Reply to: ‘Comment on: Isometric exercise versus high-intensity interval training for the management of blood pressure: a systematic review and meta-analysis by Edwards et al.’ by Wewege et al.
Edwards, J.J., Wiles, J.D., & O’Driscoll, J.M.
School of Psychology and Life Sciences, Canterbury Christ Church University, Kent, CT1 1QU
Correspondence to Dr Jamie O’Driscoll, School of Psychology and Life Sciences, Canterbury Christ Church University, North Holmes Road, Canterbury, Kent, CT1 1 QU. Email: jamie.odriscoll@canterbury.ac.uk; Telephone: 01227922711.
We thank Wewege et al. (1) for their assessment and comments on our recent work (2), highlighting their concerns over the employed statistical analysis approach, which they suggest may “invalidate the results”.
We take these comments seriously and have therefore re-performed the analysis as suggested by Wewege et al. (1) and individually addressed the points raised within this rapid response.
Wegewe et al. (1) state that the marked differences found in our study “contrast previous findings”, with reference to a previous large-scale network meta-analysis by Naci et al. (3). As detailed, Naci et al. (3) did not include high intensity interval training (HIIT), and the lower blood pressure (BP) changes observed can be attributed to a combination of differences to the present study, including a smaller pool of lower quality iso...
Reply to: ‘Comment on: Isometric exercise versus high-intensity interval training for the management of blood pressure: a systematic review and meta-analysis by Edwards et al.’ by Wewege et al.
Edwards, J.J., Wiles, J.D., & O’Driscoll, J.M.
School of Psychology and Life Sciences, Canterbury Christ Church University, Kent, CT1 1QU
Correspondence to Dr Jamie O’Driscoll, School of Psychology and Life Sciences, Canterbury Christ Church University, North Holmes Road, Canterbury, Kent, CT1 1 QU. Email: jamie.odriscoll@canterbury.ac.uk; Telephone: 01227922711.
We thank Wewege et al. (1) for their assessment and comments on our recent work (2), highlighting their concerns over the employed statistical analysis approach, which they suggest may “invalidate the results”.
We take these comments seriously and have therefore re-performed the analysis as suggested by Wewege et al. (1) and individually addressed the points raised within this rapid response.
Wegewe et al. (1) state that the marked differences found in our study “contrast previous findings”, with reference to a previous large-scale network meta-analysis by Naci et al. (3). As detailed, Naci et al. (3) did not include high intensity interval training (HIIT), and the lower blood pressure (BP) changes observed can be attributed to a combination of differences to the present study, including a smaller pool of lower quality isometric exercise training (IET) trials. Specifically, our analysis includes 8 trials that would not have been published at the time Naci et al. (3) performed their systematic search and we contrarily ensured the omission of older trials that did not meet today’s standards of methodological rigour. We would also strongly recommend a full exploration of the supplementary file of Naci et al. (3) (appendix 8) which clearly supports the comparative efficacy of IET.
The next concern raised by Wegewe et al. states that: “None of the included trials in this review appear to contain both isometric and HIIT interventions; therefore, the authors are unable to ‘directly compare’ the interventions”. As the authors (1) are probably aware, there is currently no direct randomised control trial data on the effects of IET versus HIIT. Consequently, the only available statistical approach to meta-analysing the current data is via indirect means, as performed in the present study. We agree that our wording within the first paragraph of the discussion, where we refer to “directly comparing” these modes, should not be interpreted in an analytical context but rather this statement was made in consideration of the relevant limitations of the wider literature. In hindsight, we agree that this could have been overtly explained for those not fully conversant with the current literature.
The primary concern raised by Wegewe et al. (1) questions whether the chosen statistical approach is “correct”, citing the potential of being misleading and prone to bias. We agree that there are limitations of this method of analysis; however, to label the employed statistical approach as “incorrect” is far too simplistic and implies that the process of this type of analysis selection can only be viewed in terms of black-and-white. There are advantages and limitations to all employed statistical analyses and the decision for employing the current method was informed based on the available data. As stated by Wegewe et al. (1), many of the HIIT studies (6 to be exact) did not utilise a non-intervention control group, but instead included a moderate-intensity training group. Thus, to follow the statistical method advised by Wegewe et al. (1) would mean the omission of 6 effects sizes from the final HIIT analysis, which would carry its own bias implications. However, to remove any doubt regarding the validity of our published findings, we have performed the alternative method of analysis as recommended by Wegewe et al. (1), following a between-group random-effects (exercise versus non-intervention control only) analysis. The results are as follows:
As such, following the statistical technique proposed by Wegewe et al. (1), IET still produces statistically and clinically significant reductions in BP compared to HIIT. Importantly, regardless of whether our original, or their proposed statistical approach is employed, the primary results do not meaningfully change. Thus, any concern presented by Wegewe et al. (1) regarding changes in exercise guideline recommendations for the incorporation of IET for the management of BP can now be removed.
References
1 Wewege MA, Hansford HJ, Jones MD. Comment on: ‘Isometric exercise versus high-intensity interval training for the management of blood pressure: a systematic review and meta-analysis’ by Edwards et al. Br J Sports Med Published Online First: 2022. https://bjsm.bmj.com/content/56/9/506.responses#comment-on-‘isometric-exercise-versus-high-intensity-interval-training-for-the-management-of-blood-pressure-a-systematic-review-and-meta-analysis’-by-edwards-et-al
2 Edwards J, Caux A De, Donaldson J, et al. Isometric exercise versus high-intensity interval training for the management of blood pressure: a systematic review and meta-analysis. Br J Sports Med 2021;:bjsports-2021-104642. doi:10.1136/BJSPORTS-2021-104642
3 Naci H, Salcher-Konrad M, Dias S, et al. How does exercise treatment compare with antihypertensive medications? A network meta-analysis of 391 randomised controlled trials assessing exercise and medication effects on systolic blood pressure. Br. J. Sports Med. 2019;53:859–69. doi:10.1136/bjsports-2018-099921
As a general practitioner and specialist in the musculoskeletal system, I have read the article
“Small Steps, strong shield: directly measured moderate physical activity in 65361 adults is associated with significant protective affects from severe COVID-19 outcomes” from Steenkamp et al with great interest. The covid epidemic has put a huge burden of disease on the entire world and is weighing heavily on the capacity of healthcare. More and more is known about risk and protective factors for individuals to become severely ill from COVID-19 and this study contributes to this. In addition, prevention of disease is becoming an increasingly important task of health care, partly in order to curb rising healthcare costs.(1) Good physical condition can help prevent certain diseases as mentioned in the article.
The authors have collected a large dataset from a very large group of people in South Africa. What is missing in the analysis, however, is data on BMI. Studies show that BMI is an important risk factor for severe course of COVID-19. A high BMI, or adiposity, is one of the strongest reported risk factors for severe COVID-19. (2). In this study, the BMI was available in only 50% of the study population. Authors claim that when adding BMI to the model it did not alter the outcome for severe COVID-19 disease for the different physical activity groups. The authors attribute this to associated diseases such as hypertension and DM2, however researc...
As a general practitioner and specialist in the musculoskeletal system, I have read the article
“Small Steps, strong shield: directly measured moderate physical activity in 65361 adults is associated with significant protective affects from severe COVID-19 outcomes” from Steenkamp et al with great interest. The covid epidemic has put a huge burden of disease on the entire world and is weighing heavily on the capacity of healthcare. More and more is known about risk and protective factors for individuals to become severely ill from COVID-19 and this study contributes to this. In addition, prevention of disease is becoming an increasingly important task of health care, partly in order to curb rising healthcare costs.(1) Good physical condition can help prevent certain diseases as mentioned in the article.
