416 e-Letters

  • Expression of concern over the Aspetar consensus for rehabilitation after ACL reconstruction: Premature position on the efficacy of cross-education

    Dear Editor,

    We read with interest the recent consensus statement by Kotsifaki et al. [1] on clinical practice guidelines following anterior cruciate ligament reconstruction (ACLR) and recognize their comprehensive efforts regarding an important area of sports medicine. However, we were surprised and disappointed to see their “Not Recommended” stance on the use of cross-education (i.e., interlimb transfer of strength or motor skill after engaging in unilateral motor training) for the recovery of motor function [1,2]. As a collective group of experts in cross-education and ACLR, we write this response with concern for the danger of drawing a premature conclusion given the limited research on cross-education for post-ACLR recovery [3–9]. Here, we offer a summary of the physiological rationale for the use of cross-education in rehabilitation, extending the views of Kotsifaki et al. [1].

    Physical function after ACLR is largely predicated by quadriceps strength and an attenuated quadriceps activation failure [10], and protocols that preserve and restore neuromuscular function post-ACLR are an integral aspect of rehabilitation. Cross-education can attenuate the loss in neuromuscular function during disuse [11–13], serve as an adjunct ACLR rehabilitation protocol for quadriceps strength [3–5,14], and enhance neuroplasticity in pathways known to be attenuated with ACLR [15] when implemented effectively [16,17]. Though our concern is grounded in several aspects of the...

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  • Physical activity will remain ‘overlooked’ in the treatment of depression and anxiety until we focus our research on people referred to mental health services.

    Singh and colleagues’ comprehensive systematic review of meta-analyses (97 reviews of 1039 trials including 128,119 participants) confirms that ‘physical activity (PA) is highly beneficial for improving symptoms of depression, anxiety and psychological distress’ with ‘effect size reductions in symptoms of depression (−0.43) and anxiety (−0.42) comparable to or slightly greater than those observed for psychotherapy and pharmacotherapy’.
    This finding has important clinical implications and the authors conclude that PA should be included in public health guidelines as a mainstay approach (i.e. not just as an adjunct to psychological therapy and medication). They also recognise that ‘while the benefit of exercise for depression and anxiety is generally recognised, it is often overlooked in the management of these conditions’ .

    Despite these really impressive results and their important clinical implications, it is unfortunate that the Singh et al review is unlikely to make a significant difference to clinical practice. There are many reasons why physical activity is not used as a first-line intervention for depression and other mental health problems, but one of the problems is that the field has not really addressed an issue I highlighted in a review of the field a quarter of a century ago. The evidence that PA can be an effective stand-alone or adjunctive intervention for a range of mental health problems is diluted amongst the public health/ mental wellbeing st...

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  • How to interpret spirometry data in 2023? The new criteria to retain the diagnosis of ventilatory impairments

    I read with interest the Saavedra et al.’s study1 aiming to evaluate the associations of cardiorespiratory fitness and body-mass-index with incident restrictive-ventilatory-impairment (RVI). The study’ rational is interesting since the RVI is frequent (eg; prevalence: 3 to 50%).2 One strong point of the aforementioned study1 was the use of the 2012 global-lung-function-initiative (GLI) task force of multi-ethnic norms for spirometry (GLI-2012).3 Saavedra et al.1 retained the diagnosis of a RVI in front of the combination of a low forced-vital-capacity (FVC) (ie; FVC < lower-limit-of-normal (LLN)) and a normal ratio between forced-expiratory-volume-in-one-second (FEV1) and FVC (ie; FEV1/FVC ≥ LLN). Saavedra et al.1 followed some “old” approaches. In 2022, the European-respiratory-society and the American-thoracic-society (ERS/ATS) published a “new” technical standard on interpretive strategies for lung function tests.4 This guidelines should be considered by researchers in the field of sports medicine.4 The definition applied by Saavedra et al.1 to retain the diagnosis of a RVI is questionable, and the following two points need to be clarified: i) what is a low spirometric data?, ii) what is a RVI?
    What is a low spirometric data?
    Interpretation of spirometric data necessitates 2 steps: i) comparison of the spirometric data with these of reference.4 5 , and ii) comparison of the data’ value with the distinctive thresholds of the main ventilatory-impairment not...

