You don't need to be signed in to read BMJ Blogs, but you can register here to receive updates about other BMJ products and services via our site.

E-letters

E-letter: Are there risk factors in alpine skiing?

12 Jul, 10 | by Karim Khan

This E-letter is in response to Are there risk factors in alpine skiing? A controlled multicentre survey of 1278 skiers. Abstract | Full article


We read with interest the article from Hasler et al. (2009) “Are there risk factors in alpine skiing? A controlled multicentre survey of 1278 skiers”.

In general, the answer is: ‘yes, there are internal (e.g. gender, age, fitness, skill level, risk taking) and external (equipment, environment) risk factors’ according to comprehensive model for injury causation by Bahr and Krosshaug (1). However, we would like to comment on the presented data and methods used because some results seem contrary to other studies in this research field.

Firstly, Hasler et al. reported that skiers with new equipment have a higher risk of being injured. However, there seems a mistake in the presented data because in the abstract the Odds Ratio (OR) was 59 with a 95% confidence interval of 0.37-0.93 while in Table 1 the OR was 0.59. If the OR of 0.59 was correct, new equipment would decrease injury risk. In addition, what means new equipment? Did the authors compare carving skiers with traditional skiers as done by Burtscher et al. (2) showing a reduced injury rate since the introduction of carving ski? Where is the cut off between new and old equipment? In the discussion section, Hasler et al. stated that the results might be explained by a mismatch between the abilities of the skier and the equipment. Unfortunately, they did not include skill levels in their questionnaire. Several studies showed higher injury rates in less skilled skiers and snowboarders (3, 4) while more skilled skiers had a higher risk to sustain a more severe injury (5).

Secondly, there seem mistakes concerning the presented data about snow conditions. In Figure 3, artificial snow versus old snow and fresh snow versus powder snow show OR <1 while in Table 1 the same OR are presented vice versa (OR 0.21 for old snow vs. artificial snow and OR 0.31 for old snow vs. fresh snow, respectively). It is the same with slush snow versus powder snow which is not a snow condition but a skiing condition in Figure 3 and powder snow vs. slush snow in Table 1, respectively. In addition, old snow seems to be in contrast to fresh snow. Does fresh snow mean powder snow? However, can old snow not be also old artificial snow? Therefore, it is not clear which snow condition actually increases or decreases injury risk.

Thirdly, seasonal checking of skiing equipment showed a trend to decrease injury risk (OR: 0.46, p = 0.056). In our opinion, seasonal checking of skiing equipment includes primarily an adjustment of the bindings. In accordance, Burtscher et al. (2) showed that female carving skiers with a binding adjustment older than 1 year had a twofold knee injury rate compared to those with newly adjusted bindings. The release of a binding is primarily important in preventing injuries to the lower extremity. Therefore, it would be better to define risk factors with regard to the injured body location.

Fourthly, injured skiers showed a higher readiness for risk taking in this study. In contrast, other studies  reported that injured skiers did not take more risk but were less skilled compared to uninjured skiers (6-8). Therefore, it would make sense to include skill level.

Fifthly, Hasler et al. showed a higher injury risk when skiing under bad weather conditions which is well in accordance with the study by Aschauer et al. (9). However, poor snow and weather conditions may be misjudged by injured skiers because they may look for an explanation as to why the injury occurred. In general, self-report to questions might lead to underreport or overreport of health-risk behaviours affected by cognitive and situational factors (10).

Sixthly, gender has not been found to be a significant risk factor in this study. That might be due to the fact that Hasler et al. did not differentiate between injured parts of the body, e.g. females have a higher knee injury risk (2) and males have a higher head injury risk (11) compared to the other gender.

Seventhly, Hasler et al. calculated that injury risk is higher when warming up. This result contrasts general preventive recommendations (12) and also the findings by Ruedl et al. (13) who demonstrated a twofold injury reduction in a cohort of 36.000 participants of 12 ski schools when warming up.