The authors have collected a large dataset from a very large group of people in South Africa. What is missing in the analysis, however, is data on BMI. Studies show that BMI is an important risk factor for severe course of COVID-19. A high BMI, or adiposity, is one of the strongest reported risk factors for severe COVID-19. (2). In this study, the BMI was available in only 50% of the study population. Authors claim that when adding BMI to the model it did not alter the outcome for severe COVID-19 disease for the different physical activity groups. The authors attribute this to associated diseases such as hypertension and DM2, however research suggests that adipocytes and adipocyte-like cells likely play a major role. (2) If you consider this collinearity between x and x, then why did the authors choose to analyze hypertension and DM2 and not BMI? It is an omission not to share the BMI data, for example the mean and distribution in de different physical activity groups. It is likely that the people with a high physical activity level have a lower BMI and that this explains the difference in the course of covid infection.
The study reports on the physical activity patterns/levels that patients had for 3 months in the 2 years before the start of the COVID pandemic. It is very likely that the degree of exercise has changed during the pandemic and lockdown, therefor data on 2 years prior to the exposure to COVID-19 cannot automatically be translated to the physical activity directly before the exposure. It is known that training effect on -among others- VO2 max (stroke volume and oxygen extraction; physical capacity) have almost completely worn off after approximately 5 weeks after stopping training. (3,4). It would have been interesting to see report on the physical activity shortly prior to infection with COVID-19 and during the lockdown and what effect this had on the severity of COVID-19 illness.
The study shows that a medical history of HIV positive and rheumatic arthritis has a protective effect. Authors conclude that the disease generates that effect. However, there is no data on medication use available in the study. Virus inhibitors and immunosuppressants are used specifically in these groups of patients. Research shows that these drugs can have a beneficial effect on the course of COVID-19. (5)
In conclusion, the analysis Steenberg et al made, is a small step towards more knowledge about the preventive possibilities of physical activities, however the conclusions drawn for a strong shield is likely based on the wrong interpretation of associated diseases and protective factors.
Dear editor,
I read with great appreciation the study “Exercise prehabilitation during neoadjuvant chemotherapy may enhance tumour regression in oesophageal cancer: results from a prospective non-randomised trial” [1]. The authors aimed to evaluate the clinical impact of a structured exercise intervention in patients with operable oesophageal cancer during Neoadjuvant chemotherapy compared with those on a standard treatment pathway (p. 1); and for that, they carried out a prospective non-randomised trial. The paper has an elegant rationale and I am sure that will generate new research, however, exist some methodological fragile that may compromise the results.
1st, as this study specifically assessed the impact of exercise on measures of chemotherapy response (p. 1), the exercise program should be clearly described (e.g., exercise volume, time under tension, duration, cadence and range of motion, heart and respiratory rate). 2nd, the authors established moderate intensity for exercise, based on WHO recommendations for physical activity level (p. 2), however, physical activity is different of physical exercise; besides, they did not use the repetition-maximum [2] test to assess the strength of the patients and plan the intensity individually.
3rd, the authors added aerobic exercise (p. 2) to the structured program, but it was unclear how patients were assessed for this intervention (what velocity? Incline? Heart rate? Vo2?). 4th, the strategy for sample...
Dear editor,
I read with great appreciation the study “Exercise prehabilitation during neoadjuvant chemotherapy may enhance tumour regression in oesophageal cancer: results from a prospective non-randomised trial” [1]. The authors aimed to evaluate the clinical impact of a structured exercise intervention in patients with operable oesophageal cancer during Neoadjuvant chemotherapy compared with those on a standard treatment pathway (p. 1); and for that, they carried out a prospective non-randomised trial. The paper has an elegant rationale and I am sure that will generate new research, however, exist some methodological fragile that may compromise the results.
1st, as this study specifically assessed the impact of exercise on measures of chemotherapy response (p. 1), the exercise program should be clearly described (e.g., exercise volume, time under tension, duration, cadence and range of motion, heart and respiratory rate). 2nd, the authors established moderate intensity for exercise, based on WHO recommendations for physical activity level (p. 2), however, physical activity is different of physical exercise; besides, they did not use the repetition-maximum [2] test to assess the strength of the patients and plan the intensity individually.
3rd, the authors added aerobic exercise (p. 2) to the structured program, but it was unclear how patients were assessed for this intervention (what velocity? Incline? Heart rate? Vo2?). 4th, the strategy for sample calculation is not enlightening (p. 3), impossible assessment of sampling errors; the results of this study are relevant, but we need a detailed sample calculation to evaluate statistical power (exist also no citation on the statistics of the study).
5th, the Minimal Clinically Important Difference (MCID) is omitted in the comparisons (what do the comparisons mean without the MCID?). 6th, intergroup comparisons should be evaluated through performed using the linear mixed models [3]. The results are relevant a lot! But do these outcomes present themselves in the same way through the linear mixed models?
References
1. Zylstra J, Whyte GP, Beckmann K, Pate J, Santaolalla A, Gervais-Andre L, et al. Exercise prehabilitation during neoadjuvant chemotherapy may enhance tumour regression in oesophageal cancer: results from a prospective non-randomised trial. Br J Sports Med. 2022;56(7):402-409. doi:10.1136/bjsports-2021-104243
2. ACSM. American College of Sports Medicine. American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Med Sci Sports Exerc. 2009;41(3):687-708. doi:10.1249/MSS.0b013e3181915670
3. Casals M, Girabent-Farrés M, Carrasco JL. Methodological quality and reporting of generalized linear mixed models in clinical medicine (2000-2012): A systematic review. PLoS One. 2014;9(11):1-10. doi:10.1371/journal.pone.0112653
Dear editor,
On behalf of the PTED study group, we would like to thank the authors for the rapid response on our recently published paper “Cost-effectiveness of Full Endoscopic versus Open Discectomy for Sciatica [1]. The authors mention that they don’t agree with the conclusion of this study and have several comments. Below we will respond to these comments.
Firstly, the authors suggest that “another study design is needed to investigate cost-effectiveness of PTED above conventional microdiscectomy.” We strongly disagree. The study design was an economic evaluation alongside a pragmatic randomized controlled trial examining the cost-effectiveness of full-endoscopic versus open discectomy for sciatica. An economic evaluation alongside a pragmatic randomised controlled trial is considered an adequate design, because it provides timely information on an intervention’s cost-effectiveness with high internal and sufficient external validity [2]. Furthermore, the study design was peer reviewed by the grant agency (ZONMW in the Netherlands) and we have pre-published our study protocol in an open access, peer reviewed journal [3], supported in a covenant agreement including the Dutch Neurosurgical Society (NVvN), Dutch Orthopedical Society (NOV), Dutch Spine Society and the Dutch Association for patients with low back pain (NVVR).
Secondly, the authors comment that “costs associated with endoscope equipment and disposables were not included in their cost measur...
Dear editor,
On behalf of the PTED study group, we would like to thank the authors for the rapid response on our recently published paper “Cost-effectiveness of Full Endoscopic versus Open Discectomy for Sciatica [1]. The authors mention that they don’t agree with the conclusion of this study and have several comments. Below we will respond to these comments.
Firstly, the authors suggest that “another study design is needed to investigate cost-effectiveness of PTED above conventional microdiscectomy.” We strongly disagree. The study design was an economic evaluation alongside a pragmatic randomized controlled trial examining the cost-effectiveness of full-endoscopic versus open discectomy for sciatica. An economic evaluation alongside a pragmatic randomised controlled trial is considered an adequate design, because it provides timely information on an intervention’s cost-effectiveness with high internal and sufficient external validity [2]. Furthermore, the study design was peer reviewed by the grant agency (ZONMW in the Netherlands) and we have pre-published our study protocol in an open access, peer reviewed journal [3], supported in a covenant agreement including the Dutch Neurosurgical Society (NVvN), Dutch Orthopedical Society (NOV), Dutch Spine Society and the Dutch Association for patients with low back pain (NVVR).
