Triple Your Energy Expenditure During Shuttle Runs + Learn Why Intensity and not Just Weight x Distance Counts

The shorter the distances between the cones on a shuttle run the greater the energy expenditure per meter you are sprinting - in fact the amount of energy you will burn on a 10m run is 3.5x higher than that your body will expend on the corresponding 10m of a 20m sprint - and you bet that this is not a "shuttle run"-specific effect.

I have already hinted at the unfortunate circumstance that trainees and even scientists still adhere to the (obviously) lousy hypothesis that it were possible to calculate the energy expenditure of their participants by simply multiplying the force they apply to move a given object (or themselves) from point A to point B.

It is true that the result, W (as in W-orlkload) = F (as in F-orce) x d (as in d-istance) will "look" like it should tell you the amount of Energy that's been necessary to move the object from A to B, but that would require that (a) all the bio-chemical energy your body produces would be converted to mechanical energy and none would be lost and (b) the acceleration and thus force (F = mass x acceleration) would be constant - both pretty irrational assumption even for a non-physicist, I should say.

Against that background it should not surprise you that a recent study from the School of Sports and Exercise Sciences at the University of Rome does now report:

3.5x higher energy expenditure / m on short (10m) vs. long (20m) shuttle runs

Kinetic measurement / estimation of the energy expenditure - how did that work? (1) The velocity profile during the shuttle runs was determined by means of a high-frequency camera. (2) The video was then analyzed using free software Kinovea-0.8.7 to obtain the actual distance covered by the center of mass of the subject over each nominal 2-m stretch as well as the corresponding time. (3) This allowed for the calculation of the time course of the speed [note to this ends they did not use the time-integral over M x v²/2, which would be how it's done, but simply the peak v-elocity], and, hence, of the corresponding acceleration, as well as the peak speed, which where then used to "estimate" (Buglione. 2013) the energy cost of shuttle running by multiplying it with a variable ny (~0.25; cf. Prampero. 2005) describing the efficiency of mechanical work and adding the result to energy cost of constant speed running.

To measure this difference, Buglione and di Prampero conducted two experiments. For experiment one, they invited

• 29 physically active subjects practicing in various amateur sporting activities, 
• 28 professional soccer players and 
• 8 high-level runners 

for whom the energy costs during the shuttle runs were measured directly by from gas exchange
measurements over 155 trials and

• 10 subjects of 25.4±3.9 age (years), 70.3±2.6 body mass (kg), 1.75±0.05 stature (m) belonging to the Italian national field hockey team

for whom the energy costs were calculated (the math approach) based on a kinetic approach (if you are a physics geek see the box on the right-hand side for more details).

Figure 1: Energy expenditure in J/(kg*m) plotted against running speed in m/s (left) and energy cost of shuttle running, as obtained from the kinetic (CSh-Kin) or energetic approaches (CSh-En) are plotted as a function of average speed over 20 m (open triangles, CSh-Kin; close triangles) and 10 m (open circles, CSh-Kin; dots; Buglione. 2013)

As the data in figure 1 goes to show you the energetic costs for a given sprint (~ interval) distance on the shuttle run increases linearly with the velocity v. The incline, of the graph, on the other hand, is determined by the distance with the a much steeper incline on the short (10m) vs. long (20m) shuttle runs.

Kinetics + math = cheap but not always accurate

Remember the last study involving a shuttle run? It dealt with the ergogenic effects of glycerol (read more).

Interestingly, the results from the direct measurement are in good accordance with those calculated based on the scientists kinetic approach (see figure 1, left; where the energy cost of shuttle running [J/(kg m)] obtained from the kinetic approach (CSh-Kin) is plotted as a function of the corresponding value obtained from the energetic approach (CSh-En)), for the longer distances.

This observation confirms Antonio Buglione and Pietro Enrico di Prampero hypothesis that their "kinetic approach" would qualify to as a assess the energy expenditure during high intensity (intermittent) exercises like the shuttle run over long(er) distances without having to resort to expensive experimental equipment.

