Phys Act. 2013 Jan;21(1):71-84.