Secondly, the authors comment that “costs associated with endoscope equipment and disposables were not included in their cost measurements. The direct costs only included time of the operating room, costs of medications and overnight hospital stay.” This is not entirely correct. In the article we wrote “Costs of the interventions include the time of the operating room used, the costs of the medications used during the surgery and for open microdiscectomy also the cost for one overnight hospital stay.” We didn’t state ‘only’. The PTED and OM prices were based on the corresponding so-called Diagnosis- Treatment Combinations (DBC) prices that are being used in the Netherlands. The cost associated with endoscope equipment and disposables are included, as DBCs include all costs related to the procedure (i.e. the whole package). [Note: In the Dutch health care system, treatment costs and related hospital reimbursement encompass a fixed price for each patient, defined as DBC. However, these reimbursements can differ between hospitals depending on the agreement with the health insurer.] As the PTED price was not set in stone yet, because it was not yet included in the Netherlands public health system, we also conducted sensitivity analyses in which two scenarios of PTED intervention costs were considered. In the high-cost scenario, the cost of PTED was €5000/patient, that is, €500 more than in the main analysis. In the low-cost scenario, the cost of PTED and open microdiscectomy were equal, that is, €4095 per patient. In both sensitivity analyses, the result is that PTED is dominant compared with OM. This shows that the findings are robust and hence not influenced by surgical costs but more based on productivity-related costs.
Thirdly, the authors state that for adequate comparison of costs, it should have been better when both groups had the same postoperative strategy, either both treatments in daycare, or both treatments with overnight stay. This study was funded by ZONMW’s program Healthcare Efficiency in which new interventions are typically compared with usual care. When we started this study, the most commonly used surgical technique in the Netherlands for this population was open microdiscectomy with mostly one night at the hospital. This was acknowledged by peer review. During the last couple of years more clinics/surgeons have started offering open microdiscectomy and consequently a relevant question for future research might be whether PTED is cost-effective compared with ‘daycare’ open microdiscectomy. However, the cost of one day of hospitalization in the Netherlands is approximately euro 500. We conducted a sensitivity analysis in which the cost of PTED was increased with euro 500, which is similar to one day of hospitalization. So, even if both PTED and open microdiscectomy would be associated with one day of hospitalization, the results and conclusion would be the same.
Fourthly, the authors state that the study “ultimately did not reach the initial sample size of 682 patients.” This is right and we have discussed this in the effectiveness paper in BMJ [4]. The pre-estimated sample size of 682 patients was not reached. Of the 382 patients calculated to be necessary in the final sample size of the trial (i.e., excluding learning curve cases), we were able to include 179 instead of 191 of the patients who would undergo PTED. We argue that it is unlikely that the results would have been different with 682 instead of the 613 patients that were finally included. It may have resulted in a more precise effect estimate (slightly smaller confidence interval), but not in a clinically relevant change in the effect estimate itself. The sensitivity analysis including the learning curve (N= 613) confirms the robustness of our findings.
Fifthly, the authors state that “long-term outcome data is needed to determine whether treatment with PTED will have the same revision rate as standard microdiscectomy.” We agree that long-term data are needed and therefore we have extended the follow-up of our trial to 5 years. We will analyze and publish these data once they are available.
In summary, we don’t agree with the authors of the letter who stated that they don’t agree with the conclusion of this study. The methods are state-of-the art, the results are robust, and the conclusion of this large study reflects the results. The results of our study suggest that PTED can be considered as a cost-effective alternative to open microdiscectomy in treating sciatica.
References
1 Gadjradj PS, Broulikova HM, van Dongen JM, et al. Cost-effectiveness of full endoscopic versus open discectomy for sciatica. Br J Sports Med 2022;:bjsports-2021-104808. doi:10.1136/BJSPORTS-2021-104808
2 Ramsey SD, Willke RJ, Glick H, et al. Cost-Effectiveness Analysis Alongside Clinical Trials II—An ISPOR Good Research Practices Task Force Report. Value Heal 2015;18:161–72. doi:10.1016/J.JVAL.2015.02.001
3 Seiger A, Gadjradj PS, Harhangi BS, et al. PTED study: Design of a non-inferiority, randomised controlled trial to compare the effectiveness and cost-effectiveness of percutaneous transforaminal endoscopic discectomy (PTED) versus open microdiscectomy for patients with a symptomatic lumbar disc he. BMJ Open Published Online First: 2017. doi:10.1136/bmjopen-2017-018230
4 Gadjradj PS, Rubinstein SM, Peul WC, et al. Full endoscopic versus open discectomy for sciatica: randomised controlled non-inferiority trial. BMJ 2022;376:e065846. doi:10.1136/bmj-2021-065846
We read with great interest the article by Gronwald et al. that investigated the injury inciting events of moderate and severe acute hamstring injuries in professional male football (soccer) players with systematic video analysis.1 Despite the pain-taking reviewing of videos and motion analyses by the authors, there are still some practical concerns over injury severity and subject recruitment.
Taking into account the importance of injury severity assessment that served as the basis for study subject enrollment in that study, the use of time loss to represent the severity of injury may not be optimal when considering other factors that may contribute to a prolonged rest after injury. For instance, pre-existing hamstring conditions including hamstring strings, proximal hamstring tendinopathy, or referred posterior thigh pain are not uncommon among soccer players.2 Following this argument, the recruitment of study subjects based on club or physician registration without meeting more objective criteria and without excluding those with previous hamstring injuries through a medical record review may introduce bias regarding the determination of injury severity. In this aspect, magnetic resonance imaging (MRI), which was available in 87% (45 out of 52 cases for pattern hamstring injury categorisation), may be a more reliable tool for evaluation because of its ability to show the extent of injury and the reported correlation between the size of injury a...
We read with great interest the article by Gronwald et al. that investigated the injury inciting events of moderate and severe acute hamstring injuries in professional male football (soccer) players with systematic video analysis.1 Despite the pain-taking reviewing of videos and motion analyses by the authors, there are still some practical concerns over injury severity and subject recruitment.
Taking into account the importance of injury severity assessment that served as the basis for study subject enrollment in that study, the use of time loss to represent the severity of injury may not be optimal when considering other factors that may contribute to a prolonged rest after injury. For instance, pre-existing hamstring conditions including hamstring strings, proximal hamstring tendinopathy, or referred posterior thigh pain are not uncommon among soccer players.2 Following this argument, the recruitment of study subjects based on club or physician registration without meeting more objective criteria and without excluding those with previous hamstring injuries through a medical record review may introduce bias regarding the determination of injury severity. In this aspect, magnetic resonance imaging (MRI), which was available in 87% (45 out of 52 cases for pattern hamstring injury categorisation), may be a more reliable tool for evaluation because of its ability to show the extent of injury and the reported correlation between the size of injury and the time lost from sport.3 Besides, the readers would benefit from knowledge of the severity of injury based on MRI, including grading (i.e., Grade 1–3) as well as the presence (or absence) of more serious conditions such as hamstring tendon avulsions or ischial apophyseal avulsions, which was not mentioned in the study.
References
1. Gronwald T, Klein C, Hoenig T, Pietzonka M, Bloch H, Edouard P, et al. Hamstring injury patterns in professional male football (soccer): a systematic video analysis of 52 cases. Br J Sports Med 2022;56(3):165-71.