Eighthly, there seems a mistake concerning the presented data about drug consumption. Figure 3 shows an OR > 1 for abstinence from drugs while inTable 1 drug consumption was presented vice versa. In  addition, in Table 1 an OR of 5.92 was presented while in the discussion the OR was 1.78 for drug consumption.

Since a case control design was used, the amount of exposure to the suggested risk factors was unknown which should be taken into account when interpreting the results (14). In the study by Hasler et al. the controls were interviewed when coming off slopes after skiing. This implies that controls skied probably more than 3 hours although other studies showed that most injuries to the lower extremity occurred within the first 2 or 3 hours of skiing (15, 16). A total of 782 patients were recruited over a period of 5 and a half month and 496 controls were interviewed in six different ski resorts. This means an average of about 83 controls per ski resort and an average of 15 uninjured skiers per month, respectively. However, Hasler et al. (2009) did not specify when controls have been recruited, e.g. every second day. A continuous recruitment of controls seems of utmost importance to compare prospectively potential external risk factors like snow, weather and slope conditions. In general, a prospective study design concerning internal and external risk factors in relation to gender and type of injury should be used. However, at least a case-control-design should be applied matching controls according to gender, age and skill level.

Gerhard Ruedl & Martin Burtscher
Department of Sport Science
University of Innsbruck, Austria

References

1. Bahr R, Krosshaug T. Understanding injury mechanisms: a key component of preventing injuries in sport. Br J Sports Med 2005; 39: 324-329.
2. Burtscher M, Gatterer H, Flatz M et al. Effects of modern ski equipment on the overall injury rate and the pattern of injury location in Alpine skiing. Clin J Sport Med 2008; 18:355-357.
3. Langran M, Selvaraj S. Increased injury risk among first-day skiers, snowboarders, and skiboarders. Am J Sports Med 2004;32:96-103.
4. Hagel B. Skiing and snowboarding injuries. Caine DJ, Maffulli (eds.): Epidemiology of Pediatric Sports Injuries. Individual Sports. Med Sport Sci. Basel. Karger,2005;48:74-119.
5. Goulet C, Hagel BE, Hamel D, et al. Self-reported skill level and injury severity in skiers and snowboarders. J Sci Med Sport 2008; doi: 10.1016/j.jsams.10.002
6. Bouter LM, Knipschild PG, Feij JA, et al. Sensation seeking and injury risk in downhill skiing. Person. Individ. Diff. 1988;9:667-73.
7. Cherpitel CJ, Meyers AR, Perrine MW. Alcohol consumption, sensation seeking and ski injury: a case-control study. Journal of Studies on Alcohol 1998;59:216-21.
8. Goulet C, Regnier G, Valois P, et al. Injuries and risk taking in alpine skiing. ASTM STP 1397, Skiing Trauma and Safety: Thirteenth Volume, RJ Johnson, P Zucco, JE Shealy (eds.), ASTM International, West Conshohocken, PA, 2000:139-46.
9. Aschauer E, Ritter E, Resch H et al. Injuries and injury risk in skiing and snowboarding. Unfallchirug 2007; 110: 301 306. (in German)
10. Brenner ND, Billy JOG, Grady WR. Assessment of factors affecting the validity of self-reported health-risk behavior among adolescents: evidence from the scientific literature. J Adolesc Health 2003;33:436-457.
11. Mueller BA, Cummings P, Rivara FP, et al. Injuries of the head, face, and neck in relation to ski helmet use. Epidemiology 2008;19:270-76.
12. Koehle MS, Lloyd-Smith R, Taunton JE. Alpine ski injuries and their prevention. Sports Med 2002; 32 (12): 785-793.
13. Ruedl G, Sommersacher R, Woldrich T et al. A structured warm-up program to prevent injury in recreational skiers. Senner V, Fastenbauer V, Boehm H (eds.): Book of Abstracts of the 18th Congress of the International Society for Skiing Safety, Garmisch-Partenkirchen, Germany, April 26 to May 02 2009, 77.
14. Vandenbroucke JP, von Elm E, Altman DG et al. Strengthening the reporting of observational studies in epidemiology (STROBE): explanation and elaboration. Epidemiology 2007;18 (6): 805-835.
15. Ungerholm S, Engkvist O, Gierup J et al. Skiing injuries in children and adults: a comparative study from a 8-year period. Int J Sports 16. Ruedl G, Schranz A, Fink C et al. Are ACL injuries related to perceived fatigue in female skiers? ASTM International 2010; 7 (4), Paper ID JAI102747

