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...
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 us are also attached with the broader sporting teams across the country. We are presently actively engaging medical students during their undergraduate program to build the awareness of the speciality and services going forward. Collectively, SEM Malaysia are presently represented by the Malaysian Association of Sports Medicine (MASM) and we are currently working to create a collegiate under the Academy of Medicine Malaysia (AMM) to get better advocacy and visibility nationally and internationally.
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...
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 the accuracy of the sample mean, not the distribution of individual subject values. Effect sizes incorrectly calculated using the SEM will thus be inflated by a factor of the square root of the sample size. Correcting for this leaves several still large effects (near 1) but other effect sizes drop to below 0.5. None are over 2.
The modest issue is with the first study in the table, Panda. I don't see any actual errors, but the standard deviations on the VAS are smaller than is typical for a 100 point scale. I believe this is because an inclusion criterion for that study was, "VAS score during the most painful knee movement between 40-70mm." Restricting to a max of 70 for "most painful" is a significant restriction and results in rather small standard deviations for the VAS.
On a 100-point scale a mean difference of 10 is not a large effect clinically, but Paultre et al. show differences of 5 and 7 as "large" for the Panda study because of the small standard deviations. Not until day 60 is there a mean difference much bigger than 10 on the VAS.
I would be interested to see if the authors would modify their conclusions after addressing these issues.
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References (both are from the reviewed paper)
Srivastava S, Saksena AK, Khattri S, et al. Curcuma longa extract reduces inflammatory and oxidative stress biomarkers in osteoarthritis of knee: a four-month, double-blind, randomized, placebo-controlled trial. Inflammopharmacology 2016;24:377–88
Panda SK, Nirvanashetty S, Parachur VA, et al. A randomized, double blind, placebo controlled, parallel-group study to evaluate the safety and efficacy of Curene® versus placebo in reducing symptoms of knee oa. Biomed Res Int 2018;2018:1–8.
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...
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 multidisciplinary speciality dealing with health promotion for the general population by stimulating a physically active lifestyle as well as providing diagnoses, retreatment, prevention programmes and rehabilitation following injuries or illnesses sustained by participation in physical activities, exercises and sport at all levels [5]. So, while the terminology SEM may be new, the goals and challenges to the speciality have remained the same.
Another challenge is the common recognition of the speciality across countries; however, this has not even been achieved within Europe, even after years of negotiations with governments and stakeholder. In an open market such as the European Union it makes it challenging for health care professionals, working and traveling with sports teams across Europe as well as being disadvantaged in seeking job opportunitiesin the common market.
We believe adequate employment opportunities for SEM/ sports physicians are another important challenge to be addressed. Historically sports doctors did not receive payment for attending match days or overseeing competitions/ training camps and although this has changed in some countries, this type of work remains voluntary or poorly paid in other countries. Many big international sporting events such as Olympic Games, Athletic European or World Championship and others rely on SEMs as volunteers and while this may be interesting for some SEM to gain experience or for other reasons, we believe it is a practice that should also be addressed. Many SEMs have a portfolio career, e.g., combining working with a sports team, health prevention programmes, private practice, university etc., however employers/ institutions often do not recognise this working type of pattern and are reluctant or unwilling to adapt to modern ways of working.
We agree with your statements that ‘SEM should be more visible in the health-based undergraduate curricula’ [1], and we believe it should be taught by appropriately qualified staff with the necessary qualifications. In some countries, however it is still possible to hold a university chair/ professorship in SEM/ sports medicine without even having obtained the necessary country specific sports medicine qualification or specialised training. What message does this send for the promotion of our speciality?
While we understand that an editorial cannot address all the challenges of our speciality, we hope that some of our challenges maybe also be addressed in future consultations, and we wish the current ‘generation’ of SEMs more success in tackling those challenges compared to previous generations of sports physicians.
References
1 Carrard J, Morais Azevedo A, Gojanovic B, et al. Sport and exercise medicine around the world: global challenges for a unique healthcare discipline. BMJ Open Sport Exerc Med 2023;9:e001603. doi:10.1136/bmjsem-2023-001603
2 ECOSEP. 2023.https://ecosep.eu (accessed 4 May 2023).
3 Heron N, Malliaropoulos NG. International differences in sport medicine access and clinical management. Muscles Ligaments Tendons J 2012;2:248–52.