Remember: All it takes is a cheap Casio Exilim EX-FH25 to record the runs at a high-frequency of 210 Hz and the video software.

What's the physiological underpinning of the short vs. long difference?

Now, analyzing the underlying physiological mechanisms that yield the directly measured 3.5x increase in energy expenditure during the short 20m shuttle runs was not part of the Italians' study. Therefore we will have to invoke the results of another recently published study by Jared R. Fletcher et al. from the Human Performance Laboratory at the Faculty of Kinesiology of the University of Calgary (Fletcher. 2013), who set out to answer the question: "Can muscle shortening alone, explain the energy cost of muscle contraction in vivo?"

Their results, part of which you can see in figure 2 clearly indicate that the actual energy energy that's necessary to maintain a given torque (which is what you would usually calculate based on the weight and the lever, e.g. the poundage on the bar and the length of your forearm for a simplistic model of a biceps curl), increases almost linearly with the shortening velocity.

Figure 2: The relationship between the rate of energy use to maintain a given torque and magnitude of muscle fascicle shortening (cm).

The main finding in this study was that when greater MG fascicle shortening was imposed, the rate of muscle oxygen uptake increased.

We assume this measured oxygen uptake is proportional to the total EC [energy consumption] of the muscle contractions; that is, any anaerobic energy utilization would increase in proportion with the increases in oxygen uptake. (Fletcher. 2013; my emphasis)

Moroever, kinetic (=moving the weight) vs. isokinetic (=static) exercises resulted in significantly greater muscle shortening and greater shortening velocity. I is therefore not surprising that the isokinetic plantarflexion contraction the 19 triathletes who were in the pre-competition phase of their training performed during the testing session (30 reps at 1/s) resulted in a +19% greater energy expenditure than their isometric counterpart.

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Bottom line: Overall, the two studies have a general, and two very practical take home messages. The general one is that you cannot calculate the amount of energy your body will consume during a certain exercise / movement paper based on simplistic equations that have been developed to be applied to standardized weights on straight levers that are moved with constant velocity along strictly linear or circular paths and against constant, at best linearly in-/decreasing resistances.

The practical take home messages, on the other hand, are that you (a) want to maximize muscular activity and that you (b) achieve that with short, intense, fast, yet not ballistic (no cheating the weight over 95% of the distance) kinetic movements. If you doubt the validity of this approach in terms of it's ability to help you shed body fat, you just have to take another look at one of the following posts:

• 

  Another suggested read: "Some HIIT For Life & Less LISS For More! How to Burn 27,300 Kcal Extra W/out Losing a Single Extra Pound of Fat!" A perfect example of the fallacy of simplistic energy expenditure calculations (read more)

  From 16% to 8% Body Fat in 10 Weeks: Crossfit Workout Gets The Leanest Shredded - But Only the Fittest Survive (read more)
• Eight HIIT Sessions on the Rowing Ergometer Cut Body Fat, Increase Adiponectin, VO2Max & Performance in National Level Rowers - Workmatched Classic "Cardio" Does Nothing (read more)
• Reduced Exertion High Intensity Training - A Minimalist 2x20s HIIT Protocol For The Male Convenience Generation (read more)
• The Iranian HIIT Solution: Three 200m Sprint Sessions per Week Double Insulin Sensitivity & Normalize Leptin Levels (read more)

Convinced? Well, that's what I'd expect... although, actually I would have hoped that you'd been convinced of the validity of the intensity vs. duration approach to fat loss before. You were? Ok, then today's SuppVersity post will just have reinforced what you already knew ;-)

References:

• Buglione, A. di Prampero, PE. The energy cost of shuttle running. Eur J Appl Physiol. 2013 [epub ahead of print]
• di Prampero PE, Fusi S, Sepulcri L, Morin JB, Belli A, Antonutto G. Sprint running: a new energetic approach. J Exp Biol. 2005 Jul;208(Pt 14):2809-16.
• Fletcher JR, Groves EM, Pfister TR, MacIntosh, BR. Can muscle shortening alone, explain the energy cost of muscle contraction in vivo? Eur J Appl Physiol. 2013 [epub ahead of print]

80g Glycerol + 2L Water Decreases Body Weight in Athletes & Increases Overall Performance in Sedentary Subjects

If it does not make you as swole as the colorful ad promised it must not be working, right? The jury was not even any longer "out there" for glycerol, but a recent study makes you rethink, whether you just have to look in the right place to see the benefits.

