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

Letter to the Editor: Does exercise training during pregnancy affect gestational age?

10 Sep, 08 | by Karim Khan

pregnant yoga bjsm

By Adriana Suely de Oliveira Melo, MD, MSc et al.

Barakat et al. 1 have presented us with a paper of excellent methodological quality, following all the steps recommended in the Consolidated Standards of Reporting Trials (CONSORT) and dealing with a question that never fails to generate controversy with respect to the practice of physical activity during pregnancy: prematurity. nother strong point of the paper is the fact that the physical exercise was systematized and monitored, guaranteeing that the pregnant woman indeed followed the prescribed program.

Various controversies continue to surround the topic of physical exercise and pregnancy and the real effects of exercise on the conceptus remain to be clarified. The spectrum of these effects ranges from fetal growth to the duration of the pregnancy, with some studies associating prematurity and growth restriction with the practice of physical exercise 2-4. Despite these speculations, until recently no randomized clinical trials (RCT) with adequate sample sizes had been identified in which pregnant women were systematically followed up for a period encompassing the second and third trimesters.

The excellent quality of this paper prompted us to examine it in detail in an attempt to understand some points that we would now like to put to the authors. Since the objective of the RCT was to evaluate the risk of premature labor, would it not have been better to have excluded all the pregnant women with a history of premature labor in view of the fact that the results show that one of the cases of prematurity in the intervention group was precisely due to a prior history of prematurity?

Another point that drew our attention concerns the exclusions in both groups, which were the result of various situations that may have affected the outcome “gestational age”, such as bleeding, pregnancy-induced hypertension and threatened preterm labor. In our opinion, these women should have continued in the study and an intent-to-treat analysis should have been carried out. We were also intrigued by the fact that one patient was excluded because her pregnancy was a twin pregnancy. Was a single pregnancy not one of the inclusion criteria?

It may perhaps have been interesting NOT to have included women with a history of premature delivery. Although the inclusion criteria accepted the possibility of the participants having had at the most one previous premature delivery, this may have had an effect on the mean gestational age reported in the present study.

We were unable to identify in the paper any description of the parameters used to calculate sample size to determine whether the final number of participants included was sufficient to demonstrate any
differences between the groups. Could a type II statistical error have occurred?

Another minor question we would like to pose is whether the intensity of the prescribed exercise was light-to-moderate or moderate, since it is described in different ways in the various sections of the manuscript and it is known that some outcomes are dependent on the intensity of exercise.

Finally, we would like to know whether the authors have data on other gestational or perinatal outcomes, since such a well-conducted RCT as this one should have generated interesting results that deserve to be published.

1. Barakat R, Stirling JR, Lucia A. Does exercise training during pregnancy affect gestational age? A randomised controlled trial. Br J Sports Med 2008; 42(8):674-8.

2. De Ver Dye T, Fernandez ID, Rains A, Fershteyn Z. Recent studies in the epidemiologic assessment of physical activity, fetal growth, and preterm delivery: a narrative review. Clin Obstet Gynecol 2003; 46(2):415-22.

3. Grisso JA, Main DM, Chiu G, Synder ES, Holmes JH. Effects of physical activity and life-style factors on uterine contraction frequency. Am J Perinatol 1992; 9(5-6):489-92.

4. Misra DP, Strobino DM, Stashinko EE, Nagey DA, Nanda J. Effects of physical activity on preterm birth. Am J Epidemiol 1998; 147(7):628-35.

Book Review: Martindale’s Drugs Restricted in Sport

10 Sep, 08 | by Karim Khan

Martindale35_l bjsm

Martindale’s Drugs Restricted in Sport, Pocket Companion, 2008
Sean C. Sweetman (editor)
Publisher: Pharmaceutical Press, 2008
ISBN 978-0-85369-825-8
416 pages

“Martindale’s Drugs Restricted in Sport” is unique in its kind. It is the first pharmacopia that lists all the drugs that are on the WADA list of prohibited substances, drawing on the wealth of information and clinical expertise in the full reference work: “Martindale, the complete drug refeerence”. This is a great resource for sports medicine physicians, general practitioners and all other health care professionals working with athletes. It contains over 450 monograhs pertaining to individual drug substances that may be restricted in some or all sports, either in or out of competition.