2. Sherry MA, Johnston TS, Heiderscheit BC. Rehabilitation of acute hamstring strain injuries. Clin Sports Med 2015;34(2):263-84.
3. Slavotinek JP, Verrall GM, Fon GT. Hamstring injury in athletes: using MR imaging measurements to compare extent of muscle injury with amount of time lost from competition. AJR Am J Roentgenol 2002;179(6):1621-8.
I would like to commend the authors on highlighting the risk factors for concussion in Rugby Football Union. This type of research is essential for current and future guidance and therefore to be referenced it must be of the highest academic standard.
Don Gatherer and David Hamilton have published several papers on cervical assessment in rugby and have huge experience in the biomechanical function, action, rehabilitation, and measurement of the cervical spine especially at International Rugby Football Union level.
It is with regret that we are writing to express our great concerns regarding the recent study published in BJSM in particular the prudence of the Testing Protocols and how the findings may be misleading and the results mis-interpreted.
There are a number of methodological issues with this study which will have contributed to the misinterpretation of their results and subsequent conclusions.
The scientific methodology construct of isometric testing of the Head, Neck, and Upper Shoulder Girdle (HNS) must be based upon the correct application of the principles defined in Newton’s Laws of Motion.
The Aim of this study is to produce and measure a validated ISOMETRIC FORCE MAXIMA
To clarity, the test action can be precisely stated as ‘the measurement of a one isometric voluntary muscle contraction repetition maxima’ - 1IVMCmax
I would like to commend the authors on highlighting the risk factors for concussion in Rugby Football Union. This type of research is essential for current and future guidance and therefore to be referenced it must be of the highest academic standard.
Don Gatherer and David Hamilton have published several papers on cervical assessment in rugby and have huge experience in the biomechanical function, action, rehabilitation, and measurement of the cervical spine especially at International Rugby Football Union level.
It is with regret that we are writing to express our great concerns regarding the recent study published in BJSM in particular the prudence of the Testing Protocols and how the findings may be misleading and the results mis-interpreted.
There are a number of methodological issues with this study which will have contributed to the misinterpretation of their results and subsequent conclusions.
The scientific methodology construct of isometric testing of the Head, Neck, and Upper Shoulder Girdle (HNS) must be based upon the correct application of the principles defined in Newton’s Laws of Motion.
The Aim of this study is to produce and measure a validated ISOMETRIC FORCE MAXIMA
To clarity, the test action can be precisely stated as ‘the measurement of a one isometric voluntary muscle contraction repetition maxima’ - 1IVMCmax
Principles and Forces related to this study.
INTRINSIC FORCE
• Head, Neck, and Upper Shoulder Girdle are held in the neutral test position by Intrinsic Forces
• Intrinsic Force is defined as the Biomechanical properties of the NMSK system of the HNS
• Intrinsic Force – In this experiment is UNKNOWN and is the force to be measured and defined.
• HNS held in test position isometrically in a defined position for each action
• Intrinsic Force MUST be LESS than the Extrinsic Force for test completion and validity.
EXTRINSIC FORCE
• Extrinsic Force is defined as an external force applied to the Head affecting the HNS.
• Extrinsic Force application is via auto means of manual hand compression through a load cell.
• Extrinsic Force – In this experiment IS KNOWN as the force Maxima must be defined by compression of the load cell in each test action.
• Extrinsic Force test position, once defined, will set the Test Maxima of that test.
• Extrinsic Force application is via single or double action arm actions and thus of different magnitude.
• Extrinsic Force application must be directed at right angles to the point of contact with a controlled rate of force development that allows maximal motor unit recruitment whilst avoiding jerking.
• Extrinsic Force MUST be GREATER than Intrinsic Force for test completion and validity.
APPLICATION
• If an Extrinsic force is applied, the HNS will remain in the neutral test position unless the Intrinsic Force is exceeded by the Extrinsic Force.
• An Extrinsic Force overload will result in Loss of the neutral test position, and this defines the test End Point.
• The End Point represents the HNS Isometric Force Maxima of the Intrinsic Force relative to that test set up and position which can be measured and recorded.
• If the HNS Isometric Force Maxima End Point is not achieved by an applied extrinsic force, the HNS will not move. The resultant Extrinsic force measurement therefore does NOT represent a Force Maxima but an Isometric Force Sub Maxima of the Intrinsic Force.
• Timing out a held Sub Maxima Force also does NOT define or represent a Force Maxima.
Chosen Methodology
• Auto Testing
• Compression load cell
• Timed End Point i.e. Load cell bleep when the input does not increase for 3 seconds.
The TEST must have three basic reproducible elements:
1. A defined Start Point
2. An appropriate application of an Extrinsic force Maxima
3. A defined End Point
Failure to adhere to any one of these basic elements will invalidate the test data
This paper fails on points 2 and 3.
It is important to note that the extrinsic force maxima of all test positions cannot be shown to be GREATER than the Intrinsic force maxima on any of the tests shown in this paper and therefore the input data is flawed and invalid.
Please try the Side Flexion test with your hand and see if you can exert sufficient force to overcome the cervical side flexors by moving the head out of the test position.
You simply cannot because our research shows that the extrinsic force maxima of this test set up is at least 25% lower than the intrinsic force maxima.
Therefore, all tests will register a sub maxima intrinsic score that is equates to the extrinsic force maxima.
Don Gatherer MCSP
We are writing to express our concerns regarding this recent study published in BJSM and how the findings may be misleading and the results misinterpreted.
Farley, T., Barry, E., Sylvester, R., De Medici, A., & Wilson, M. G. (2022). Poor isometric neck extension strength as a risk factor for concussion in male professional Rugby Union players. British Journal of Sports Medicine.
There are a number of methodological issues with this study which will have contributed to the interpretation of their results and subsequently how these might be used in practice. Most of these issues were not mentioned or addressed in the limitations of the study and should be highlighted as potential confounders:
Method for assessing neck strength- is it valid for use in rugby players?
Neck extensors
Although the authors use a method of assessing neck strength which has documented reliability in an earlier study,(1) this method has not been validated in rugby players (the published reliability was in healthy adults). The reason this method might not be the most appropriate method for assessing neck strength in rugby players is that these athletes have particularly strong necks, much stronger than the average population. The method used in the Farley et al. study requires the player to self-assess their own neck extensors with the player’s shoulders placed in an anatomically weak position where they may not be able to generate enough strength to counter >...
We are writing to express our concerns regarding this recent study published in BJSM and how the findings may be misleading and the results misinterpreted.
Farley, T., Barry, E., Sylvester, R., De Medici, A., & Wilson, M. G. (2022). Poor isometric neck extension strength as a risk factor for concussion in male professional Rugby Union players. British Journal of Sports Medicine.
There are a number of methodological issues with this study which will have contributed to the interpretation of their results and subsequently how these might be used in practice. Most of these issues were not mentioned or addressed in the limitations of the study and should be highlighted as potential confounders:
Method for assessing neck strength- is it valid for use in rugby players?
Neck extensors
Although the authors use a method of assessing neck strength which has documented reliability in an earlier study,(1) this method has not been validated in rugby players (the published reliability was in healthy adults). The reason this method might not be the most appropriate method for assessing neck strength in rugby players is that these athletes have particularly strong necks, much stronger than the average population. The method used in the Farley et al. study requires the player to self-assess their own neck extensors with the player’s shoulders placed in an anatomically weak position where they may not be able to generate enough strength to counter >60kg of force to measure isometric neck extensors as reported in earlier studies.(2 3) It is appreciated that the authors did attempt to test shoulder strength, however, they did not replicate the position that the shoulders would be in when resisting the neck extensors (or in fact any of the neck muscle groups). The authors tested shoulder strength in horizontal adduction in front of their chest (figure 1A), whereas for the neck extensor test, the shoulders are in approximately 100 degrees of forward flexion (figure 1C). Therefore, it is disputed that all or some of the rugby player’s will have had the required shoulder strength to self-assess a maximal isometric contraction of their neck extensors (the strongest muscle group of the neck). The results might be more reflective of the player’s shoulder strength to resist the neck extensors in the documented position rather than the neck extensors themselves.