Another of the "odd" Thursdays without an update from "Your's Truly" Adelfo Cerame. And since there is holiday today, over here, I even thought there would not be a SuppVersity Science Round Up today. But hey, you are lucky you (and Carl) got to work, so you can tune in live at 1PM EST, or even better, start listening live at 1PM in order not to miss the Strength and Hypertrophy Round Table!

As far the  topics for today's installment of the SuppVersity Science Round Up are concerned, you are actually only a couple of lines away from reading about one that's on the list:  The effects of glycerol on exercise performance. I don't have to tell you though that this is not everything. Other things I believe you may be interested in are...

• childhood obesity, physical education and attention at school
• wheat gluten hydrolysate and how they don't come up to the expectations early trials have raised
• ammonia accumulation brain-fog, toxicity, liver 'pathologies' and workout performance
• running next to a street entails 'particular downsides' ("particular" is to be taken literally, here ;-)
• homocysteine levels, mortality, cognitive impairment and more
• epigenetic programming by nicotine and different protein contents before birth

These topics alone obviously won't fit into a single episode, but by now you should be aware that the SuppVersity Science Round Up Seconds, which are always published one day after the show aired, will provide you with the things we have missed and additional information, suggested reads and graphs to the topics we covered...  apropos "won't fit in", since the above is not even everything I have up my sleeve, I thought it would be wise to take the glycerol news from the compilation and tackle it on its own, today.

Can the backbone of bad triglycerides really be good for you?

Glycerol, a 3-carbon sugar alcohol that provides the backbone of triglycerides and is naturally found in foods as a component of dietary fats (Burke. 2011), is one of those supplements that have been all the rage for some time, didn't produce the expected instant results everybody was looking for (in this particlar case mostly "skinbursting pumps" and have eventually, in the course of one or two cycles of the regular yearly reformulations of the pre-workout supplements, completely disappeared from the market. I was therefore surprised, when I hit onto a recent study by researchers from the Physical Education and Sport High School in Konya (Turkey) that was published in one of the latest issues of the Journal of Human Kinetics (Patlar. 2012).

Is glycerol save? There have not been any reported toxicity effects up to doses of 5g/kg body weight. Glycerol does accumulates in body fluids, with the exception of the brain and the eyes and increases osmotic pressure (which was the reason why people used it in "pump supplements"), as well as the total volume of water in the body. If anything was 'dangerous', or I should probably rather say 'detrimental' to it, it would probably be its energy content (it is subject to gluconeogensis in the liver), which puts you at 'danger' of adding one or another pound of body fat you would probably want to avoid. The results of the study at hand to yet suggest that this is not an issue as long as you are active.

In essence the study protocol is nothing extraordinary: Take a couple of guys, 40 in this case (age 22.82 ± 1.49 years), and feed and water them using...

• 1.2 g/kg body weight) followed by water (26 ml/kg body weight) to 10 sedentary individuals (GS) and 10 soccer players from the University team
• just plain water to the another 10 sedentary men and 10 soccer players

Conduct a baseline test in the course of which all subjects are familiarized with the exercise equipment, a cycle ergometer (Monark 814-E) and required to perform an...

• Astrand Cycle Ergometer Test and an
  
• Wingate Anaerobic Power Test
  *the videos are don't show the study participants

in a room that is kept at 30°C and a barometrical pressure of 668 mm-Hg. For the next twenty days, have half of the guys (athletic groups E and GE) perform a 20-m shuttle run test every day. And finally perform a second follow up to see and evaluate the individual and joint effects of exercise and glycerol supplementation.

