Professional Cycling - Anti-Doping in Cycling
As a sports medicine physician and a student and fan of professional cycling, the topic of doping in cycling has always been of great interest. The history of doping in professional cycling is long and troubling, beginning with the deaths of cyclists involved in the Tour de France and Olympics in the 60’s. For many, the seizure of the Festina team car at the 1998 Tour de France, was most impactful, opening up cycling fan’s eyes to the pervasiveness of doping. The confiscation by police of large supplies of performance enhancing drugs from the Festina team car was followed by multiple other doping scandals over the next couple decades, including the involvement of the Tour’s greatest winner.
A recent article by Olaf Schumacher (2016) provides a nice review of doping and anti-doping and the steps that have been taken to improve the sport both for the health of the athlete as well as the image of cycling. Specifically, he takes an interesting look at the testing procedure now and considers how it may look in the future.
Regarding endurance sports, one of the largest impacts concerning doping was the availability of a recombinant human erythropoietin (EPO). EPO is a naturally produced glycoprotein involved in erythropoiesis or the production of red blood cells. EPO stimulates cells in the bone marrow to produce new erythrocytes or red blood cells. The artificial form was produced to help patients with chronic kidney disease to fight their associated anemia. Very quickly, the application to endurance sports was realized, and endurance athletes and coaches saw EPO replacing traditional blood doping. The use of EPO would, in theory, increase the athlete’s red cell mass, therefore allowing more oxygen carrying capacity. The traditional thought from the literature is that maximal oxygen uptake (VO 2max ) could be improved by as much as 5% with the use of EPO. Obviously, an increase of 5% would be a difference maker for the elite endurance athlete. Interestingly, there are researchers who feel that the actual performance benefit of synthetic EPO to the athlete lacks sound evidence and that there are multiple other factors involved which affect performance in the elite endurance athlete. It will be interesting to watch as further research explores this area.
Because of the ever changing pharmaceutical landscape where there are now several versions of “EPO”, the anti-doping efforts have taken an indirect detection method. They now use a longitudinal evaluation of biomarkers, called the “Athlete Biological Passport” (ABP). This is a collection of blood markers which are followed over time, such as hemoglobin, hematocrit and reticulocyte count (a marker of young red blood cells). The ABP consists of hematological and steroid modules with others being developed. The hematological module attempts to detect blood manipulation via EPO-like products or blood transfusions while the steroid module aims to identify exogenous steroid usage. If an athlete’s results are not within their individual ABP, the sample is then submitted for further, more detailed testing. Interestingly, a study by Zorzoli and Rossi looking at the impact of the ABP, felt there has been a decrease in the very high and low reticulocyte patterns seen previously. This may be an indication of the deterrent effect of testing and a positive behavior change. This is a combined effort of the Union Cycliste Internationale (UCI) and the World Anti-Doping Agency (WADA) and is managed by the Cycling Anti-Doping Foundation (CADF), which is an independent foundation.
As the primary goal of performance enhancing drugs (PED’s) is improved performance, a performance monitoring system for cycling has been proposed. Over time, a “performance passport or power profile” will be developed for each individual athlete and any unusual change in the performance profile would be further evaluated via additional anti-doping testing. With almost every elite and many non-elite cyclists wearing heart rate monitors and having power meters on their bikes, the sport of cycling lends itself to evaluation by numbers, especially power, so similar climbs or sprints possibly allows comparing the power profile of individual riders.
Cycling has attempted to control doping in the sport for multiple reasons: for the health of the athlete, to level the playing field, and improve its image. In a sport where shaving off a gram or two from your bike weight is thought to be essential, there will always be those who are pushing the envelope, legal or not. That remains a fact in many areas of sport. From the outside, many of these changes have improved the sport of cycling. However, as a fan of the sport, I think it is essential for those involved to continue to strive to make the sport as clean and fair as possible.
SchumacherYO.Doping and anti-doping in cycling. AspetarSportsMedicineJournal, December2016
Heuberger JA, Tervaert JM, Schepers FM, et al. Erythropoietin doping in cycling: lack of evidence for efficacy and a negative risk-benefit. British Journal of Pharmacology , 2012.