Tuesday, November 20, 2012

"Just One More Set" (1/2): Metabolic Response to 10,000kg vs. 20,000kg Regimen. EPOC: Do Reps and Loads Both Figure? And What About Elite Athletes Do They Need More?

"Ah come on, just another set!" ... "I don't know man, we've already pumped away 100,000kg today... do you really believe that's going to be productive, I mean, yeah, we are cuttin', but still... I mean I don't dig this epic!", "EPOC man, it's called EPOC!" *shakes his head* "Call it whatever you want, bro, I am out!"
If you want, you can think of today's SuppVersity post as an extension to yesterday's "Bigger, Stronger, Faster" special of the On Short Notice series; to be more precise: As a practically more relevant version of the rodent study on hypertrophy vs. strength training that was part of the aforementioned post. Yep, we are "talking volume" today. How much is too much?  And though this is never-ending debate, it appears that at least as far as research goes, a little more debating certainly would not hurt. Therefore I am happy to have not one, but two studies for you which don't just address this issue, but have also been conducted with human subjects!

In view of the fact that these are no "short notices", I will discuss one today and the other tomorrow - yep, that means that you can already make a mental note to come back tomorrow ;-)

"Just one more set, ..." - how productive can that be?

Today's study comes from the Human Performance Laboratory at the Florida State University and deals with the energetic side of things - specifically the often-cited EPOC (excess post-exercise oxygen consumption), which is often touted as one of the most important aspects why strength training in general and higher volume / intensity strength training, in particularly, would have the edge over cardio training. The reasoning is easy: You don't burn so much energy while you work out, but in the time after, your body will (a) still expend more energy per minute / hour and (b) has the advantage of emptied glycogen stores, which will force it to tap into its body fat stores the source for the required energy.

All of you who have read the complete Athletes' Triad series, will by now already know that at least argument (b) is pretty idiotic, because it wouldn't allow you to replenish your muscle and liver glycogen after workouts and thus pave the way into the dreaded vicious circle of the athlete's triad. The former argument, on the other hand has - on a way more general level - only been confirmed a couple of days ago (see "Scientists resolve the paradox of stable muscle metabolism but greater mitochondrial respiration in muscle of inactive vs. active subjects", read more), the question still remains: How much weight do you have to lift to set the 'afterburner' into full gear? 

10 metric tonne or 20 metric tonnes? What do you say?

I see, you are laughing, but basically the above question is what the George J. Abboud and his colleagues tried to find out, when they recruited 8 healthy men aged19-29 yrs who had 
"at least 12 months of RT experience with no more than 2 wks rest at a time, less than a total of 4 wks off within the last 6 months, or 9 wks off within the last 12 months [and] reported no prior or current use of illegal performance enhancing substances." (Abboud. 2012)
Suggested read "Three is More Than One: Higher Volume Increases Strength Gains in Legs, and Satellite Cell Recruitment and Fiber Size in Legs & Traps."
As usual the subjects had to fill food logs for the three days before the testing and were instructed to replicate the same eating pattern on the second occasion in which they were randomly assigned to perform a standardized resistance training (RT) regimen consisting of 4 exercises performed on a non-counterbalanced smith machine so that the range of motion during

  • bench press, 
  • squat, 
  • bent-over row and 
  • Romanian deadlift 
could be controlled for easily. Other than the equipment and the exercises, which were identical on both occasions, the volume of the training sessions varied and if you express this volme in kg or metric tons, it was a competition of 10,000 kg (10 metric tonnes) vs. 20,000 kg (20 metric tonnes) of weight. 
"The loads were divided between the 4 exercises as follows: 35% to squats, 30% to bench press, 20% to bent-over rows and 15% to Romanian deadlift. For each set, subjects lifted approximately 85% of their 1RM for 6-8 repetitions. If 6 repetitions could not be completed at any point, the load was reduced by 10% for the subsequent set." (Abboud. 2012)
Both sessions were supervised by three testers : One monitored the metabolic cart, one made sure the proper range of motion was used and one monitored the proper lifting form. The subjects had to perform the concentric portion of each lift with maximal speed and ensure a controlled eccentric descent. A specific time interval was not dictated. Sets were stopped if "subjects broke form" (Abboud. 2012) and 2 minutes of rest were given between sets. In this fashion the subjects simply kept lifting set after set until the volume prescription for the respective trial was reached.
Figure 1: Resting metabolic rate (RMR) per kg body weight, 30min energy expenditure and respiratory exchange ratio (RER; lower values = higher fat, lower glucose  oxidation)  after low and high volume trial (based on Abboud. 2012)
As you can see in figure 1 there were differences as far as the effects of the high (20,000) vs. low (10,000kg) regimen on the resting metabolic rate, 30 min energy expenditure, and the respiratory quotient (lower values = higher fat, lower glucose oxidation), but in view of the fact that the high volume group moved 2x more weight and should thus (at least theoretically) have expended twice the energy (assuming they performed all reps with perfect form and identical speed), those differences are more than disappointing. 