What's a shuttle run? I guess those of you who play soccer or basketball will know similar drills (at least I have been tormented by my trainers with them before in both sports and could imagine they are also among the standard repertoire of football coaches - though I have never played that myself):

Video 1: The shuttle run is every trainer's darling and would actually make a nice conditioning workout to be implemented into your own routine - whatever it may you are training for (note: the video is a random pick from YouTube and has no relation to the study at hand).

"The subjects warmed up for several minutes by jogging followed by stretching. The test program was installed on the computer and  initiated. A single beep was emitted at regular intervals. The subjects had to complete a lap or shuttle (foot on or over the line) with each beep. If the subjects completed a lap early they had to wait for the beep before starting the next lap. A triple beep indicated the start of a new level with a slightly faster speed required to complete each  lap.

The subjects were encouraged to complete as many levels as possible. An observer monitored the progress of a given subject, recording each completed lap on the recorder form. The subjects were instructed to turn by pivoting and not to run in a wide arc. The test was terminated when a subject was two or more steps from the line, for two consecutive laps. The observer alerted the subject at this time." (Patlar. 2012)

The shuttle run was followed by a couple of minutes of walking to cool down and a stretching exercise. The data was collected, logged and archived for evaluation.

Now if we take a look at the results of this undertaking they are unquestionably somewhat surprising - at least at first sight (see figure 1). In absolute terms it looks as if we had an across the board, almost identical increase in performance due to the daily shuttle runs in the exercise groups and a surprisingly large beneficial effect of glycerol only in the sedentary subjects (which would by the way be in line with many of the more or less disappointing trials on the benefits of glycerol supplementation in athletes; cd. Burke. 2011):

Figure 1: Changes in anaerobic and aerobic performance - relative values on the left, absolute before (white) and after (black) on the right (Patlar. 2012)

If you take a look at the relative pre-post changes in figure 1 (left), instead of the absolute changes a more distinct picture emerges:

• the benefit the sedentary subjects derived from the supplementation looks even more pronounced,
• the aerobic performance of the soccer players in the exercise group did likewise benefit, albeit less than the performance of the sedentary group, and
• shockingly the increase in anaerobic performance which looks pretty much identical is not statistically significant, yet still reduced in the glycerol supplemented athletes in the exercise + glycerol group (note: there is an increase, it's only relatively smaller)

Now, we all know that hyperhydration goes hand in hand with an increase in body water. In figure 1 I did even plaster a huge red sticker with "hyperhydration" onto the graph to give you an idea of a possible mechanism of action. So, if we wanted to be fair, we would have to take that into account... what? Yeah and you want to know if it will make you blow up like a wale, right, ... so let's see:

Figure 2: Changes in body weight and relative power (watts per body weight) in the course of the trial (data based on Patlar. 2012)

If we assume you are a sedentary slob at 80kg you could in fact gain 1.6kg... whether that's only water or if there is some fat there, as well, I cannot tell. Notwithstanding, I mentioned in the red box on safety issues, already that you can hardly expect to down 80g of glycerol with an energetic value of 4.32kcal/g (i.e. 350kcal per day) extra everyday without gaining at least some weight (assuming all other parameters are constant; plus, this could be muscle as well - well, not if you don't work out, though ;-).

You cannot expect to lose weight, but surprisingly it may still happen that you do if you consume those 350kcal of glycerol with 2l water right before your daily shuttle run. 