The book is arranged alphabetically by drug substance. The international nonproprietary name or generic name is used, where one exists.

Other synonyms listed include British approved names, the French, Latin, Spanish, and Russian variants of generic names, names used in other European, Baltic, and Scandinavian countries, comon synonyms, and maufacturer codes.

The clinical profile is based on the full text of “Martindale: the complete drug reference” and describes the basis action and uses of the substance.

The WADA status indicates whether the substance is prohobited in or out of competition.

The WADA class gives an indication of the reason for the prohibition and gives more information about the range of substances covered in that class, plus any special circumstances. It is a great asset of the book that this is repeated with every substance, so you don’t need to go somewhere else to read all the information of the particular substances you are interested in. All the information is given right there where you need it.

A comprehensive index of over 15200 entries is to be found at the back of the book, and includes all names, synonyms, and proprietary (trade) names found in he tex. Even Cyrillic names are listed!

This is a great book for those of us who have been in the awkward situation where our athlete phones us, while away on a trip in Norway, Egypt or Russia, have gotten sick and are not sure of the medication the doctor has given him, and can only provide you, let’s say, the Russian trade name. What do you do?

The player is “strictly liable”, but is depending on you. And it is your name who will appear in the court case on internet for many years to go when you make a mistake. And there is no way you will find that Russian trade name on the WADA doping list!

So now there is a solution to all of these problems: Martindale’s Drugs Restricted in Sport Pocket Companion! The only thing missing is a short summary of the categories of the WADA list of prohibited substances and methods – it would be really helpful is that would be included at the front of the book as well.

Babette Pluim,
Sports physician

Hot Topic: Current Anti-Doping Policies

7 Aug, 08 | by Karim Khan

legs bjsm

A recent editorial by Babette Pluim entitled, “A doping sinner is not always a cheat” [excerpt below], has created some fiery discussion amongst BJSM editors and readers this month.

The doping rules these days are really tough. The basic principle is: first offense gets a 2 year ban, second offence a lifetime ban. Everyone seems to agree that doping is cheating, and those who cheat should be sanctioned, so if an athlete provides a positive sample in any sporting situation, the inference must be that they are cheating. Unfortunately, both for the athlete and the anti-doping system, that is not always the case.

Here is a selection of BJSM editors’ & readers’ reactions:

“Drug cheats – or are they?”
By Dr Tim Wood, Chief medical officer for the Australian Open Tennis Championship and a member of Tennis Australia’s Anti-Doping Review Board

With the formation of the World Anti-Doping Agency (WADA) and the universal harmonization in the fight against the drug cheats in the late 90s everyone applauded. What we didn’t realize at the time was how many ’innocent’ victims would be caught up in the new rules and regulations. I therefore applaud Dr Babette Pluim’s BJSM editorial which reviews the positive doping cases recorded by the International Tennis Federation from 2001-07. She found that the majority of so-called ‘positive’ tests are no more than innocent mistakes by players and officials alike. Nevertheless, the trauma suffered and the tainting of these players is irreversible.

Having been involved in professional tennis for the last 7 years, I also experience frustration at the paperwork required to allow player with genuine medical conditions to take legitimate, scientifically proven drugs that certainly do not enhance performance. The most recent ‘crazy redtape’ is the requirement for a full Therapeutic Use Exemption (TUE) to allow an athlete to have intravenous fluid during elective surgery (Babette has some stories about that!).

Fortunately, it would appear that sanity may be about to prevail on at least three fronts. First, abbreviated TUEs (ATUES for those in the know, even though it sounds like a sneeze) that are currently required for intra-articular cortisone injections will be changed to notification via ADAMS (WADA’s web-based anti-doping management system). Second, ATUEs for beta-2 agonists will be valid for four years instead of needing to be renewed annually but this will come with more stringent proof of the player’s asthmatic status. And finally, many of us hope that the intravenous rule will revert to the 2007 ruling ‘… except for genuine medical situations’.