Neck flexors
In contrast, the mean neck flexor strength of 31.3-34.2 kg in study by Farley et al.(4) compares more favourably to earlier studies of between 25-36kg,(2 5 6) further raising the question whether the neck strength assessment method used in the study by Farley et al.(4) was valid for assessing neck extensor strength, with the true neck extensor score likely being under-estimated.(7)
Flexor/Extensor ratio
In the Farley et al. study the Flexor/Extensor ratio (F/E) is 0.75 (pre), 0.77 (mid) and 0.82 (post).(4) which is much higher than the F/E ratio of between 0.65 to 0.70 reported in an earlier systematic review.(3) A high F/E is strongly influenced by weak neck extensors (or a sub-maximal extensor strength score) and/or strong neck flexors.
Lateral flexors
In the Farley et al.(4) study the lateral flexors are lower than the mean flexor strength score by 20-25%. This is most unusual. Normative data from healthy adults has shown the lateral flexors to be similar or stronger than the flexors,(8) including the study of healthy adults by Versteegh et al.(1) on which the neck strength testing method is based. In rugby players, this strength profile is more pronounced, with every study (2 5 6 9-13) in a recent systematic review (3) of neck strength in rugby players which tested players in a seated position reporting the lateral flexors to be higher than the neck flexors which is particularly pronounced in forward players.(3) It is possible that a sub-maximal result for lateral flexors was also achieved in the Farley et al. study which might be due to the testing method requiring only one arm to self-resist the lateral flexors (left and right), whereas two arms are used to self-resist the extensors and flexors. Even if we accept that a make technique will lead to lower isometric neck strength values than a break technique, it does not explain why the lateral flexors are the weakest group by some margin in this study (in conflict with virtually every other study in rugby).
Testing sequence
It is possible that in the study by Farley et al. because every player was tested using the exact same sequence of neck strength testing, with the flexors tested before the extensors and lateral flexors, that this may also have contributed to the findings. Something which is also not discussed as a potential confounder.
Player demographics
Playing positions
The breakdown of the playing positions of the included participants was not reported.(4) Studies in rugby which have assessed neck strength by position (forwards and backs) have shown that forwards are considerably stronger than backs particularly in their neck extensors.(3) This is also not presented as a limitation and potential confounding factor.
Neck strengthening
It is unclear from the Farley et al. study whether any of the players already participated in neck strengthening exercises, or some other activity which may have contributed to the neck flexors reporting higher mean values than the lateral flexors as well as contributing to higher starting mean F/E ratio (Table 1)4 than the F/E ratio reported in earlier rugby studies,(3)Thus, potentially confounding the results.
Other methodological concerns
High dropout rate
Another issue is the high dropout rate. Only 33% of players completed post-season testing including almost all of the international players (likely the strongest players in the study). It was unclear how missing data were handled and how this may have influenced the findings. Also, the number of concussions reported is a bit confusing. From what we could tell, the data are presented for 30 concussions in 29 players, but there were 39 players noted as not attending one of the test sessions due to a concussion, cervical or shoulder injury across the 2 follow-up periods, it is unclear if that’s in addition to the 29 reported and how this influences the results.
Measure of Variance
In Tables 1 and 3 the strength means have very small standard deviations which seems to imply that either the players showed roughly the same assessed strength or there were issues with the testing method. In Table 3,4 the unadjusted Incidence Rate Ratio (IRR) for the extensors is 0.87 with 95% CI of 0.75-1.00 with the upper 95% CI of 1. These results are not dissimilar to IRR for the lateral flexors (except for having a non-significant p value). Given the concerns with the testing method, caution is advised in presenting the neck extensors as being the most important muscle group for reducing concussion risk.
Interpretation of the results
The concern is that if the testing method does not accurately reflect the true strength values of the neck extensors or the lateral flexors, the study’s main finding that poor neck extensor strength is a risk factor for concussion(4) is compromised and should be interpreted with extreme caution.
Based on their results, the authors of the Farley et al. study state in their discussion “that the extensor muscles may have a larger role to play than previously thought in attenuating forces of impact” and that it is possible that extensors provide a “defensive mechanism at reducing the forces of impacts during sagittal plane impact.”(4) However, the authors do not present any rationale on how the extensors alone would do this. It is certainly possible that there is a strength threshold for all neck muscle groups, however, strong extensors alone are unlikely to reduce the risk of injury without also having strong flexors and strong lateral flexors. Even if we assume that the method for testing neck strength achieved maximal isometric results for all directions of movement, the results of this study are almost certainly confounded by a high starting mean F/E ratio, which is not discussed as a limitation. The real concern is that readers will implement “a team wide neck extension program”(4) (as stated in their discussion) at the expense of neglecting to strengthen the neck flexors and lateral flexors. By selectively strengthening one muscle group, there is a potential to increase injury risk by adversely altering a normal neck strength profile.
In summary, we believe that there are important methodological issues within this paper which compromise the data and interpretation of the results.
We welcome clarification from the authors.
We would like to point out that at the IOC conference in Monaco in 2021, Kerry did voice her concerns with the lead author of this paper about their findings before this study was published, which is why we feel compelled to raise them again here as none of the concerns raised have been addressed in the published paper.
References:
1. Versteegh T, Beaudet D, Greenbaum M, et al. Evaluating the reliability of a novel neck-strength assessment protocol for healthy adults using self-generated resistance with a hand-held dynamometer. Physiotherapy Canada 2015;67(1):58-64.
2. Geary K, Green BS, Delahunt E. Effects of neck strength training on isometric neck strength in rugby union players. Clinical Journal of Sport Medicine 2014;24(6):502-08.
3. Chavarro-Nieto C, Beaven M, Gill N, et al. Neck strength in Rugby Union players: a systematic review of the literature. The Physician and Sportsmedicine 2021;49(4):392-409.
4. Farley T, Barry E, Sylvester R, et al. Poor isometric neck extension strength as a risk factor for concussion in male professional Rugby Union players. British journal of sports medicine 2022
5. Geary KBBa, Green BSPb, Delahunt EPBcd. Intrarater Reliability of Neck Strength Measurement of Rugby Union Players Using a Handheld Dynamometer. Journal of Manipulative & Physiological Therapeutics 2013;36(7):444-49.
6. Hamilton D, Gatherer D, Robson J, et al. Comparative cervical profiles of adult and under-18 front-row rugby players: implications for playing policy. BMJ open 2014;4(5):e004975.
7. Ashall A, Dobbin N, Thorpe C. The concurrent validity and intrarater reliability of a hand-held dynamometer for the assessment of neck strength in semi-professional rugby union players. Physical Therapy in Sport 2021;49:229-35.
8. Seng K-Y, Peter V-SL, Lam P-M. Neck muscle strength across the sagittal and coronal planes: an isometric study. Clinical Biomechanics 2002;17(7):545-47.
9. Maconi F, Venturelli M, Limonta E, et al. Effects of a 12-week neck muscles training on muscle function and perceived level of muscle soreness in amateur rugby players. Sport Sciences for Health 2016;12(3):443-52.