4 West L, Malliaropoulos N, De Jonge S. ECOSEP: bringing the European SEM family together. Br J Sports Med 2014;48:1585–1585. doi:10.1136/bjsports-2014-094167
5 Ergen E, Pigozzi F, Bachl N, et al. Sport medicine specialty training core curriculum for European countries. J Sports Med Phys Fitness 2008;48:419–33.
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.
References
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
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.
GENERAL CONCEPTS
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...
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.
GENERAL CONCEPTS
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 into sections by “knots”, determine which polynomials best predict the observed data within the sections defined by the knots, and apply a smoothing function to join the polynomials. The placement of the knots is important. In simulations, we know the true data generating process. In real-world observational data, we do not. Although we believe subjective a priori knot placement is sometimes better than data driven methods, researchers should be aware that gross errors may occur if the assumptions are incorrect.
RCS methods are more flexible than FP because they allow the functions between knots to be different from each other. We highlight two technical points. First, the “restriction” in the RCS method used by Bache-Matiesen appears restricted to using linear functions before the first knot and after the last knot. RCS can include other types of restrictions as well. Second, FP and RCS are just two forms of GAM(M)s. Two other popular forms are penalized regression spline and thin plate regression spline (e.g. default in mgcv package in the statistical program R (5)). The major difference between RCS and the penalized/thin plate regression splines is the shape of the polynomial that is used. The optimal choice depends partly on the research question and partly on the observed data.
SPECIFIC COMMENTS ON RECOMMENDATIONS BY BACHE-MATIESEN
1. Based on their simulations, Bache-Matiesen suggests RCS performs better than FP for predictive modeling. We believe the conclusion is too strong. RCS can be used in situations when there is a more complex underlying structure than FP. However, fitting more complex structure requires more data. When there is limited data and less complex structure, FP could outperform RCS.
2. Bache-Matiesen claim that RCS allowed the authors to model the relationship at high training loads where there were few data points. We caution against this due to the limited information. In our own study on children,(3) we restricted our conclusions about the relationship between acute:chronic workload ratio (ACWR) and injury risk to ACWR <3 where there were enough data. We show the full range of the relationship in the supplementary material to be fully transparent and to help generate hypotheses for future studies but did not feel it appropriate to make inferences.
3. We disagree with Bache-Matiesen that FP is more interpretable than RCS for causal effects, and that RCS results “can only be interpreted in the form of p values and visualisation”. First, we hope that most sport medicine researchers have moved beyond making inferences on p-values because of its severe limitations.(6, 7) Second, for causal questions, we generally estimate the difference in outcome when exposure is set to two different levels. When causal inference assumptions are reasonable, one estimates the causal effect with g-computation using predicted data from the model;(8) this is applicable for both linear and non-linear models. In brief, the magnitude of the causal effect in a non-linear model necessarily depends on the two chosen exposure levels. Although FP has only a single function over its entire range, the causal effect between the chosen exposure levels still requires using g-computation and the predicted values from the FP function. The causal effect using other GAM(M) methods is obtained with the same process; one uses the predicted values provided by the statistical software over the chosen exposure range.
4. The authors discuss the need to add a small constant to training load when it can equal 0, in order to allow for analyses on the log scale. The choice should have theoretical justification. For example, if activity (i.e. training load) is a proxy for time at risk (e.g. game injuries and a game was not played), adding a constant is inconsistent with the research question. However, in the ACWR, activity is a proxy for fatigue in the numerator and a proxy for fitness in the denominator. Both fatigue and fitness are affected by activities of daily living (e.g. occupation, transportation) outside of regular sports. In our analysis on children, we added a constant of 0.1 to activity to reflect our belief that activities of daily living might contribute 10% to each of fatigue and fitness. In supplementary analyses, we explored the effects if the contribution were 25% or 50%.
5. Finally, if we believe tripling the activity will triple the injury risk (e.g. 3 games vs 1 game), then activity (or ACWR) should be plotted on the log scale.(3)
REFERENCES
1. Bache-Mathiesen LK, Andersen TE, Dalen-Lorentsen T, et al. Not straightforward: modelling non-linearity in training load and injury research. BMJ Open Sport Exerc Med. 2021;7(3):e001119.