Everyone involved in professional sport strongly supports WADA and their efforts to catch the cheats but the rules shouldn’t catch innocent athletes, particularly those with genuine medical conditions.

swimmer bjsm

“WADA is on the verge of losing the plot”
By John Orchard, Sports Physician

The idea to create the World Anti-Doping Agency (WADA) was a good one, particularly for international sports. It meant that rogue states like the USA, which had a track record of going soft on their own athletes who tested positive, could be forced to implement universal sanctions.

The big problem with WADA is that it is a monopoly. And it is being run increasingly like one, currently under the Presidency of our own ex-politician John Fahey. WADA’s aim should be to stamp out cheating in sport. This is quite difficult to do, as the cheats are usually very clever. WADA instead is trying to maximise scalps of athletes who “test positive for drugs”, without apparent concern for whether they are actually cheating. Instead of concentrating only on the genuinely performance-enhancing (and usually difficult-to-detect) drugs, the WADA banned list is ever-expanding. It now includes commonly used medications which are much easier to detect and “might conceivably” be used for performance-enhancing in rare circumstances. Whether these rare circumstances exist when an athlete tests positive don’t seem faze WADA, as there is a presumption of guilt rather than innocence.

Banned medications now include asthma puffers and cortisone injections, which are generally considered by doctors and scientists to not be performing-enhancing. Intravenous fluids, including those given for an anaesthetic as part of surgery, are now also banned as of 2008. The status quo is now the farcical situation that the vast majority of athletes are breaking the WADA code whenever they go in for elective surgery. In theory, the only thing stopping these athletes from being suspended is that drug testers aren’t (yet) following them into hospitals.

An editorial just published in the British Journal of Sports Medicine found that in the last 5 years of drug testing in tennis, it was accepted that 68% of the players who were banned for positive drug tests were not actually cheating. They were banned presumably because WADA wanted to increase their tally of convictions. They include cases such as known asthmatics taking puffers such as Ventolin for asthma attacks, but whose ‘permits’ to treat their asthma with appropriate medication had either recently expired or been faxed to the wrong number. In 2009, WADA has plans that asthmatics should apply to a panel to ‘prove’ they have asthma, or else they will be banned from sport for using their puffers. The Howard government basically held the funding gun to the head of all Australian sports in 2005 and forced them to sign up to WADA, despite many sports fearing the situation we are now in. This being that the universal drug code has become draconian and the sports have signed away all rights to do anything about it.

runner bjsm

“Accidental cheating?”
By Giuseppe Lippi, Associate Professor of Clinical Biochemistry, Università di Verona

In an overview of the 40 most recent cases of doping in tennis, Babette Pluim highlighted that in only 13 of the cases (32%) was a prohibited substance taken to enhance performance, whereas most frequently banned substances were taken with no intent to enhance performance or without (significant) fault or negligence.1

I definitely agree that products that are on the list of prohibited substances should be critically reviewed, but I also emphasize that the current anti-doping policy is essentially a costly, repressive, zero tolerance approach, which seems only partly successful.2 It is also to mention, however, that there may be additional explanations to justify adverse findings on antidoping testing, which have little to do with cheating.

The use of dietary supplements is commonplace in sports, most elite athletes using some form of licit supplementation to burst athletic performance and improve recovery after training or competition. Nevertheless, there is widespread evidence that some of these legitimate products, especially those sold on the “black market”, contain banned substances that are not claimed as a result of poor manufacturing practice or adulteration.

Contaminants mostly include anabolic androgenic steroids, hormones, ephedrine and caffeine.3,4 Indeed, in some cases the adverse findings might be the consequence of deliberate cheating. However, we should still consider the possibility that some positive tests might arise from unintentional consumption of prohibited substances, contaminating dietary supplements. In this respect, not only antidoping agencies should focus on products that are truly harmful and performance-enhancing, but they should also issue a clear regulation on the use of nutritional supplements and establish appropriate bans for inadvertent use of banned molecules. Doping is always to blame, especially when the athletes use illicit methodsor substances that might produce a serious risk for their health. However, as different sanctions are imposed when crimes are intentional or preterintentional, bans should also be clearly differentiated from deliberate and unintentional positivity to banned substances.