10. Naish R, Burnett A, Burrows S, et al. Can a Specific Neck Strengthening Program Decrease Cervical Spine Injuries in a Men's Professional Rugby Union Team? A Retrospective Analysis. Journal of Sports Science & Medicine 2013;12(3):542-50.
11. Olivier PE, Du Toit DE. Isokinetic neck strength profile of senior elite rugby union players. Journal of Science & Medicine in Sport 2008;11(2):96-105.
12. Hamilton DF, Gatherer D. Cervical isometric strength and range of motion of elite rugby union players: a cohort study. BMC Sports Science, Medicine and Rehabilitation 2014;6(1):32.
13. Barrett MD, McLoughlin TF, Gallagher KR, et al. Effectiveness of a tailored neck training program on neck strength, movement, and fatigue in under-19 male rugby players: a randomized controlled pilot study. Open access Journal of Sports Medicine 2015;6:137.
We like to commend the authors with the recent publication of the results of a multicenter randomized controlled trial comparing percutaneous transforaminal discectomy (PTED) versus open microdiscectomy in the treatment of patients with symptomatic lumbar disc herniation[1].
Based on the data of the non-inferiority trial, we fully agree with the authors conclusion that PTED is non-inferior to open microdiscectomy and can therefore be considered as an effective alternative surgical treatment. The improvement of leg pain and low back in the first 3 months is similar between both groups within the non-inferior margin. Patients treated with PTED seem to report less leg pain (mean difference 7.1) and low back pain (mean difference 6.0) at 12 months. However, these differences were small and did not reach the minimal clinically important difference of 20 mm on a VAS score[2].
In contrast to the BMJ paper, we do not agree with the suggestion stated in the Br J Sports Med paper, that PTED is less costly and more effective for various reasons. Firstly, costs associated with endoscope equipment and disposables were not included in their cost measurements. The direct costs only included time of the operating room, costs of medications and overnight hospital stay. Secondly, the study protocol reported that all PTED procedures should be performed in daycare and the open microdiscectomy patients were admitted in the hospital for one to two days[3]. For adequate comparison of...
We like to commend the authors with the recent publication of the results of a multicenter randomized controlled trial comparing percutaneous transforaminal discectomy (PTED) versus open microdiscectomy in the treatment of patients with symptomatic lumbar disc herniation[1].
Based on the data of the non-inferiority trial, we fully agree with the authors conclusion that PTED is non-inferior to open microdiscectomy and can therefore be considered as an effective alternative surgical treatment. The improvement of leg pain and low back in the first 3 months is similar between both groups within the non-inferior margin. Patients treated with PTED seem to report less leg pain (mean difference 7.1) and low back pain (mean difference 6.0) at 12 months. However, these differences were small and did not reach the minimal clinically important difference of 20 mm on a VAS score[2].
In contrast to the BMJ paper, we do not agree with the suggestion stated in the Br J Sports Med paper, that PTED is less costly and more effective for various reasons. Firstly, costs associated with endoscope equipment and disposables were not included in their cost measurements. The direct costs only included time of the operating room, costs of medications and overnight hospital stay. Secondly, the study protocol reported that all PTED procedures should be performed in daycare and the open microdiscectomy patients were admitted in the hospital for one to two days[3]. For adequate comparison of costs, it should have been better when both groups had the same postoperative strategy, either both treatments in daycare, or both treatments with overnight stay. Microdiscectomy in daycare is currently already standard in many hospitals. Thirdly, although the authors are rewarded for excluding the initial 50 patients treated with PTED during the learning curve, they ultimately did not reach the initial sample size of 682 patients.
Therefore, we disagree with the conclusion of the authors. Although PTED is non-inferior to conventional microdiscectomy, any conclusion about cost effectiveness cannot be made. In our opinion, another study design is needed to investigate the cost effectiveness of PTED above conventional microdiscectomy. Furthermore, long-term outcome data is needed to determine whether treatment with PTED will have the same revision rate as standard microdiscectomy. Only evaluation stage 3 according to the IDEAL framework for surgical innovation is now partly fulfilled[4]. Microdiscectomy will thus remain the golden standard for treating of patients with symptomatic lumbar disc herniation.
References
1. Gadjradj PS, Rubinstein SM, Peul WC et al. Full endoscopic versus open discectomy for sciatica: randomised controlled non-inferiority trial. BMJ 2022; 376: e065846.
2. Ostelo RW, de Vet HC. Clinically important outcomes in low back pain. Best Pract Res Clin Rheumatol 2005; 19: 593-607.
3. Seiger A, Gadjradj PS, Harhangi BS et al. PTED study: design of a non-inferiority, randomised controlled trial to compare the effectiveness and cost-effectiveness of percutaneous transforaminal endoscopic discectomy (PTED) versus open microdiscectomy for patients with a symptomatic lumbar disc herniation. BMJ Open 2017; 7: e018230.
4. IDEAL framework for surgical innovation 3: randomised controlled trials in the assessment stage and evaluations in the long term study stage. Jonathan A Cook, Peter McCulloch, Jane M Blazeby, David J Beard, Danica Marinac-Dabic, Art Sedrakyan BMJ. 2013; 346: f2820. Published online 2013 Jun 18. doi: 10.1136/bmj.f2820
In their systematic review and meta-analysis, Edwards et al. (1) aimed to ‘directly compare’ the efficacy of isometric exercise and high-intensity interval training (HIIT) for the management of resting blood pressure. They included 38 randomised controlled trials (18 for isometric, 20 for HIIT) in their pairwise meta-analysis and concluded that isometric exercise appears to be superior to HIIT for improving both systolic blood pressure (mean difference between exercise types = 5.29 mmHg, 95% confidence interval 3.97 to 6.61) and diastolic blood pressure (mean difference between exercise types = 3.25 mmHg, 95% confidence interval 2.53 to 3.96). We were interested in these marked differences because they contrast previous findings (2) and, if correct, may necessitate important changes to guidelines. However, in further examining the article, we identified some issues that we believe require attention as they may invalidate the results and are relevant to readers of this journal.
None of the included trials in this review appear to contain both isometric and HIIT interventions; therefore, the authors are unable to ‘directly compare’ the interventions. Instead, by analysing the differences between isometric and HIIT subgroups in the meta-analysis, Edwards et al. (1) are making an inference based on the indirect effect, which assumes that the differences between exercise types can be inferred via a common comparator (in this case, the control group) (3). This is, in effe...
In their systematic review and meta-analysis, Edwards et al. (1) aimed to ‘directly compare’ the efficacy of isometric exercise and high-intensity interval training (HIIT) for the management of resting blood pressure. They included 38 randomised controlled trials (18 for isometric, 20 for HIIT) in their pairwise meta-analysis and concluded that isometric exercise appears to be superior to HIIT for improving both systolic blood pressure (mean difference between exercise types = 5.29 mmHg, 95% confidence interval 3.97 to 6.61) and diastolic blood pressure (mean difference between exercise types = 3.25 mmHg, 95% confidence interval 2.53 to 3.96). We were interested in these marked differences because they contrast previous findings (2) and, if correct, may necessitate important changes to guidelines. However, in further examining the article, we identified some issues that we believe require attention as they may invalidate the results and are relevant to readers of this journal.
