18 e-Letters

  • Stretching the conclusions a little too far?

    To the Editor,

    We read the recent publication by Nathan, Davies & Swaine (2018) with great interest due to a mutual interest in the subject of Generalised Joint Hypermobility (GJH) and its influence on injuries within elite sport. The authors of this paper should be commended for undertaking a study with such good participant numbers over a range of sports. We believe that the findings of this study suggesting that GJH may be protective of joint ligament damage may be a very important initial paper leading to valuable further exploration within specific sports and specific joints. However despite this good work we would like to take the opportunity to raise a concern over one of their conclusions and how this may confuse readers of the article.

    In the discussion section of this paper Nathan et al. (2018) suggest that the findings of this study may suggest that “regular stretching may increase flexibility, and this could subsequently reduce rates of injury in those that are less flexible.” We believe that this statement may lead to misunderstanding as the terms “flexibility” and “joint hypermobility” are two completely different entities.

    GJH is a hereditary physiological entity whereby most synovial joints move beyond their normal limits (Pacey et al., 2010) and may, or may not be symptomatic. This entity is commonly classified by the use of the Beighton Scale, as in the Nathan et al. (2018) paper, whereby adult participants are deemed positive i...

    Show More
  • Strong conclusions made on limited and inconsistent evidence

    To the Editor,

    We read with great interest the systematic review by Joschtel et al.1 on the effects exercise training on physical and psychological health in children with pediatric respiratory diseases such as asthma, bronchiectasis, bronchopulmonary dysplasia and cystic fibrosis (CF). Undoubtedly, the authors should be commended for their effort that they have put into this systematic review on an important research topic. However, we would like to take the opportunity to express some methodological concerns related to the CF studies included in this review.

    Joschtel et al.1 included studies on children, adolescents and young adults aged between 4 and 21 years and excluded those with a study population mean age of 21 years. These contradictory criteria have led to a false inclusion of one study 2 that included patients aged 12-40 years (although with a mean (SD) age of 19.5 (6.4) and 19.4 (5.3) for the intervention and control groups, respectively). Other studies 3 4, in which the mean age of the participants is <21 years were not considered for this review. Specifically, 3 out of 4 groups from the Kriemler et al. study 3 would qualify to be included in this review. Joschtel et al.1 did not publish a review protocol and therefore pre-specified inclusion and exclusion criteria cannot be verified.

    Joschtel et al.1 have conducted a meta-analysis on peak oxygen uptake (VO2peak), despite substantial heterogeneity of study characteristics (i.e., study...

    Show More
  • The Physical Inactivity Economic Cost and Burden Data in Developing Countries

    Thank you to the authors for emphasizing this topic. Physical inactivity remains the big problem and major pandemic in the world. Besides Sweden, many developing and developed countries have this serious problems. Researchers may suggest that physical inactivity cost lead to bigger healthcare cost and economic burden in the future. Physical inactivity is contributed to about 6-10% of ischaemic heart disease, stroke, diabetes, breast and colon cancer(1). Global physical inactivity cost is estimated $67.5 billions in total which consist direct cost around $53.8 billions and indirect cost around $13.7 billions (2). As for Europe and North America, it remains higher cost than in Asia. In China, the total cost of physical inactivity is estimated total about $6.7 billions (3). As for Korea, cost as much as 83.6 million was contributed to physical inactivity(4). While in North America and Europe, it remains high each $28.9 billions and $15.5 billions in total cost (2).

    It is much appreciated that the research filling the gap of data especially in Sweden. Other countries especially developing countries, should have the same idea about calculating the economic cost of physical inactivity. The current data in developing countries are inadequate, both direct and indirect cost which are very important. So that, the government can realize the important and dangerous effects of physical inactivity. Implementation should be underlined more on promotive and preventive action rath...

    Show More
  • The current evidence no longer supports the term “extreme conditioning programes;” let’s call it high-intensity functional training instead.

    Dear Editor in Chief:

    We read with great interest the recently published article by Tibana and de Sousa (1) titled “Are extreme conditioning programmes effective and safe? A narrative review of high intensity functional training methods research paradigms and findings.” We appreciate the opportunity to write this letter and hope to clarify some of the authors’ conclusions. Although the authors provide several examples of what they refer to as “extreme conditioning programs” we will focus mainly on the statements and evidence related to High Intensity Functional Training (HIFT), more commonly known as CrossFitTM training, as the authors’ review focuses primarily on this particular training program. We feel the authors have taken a biased position in describing this type of training and that their position is based on inaccurate and highly speculative interpretations of a fraction of the existing literature.

    Research examining the acute and long-term responses to HIFT, as well as the incidence of injury, is quite limited. The observed responses predominantly describe changes from baseline and in the case of long-term adaptations, generally show a positive outcome. Further, the few studies that make comparisons to other exercise forms only show select differences. More importantly, by the authors’ own admission, research examining the risk of injury do not suggest HIFT/CrossFitTM to be different from other forms of recreational exercise. Yet, the authors descri...