References

1. Pluim B. A doping sinner is not always a cheat. Br J Sports Med 2008;42:549-50.

2. Kayser B, Smith AC. Globalisation of anti-doping: the reverse side of the medal. BMJ 2008 Jul 4;337:a584. doi: 10.1136/bmj.a584.

3. Maughan RJ. Contamination of dietary supplements and positive drug tests in sport. J Sports Sci 2005;23:883-9.

4. Linksvan der Merwe PJ, Grobbelaar E. Unintentional doping through the use of contaminated nutritional supplements. S Afr Med J 2005;95:510- 1.

Combine Science & Exotic Travel in the High Arctic

31 Jul, 08 | by Karim Khan

high arctic expedition

Sometimes readers are looking to combine science with exotic travel, the 2009 Arctic Conference next June, will be hard to beat. Up close and personal with Paul Hodges and LJ Lee not to mention penguins, polar bears and giant Aleutian seals.

It will be a great trip and a great blend of the latest science and clinical application for lumbopelvic-pain and postpartum health. The conference program is listed on the website and it is for both physicians and physiotherapists.

Collegiate rugby union injury patterns

28 Jul, 08 | by Karim Khan

rugby world cup

BJSM eLetter from Henare R Broughton of Auckland Rugby referees’ Association.

The study presented by Hamish Kerr et al., Collegiate rugby union injury patterns in New England: A prospective cohort study, deserves comment. In a general sense the injury pattern may be attributed to the confrontational type of game that the players had been taught. The tackle features as the event with more injuries occurring as illustrated in the study. In this type of game the fact that T-boning occurs, that is, where the ball carrier runs directly towards an oncoming defender(s) the tackler(s) creates an opportunity for a front-on tackle where head/neck and shoulder injuries are a commonality for the tackler and lower limb injuries for the ball carrier.

Reference is made to ‘ball in play’ time of 42 percent in 2003 Rugby World Cup but at the Under 21 Rugby World Cup in 2006 this was 40 percent with an average of 134 rucks/game. These figures may suggest that most of the time more infringements were occurring and that there were more interaction instances between the ball carrier and the defenders. The authors however, suggest that U.S collegiate games may have lower ‘ball in play’ time and fewer rucks (Law 16) and tackles (Law 15) per game. Does less ‘ball in play’ time mean that there were more stoppages? More infringements occurring?

Nevertheless, the authors’ observations where there were fewer rucks in a game suggests that there may have been fewer tackles and a more open type of game was being played. Less tackle injuries could be expected if that were the case. The results from the data could have benefited from categorizing the injury data as relating to the defense injury pattern and the offensive injury pattern. Such an account would enhance the interpretations to be made of the data. This study provides an opportunity for relating injuries to how the game is played.A comparison with an open type of game may be worth an analysis.

Reference: The International Rugby Board. (2007). Laws of the game. Dublin: The International Rugby Board.

The full article can be found here.

Patient Info Sheet: Lateral Hip Pain

26 Jul, 08 | by Karim Khan

Another excellent patient information to download!

Patient Information Sheet 17 - Lateral hip pain

More patient information sheets can be found here.

Measuring exercise performance

26 Jul, 08 | by Karim Khan

Another response by Fergus J. Dignan to Noakes’ paper <em>How did A V Hill understand the VO2max and the “plateau phenomenon”? Still no clarity?

Click to view more reader responses to this article.

Dear Editor,

I very much enjoyed reading the Review article (1) by Professor Noakes and the letter (2) in the same edition of the BJSM July 2008.

As he rightly states measurement of VO2max has several limitations in determining an athlete’s potential. He also pointed out in the letter that research has shown that ‘the rating of perceived exertion (RPE) rises as a linear function of the duration of exercise that remains’, and extrapolation from this ‘that humans have an exquisite capacity to predict accurately the duration of exercise they will be able to sustain at any exercise intensity’.

Would it therefore not be possible to determine an athlete’s optimal running distance by getting them to run on a treadmill for 10 minutes and asking them to run as fast as possible for imagined
distances of 5k, 10k, 40k, etc?

