Welcome to the Science of Sport, where we bring you the second, third, and fourth level of analysis you will not find anywhere else.

Be it doping in sport, hot topics like Caster Semenya or Oscar Pistorius, or the dehydration myth, we try to translate the science behind sports and sports performance.

Consider a donation if you like what you see here!

Did you know?
We published The Runner's Body in May 2009. With an average 4.4/5 stars on Amazon.com, it has been receiving positive reviews from runners and non-runners alike.

Available for the Kindle and also in the traditional paper back. It will make a great gift for the runners you know, and helps support our work here on The Science of Sport.

Tuesday, May 04, 2010

Growth hormone - 0.4s faster over 100m

Growth hormone improves performance by 0.4 seconds - WADA funded research

I'm sure that by now, many of you have seen the initial reports on a WADA-funded growth hormone study, which was published yesterday in the Annals of Internal Medicine.  It's an intriguing study, one that is bound to stimulate discussion, so I thought I'd do a very short post more to say that I've seen the reports, I am hunting the study down as you read this and I hope do a more comprehensive post on it as soon as time allows.

I've found the news reporting quite vague and uninformative about the study, and so hopefully I'll be able to bring out much more of the study's findings when I get hold of the original paper and then do a post, hopefully tomorrow.  But in a nutshell, what has been found is that in a group of recreationally active men, aged 18 to 40, growth hormone use improved their sprint capacity enough to lead researchers to conclude that it was worth 0.4 seconds in a 100m race.

If you think that's a pretty small difference, think back to to when Usain Bolt won the 100m title in a world record of 9.58s last year in Berlin.  The man who finished seventh was Marc Burns, in a time of 10.00s.  Now remember the race...did you notice Marc Burns, finishing 0.42 seconds behind Bolt?  Doubtful, and that's because at 0.42 seconds, he was a life-time behind Bolt in sprinting terms, but that is the same difference made by growth hormone, according to the research paper.

There will be, as there always are, problems and questions about the paper's method and the conclusions drawn from it.  For one thing, the study didn't use elite, highly trained sprinters, and so the margin of performance improvement may over-estimate the actual benefit gained by elite athletes.  Or under-estimate it, depending on what your inclination is - this is always a problem with these kinds of studies.  We've discussed this before with reference to EPO use, where studies find improvements that are probably inflated compared to what an elite athlete would achieve.  Then again, the elite athlete gaining even 2% is going to change their "life" as a result, and they benefit from a controlled, systematic environment within to dope, so this is a contentious issue.

Further, the study used a dose that the researchers described as lower than what athletes are reported to use, and for a shorter time, which means, in theory, that the 0.4s improvement predicted may be less than what is actually achieved.  According to the lead researcher, Ken Ho: "The drug’s effects on performance might be greater than shown in this study, and its side effects might be more serious".

So there is lots to discuss, but unfortunately, that's for another time, as I said.  Hopefully tomorrow, when I'll try to break down the method and findings in a lot more detail.



octopusmagnificens said...

Assuming Usain Bolt is clean, nobody in his right mind can argue that he would run the 100 in 09.18. The conclusion is obvious: all athletes under 10 seconds are superdoped and we can say that the races are fair. Obi-Wan: "Luke, you're going to find that many of the truths we cling to depend greatly on our own point of view".

Mark Boen said...

I'm still waiting on you guys to write about Chris Solinsky.

Anonymous said...


Not out on pubmed yet, the wait continues.

Ross Tucker and Jonathan Dugas said...

Hi folks

Thanks for the quick comments!

To Octopusmagnificens:

Not sure that the result of the study can be used to argue that Bolt could run 9.18s. Yes, you get there if you take 0.4s off his current time, but this is where I think the results of this study have been applied incorrectly. For one, the individual responses are not going to be the same. For all we know, there are responders and non-responders. Also, I highly doubt the effect is as large in an athlete who is already near the maximum of what their bodies will allow. Instead, I think the likely effect of doping is that it improves recovery from training and allows athletes to remain injury free and have longer careers.

That said, you raise an interesting point - what if? And I don't know the answer to that. I don't, for example, believe that Bolt was doped as a young 17 year old who broke 20 seconds over 200m. If you do, then you're arguing that growth hormone and steroids were accessible to him in Jamaica. I find that hard to buy.

So then you would have to assume that he was close to his limit by about 19, and then took another 0.4s off it using GH. Feasible? Who knows? Some would say so, others not. Back to Obi...

To Mark Boen:

True. The reason I haven't is that I don't know enough about him to give a reasonable view. I'd be making a lot of it up and claiming something I don't know. I'm quite wary of that! But a great performance, and I think more than the individual, it's indicative of the tide in US running. You have the sub-60min half marathon, a 12:56 guy, a NY champion, at least two consistently great marathon runners, and now a sub-27 10k. It's great for the sport.

Something we must tackle, but too much to write, too little time!

To anonymous:

Yes indeed, we'll have to hold our breaths! Hopefully by Thursday!


Howard said...

It is a shame that this study only used recreational athletes.
Excuse my ignorance, but: "Growth hormone didn’t improve recipients’ strength, power or endurance, nor increase muscle mass, the researchers found"
What is the suggested mechanism for improvement in sprint performance?

octopusmagnificens said...

Growth hormone, steroids, stimulants... There is always a weapon available. Doping is an arms race, just like training, nutrition and material.