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  • Comment On: “Injury incidence rates in women’s football: a systematic review and meta-analysis of prospective injury surveillance studies”

    We wish to commend Horan et al. (Horan et al., 2022) on their systematic review and meta-analysis which established overall, match and training IIRs in senior women’s football. It is encouraging to see continued work in this specific area of women’s football epidemiological research.

    We would like to draw the authors attention to the following error contained within their work. We respectfully request that it is amended accordingly so that the readership are aware of all available work in this area.

    Horan et al. (Horan et al., 2022) refer to the systematic review and meta-analysis of López Valenciano et al (López-Valenciano et al., 2021) which they report was recently ‘criticised’ in a published commentary by Mayhew et al (2021). The authors use the following citation:

    30. Mayhew, L. et al. (2021) ‘Incidence of injury in adult elite women’s football: a systematic review and meta-analysis’, BMJ Open Sport & Exercise Medicine, 7(3), p. e001094. doi:10.1136/bmjsem-2021-001094

    The readership should be aware that the citation Horan et al. (Horan et al., 2022) use in their work is not a published commentary but a systematic review and meta-analysis on the incidence of injury in elite women’s football. Our publication was PROSPERO registered and published ahead of Horan et al. (Horan et al., 2022) in BJSM’s sister journal (BMJ Open Sport & Exercise Medicine).

    The corrected citation should be:

    Mayhew, L., Johnson, M.I. and...

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  • Cardiopulmonary capacity and muscle strength in transgender women on long-term gender-affirming hormone therapy: A cross-sectional study.

    I appreciate the thoughtful considerations raised. Scientific discussion is always the best way for the opportunity to review points, exchange thoughts and evolve in knowledge. Here are some additional considerations below:

    - About strength and VO2peak controlled by FFM and/or weight:
    We showed these data in the article (strength/FFM; VO2peak/FFM; VO2peak/weight) in the results and table 2. There are no statistical differences comparing all populations (TW,CM and CW).

    - TW with 637 ng/dL testosterone on the day of the tests:
    In the long-term follow-up of a cohort of individuals with daily medication use, temporary failures in the regular use of medications are not uncommon. One of the participants had a high level of testosterone at the time of the study. However, we emphasize that we were careful to assess testosterone levels in the year before the study so that we could confirm the correlation of the values obtained at the time of the study with those in the last year. In addition, the values of haemoglobin denoted testosterone supression in the past 4 months. Although one of the TW was not blocked on test day (total testosterone =637 ng/dL), her value was 79 ng/dL six months before the study. This point did not interfere with her VO2 results (supplementary figure 2).

    - Weight and height:
    Studies in sports medicine generally eliminate the height as an interfering factor in the analyses.
    Height is a consequent characteristic o...

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  • Does exercise really boost immune response to Covid-19 Vaccine ?

    There is absolutely no doubt that physical activity is a beautiful phenomenon. In the above study, the study is fair to the extent that those subjects who regularly exercised had lesser hospitalisations. Here both reason and effect exist, but can a direct causal relationship be established between the two?
    Can it be inferred beyond doubt that "the vaccine prevented complications of Covid-19 because exercise strengthened the immune response? The possibility of such a remarkable effect in the short term is pretty unlikely. And all the more, such findings can't be generalised to a larger population.

    Authors seem to be ignoring a hidden confounder affecting the validity of the study, and this confounder is 'frailty'. Simply those doing less exercise were unable to do so because they were frail. And obviously, frailty can be present independent of comorbidities like DM, heart failure or obesity, which were evenly matched between the high and low-exercise groups.

    So, the correct conclusions will likely differ if this confounder is considered. one may not forget that 'Correlation, even if present in a statistically significant portion, may not amount to causation.

    The study might prompt some frail people or even morbidly obese people to engage in heavy exercise soon after the vaccination despite muscle aches and fever (common side effects of the Covid-19 vaccines). And these might have disastrous consequences. So the wo...

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  • High quality and relevant research needed to inform policy and help in decisions about the participation of transgender women in elite sport.

    Dear Editor:

    Alvares et al. [1] conducted a study to compare performance-related measures such as cardiopulmonary exercise capacity and muscle strength in non-athlete transgender women (TW) undergoing long-term gender-affirming hormone therapy to non-athlete cisgender men (CM) and non-athlete cisgender women (CW). The authors report higher absolute VO2peak (L/min) and muscle strength (kg) in TW compared to CW and lower than CM. The authors conclude that their “…findings could inform policy and help in decisions about the participation of transgender women in sporting activities”.