2. Wang C, Stokes T, Vargas JT, et al. Injury risk increases minimally over a large range of changes in activity level in children. arXiv. 2021;2010.02952v2 [q-bio.QM].
3. Wang C, Stokes T, Vargas JT, et al. Injury risk increases minimally over a large range of changes in activity level in children (In Press). Am J Epidemiol. 2021.
4. Kaufman JS. Commentary: Why are we biased against bias? Int J Epidemiol. 2008;37(3):624-626.
5. Wood S. mgcv. In: R: A language and environment for statistical computing R Foundation for Statistical Computing Vienna, Austria; 2021.
6. Amrhein V, Greenland S, McShane B. Scientists rise up against statistical significance. Nature. 2019;567(7748):305-307.
7. Wasserstein RL, Lazar NA. The ASA statement on p-values: context, process, and purpose. Am Stat. 2019;70(2):129-133.
8. Hernán MA, Robins JM. Causal inference: What if. Boca Raton: Chapman & Hall/CRC, 2020.
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.
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)...
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) or when the stakes are unusually high and uncertainty persists (such as in some professional athletes). Moreover, young elite athletes may need repeated imaging for lumbar stress injuries, further supporting the use of MRI over SPECT/CT and repeated exposure to ionising radiation.
We readily acknowledge that radiation doses from SPECT/CT have decreased in recent years, however this does not compare with ‘zero’ exposure for MRI. To continue to endorse SPECT/CT as a routine first line investigation condemns a cohort of predominantly young individuals to unnecessary exposure to ionising radiation, something that basic principles of radiation protection advocate against.
Thank you again for your interest and points raised to allow us to respond.
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...
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)/computed tomography. Bone scintigraphy (with SPECT) should remain the first-line investigation of active athletes with low back pain followed by limited computed tomography if bone scintigraphy is positive” [3], 39 subjects and 50 pars interarticularis were included. The authors of the review make the opposite conclusion, that there were no false negative results of MRI, but false positive results of SPECT/CT due to SPECT´s high sensitivity of ongoing bone turnover activity and lacked classification system for SPECT.
Regarding to metabolic bone turnover activity I would like kindly remind a metabolism of 99mTc-diphosphonates, which is used for scintigraphy. The incorporation of diphosphonates is carried out in the hydroxyapatite crystals, in such a way that the degree of uptake will be proportional to the presence of those crystals, which, will be proportional to the osteoblastic activity and, therefore, to the metabolic turnover bone activity. The metabolism cannot be deceived, if it is increased focally or diffusely, there are more crystals that will bind with more diphosphonates in the exact localization [4].
Third, the authors mention that there is no established grading system defining SPECT abnormality in lumbar spine. System which normally used in Nuclear Medicine for defining an uptake in scintigraphy with/without SPECT is a semi-quantitative scale or a color scale of ROI (region of interest) lesion. Also nowadays quantitative SPECT has been commercially available for several years [5].
Forth, the authors mention possible false positive results of SPECT/TC, saying that scintigraphy uptake occurs frequently in athletes (34-45.2%) in non-painful sites, making a conclusion that such false positive cases are commonly regarded as adaptive changes and are perceived normal, giving as a link an article “Assessment o a clinical significance of asymptomatic lower extremity uptake abnormality in Young Athletes” [6]. Skipping the fact that in this study was used planar scintigraphy of lower extremities and not SPECT/CT of spine, there is a huge difference between false positive and asymptomatic abnormality, which can be translate into some irrelevant for treatment or following but present detection, and this is really frequent in athletes, that’s why it is not recommended to make scintigraphy in the absence of pain [6]. As you can check the images of this article, there are uptakes which are not considered as false positives, the authors are discussing its origin and relevance, but not calling in question the fact of the uptakes.