At least this is what happened to the soccer players in the supplementation group: They lost 2.66lbs of body weight on average. "Weight" is the unfortunate key word here, because we have no way of telling whether that was muscle, water or fat weight, as the scientists did not measure that separately. But let's be honest, it appears more than unlikely that it is (a) water or (b) muscle. After all the relative anaerobic power increased equally in both groups and why on earth would you lose water when you hyperhydrate? Ok, it could be one of those counter-regulatory reactions our bodies love. That again should however lead to performance decrements we did not see... you see, it's like the idiomatic dog that's chasing his tail. Why don't you play ginea pig and let us know what happens ;-)

WADA Warning for competitive athletes: If you are a WADA controlled athlete, you better avoid glycerol. It may sound hilarious, but it is on the WADA list of prohibited supplements since 2012. Why? Well, the increase in blood volume could mask the use of testosterone and co. because the /dl count would be lower if the total blood volume is higher -- this is something the WADA officials consider call a "masking agent" (Wada. 2012).

How much do you need? Don't forget, for glycerol to work its hyperhydrating magic, you must consume it with similarly hilarious amounts of water as the subjects in the study at hand. According to van Rosendal et al. an effective protocol comprises 1-1.5 g/kg glycerol + 25–35 ml/kg of fluid. Assuming you weigh 80 kg you can't get way with anything below 80g of glycerol + 2l water! Obviously way more than what any of the hitherto no longer available 'pump' or pre-workout supplements contained (at least I have not come across one that has a 80g scoop and says "consume with at least 2l of water on the label" - have you?)

Bottom line: I want to be honest, I still have to make up my mind about the usefulness of this supplement. I guess what actually does the trick is the combination of hyperhydration + energy availability. I have been preaching more than enough about the importance of energy availability over the last couple weeks, so I don't think I have to go into any more details here.

What I do think, however, is that few of you will be aware of the 2008 paper by Judelson et al. in which they report that hydration status is a fundamental determinant of the endocrine response to exercise, with dehydration leading to inappropriately high cortisol and norepinephrine levels that go hand in hand with an attenuation of the testosterone response to exercise, and negative effects on carbohydrate and lipid metabolism (Judelson. 2008).

Since you should by now have gotten the notion that insufficient energy does exactly the same, glycerol could well provide a means to counter this ergolytic double whammy. Against that background it is however strange that the athletes could not derive any athletic benefit from it... and weight loss without dieting (at least they were advised to stick to their habitual diets)?

If there is one definitive message you can take home from this study, though, it would be related to the dosage advice in the blueish info-box on the top right of this last paragraph: You better know how to use a supplement correctly! And this goes for the manufacturers of supps, as well as for the consumers: While the formers should finally stop putting ingredients into their supps to have them on the label, consumers should learn to identify hilariously underdosed and thus useless 'kitchen sink supplements' that 'have it all', but in doses where 'all' does not produce 'any' effect... how you can do that? Easy: Just make sure you get your daily dose of educative SuppVersity posts every day!

References:

• Burke LM, Stear SJ, Lobb A, Ellison M, Castell LM. A-Z of nutritional supplements: dietary supplements, sports nutrition foods and ergogenic aids for health and performance--Part 19. Br J Sports Med. 2011 Apr;45(5):456-8. 
• Judelson DA, Maresh CM, Yamamoto LM, Farrell MJ, Armstrong LE, Kraemer WJ, Volek JS, Spiering BA, Casa DJ, Anderson JM. Effect of hydration state on resistance exercise-induced endocrine markers of anabolism, catabolism, and metabolism. J Appl Physiol. 2008 Sep;105(3):816-24
• Patlar S, Yalcin H, Boyali E. The Effect of Glycerol Supplements on Aerobic and Anaerobic Performance of Athletes and Sedentary Subjects. Journal of Human Kinetics. 2012; 34: 69-70. 
• Van Rosendal SP, Osborne MA, Fassett RG, Coombes JS. Guidelines for glycerol use in hyperhydration and rehydration associated with exercise. Sports Med. 2010 Feb 1;40(2):113-29.
• World Anti Doping Association. WADA Prohibited List 2010. < http://www.wada-ama.org/Documents/World_Anti-Doping_Program/WADP-Prohibited-list/2012/WADA_Prohibited_List_2012_EN.pdf > retrieved Nov. 01, 2012.