E-letter: Energy Expenditures of the Masai

13 Mar, 10 | by Karim Khan

This E-letter is in response to Daily energy expenditure and cardiovascular risk in Masai, rural and urban Bantu Tanzanians Abstract | Full Article


Mbalilaki and associates have reported very high daily energy expenditures for a sample of Masai pastoralists and farmers (56% of whom were women)(1). The stated average of 10.7 MJ/day (2565 kcal/day) appears to be a gross value for that part of the day when the subjects were physically active, although this is not specifically indicated in their paper. The expenditure is suggested as equivalent to 19 km of walking, which would occupy a total of some 4 hours. The remaining 20 hours would contribute at least a further 6 MJ of resting energy expenditure, for a daily total of some 16.7 MJ or 4010 kcal. One earlier Kofranyi-Michaelis respirometer study of traditional male Inuit did observe daily expenditures ranging from 10.5 to 18.5 MJ/day for different categories of hunting in a harsh arctic environment (2). However, the figure of 16.7 MJ/day proposed for the Masai sample is somewhat surprising on several counts, including the low average body mass of the subjects (56.8 kg), the relatively low physical working capacity seen in a previous Masai sample (3) and the conclusions from at least one energy input-output analysis that food requirements in this environment could be satisfied by working only two days per week (4).

One potential issue is the method adopted when determining energy expenditures. Mbalilaki and associates (1) apparently based their estimate on an interviewer-administered North American  questionnaire (5), translated into Swahili and slightly adjusted for Tanzanian conditions. The nature of these slight adjustments and their possible impact on test validity are not discussed, but there are clearly important limitations to the absolute accuracy of information obtained from most physical activity questionnaires (including the instrument of Paffenbarger and associates, 5) even in an urban North American environment (6),and many of the items listed in the published version of the instrument of Paffenbarger et al.(5) would have little relevance to the Masai sample.

Given the importance of understanding physical activity patterns in populations that have a low prevalence of cardiovascular risk factors, I hope that Mbalilaki and associates will soon find opportunity to replicate their interesting observations, using currently available and relatively inexpensive objective physical activity monitors.

Roy J. Shepard
Professor Emeritus
University of Toronto

References

1. Mbalilaki JA, Msesa Z, Stromme SB et al. Daily energy expenditure and cardiovascular risk in Masai, rural and urban Bantu Tanzanians. Br J Sports Med 2010; 44: 121-126.

2. Godin G, Shephard RJ. Activity patterns in the Canadian Eskimo.  In: Edholm O, Gunderson EK, eds. Polar Human Biology, London, UK:  Heinemann, 1973.

3. Wyndham CH, Strydom NB, Morrison JF et al. Differences between ethnic groups in physical working capacity.  J Appl Physiol 1963; 18: 361- 366.

4. Lee RB. Kung bushmen subsistence: An input-output analysis. In:  Vayda AP. Environment and cultural behavior. New York, NY: Natural History Press.

5. Paffenbarger RS, Blair SN, Lee IM et al. Measuring physical activity to assess health effects in free-living populations. Med Sci Sports Exerc 1993; 25: 60-70.

6. Shephard RJ. Limits to the measurement of habitual physical activity by questionnaires. Br J Sports Med 2003; 37: 197-206.