And the last, the risk of cancer development using nuclear medicine techniques is very low, even if the authors mention that “The effective dose from a single course of X-ray and SPECT-CT scans is 10X more, than what UK dwellings get in a year from natural background radiation exposure”. I can suppose that the authors took an effective dose of ionizing radiation 1mSv per year for UK dwelling and compared with approximately 10mSv received from SPECT/CT. There are epidemiological studies on populations exposed to radiation, such as atomic bomb survivors or radiotherapy patients, showed a significant increase of cancer risk at doses above 100 mSv [7] and despite intensive study, evidence to prove an increased cancer risk associated with radiation doses below ~100 mSv is lacking; however, concerns about ionizing radiation in medical imaging remain and can affect patient care [8]. Also nowadays it is used a lower dose CT protocols when performing SPECT-CT, permitting a reduction in the mean effective dose to 1.8 mSv from 4.0 mSv without a loss of CT image quality [9]. As an effective dose of an adult bone scintigraphy is between 2.9-4mSv [10], so the final effective dose of SPECT/CT is much lower than considered as risky for human health.
As a conclusion, with the analysed studies of this systematic review we can make a conclusion, that SPECT/CT has better sensitivity (100%), than MRI (80%) in 1 study [3], which means a loss of the fifth part of pathology, not detected by MRI and concordant results in the other article [2]. The SPECT/CT is still a technique of choice in patients with PEBSI without neurological symptoms. In the absence of risk, it would be preferably to use more sensible technique, although further research is desired to find out the best test for diagnosing PEBSI.
1) 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. BMJ Open Sport & Exercise Medicine 2020;0:e000764. doi:10.1136/ bmjsem-2020-000764
2) Campbell et al. Juvenil spondilolysis: a comparative analysis of CT, SPECT and MRI. Skeletal Radiology volume 34, pages63–73(2005) https://link.springer.com/article/10.1007/s00256-004-0878-3
3) Masci et al. 2005. Use of the one-legged hyperextension test and magnetic resonance imaging in the diagnosis of active spondylolysis. Br J Sports Med 2006; 40:940–946. doi: 10.1136/bjsm.2006.030023 https://www.researchgate.net/publication/6812831_Use_of_the_one-legged_h...
4) Yuda, H., Wakao, H. 99mTc-MDP accumulation mechanisms in bone: Basic study on the adsorption onto hydroxyapatite. Oral Radiol. 12, 27–32 (1996) https://link.springer.com/article/10.1007/BF02351579
5) Kangasmaa, T.S., Constable, C. & Sohlberg, A.O. Quantitative bone SPECT/CT reconstruction utilizing anatomical information. EJNMMI Phys 8, 2 (2021). https://doi.org/10.1186/s40658-020-00348-1
6) Laura A. Drubach, Leonard P. Connolly, Pierre A. D’Hemecourt and S. Ted Treves. Assessment of the Clinical Significance of Asymptomatic Lower Extremity Uptake Abnormality in Young Athletes Journal of Nuclear Medicine February 2001, 42 (2) 209-212. https://jnm.snmjournals.org/content/42/2/209
7) https://www.who.int/news-room/fact-sheets/detail/ionizing-radiation-heal...
8) Ferrero A. et al. Understanding, justifying, and optimizing radiation exposure for CT imaging in nephrourology. Nature reviews. Urology, 01 Apr 2019, 16(4):231-244 https://scite.ai/reports/10.1038/s41585-019-0148-8
9) Sandeep Kumar Gupta et al. Radionuclide bone scan SPECT-CT: lowering the dose of CT significantly reduces radiation dose without impacting CT image quality. Am J Nucl Med Mol Imaging 2017;7(2):63-73 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5435612/pdf/ajnmmi0007-0063...
10) The EANM practice guidelines for bone scintigraphy. T. Van den Wyngaert, K. Strobel, W. U. Kampen, T. Kuwert, W. van der Bruggen, H. K. Mohan, G. Gnanasegaran, R. Delgado-Bolton, W. A. Weber, M. Beheshti, W. Langsteger, F. Giammarile, F. M. Mottaghy, F. Paycha, On behalf of the EANM Bone & Joint Committee and the Oncology Committee. Eur J Nucl Med Mol Imaging. 2016; 43: 1723–1738. Published online 2016 Jun 4. doi: 10.1007/s00259-016-3415-4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4932135/pdf/259_2016_Articl...
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.
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...
Show MoreThe 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...
Show MoreAn 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/
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...
Show MoreWe 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.
References
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
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.
GENERAL CONCEPTS
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...
Show MoreThanks 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.
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)...
Show MoreDear 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.
Show MoreFirst, 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...
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.
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