    Show More
  • Leucocyte Rich and Poor Platelet Concentrates and Tenocyte Proliferation

    We read with interest the article by Parrish et al, “Normal platelet function in platelet concentrates requires non-platelet cells: a comparative in vitro evaluation of leucocyte-rich (type 1a) and leucocyte-poor (type 3b) platelet concentrates.”(1)

    Parrish et al define PRP as a preparation with a platelet concentration of at least 5x over baseline, yet the LP-PRP they prepared (Arthrex Autologous Conditioned Plasma) was significantly lower at 2x over baseline, while the LR-PRP (Mitek Sports Medicine PEAK PRP) was significantly higher at 8x over baseline. We might reasonably expect that the ratio of growth factors between their LR-PRP and their LP-PRP to be approximately 8x/2x or 4:1, and this was indeed the case as seen in their Figure 4.

    Subsequently, the authors grew tenocytes (tendon cells) exposed to serum derived from LR-PRP and LP-PRP preparations. Given that their LR-PRP was approximately 4 times richer in growth factors than their LP-PRP, we might reasonably expect that the 2.5% solution of serum derived from their LR-PRP have approximately the same effect as the 10% solution of serum derived from their LP-PRP. However, their 10% LP-PRP solution actually resulted in higher growth of tenocytes (2656 light units) than their 2.5% LR-PRP solution (1001 light units), as seen in their Table 5, but not discussed by the authors. The fact that their 10% LR-PRP-derived serum caused tenocytes to grow to confluence while their 10% LP-PRP-derived serum did...

    Show More
  • Lessons from a broad view of science: a commentary on Dr Robergs’ article

    I have read Dr Robergs’ article 1 with much enthusiasm, from the first to the last paragraph. He criticized my occasional piece article suggesting a probable Kuhnian paradigm shift in Exercise Sciences2. I was expecting comments and critiques to my provocative essay since its publication, approximately five years ago. Perhaps, as Philosophy of Science is complex and purely reflexive, just a few exercise scientists have devoted enough time to study it. I now have the opportunity to continue debating and applying some Philosophy in the Exercise Sciences perspective.
    Reading Dr Robergs’ 1 article drove me back to the Philosophy of Science to reexamine some crucial academic works essential to a better understanding of how science operates. Since my first critical essay as a beginner student in science, about “The objective knowledge” of Karl Popper 3 during lectures on the Philosophy of Science by Emeritus Professor Michel Paty at the University of São Paulo, my thinking has evolved through different views of science, from Francis Bacon to Karl Popper, from Thomas Kuhn to Paul Feyerabend. Thus, the biased commentary promoted by Dr Robergs towards the falsification method did not surprise me because Karl Popper was one of the first philosophers I read as a beginner in science. Neither was Dr Robergs’ 1 claim in favor of the falsification criteria in Exercise Sciences entirely new 4. As a philosophy-oriented scientist I learned that we may benefit from a wider view of scie...

    Show More
  • What, no consideration of heel-to-toe drop?

    I was surprised the authors did not take into consideration heel-to-toe height variances in SRSs, which can be significant (10+ mm). While this may have less effect on one's ability to land "softly" when running uphill, the opposite holds true on downward slopes; depending on the degree of slope, the heel is more likely to contact ground before or concurrent to the forefoot. At least, this has been my experience.

    Secondly, while it may be true that a directive to "run softly" will effect the gait and form of a runner upon hearing the instructions, and may even hold sway for a few minutes, the truth is that we all tend to revert to habits after a time, and doubly so when fatigue sets in.


  • The altered right/left heart stroke volume balance could play an essential role in the development of immersion pulmonary edema.

    To the editor,
    The postulated mechanisms of immersion pulmonary edema (IPE) or swimming induced pulmonary edema (SIPE) are not well understood. Most groups agree that an increase of cardiac preload plays a primary role. Several groups have assessed the effects of cold water and exercise on the increase of the filling of the heart right and pulmonary pressure.
    In a recent report by Moon et al1, the authors investigated, in a series of sudden deaths during triathlon training. They identified 58 deaths, of which 42 (72.4%) occurred during the swim. They found that, when compared with healthy triathletes and the general population, individuals who died during a triathlon or in training had a higher prevalence of cardiac anomalies that could predispose to immersion pulmonary oedema (IPO). The authors suggested that triathletes susceptible to IPO may have abnormal myocardial diastolic compliance (lusitropy) -or stiff hearts. They proposed that abnormal left ventricle (LV) diastolic compliance is partly responsible for elevated LV end-diastolic pressure similar to that observed in patients suffering from heart failure with preserved ejection fraction.
    It was shown, in a previous study by Moon et al. in this journal,2 that pulmonary artery and pulmonary artery wedge pressures are higher in SIPE-susceptible individuals during submerged exercise compared with the general population and these pressures are reduced by sildenafil. They confirmed the important role of...

    Show More