    However, the authors interpreted their findings on the basis of the absolute data they present and not the relative data that was controlled for body mass and fat-free mass (FFM), as would be appropriate for comparisons of such performance metrics (e.g., aerobic capacity and muscle strength). By focusing on the absolute data, the authors over-emphasise differences between comparison groups (e.g., TW and CW) that are clearly driven by differences in anthropometry. For example, when the data reported in Table 2 [1] are corrected for body mass and fat-free mass (FFM), differences in aerobic capacity and strength between TW and CW disappear. Yet, in the section “WHAT THIS STUDY ADDS” [1], which is the primary focus of many readers, the authors omit the results that control for body mass and FFM, instead leaving the reader with the misleading message that “[t]he mean strength and VO2peak...

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  • No observed differences in cardiopulmonary capacity in a small cohort of transgender and cisgender women from San Paulo, Brazil when corrected for body weight

    The topic of transgender inclusion in women’s sports is politically fraught. Sport’s governing bodies are grappling with the competing priorities of inclusivity and fairness due to any perceived competitive advantage above and beyond the large and broad continuum of biological variables found within cisgender women (e.g. height, bone mass, bone length, fiber cross-sectional diameter, etc.) associated with testosterone exposure during puberty. This active area of research is rapidly evolving due to the multitude of new studies published over the previous 5 years. In fact, there have been over a dozen primary prospective and case-control research studies published on this topic since 2018 resulting in the lowering of the maximum allowable testosterone level in transgender elite athletes (i.e., from 5.0 to 2.5nmol/L) by several sports’ governing bodies.

    The preponderance of evidence suggests that hematological differences in hematocrit, red cell number, and hemoglobin are largely normalized within 120 days of testosterone suppression, which is biologically plausible as this corresponds with the average lifespan of a red cell (~ 120 days). Since oxygen delivery to peripheral tissues is performance limiting in aerobic sports, any competitive advantage is likely largely diminished within a year of testosterone suppression. Studies evaluating changes in strength, muscle mass, and body composition are more equivocal and most likely occur over a longer time span (12-36 mon...

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  • Low DHEA causes Covid-19 Infection and Subsequent Pathology. Exercise Increases DHEA

    I suggest the basis of the Ezzatvar, et al., report is increased dehydroepiandrosterone (DHEA). It is known exercise increases DHEA. It is my hypothesis of 2020 that low DHEA is linked to the severity of Covid-19 infection and subsequent pathology (© Copyright 2020, James Michael Howard, Fayetteville, Arkansas, U.S.A.) New research, 2022, regarding DHEA has been published that supports my hypothesis that severe Covid-19 illness is associated with low DHEA: “COVID-19 patients with altered steroid hormone levels are more likely to have higher disease severity,” ( 2022 Jul 30. doi: 10.1007/s12020-022-03140-6.) “DHEA was an independent indicator of the disease severity with COVID-19.”

  • RE: Device-measured physical activity, adiposity and mortality

    Tarp et al. evaluated the associations of total and intensity-specific physical activity and all-cause mortality (1). Compared with the obese-low total physical activity reference, the hazard ratios (HRs) (95% confidence intervals [CIs]) of subjects with normal weight-high total activity and obese-high total activity for mortality were 0.59 (0.44 to 0.79) 0.67 (0.48 to 0.94), respectively. In contrast, the HR (95% CI) of subjects with normal weight-low total physical activity for mortality was 1.28 (0.99 to 1.67). Physical activity has a preventive effect on mortality regardless of obesity, and I have some comments about the study with special reference to sedentary time and aging.

    Li et al. reported that the adjusted HRs (95% CIs) of daily sedentary time per 1 hour increase for all-cause mortality was 1.03 (1.01-1.05) and significant increase of the adjusted HR was observed in subjects with daily sedentary time of 8 or longer (2). This means that physically inactive lifestyle has an effect on increased risk in mortality, and physical activity and sedentary behaviour should be checked simultaneously. In addition, I suppose that the content of physical activity should be specified; such as leisure-time and work-related activity.

    Yang et al. conducted a meta-analysis to evaluate the effect of physical activity and sedentary behaviour over adulthood on all-cause and cause-specific mortality (3). They clarified that active subjects over adulthood was significantl...

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