E-letter: Rifaximin for the Prevention of Travellers’ Diarrhoea in Elite Athletes

11 Mar, 10 | by Karim Khan

This E-lettter is in response to Setting standards for the prevention and management of travellers’ diarrhoea in elite athletes: an audit of one team during the Youth Commonwealth Games in India Abstract | Full Article


The article by Tillett and Loosemore describes guidelines for the prevention and management of travellers’ diarrhoea (TD) based on their experience with the elite athletes and noncompeting members of Team England during the 2008 Youth Commonwealth Games in India. The authors recommended that all team members receive oral and written advice regarding prevention of TD, that all team members are issued alcohol hand gel and instruction for its use, and that all noncompeting team members receive ciprofloxacin for TD prophylaxis. As ciprofloxacin use in elite athletes is considered controversial because of a possible association with tendon rupture, the authors recommended that elite athletes consider the nonabsorbable antibiotic rifaximin as a prophylactic for TD. However, none of the elite athletes on Team England actually received rifaximin as a prophylactic therapy for TD. Further, the authors stopped short of recommending rifaximin for the treatment of TD, simply recommending treatment with empiric antibiotics per local advice and the results of stool culture.

We report here that, in 2008, some elite athletes from the United States received rifaximin either for the prophylaxis or treatment of TD while in Beijing, China. In this small sample of elite athletes, rifaximin was safe and well tolerated, and no adverse events were reported. Rifaximin has been found safe, well tolerated, and effective for both the prophylaxis and treatment of TD in other populations1-8. Based on our experience and the excellent safety profile of rifaximin for the treatment of TD, the use of rifaximin as an antibiotic therapy for the treatment of TD in elite athletes deserves further consideration.

Bradley Connor and Scott Rodeo

References

1.           DuPont HL, Ericsson CD, de la Cabada FJ, et al. Prevention of travelers’ diarrhea with rifaximin- a phase 3 randomized double-blind placebo-controlled trial in U.S. students in Mexico [abstract]. Am J Gastroenterol. 2006;101(suppl):S197-S198.

2.           DuPont HL, Ericsson CD, Mathewson JJ, et al. Rifaximin: a nonabsorbed antimicrobial in the therapy of travelers’ diarrhea. Digestion. 1998;59(6):708-714.

3.           DuPont HL, Haake R, Taylor DN, et al. Rifaximin treatment of pathogen- negative travelers’ diarrhea. J Travel Med. 2007;14:16-19.

4.           DuPont HL, Jiang ZD, Ericsson CD, et al. Rifaximin versus ciprofloxacin for the treatment of traveler’s diarrhea: a randomized, double-blind clinical trial. Clin Infect Dis. 2001;33(11):1807-1815.

5.           DuPont HL, Jiang Z-D, Belkind-Gerson J, et al. Treatment of travelers’ diarrhea: randomized trial comparing rifaximin, rifaximin plus loperamide, and loperamide alone. Clin Gastroenterol Hepatol. 2007;5:451-456.

6.           DuPont HL, Jiang Z-D, Okhuysen PC, et al. A randomized, double-blind,
placebo-controlled trial of rifaximin to prevent travelers’ diarrhea.
Ann
Intern Med. 2005;142(10):805-812.

7.           Steffen R, Sack DA, Riopel L, et al. Therapy of travelers’ diarrhea with rifaximin on various continents. Am J Gastroenterol. 2003;98:1073- 1078.

8.           Taylor DN, Bourgeois AL, Ericsson CD, et al. A randomized, double- blind, multicenter study of rifaximin compared with placebo and with ciprofloxacin in the treatment of travelers’ diarrhea. Am J Trop Med Hyg. 2006;74:1060-1066.

Conflict of Interest

Dr Connor has received grant support from and is a consultant for Salix Pharmaceuticals, Inc.
Dr Rodeo has nothing to disclose.

