12 e-Letters

published between 2020 and 2023

  • Dr Lim Zhuang Li

    Many thanks for producing the thoroughly enjoyable article on SEM practitioners around the world. We would like to add that SEM in Malaysia has also been well established as a standalone speciality since 2002. The impetus for for kickstarting the speciality was having being appointed the host city for Commonwealth Games 1998 (Kuala Lumpur). Our training programme, was in effect a combined 4 year run-through standalone clinical training, in its inception together with Rehabilitation Medicine originally, of which very early then branched out into an independent Sports Medicine Masters training program in the early 2000s, with on average 4 to 6 trainees a year qualifying out of the program. At the moment, we have approximately nearly 60 practitioners throughout the broader Malaysia with a large number of my contemporaries working within the Ministry of Health Malaysia. Our core service focuses on optimising musculoskeletal health across all spectrum of age and health, performing diagnostic imaging and guided-pain interventional, therapeutic and regenerative procedures, sideline and team physician management, prescriptive exercise clinics and fitness/performance testing, and various collaborative work with public health in being an advocate for healthy living. The training program is indeed quite similar as to how the Australasian and British FSEM curriculum content-wise, and has been traditionally done at the University of Malaya throughout the whole clinical course. Many of...

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  • Two issues with this paper, one of which is a significant calculational error

    The systematic review by Paultre et al. supports the use of turmeric or curcumin extract for knee osteoarthritis pain.

    They did not perform a formal meta-analysis but summarize the results of individual studies by calculating effect sizes based on the data in the original papers. Unfortunately there are two problems with these, one major and the other more modest.

    The major issue is with the last study reported in table 3, Srivastava (2016). Paultre et al. report very large effect sizes for this study, such as 8.6, 9.5, and even 11 for a visual analogue scale. These effect sizes are the usual "d" value, that is the mean difference divided by the standard deviation. Effect sizes of such high magnitudes should raise a red flag that something is wrong, as they are rarely attained in clinical studies.

    The authors' impressive effect sizes for Srivastava are errors due to using a standard error of the mean (SE) as if it were a standard deviation (SD). Srivastava et al. define the statistic used in the statistical methods: "The results are presented as mean ± SE." The values shown are also impossibly small to be standard deviations, which is what caught my attention. Both at 60 days and 120 days, the "standard deviations" shown for a 10-point VAS scale are around 0.1. This suggests a range of responses of about 0.5, which is not plausible.

    The SEM is the SD divided by the square root of the sample size and represents...

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  • Available implementations

    An implementation of REDI as a dedicated R package is now available: https://grenouil.github.io/REDI/.
    A code-free web app is also provided to compute REDI directly on your datasets: https://arthurleroy.shinyapps.io/REDI/

  • Reply to editor and authors

    Dear editor/ dear authors,

    We read with interest your editorial ‘Sport and exercise medicine around the world: global challenges for a unique healthcare discipline’ [1] in BMJ Open Sport and Exercise Medicine. We would like to congratulate the authors for bringing the challenges of our speciality back into the spotlight again.

    While Sports and Exercise Medicine (SEM) may be a modern and more inclusive terminology than sports medicine, many of the challenges of our speciality have remained the same over the years. Societies such as the European College of Sports and Exercise Physicians (ECOSEP) have championed for years for the advancement of sports medicine/ SEM speciality across Europe by providing education, publishing research, organising congresses, collaborating with other organisations and serving as a source of information to the public [2–4]. ECOSEP has been promoting exercise for prevention and treatment to policy holders, creating post-graduate programmes and seminars to provide further training for physicians and bringing practitioners together, not only with biannual congress but also through promoting professional dialogue and standards [2–4]. Other societies, like the European Federation of Sports Medicine Associations (EFSMA) have been champing for a common sports medicine speciality within Europe for over 20 years, providing a detailed curriculum for sports medicine practitioners [5]. Even back then they recognised that sports medicine is a m...

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  • Response to “Important Nuances for Non-Linear Modeling”

    We thank Shrier et al. for a thoughtful expansion on the topic of non-linearity.1 The comments from the authors provide valuable insights and detail to both the handling and the interpretation of fractional polynomials and splines, and may interest readers who seek more information than the short introduction in Bache-Mathiesen, et al. 2.

    We are especially grateful for elaborating on the interpretation of restricted cubic splines, and the solution of adding a small constant (i.e. 0.1) to all values to handle the value “0” when using fractional polynomials. These topics could not be sufficiently addressed within the limited wordcount of the original article, and we encourage readers to consider these comments.

    Conflict of Interest:
    None declared.

    1. Shrier I, Wang C, Stokes T, et al. Important Nuances for Non-Linear Modeling. BMJ Open Sport & Exercise Medicine 2021
    2. Bache-Mathiesen LK, Andersen TE, Dalen-Lorentsen T, et al. Not straightforward: modelling non-linearity in training load and injury research. BMJ Open Sport & Exercise Medicine 2021;7(3):e001119. doi: 10.1136/bmjsem-2021-001119

  • Important Nuances for Non-Linear Modeling

    We would like to thank Bache-Matiesen et al.(1) for their thoughtful article on non-linear modelling in sport medicine. Our own study on the non-linear relationship between acute: chronic workload ratio (ACWR) and injury risk in children was published as a preprint (2) and recently accepted by the American Journal of Epidemiology.(3) Below, we highlight some additional underlying principles in non-linear modelling that readers should understand.