1. NOAKES TD. Testing for maximum oxygen consumption has produced a brainless model of human exercise performance. Br J Sports Med 2008; 42:551-555

2. NOAKES TD. Rating of perceived exertion as a predictor of the duration of exercise that remains until exhaustion. Br J Sports Med 2008; 42:623-624

Travel fatigue and jet-lag are not synonyms

25 Jun, 08 | by Karim Khan

beijing airport

Dear Editor,

We were pleased to see the ‘original article’ by Milne and Shaw (2008) offering advice for those traveling to the Beijing Summer Olympics Games in August later this year in a professional or participatory capacity. The authors are to be complimented on their endeavours to accommodate a comprehensive range of environmental aspects that might influence health and performance. Their experiences in China in particular should be of interest to other groups, especially those hitherto unable to make reconnaissance visits to its competitive venues and training camps to experience and monitor the challenges to be faced.

Besides they are in good time to be of use for devising travel strategies and general advice to be circulated to all athletes selected to participate and their support staff.

There is one area that we would wish to comment on, the issue of travel fatigue and jet-lag. These problems will be worse for European, African and American athletes than for those from Australia and New Zealand in view of the difference in time-zone transitions. Furthermore, some of the advice about dealing with jet-lag should not be based on the previous report of Milne and Fuard (2007) in this journal. The interpretation of anecdotal information, on one individual, was flawed. It is easy to beat an opponent who does not exist and the conditions that provoke jet-lag may not have applied in the trip they described.

In the original report, a brief account was given about one subject who traveled between Europe and New Zealand and back within a few days.

The itinerary focused upon constituted a net zero time-zone transition by which time body-clock time and local time were resynchronised. The root cause of jet-lag is the desynchronisation that occurs between the endogenous circadian rhythm and local environmental time. Prior to undertaking the last trip before the critical final game, the athlete would not have been in France long enough to adjust to European time, is unlikely to have experienced anything more severe than mild jet-lag, even if travel fatigue was severe.

The authors made no attempt to measure jet-lag, either subjectively or by means of an appropriate biological marker. Jet-lag is likely to have been minimal by the time of the criterion match since there would have been limited adjustment before the last 12-hour time-zone transition and hence no need of a further re-adjustment. Besides, there was no valid measure of performance used. Evidence consists of an anecdotal comment that the player’s performance was up to its usual high standard (open skills) and that he kicked a conversion and three penalty kicks (closed skills). Finally, the cocktail of soporifics that were advocated are not recommended as a panacea for jet-lag in recent reviews (Waterhouse et al., 2007) or in consensus statements about alleviating jet-lag (Reilly et al., 2007a).

Lastly, the notes about travellers’ diarrhoea and on food are to be welcomed. Whilst the notes are necessarily brief, an appropriate further reference would be that of Reilly et al. (2007b). In this consensus, supported by the International Association of Athletics Federations, more detailed advice on food and nutrition is given, as is an account of other gastrointestinal problems that traveling athletes face.

By:
Reilly, Thomas; Atkinson, Greg; Edwards, Ben; Waterhouse, Jim
Chronobiology Research Group
Research Institute for Sport and Exercise Sciences
Liverpool John Moores University

References

Milne C. Fuard MH. Beating jet lag. Br J Sports Med 2007; 41: 401.

Milne CJ. Shaw MTM. Travelling to China for the Beijing 2008 Olympic Games. Br J Sports Med 2008; 42: 321-326.

Reilly T. Atkinson G. Edwards B. et al. Coping with jet lag: a Position Statement for the European College of Sport Science . Europ J Sport Sci 2007a; 7: 1-7.

Reilly T. Waterhouse J. Burke LM. Alonso JM. Nutrition for travel. J Sports Sci 2007b; 25: S125-134.

Waterhouse J. Reilly T. Atkinson G. Edwards B. Jet lag: trends and coping strategies. The Lancet; 2007; 369: 1117-1129.

Program for the International Concussion Congress in Zurich

15 Jun, 08 | by Karim Khan

Here is the latest information for Concussion III, the International Concussion Congress that is being held in Zurich, at the home of FIFA, on October 30, 2008.

Download a program here.

Tennis Elbow Handout

30 May, 08 | by Karim Khan

tennis_ball_bjsm

Another excellent patient handout.

Patient Information Sheet 8 - Tennis elbow

BJSM blog homepage

BJSM

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

BMJ Clinical Evidence updates