E-letter: Pre-participation screening in competitive athletes in Portugal

11 Mar, 10 | by Karim Khan

This E-letter is in response to ECG As A Part of the Pre-Participation Screening Programme: An Old an Still Present International Dilemma (Abstract)


Pre-participation screening in competitive athletes in Portugal has been compulsory for more than 40 years. Yearly ECG was introduced in the screening at about the same time as in Italy, for all athletes evaluated at the Sports Medicine Centres in Portugal. The very rare cases of sudden cardiovascular death that have ocurred in the past 25 years in Portugal were not screened at the Centres or had further cardiovascular evaluation pending, and threfore were not qualified for practice. Several athletes have been disqualified from sports participation for cardiovascular reasons, most of them were further investigated because of rest ECG changes findings. We strongly favour the use of 12 lead ECG in the pre- participation screening process. Presently, we routinely screen about 20.000 athletes per year in the 3 Sports Medicine Centres in Portugal.

Marcos A. Miranda
Sports Medicine Specialist
Lisbon Sports Medicine Centre

E-letter: Level Playing Field for SEM Entrants

1 Jan, 10 | by Karim Khan

This E-letter is in response to The role of the sports and exercise medicine physician in the National Health Service: a questionnaire-based survey Abstract | Full Article


I would like to thank P O’Halloran for conducting this survey. One of the results which strikes clearly is the need for training in Orthopaedics by all the participants ( 85% of all participants) [Figure 1, page 1145 (1)] This is something which I have felt for a long time as most of the injuries are seen by Orthopaedics in UK including tendinosis and their treatments.

The irony is that criteria for SEM Entry does not state or give any preference to those with any or some Orthopaedics experience. One would think that Orthopaedics experience would be handy and mutually symbiotic for SEM as this study proves.

I can tell from my personal experience from earlier this year trying to apply for SEM posts that I did not fulfill the criteria to apply for the SEM posts although I had SEM diploma and vast Orthopaedics experience.

I am pleased to find that Prof Maffuli is an author on this paper. I hope that he will be able to plead the case for those with Orthopaedics experience and SEM Qualifications. Doctors interested in SEM with surgical experience should not be seen as threat and should be encouraged to become part of the SEM fraternity. This will not help make this speciality more interesting.

Turab A. Syed
Registrar Trauma & Orthopaedics cum Sports Doctor
Milton Keynes Foundation Hospital NHS Trust

References

1: The role of the sports and exercise medicine physician in the National Health Service: a questionnaire-based survey: P O Halloran, V Tzortziou Brown, K Morgan, N Maffulli, M Perry, and D Morrissey Br. J. Sports Med. 2009 43:1143-1148; doi:10.1136/bjsm.2009.064972

Conflict of Interest: Orthopaedic Registrar with SEM Diploma hoping to get recognition in SEM Field

E-letter: Anticipatory regulation are cognitive and affective processes involved?

11 Dec, 09 | by Karim Khan

I read your fascinating article with much interest. Do you think that in simple terms that anticipatory regulation may be an aspect of the decision-making the athlete makes before execution of an action. In the instance of longer duration exercise eg a marathon a decision is made then physiological systems amongst others come into action as you have described. Prior learning and adaptation may be involved as well as genetic and environmental factors. The particular learning aspects include; cognition, perception and affection. The knowledge to be gained from this study could have particular importance to injury prevention in sport, notably when fatigue is an issue. Central fatigue and peripheral fatigue.

Henare Broughton
PhD candidate
School of Psychology
Trinity College
Dublin, Ireland.

E-letter: Abduction/Valgus Kinematics of Lower Leg Relative to Femur

11 Dec, 09 | by Karim Khan

This e-letter is in response to Non-contact ACL injuries in female athletes: an International Olympic Committee current concepts statement. Abstract | Full Article


This outstanding body of research is a watershed in the fight against ACL-injuries.  This group should be richly commended for this excellent work.

The work points to (a priori) how, in the case of alpine skiing, excessive abduction loading / valgus torque of the lower leg structure relative to the upper leg (about the knee) can be truncated by “detaching” the imposing load from the point of load application at the playing surface in the direction of the applied load.  E.G., if the medial load that applies abduction to the lower leg can be “released” from the lower leg — the abduction / valgus loading will dissipate.  An alpine ski-binding with this capability (via lateral heel release) will provide this capability when the applied load is “released” (when the applied abduction load approaches a pre-determined level that is well below the elastic limit of the acl but which level is above that which is needed to provide “controlled” skiing maneuvers).  Such a binding exists, today, and a prospective intervention study should be considered to study its merits for skiers.