    Models are based on information, which includes both data and assumptions. Simple linear models are more prone to bias because they assume a data generating process that is likely incorrect. The flexibility of non-linear models leads to less risk of bias, but also less precision. The optimal choice between bias and uncertainty depends on the context.(4)

    Bache-Matiesen describe three non-linear modelling options: quadratic modelling, fractional polynomials (FP), and restricted cubic splines (RCS, where knots are determined by either data driven or a priori methods). These all fall under generalized additive models (GAMs), or generalized additive mixed models (GAMMs; if one uses “random effects” to adjust for repeated measures on participants).

    FP methods use a single polynomial function over the entire range of exposures to predict the outcome. Quadratic models are special cases of FP (with exponents of 0, 1 and 2) and are too restrictive to be generally recommended. RCS separate data i...

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  • Interesting study

    Thanks to the authors for providing some preliminary data on the potential effectiveness of bike-fitting to reduce pain and discomfort in cycling.
    Very interesting study, but probably some questions are worth comments from authors:
    1- Was there a proper ethics approval for this study? It seems that data was obtained retrospectively from clinical records.
    2- How transferable to training is 100W of cycling?
    3- Would authors be able to disclose the source of the 'measurement reference values'? Elaborating the criteria used for changes in bike-fit is critical to understand how and why cyclists improved their posture on the bike.

    It would have been nice to see a control group to determine how much of the perceived changes are from placebo-effect.

  • Response to Best test for diagnosing PEBSI

    Dear Dr Obedkova

    Thank you for your e-letter of 5th April 2021 regarding our publication ‘Diagnostic accuracy of MRI for identifying posterior element bone stress injury in athletes with low back pain: a systematic review and narrative synthesis. BMJ Open Sport & Exercise Medicine 2020;0:e000764. doi:10.1136/ bmjsem-2020-000764’. We welcome your comments and interest in this research as it further highlights the importance of evidence based safe and ethical practice. Our own interest and rationale for this review stems from extensive working with young adults and adolescents involved in elite sport with low back pain.

    We take on board your comments, although where good evidence to support one modality over another is lacking, the merits of different approaches concerning risk v benefit must be central to clinical decision making. In this instance, evidence based practice in the UK overwhelmingly supports the use of MRI as the first line investigation; recognising SPECT/CT involves ionising radiation, and that a safe alternative exists with MRI. When undertaken and interpreted correctly, MRI permits the sensitive detection of posterior element bone stress injury in the vast majority of cases and should therefore be used as the first line investigation. SPECT/CT should therefore be reserved for those small minority of cases where (following MRI) diagnostic doubt remains, where there are underlying complexities (such as previous same-level stress injuries)...

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  • Best test for diagnosing PEBSI.

    Dear colleagues, I have read with a great interest this systematic review “Esh R, Grødahl LHJ, Kerslake R, et al. Diagnostic accuracy of MRI for identifying posterior element bone stress injury in athletes with low back pain: a systematic review and narrative synthesis”[1] and would like to make some comments. Further research, as authors concluded, are always desired and I wish there are appropriate studies in the next future to decide if MRI could be a modality of choice for diagnosing PEBSI and not SPECT/CT as it is by now. But the referred articles from this review do not support this assertion for the following reasons.
    First, there are just 2 articles from 4 included in this review compared MRI and SPECT/CT and just in 1 of them (Juvenil spondilolysis: a comparative analysis of CT, SPECT and MRI) the results of both techniques were concordant, although the main causes of discrepancy were between MRI and SPECT/CT for diagnoses of stress reaction in absence of overt fracture and distinguishing incomplete fracture from intact pars of complete defects (22 patients and 40 pars defect) [2].
    Second, in the 2nd article the authors mention that sensitivity and specificity of MRI was 80 and 100% respectively skipping the SPECT/CT results and author’s conclusion that in the original article was following: “These results suggest that there is a high rate of active spondylolysis in active athletes with low back pain. MRI is inferior to bone scintigraphy (with SPECT)/c...

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  • A dog is not a standardised intervention

    Nice study, and great to see you including dog ownership in your COI statements! A plea from a veterinary surgeon interested in dog walking though: please collect and report data about the dogs. A dog isn't a standardised intervention like a Fitbit. Their exercise capacity and exercise desire will vary with breed, age, comorbidities, body condition score, behaviour yet no data about the dogs is included in this publication. In addition, research suggests that owning an ill or behaviourally problematic dog can be very stressful. These canine attributes may have introduced a level of unaccounted for heterogeneity into your intervention arm which may have confounded your results. I'd be happy to point any researchers in this field towards the relevant canine literature, or assist with dog aspects of a study design.