The minuscle effect size is yet not the most "disappointing" (or "surprising" ?) result

In fact, contrary to the low volume workout the 20,000kg workout did not produce any increases in resting metabolic rate and 30min energy expenditure, at all - put simply: There was no EPOC after the high volume trainingAnd this did not change over the whole 48h period (and I know you guys, you won't rest longer anyway ;-).

Now you may say that this was a crazy protocol, but let's do the math, let's assume the guys did squat 100kg, benched and rowed their own body weight of ~80kg and deadlifted 125kg. With 10 reps per set thats 1,000kg + 2x800kg + 1,250kg per set respectively. If they did three sets per exercise they would thus already be up to 9,950kg! If you still think that's crazy, let's hear what the scientists have to say:
"As subjects in the present study were well adapted to RT, the training stimulus needed to elicit increases in EPOC arguably needed to be much higher compared to that used in previous research  Two studies using intensities of 70% 1RM report significant increases in RMR. Melby et al. had subjects perform 6 setsof 10 different exercises for a total of 60 sets. The repetition range for this protocol was 8-12 repetitions per set. This amounts to approximately 600 repetitions performed during the course of the exercise bout. The range of load-volume lifted by these subjects was 15,000-38,000 kg. [...]" (Abboud. 2012)
The list goes on and you just have to go to your gym and I guarantee you, no matter how few people are on the floor you will see a guy who (often without noticing is) will be pounding away much more word within a single workout. Moreover, the the subjects in the present study completed their trials
with a drastically lower number of repetitions -  a mean of 199. Had they performed the crazy rep-volume of the Melby study, they would probably have come close to 50,000 kg. This raises an interesting question is "volume" correctly defined by giving the total amount of weight you lift? Or is the number of reps maybe more important as far as the after-burner EPOC is concerned?

Too much of a good thing? But what if you are a highly trained athlete?

A previous study, by Hackney et al. would support the notion that heavy lifting is an obligatory part of the EPOC equation. In the latter study, EPOC trained individuals who used a lower load-volume than the trainees in the study at hand  had increased resting metabolic rates for up to 72h (Hackney. 2008). Since the Hackney study also put an emphasis on eccentric contractions and will thus probably have lead to even greater muscle damage than the protocol of the study at hand (CK(10,000kg) = 729U/L vs.CK(20,000kg)  = 1,159IU/L), Abboud et al. speculate that ...
"[a]s protein synthesis required for repair is energetically expensive, it is logical that untrained subjects will show greater and longer alterations in EPOC post-RT. Judging by training history, strength levels and CK responses, subjects in the present study had most likely reached a higher level of adaptation than ones in previous studies, and therefore were less sensitive to the metabolic effects of recovery from RT." (Abboud. 2012)
In other words, for you, probably a seasoned strength trainee, the 'more is more' principle is not going to yield better results - even if your goal is to shed body fat. And ...
"Although RT is an important component in any weight loss program to attenuate the loss of fat free mass and therefore better preserve RMR, it is unlikely that the total energetic cost (during and post-exercise) of a typical duration workout will be adequate for significant weight reduction in highly trained recreational lifters without caloric restriction and/or additional aerobic or high intensity interval training." (Abboud. 2012)
And since I rarely encounter a conclusion that's so to the point, I'll leave you with that for today and remind you to come back tomorrow to learn, when and for which body parts doing somewhat more may still be beneficial - read me tomorrow ;-)

  • Abboud GJ, Greer BK, Campbell SC, Panton LB. Effects of Load-Volume on EPOC after Acute Bouts of Resistance Training in Resistance Trained Males. J Strength Cond Res. 2012 Oct 18.
  • Hackney KJ, Engels HJ, and Gretebeck RJ. Resting energy expenditure and delayed-onset muscle soreness after full-body resistance trainingwith an eccentric concentration. J Strength Cond Res. 2008; 22: 1602-1609.
  • Melby C, Scholl C, Edwards G, and Bullough R. Effect of acute resistance exercise on postexercise energy expenditure and resting metabolic rate. J Appl Physiol. 1993; 75: 1847-1853.