None of the included trials in this review appear to contain both isometric and HIIT interventions; therefore, the authors are unable to ‘directly compare’ the interventions. Instead, by analysing the differences between isometric and HIIT subgroups in the meta-analysis, Edwards et al. (1) are making an inference based on the indirect effect, which assumes that the differences between exercise types can be inferred via a common comparator (in this case, the control group) (3). This is, in effect, the simplest version of a network meta-analysis. However, Edwards et al. (1) only analyse the intervention group’s change from baseline from each study (as shown in Figures 2 & 3 of their article) and report separate meta-analyses of the control change from baseline. This method is not correct. Analysing a single group’s change from baseline in a trial, or a meta-analysis, as opposed to the between-group effect (the change/endpoint in the intervention group minus the change/endpoint in the control group), is misleading because several statistical phenomena like regression to the mean and natural history are not accounted for (4, 5). Regression to the mean in hypertension has been shown to be, at times, as large as the effect of treatment itself (6). In using change from baseline values without comparison to control, the data presented in the meta-analyses are now equivalent to cohort studies and causal inferences are unable to be made (7). By extension, attempting to estimate the indirect effect using change from baseline scores, rather than between-group differences, is prone to bias and is not recommended (3).
We believe that the results and conclusions presented by Edwards et al. (1) may be biased due to the use of change scores, rather than between-group differences, for their comparison between isometric exercise and HIIT. Therefore, we urge caution for anyone who may consider altering their clinical practice until the results are updated.
Correctly re-estimating the indirect effect of isometric exercise versus HIIT via the control group may provide valuable information to clinicians; the network meta-analysis by Naci et al. (2) found similar effects for endurance exercise and isometric exercise, but did not further explore the potential unique effects of HIIT. However, transitivity – the assumption that it is appropriate to learn about isometric exercise versus HIIT via a common control group – requires strong consideration to ensure the validity of the indirect effect (8). It requires that effect modifiers be similarly distributed across the different comparisons. If intervention duration is thought to modify the effect of exercise, it is important to confirm both studies of isometric exercise versus control (8.2 weeks) and studies of HIIT versus control (8.1 weeks) are delivered for a similar duration in the included studies, which appears to be true. Another effect modifier might be the control group intervention/effect, which does not appear to be similarly distributed across the two comparisons. All isometric exercise studies appear to use a minimal/no exercise control, but several HIIT studies use a moderate-intensity continuous training comparator. Given a no exercise control will have a different effect to a moderate-intensity continuous training control, and these are not similarly distributed across the two exercise types, this will threaten the assumption of transitivity and introduce bias in the indirect effect (8). Therefore, to ensure transitivity holds, it may only be appropriate to include HIIT studies that use a no exercise control. Several other clinical and methodological characteristics may also need to be considered, adding to the complexity of indirect effect estimation, especially as the network of interventions increases. This is best done a priori with a study protocol, utilising a team that contains clinical and methodological/statistical expertise.
References
1. Edwards J, De Caux A, Donaldson J, Wiles J, O'Driscoll J. Isometric exercise versus high-intensity interval training for the management of blood pressure: a systematic review and meta-analysis. British Journal of Sports Medicine. 2021:bjsports-2021-104642.
2. Naci H, Salcher-Konrad M, Dias S, Blum MR, Sahoo SA, Nunan D, et al. How does exercise treatment compare with antihypertensive medications? A network meta-analysis of 391 randomised controlled trials assessing exercise and medication effects on systolic blood pressure. British Journal of Sports Medicine. 2019;53(14):859.
3. Bucher HC, Guyatt GH, Griffith LE, Walter SD. The results of direct and indirect treatment comparisons in meta-analysis of randomized controlled trials. Journal of clinical epidemiology. 1997;50(6):683-91.
4. Bland JM, Altman DG. Comparisons against baseline within randomised groups are often used and can be highly misleading. Trials. 2011;12(1):264.
5. Bland JM, Altman DG. Comparisons within randomised groups can be very misleading. BMJ. 2011;342:d561.
6. Salam A, Atkins E, Sundström J, Hirakawa Y, Ettehad D, Emdin C, et al. Effects of blood pressure lowering on cardiovascular events, in the context of regression to the mean: a systematic review of randomized trials. J Hypertens. 2019;37(1):16-23.
7. Tennant PWG, Arnold KF, Ellison GTH, Gilthorpe MS. Analyses of ‘change scores’ do not estimate causal effects in observational data. International Journal of Epidemiology. 2021:dyab050.
8. Salanti G. Indirect and mixed-treatment comparison, network, or multiple-treatments meta-analysis: many names, many benefits, many concerns for the next generation evidence synthesis tool. Research synthesis methods. 2012;3(2):80-97.
This is a classic example of misinterpretation of the available data. Of course, national death rates may be higher than the overall rate for 67 countries. Furthermore, the range of media coverage at the national level is massive, so a comparison with an international registry is not valid.
Reply to: ‘Comment on: Isometric exercise versus high-intensity interval training for the management of blood pressure: a systematic review and meta-analysis by Edwards et al.’ by Wewege et al.
Edwards, J.J., Wiles, J.D., & O’Driscoll, J.M.
School of Psychology and Life Sciences, Canterbury Christ Church University, Kent, CT1 1QU
Correspondence to Dr Jamie O’Driscoll, School of Psychology and Life Sciences, Canterbury Christ Church University, North Holmes Road, Canterbury, Kent, CT1 1 QU. Email: jamie.odriscoll@canterbury.ac.uk; Telephone: 01227922711.
We thank Wewege et al. (1) for their assessment and comments on our recent work (2), highlighting their concerns over the employed statistical analysis approach, which they suggest may “invalidate the results”.
We take these comments seriously and have therefore re-performed the analysis as suggested by Wewege et al. (1) and individually addressed the points raised within this rapid response.
Wegewe et al. (1) state that the marked differences found in our study “contrast previous findings”, with reference to a previous large-scale network meta-analysis by Naci et al. (3). As detailed, Naci et al. (3) did not include high intensity interval training (HIIT), and the lower blood pressure (BP) changes observed can be attributed to a combination of differences to the present study, including a smaller pool of lower quality iso...
Show MoreDear Editor,
As a general practitioner and specialist in the musculoskeletal system, I have read the article
“Small Steps, strong shield: directly measured moderate physical activity in 65361 adults is associated with significant protective affects from severe COVID-19 outcomes” from Steenkamp et al with great interest. The covid epidemic has put a huge burden of disease on the entire world and is weighing heavily on the capacity of healthcare. More and more is known about risk and protective factors for individuals to become severely ill from COVID-19 and this study contributes to this. In addition, prevention of disease is becoming an increasingly important task of health care, partly in order to curb rising healthcare costs.(1) Good physical condition can help prevent certain diseases as mentioned in the article.
The authors have collected a large dataset from a very large group of people in South Africa. What is missing in the analysis, however, is data on BMI. Studies show that BMI is an important risk factor for severe course of COVID-19. A high BMI, or adiposity, is one of the strongest reported risk factors for severe COVID-19. (2). In this study, the BMI was available in only 50% of the study population. Authors claim that when adding BMI to the model it did not alter the outcome for severe COVID-19 disease for the different physical activity groups. The authors attribute this to associated diseases such as hypertension and DM2, however researc...
Show MoreDear editor,
I read with great appreciation the study “Exercise prehabilitation during neoadjuvant chemotherapy may enhance tumour regression in oesophageal cancer: results from a prospective non-randomised trial” [1]. The authors aimed to evaluate the clinical impact of a structured exercise intervention in patients with operable oesophageal cancer during Neoadjuvant chemotherapy compared with those on a standard treatment pathway (p. 1); and for that, they carried out a prospective non-randomised trial. The paper has an elegant rationale and I am sure that will generate new research, however, exist some methodological fragile that may compromise the results.