John said...

@ Howard, it is possible if they lost weight. Then, speed could increase withouto power increasing. They probably were just incorrect with what they said though.

How long did they receive the HGH supplement for? This would seem important information...

Ross Tucker and Jonathan Dugas said...

Hi Howard:

Yes, it is a shame they had to use recreational athletes only. I guess logistically and ethically, finding elite performers is just too difficult - this is a massive issue with the understanding of doping, by the way.

To answer you though, I gather from news reports on the study that the authors have shown that the performance improvement is due to metabolic factors that improve energy production for sprinting. Quite what that means, I don't know - this is why I really want to see the actual paper. The news reports I've read have been very unclear and confusing.

So that's why I am looking forward to seeing the full study, and then tackling this paper in a full post. It will produce fascinating debate - the quality of athletes used, the duration and dose of GH use, the performance tests used - all will be debatable, so it should be fun to discuss. But only in a few days, unfortunately, because the actual study is not out yet!

You can read the abstract here though:


You'll see here, John, that the study lasted 8 weeks, plus another 6 to monitor the "washout". In terms of dose, they're saying placebo, growth hormone (2 mg/d subcutaneously), testosterone (250 mg/wk intramuscularly), or combined treatments. As I mentioned in the post, they reckon that's much less than elite athletes use. I wouldn't want to guess at that.

More to come, just as soon as the paper is out!


Martin said...

another problem with using elite athletes in a study on doping is that it is not unlikely they're already on it! so if you test lance armstrong to see how he'd respond to blood doping, it's not like it's his first refill, is it. Which means he'd probably show up as a poor responder as he's already taken up on a lot of that potential in him (and i hear he's the best responder out there)

Ross Tucker and Jonathan Dugas said...

Hi Martin

True, true. Big problem with studies on ergogenic aids in general. We were looking at doing a study on a protein supplement, and one of the biggest barriers is existing "supplementation", which often includes anabolic steroids! The assumption made is that the athletes tested are clean, and of course, with elite athletes, this may well miss the mark. And even if they are, their history of use might affect the outcome.


Phil said...

Hesitate to comment before reading the actual study, but if it were really true that HGH gave a 4-5% improvement among elites the implications would be worrying. According to Wikipedia 70 men have run under 10 seconds (not all of them currently active sprinters), so at a minimum there must be 50 or more guys with the natural talent to run say 10.1 seconds. If this is true, all of those guys (many of whom are practically unknown and have much less to lose) would have a shot at an Olympic gold... if only they succumbed to temptation. Since it's almost inconceivable that everyone in such a large pool would stay clean, the obvious conclusion would be that all the top competitors were doped...

More likely, perhaps, that the benefit among the best competitors is much smaller. One wonders how many more athletes will feel the need to take HGH as a result of this study though!

octopusmagnificens said...

Phil is right.

Dr. Stephen Seiler said...

Looking forward to seeing this full paper. However, the abstract states that the only power measure that improved was Wingate bicycle performance. This 4% improvement was then (presumably) exemplified in a similar 4% improvement in sprinting speed.
So, there are some leaps of faith here. Wingate test performance is subject to learning effects, for example. Don't know about the specifics of the testing, like did the subjects get to do the Wingate test once as a practice before the "REAL" pretest? So the fact that it improved but other measures of power and strength did not, MAY be explained by this issue.

Ross Tucker and Jonathan Dugas said...

Hi Stephen!

Thanks for the comment!

You're 100% right, that is a concern. I've looked at the paper, just haven't had the time to do a post on it yet, but I can tell you that:

a) The Wingate power output improved by 0.7kJ (that's total work done during the 30 seconds). They don't actually report the power output or work per trial, just the difference POST - PRE. But I guess given that it's a 3.9% improvement, you could work it out. I would have liked to see the power output and whether the increase came from a higher peak, reduced drop-off etc.

b) They don't mention whether the subjects did more than a pre- and post-trial, to reduce that learning effect. It would appear not. Certainly, the testing sessions were conducted 6 weeks apart, and my reading of it is that they had the subjects come in and undergo this massive battery of tests over the course of a day.

Interestingly, they report that the CV of the Wingate test is 4.2%, larger than the difference produced by GH, which raises some questions too.

I think the extrapolation of a Wingate to a 100m running trial is dodgy anyway. For one, there is the duration - 30 s versus 10s. Do we assume that a 4% improvement over 30s of cycling translates into 4% over 10s of running? I don't think it does, partly because the Wingate is, in my experience and opinion, quite an artificial test. THe drop off in power in the Wingate is very different to the drop off in running speed in a 100m race, so there's something metabolically different between them. Must be.

Then also, the mechanical difference is huge between cycling and running. Bolt and co are surely "limited/regulated" by mechanical factors as much, if not more, than they are by metabolic, and so I suspect that even a 10% increase in metabolic energy supply would not translate into a 10% improvement in running performance, because there are other limits.

It's like if I gave you another ten gearboxes and ten engines, but only 4 wheels, you could still only manufacture one car...

Anyway, will read it much more closely and then post on it in the future. Your thoughts are welcome!


Anonymous said...

I have seen master runners(over 50) running under 16:00 for the 5K. Those people come from nowhere and improve so much in a couple years. Their jaws look large and out of place. HGH, for sure. I don't know whom financed this study, but I think HGH produce better results than this study. Otherwise, why so many people seem to be taking it?