Rick Howell
Dipl. Eng.
Stowe, Vermont, USA

Conflict of Interest: Inventor of alpine ski-binding with independently adjustable, non-inadvertant abduction release in response to excessive valgus loading, but am presently cut-off from financial gain in this IP due to on-going litigation re: ownership rights.

E-letter: No discrepancy between protocol and trial report

30 Aug, 09 | by Karim Khan

Click here to read the original article.


We thank Professor Thornton for raising these issues and are grateful for the opportunity to clarify details of the trial protocol and analysis.

There is, in fact, no discrepancy between the description of outcomes in the trial protocol published on the trial web site, the protocol that was registered on the Australian New Zealand Clinical Trials Registry, and the report published in the British Journal of Sports Medicine. All three sources describe the same primary outcomes (risk of soreness and time to injury) and the same secondary outcomes (severity of soreness, time to (“preventable”) muscle/ligament/tendon injuries, time to injuries for which professional care was sought, and perceptions of looseness during and after exercise). In addition, all three sources describe the same secondary analyses of the interactions between frequency of activity, age and strength of belief in affects of stretching and each of the two primary outcomes. Confusion may have arisen because in the trial report we refer to the analysis of the interactions as “outcomes”, although the analyses of interactions were conducted on the same primary and secondary outcomes as listed above. And we may have added to the confusion by inconsistently referring to the perceptions of looseness during and after exercise as either one or two outcomes. We acknowledge that the wording may not have been clear but we reiterate that there was no inconsistency between the analyses described in the protocol, register and trial report.

The protocol, register and trial report describe an analysis of the subset of injuries which could plausibly be prevented by stretching. The protocol (which is more detailed than the registry entry) indicated that the classification of injuries into those that could and could not plausibly be prevented by stretching would be classified by an independent expert. We found that the data lacked sufficient detail to inform decisions about whether individual injuries were preventable so we decided simply to classify all muscle, ligament and tendon injuries as potentially preventable. This decision was made before the allocation code was broken without reference to the data. We did not know, at the time that decision was made, that there would be a significant effect of stretching on the subset of muscle, ligament and tendon injuries.

As the protocol indicated, no adjustment was made for multiple comparisons. We interpret frequentist analyses as Bayesian analyses with vague priors[1] and, from this perspective, the decision not to make adjustments for multiple comparisons is justified. At any rate, there were only two primary outcomes so adjustment for multiple comparisons would not have changed the conclusions from the primary analysis. We agree that the finding of an effect on the secondary outcome of muscle, ligament and tendon injuries is less robust than the finding of an effect on the primary outcome risk of soreness because muscle, ligament and tendon injuries were a secondary outcome. That is why we concluded that stretching “probably reduces the risk of some injuries and does reduce the risk of bothersome soreness”.

Gro Jamtvedt
Executive Director
Norwegian Knowledge Centre for the Health Services, Oslo, Norway

Reference:

1. Barnett V (1973). Comparative Statistical Inference. London:
Wiley.

E-letter: Response to “Evolution and pacing strategies”

28 Jul, 09 | by Karim Khan

I read the review article (abstract; full article) on the anticipatory regulation of performance and pacing strategies by Dr R Tucker in the June edition of BJSM with great interest. The idea that there is a part of the brain, as yet undiscovered, which enables one to judge the optimal work rate for a given task, is an intriguing one.

From a Darwinian view point, the idea of there being a template in the brain that one could draw upon in determining pacing strategy, carries great merit. Anthropologists have learnt of a hunting strategy used by Bushmen from Southern Africa in which the prey, such as a Kudo, is chased for many hours until it collapses in exhaustion. The Bushmen pace themselves, such that they do not succumb to exhaustion, and are able to follow the tracks of the animal when they lose sight of it. The same principle can be seen with the hunting behaviour of wolves. Having spotted a weak member of a herd of elk or other deer, they will chase it for hours on end if necessary.

