A potential new method of performance-enhancement: ultrasound and platelet-rich plasma

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If there’s one thing we can learn from the history of professional cycling, it’s that there will always be riders that are willing to take risks and break rules to get an edge over their rivals. Whether it’s via good old-fashioned EPO, the use of a hidden motor, “oxygen in a pill”, or something else entirely, it seems clear that athletes will continue to explore and push beyond the boundaries of what’s acceptable in the sport.

Which is why the World Anti-Doping Authority (WADA) should perhaps look into a new combination of treatments that may be prone to abuse for performance enhancement: ultrasound and platelet-rich plasma.

WADA’s Prohibited List specifically bans “any form of intravascular manipulation of the blood or blood components by physical or chemical means” and “the administration or reintroduction of any quantity of … blood, or red blood cell products of any origin into the circulatory system.”

But the combination of ultrasound and platelet-rich plasma might allow legal substances to be introduced to an athlete’s body, with the possible aim of improving athletic performance, all without breaching WADA’s rules.

Ultrasound and platelet-rich plasma

The use of low-frequency ultrasound — sound waves with frequencies higher than the human ear can detect — has been shown to improve healing rates, promote tissue relaxation, increase blood flow, break down scar tissue and more. The use of this technology in sport isn’t new — if you’ve visited a physiotherapist you might have even had such treatment yourself.

Newer research, however, suggests that the combination of ultrasound and specific substances might be beneficial when it comes to treating wounds. And then there’s a 2015 paper by Chinese scientists which suggests that the combination of low-frequency ultrasound and substances abundant in platelet-rich plasma might promote the regeneration of dying bone.

If this treatment works to heal dying bone, then various other substances in platelet-rich plasma might also be able to assist in the recovery and repair of soft-tissue for those engaged in strenuous exercise. And in a sport where recovery is so vitally important — particularly in the Grand Tours — the ability to recover more quickly than normal could provide riders with a non-negligible improvement in performance.

So what is platelet-rich plasma? In order to answer this we need to take a quick look at what makes up our blood.

The composition of blood

Roughly 45% of our blood volume is comprised of three types of blood cells: red blood cells, white blood cells and platelets. Red blood cells carry oxygen around the body, white blood cells power the immune system, and platelets ensure the blood clots properly. Importantly for this discussion, platelets also contain a multitude of substances known as growth factors which facilitate and promote tissue repair.

While platelets normally only account for 6% of an individual’s blood volume, that percentage is much higher in the case of platelet-rich plasma.

Plasma comprises the remaining 55% of an individual’s blood volume that’s not made up of blood cells. It is this pale yellow liquid that keeps blood cells suspended in the blood. By using a centrifuge to separate the different components of blood, a solution can be prepared containing a high concentration of platelets in plasma. Hence platelet-rich plasma (PRP).

PRP injections were first used in 1987 to promote tissue repair during open-heart surgery. Since then this therapy has been used in a number of fields and to help treat various medical conditions, not least tendonitis and osteoarthritis.

Such injections have been used by professional athletes in various sports, most notably golfer Tiger Woods and tennis player Rafael Nadal who both hit the headlines earlier this decade for using PRP to treat knee injuries.

Application and how it might work

While PRP is normally injected into the damaged area to promote healing, new methods could see a cream containing PRP applied directly to the skin with ultrasound used to promote penetration into the muscles and other soft tissue below.1

What the Chinese researchers suggested in their 2015 paper was that low-frequency ultrasound could be used to deliver a growth factor called bFGF (found in PRP) into bone. It seems reasonable to expect that this technique could also be used to deliver bFGF to muscles and other soft tissue, promoting healing and recovery.

So what could this mean for cyclists? Given some ultrasound machines aren’t hugely bulky, it seems possible that such devices could be taken on the road, assisting with rider recovery during a Grand Tour, for example. This would get around the UCI’s no-needle policy (i.e. no need to inject PRP directly), while still giving riders access to the potential benefits provided by PRP and its constituents.

The implications

So where does WADA stand on the issue of PRP? Back in 2010 the organisation banned the therapy for professional athletes, responding to fears about performance enhancement. WADA changed its mind the following year, however, citing a “lack of any current evidence concerning the use of these methods for purposes of performance enhancement”.”

As of March 2016, the use of PRP is still legal for professional athletes, including cyclists2. But while many practitioners swear by the treatment, and as WADA suggested, there is still a lack of consensus about the effectiveness of PRP in a sporting context.

A 2009 scientific review described PRP as “a promising, but not proven, treatment option for joint, tendon, ligament, and muscle injuries” and a 2014 review suggested “there is currently insufficient evidence to support the use of [platelet-rich therapies] for treating musculoskeletal soft tissue injuries.”

That said, the combination of PRP and ultrasound might yet provide a practical benefit for athletes on the road.

Where to from here

So what does this all mean for WADA and for professional athletes? For now, in the absence of compelling evidence, it seems unlikely WADA will change its mind about the legality of PRP. And the combination of PRP and ultrasound, unless shown to improve athletic performance and/or recovery, seems equally unlikely to reach the banned list. After all, ultrasound itself is known to be largely safe, and likewise with PRP. While combining the two hasn’t yet been explored, it is highly unlikely to be unsafe.

Then again, the reasons for inclusion on the ban list have not always been consistent nor based on robust scientific evidence.

Should this method gain traction among athletes, it could pose something of a challenge to WADA, just as the case of Marcel Kittel’s “black light” blood treatments did. The Court of Arbitration of Sport (CAS) deemed at that the time that the procedure could not be considered doping, overturning concerns held by both the German National Anti-Doping Agency and by WADA. [Note: Kittel’s treatment happened at a time when such interventions were not banned – ed.]

Should PRP/ultrasound be banned and a rider was found to be using it, CAS could follow the same decision in the Kittel case and argue that, considering the lack of current evidence about the treatment’s efficacy, any consequent ban shouldn’t be upheld.

All that said, it’s our view that WADA shouldn’t ignore the possibility that the ultrasound/PRP combination might be effective, nor the possibility that athletes might already be using it in the hope of improving their recovery and/or performance. At the very least it’s something for the organisation to look out for in the near future.

CyclingTips does not advocate nor condone the use of performance-enhancing drugs.


1. “Transdermal” or “through-the-skin” drug delivery has several advantages over other methods but is made more complicated by the fact the outermost skin layer seems to act as a barrier for some substances. The use of ultrasound seems to increase the permeability of that skin layer, allowing some substances to pass through more easily.
2. The administration of individual growth factors within PRP is still banned.

About the authors

Dr Ben Koh is a sports doctor with a doctorate on medical risk stratification in the context of the use of conventional, complementary and alternative medicine (CAM) in elite level sports. His research also focuses on the legal implications and how the guidelines under the WADA code may be confusing to athletes in the field, and how inadvertent doping risk is higher than acknowledged in the literature. Dr Koh also has a post-graduate degree in psychology and is pursuing a degree in law.

Dr Koh was previously an elite level athlete and has been offered numerous sports scholarships. Although trained initially as an orthopaedic surgeon, his subsequent experience in emergency medicine and sports medicine coupled with his cultural background and exposure to CAM provided him with the tools to pursue his research passion in an area where elite level sport, medical risks, use of allopathic medicine and CAM intersect.
Matt de Neef is the Australian editor of CyclingTips. You can read more about Matt and his background here.

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