1st, as this study specifically assessed the impact of exercise on measures of chemotherapy response (p. 1), the exercise program should be clearly described (e.g., exercise volume, time under tension, duration, cadence and range of motion, heart and respiratory rate). 2nd, the authors established moderate intensity for exercise, based on WHO recommendations for physical activity level (p. 2), however, physical activity is different of physical exercise; besides, they did not use the repetition-maximum [2] test to assess the strength of the patients and plan the intensity individually.
3rd, the authors added aerobic exercise (p. 2) to the structured program, but it was unclear how patients were assessed for this intervention (what velocity? Incline? Heart rate? Vo2?). 4th, the strategy for sample...
Show MoreDear editor,
On behalf of the PTED study group, we would like to thank the authors for the rapid response on our recently published paper “Cost-effectiveness of Full Endoscopic versus Open Discectomy for Sciatica [1]. The authors mention that they don’t agree with the conclusion of this study and have several comments. Below we will respond to these comments.
Firstly, the authors suggest that “another study design is needed to investigate cost-effectiveness of PTED above conventional microdiscectomy.” We strongly disagree. The study design was an economic evaluation alongside a pragmatic randomized controlled trial examining the cost-effectiveness of full-endoscopic versus open discectomy for sciatica. An economic evaluation alongside a pragmatic randomised controlled trial is considered an adequate design, because it provides timely information on an intervention’s cost-effectiveness with high internal and sufficient external validity [2]. Furthermore, the study design was peer reviewed by the grant agency (ZONMW in the Netherlands) and we have pre-published our study protocol in an open access, peer reviewed journal [3], supported in a covenant agreement including the Dutch Neurosurgical Society (NVvN), Dutch Orthopedical Society (NOV), Dutch Spine Society and the Dutch Association for patients with low back pain (NVVR).
Secondly, the authors comment that “costs associated with endoscope equipment and disposables were not included in their cost measur...
Show MoreDear Editor,
We read with great interest the article by Gronwald et al. that investigated the injury inciting events of moderate and severe acute hamstring injuries in professional male football (soccer) players with systematic video analysis.1 Despite the pain-taking reviewing of videos and motion analyses by the authors, there are still some practical concerns over injury severity and subject recruitment.
Taking into account the importance of injury severity assessment that served as the basis for study subject enrollment in that study, the use of time loss to represent the severity of injury may not be optimal when considering other factors that may contribute to a prolonged rest after injury. For instance, pre-existing hamstring conditions including hamstring strings, proximal hamstring tendinopathy, or referred posterior thigh pain are not uncommon among soccer players.2 Following this argument, the recruitment of study subjects based on club or physician registration without meeting more objective criteria and without excluding those with previous hamstring injuries through a medical record review may introduce bias regarding the determination of injury severity. In this aspect, magnetic resonance imaging (MRI), which was available in 87% (45 out of 52 cases for pattern hamstring injury categorisation), may be a more reliable tool for evaluation because of its ability to show the extent of injury and the reported correlation between the size of injury a...
Show MoreI would like to commend the authors on highlighting the risk factors for concussion in Rugby Football Union. This type of research is essential for current and future guidance and therefore to be referenced it must be of the highest academic standard.
Don Gatherer and David Hamilton have published several papers on cervical assessment in rugby and have huge experience in the biomechanical function, action, rehabilitation, and measurement of the cervical spine especially at International Rugby Football Union level.
It is with regret that we are writing to express our great concerns regarding the recent study published in BJSM in particular the prudence of the Testing Protocols and how the findings may be misleading and the results mis-interpreted.
There are a number of methodological issues with this study which will have contributed to the misinterpretation of their results and subsequent conclusions.
The scientific methodology construct of isometric testing of the Head, Neck, and Upper Shoulder Girdle (HNS) must be based upon the correct application of the principles defined in Newton’s Laws of Motion.
The Aim of this study is to produce and measure a validated ISOMETRIC FORCE MAXIMA
To clarity, the test action can be precisely stated as ‘the measurement of a one isometric voluntary muscle contraction repetition maxima’ - 1IVMCmax
Principles and Forces related to this study.
INTRINSIC FORCE
Show More• Head, Neck, and Upper S...
We are writing to express our concerns regarding this recent study published in BJSM and how the findings may be misleading and the results misinterpreted.
Farley, T., Barry, E., Sylvester, R., De Medici, A., & Wilson, M. G. (2022). Poor isometric neck extension strength as a risk factor for concussion in male professional Rugby Union players. British Journal of Sports Medicine.
There are a number of methodological issues with this study which will have contributed to the interpretation of their results and subsequently how these might be used in practice. Most of these issues were not mentioned or addressed in the limitations of the study and should be highlighted as potential confounders:
Method for assessing neck strength- is it valid for use in rugby players?
Neck extensors
Although the authors use a method of assessing neck strength which has documented reliability in an earlier study,(1) this method has not been validated in rugby players (the published reliability was in healthy adults). The reason this method might not be the most appropriate method for assessing neck strength in rugby players is that these athletes have particularly strong necks, much stronger than the average population. The method used in the Farley et al. study requires the player to self-assess their own neck extensors with the player’s shoulders placed in an anatomically weak position where they may not be able to generate enough strength to counter >...
Show MoreWe like to commend the authors with the recent publication of the results of a multicenter randomized controlled trial comparing percutaneous transforaminal discectomy (PTED) versus open microdiscectomy in the treatment of patients with symptomatic lumbar disc herniation[1].
Show MoreBased on the data of the non-inferiority trial, we fully agree with the authors conclusion that PTED is non-inferior to open microdiscectomy and can therefore be considered as an effective alternative surgical treatment. The improvement of leg pain and low back in the first 3 months is similar between both groups within the non-inferior margin. Patients treated with PTED seem to report less leg pain (mean difference 7.1) and low back pain (mean difference 6.0) at 12 months. However, these differences were small and did not reach the minimal clinically important difference of 20 mm on a VAS score[2].
In contrast to the BMJ paper, we do not agree with the suggestion stated in the Br J Sports Med paper, that PTED is less costly and more effective for various reasons. Firstly, costs associated with endoscope equipment and disposables were not included in their cost measurements. The direct costs only included time of the operating room, costs of medications and overnight hospital stay. Secondly, the study protocol reported that all PTED procedures should be performed in daycare and the open microdiscectomy patients were admitted in the hospital for one to two days[3]. For adequate comparison of...
In their systematic review and meta-analysis, Edwards et al. (1) aimed to ‘directly compare’ the efficacy of isometric exercise and high-intensity interval training (HIIT) for the management of resting blood pressure. They included 38 randomised controlled trials (18 for isometric, 20 for HIIT) in their pairwise meta-analysis and concluded that isometric exercise appears to be superior to HIIT for improving both systolic blood pressure (mean difference between exercise types = 5.29 mmHg, 95% confidence interval 3.97 to 6.61) and diastolic blood pressure (mean difference between exercise types = 3.25 mmHg, 95% confidence interval 2.53 to 3.96). We were interested in these marked differences because they contrast previous findings (2) and, if correct, may necessitate important changes to guidelines. However, in further examining the article, we identified some issues that we believe require attention as they may invalidate the results and are relevant to readers of this journal.
None of the included trials in this review appear to contain both isometric and HIIT interventions; therefore, the authors are unable to ‘directly compare’ the interventions. Instead, by analysing the differences between isometric and HIIT subgroups in the meta-analysis, Edwards et al. (1) are making an inference based on the indirect effect, which assumes that the differences between exercise types can be inferred via a common comparator (in this case, the control group) (3). This is, in effe...
Show MoreThis is a classic example of misinterpretation of the available data. Of course, national death rates may be higher than the overall rate for 67 countries. Furthermore, the range of media coverage at the national level is massive, so a comparison with an international registry is not valid.
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