It is obvious that the most successful hunters will be those who can judge their pace the best. The genes of these hunters are more likely to be passed through to the next generation. An athlete’s ability to judge pace is therefore likely to be the consequence of millions of years of mammalian evolution.

Dr. Fergus J. Dignan

E-letter: Question regarding the use of autologous PRP injections for tendinopathies

23 Jul, 09 | by Karim Khan

The following is a letter to BJSM from Ralph S. Bovard MD:

Dear BJSM,

I have a question regarding the use of autologous platelet rich plasma (PRP) injections for tendinopathies of various sorts.  This procedure has been gaining favor with sports medicine clinicians for use in athletes with tendon injuries that are slow to respond or resistant to conservative therapies.  Despite the fact that it would appear to be a seemingly innocent matter of re-injecting one’s own spun down blood products, the World Anti-Doping Agency (WADA) most recent 2009 Prohibited List, if taken literally, would make it an illegal procedure for international competition or national competition under any NGB’s who endorse WADA.  The culprit substances in this case would be growth hormone (GH), Insulin-like Growth Factors (IGF-1), and Mechano Growth Factors (MGF’s).

The relevant section from the code is included below:

S2. HORMONES AND RELATED SUBSTANCES

The following substances and their releasing factors, are prohibited:
1. Erythropoiesis-Stimulating Agents (e.g. erythropoietin (EPO), darbepoietin (dEPO), hematide);
2. Growth Hormone (GH), Insulin-like Growth Factors (e.g. IGF-1), Mechano Growth Factors (MGFs);
3. Chorionic Gonadotrophin (CG) and Luteinizing Hormone (LH) in males;
4. Insulins;
5. Corticotrophins;
and other substances with similar chemical structure or similar biological effect(s).

[Comment to class S2:
Unless the Athlete can demonstrate that the concentration was due to a physiological or pathological condition, a Sample will be deemed to contain a Prohibited Substance (as listed above) where the concentration of the Prohibited Substance or its metabolites and/or relevant ratios or markers in the Athlete’s Sample satisfies positivity criteria established by WADA or otherwise so exceeds the range of values normally found in humans that it is unlikely to be consistent with normal endogenous production.

If a laboratory reports, using a reliable analytical method, that the Prohibited Substance is of exogenous origin, the Sample will be deemed to contain a Prohibited Substance and shall be reported as an Adverse Analytical Finding.] The Prohibited List 2009 20 September 2008

It would thus seem that PRP is banned under “Class S2: Hormones and Related Substances”, rather than under “M1: Blood Doping”.  The re-delivery of blood is prohibited under blood doping; regardless of whether it is endogenous or exogenous.  There is no mention or attempt to discriminate between blood products that are re-injected immediately into soft tissues versus those that are shelved and re-infused by IV weeks or months later in the typical manner of “blood doping”.

The argument is made that while PRP indeed delivers  the athletes own growth factors to a musculoskeletal site, the platelets are concentrated to a level not normally achieved physiologically, and they are activated either chemically (via calcium addition) or mechanically (centrifugation) and thus degranulate  rapidly and deliver a bolus of factors never “normally” or physiologically achieved.

Given this stance it would seem that the use of platelet rich plasma injections is clearly prohibited.   Tendinopathies are not life threatening or otherwise serious medical conditions and as such the rational of applying for a therapeutic use exemption (TUE) would seem a difficult argument.   Yet how would PRP injections be detected other than by admission?  What is the opinion of the BJSM readership regarding this topic?

Thank you,

Raph S. Bovard MD

BJSM blog homepage

BJSM

A peer review journal for health professionals and researchers in sport and exercise medicine. Visit site

Latest from British Journal of Sports Medicine

Latest from British Journal of Sports Medicine