Usage of accelerometers within player tracking devices in sport to quantify load, vertical ground reaction force (vGRF) or energy expenditure is contrary to placement guidelines. This study aimed to determine whether trunk-mounted accelerometers were a valid and reliable method to estimate thoracic segment or centre of gravity (COG) acceleration or vGRF, and the whether the elasticised harness contributes to the overestimation of acceleration. Ten male amateur rugby players performed five linear running tasks per lower limb at three speeds, twice, each with a different player tracking unit. Three-dimensional data were recorded and triaxial accelerometers were attached lateral to the device on the harness and skin and both shanks. Accelerometers demonstrated poor reliability (ICC:0.0–0.67), high variability (CV%:14–33%) and change in mean (41–160%), and were not valid to estimate vertical acceleration of the COG and thoracic segment nor vGRF. Caution is advised when utilising trunk-mounted triaxial accelerometer data as it is not a valid or reliable means to estimate peak vertical acceleration for its thoracic location nor whole-body COG acceleration or vGRF during running. To improve player tracking instrument validity and reliability, a new attachment method and/or harness material(s), that reduce or eliminate extraneous acceleration during running, are urgently required.

In the November issue of Physiology , Sun et al. ([12][1]) published a review describing the role of lactate as a multi-tissue autocrine regulatory molecule influencing multiple cellular and systemic physiological functions. Such functions included transmembrane H+ transport, enzyme regulation,

A connection has been made to the possible role of the central governor model (CGM) to be a paradigm shift within the exercise sciences. Unfortunately, very little evidence was presented to support this notion, and a narrow view of scientific philosophy was used to reflect on the role of the CGM in understanding exercise physiology and the pursuit of a more ideal scientific method. When contrasting the scientific philosophies of Kuhn to Popper, and applying the tenant of falsification to the research and commentary on the CGM, it is probable that the scholarship pertaining to the CGM adheres more to pseudoscience than science. To improve the scientific contributions of research on the CGM, fellow scientists need to adopt a more critical platform where questions are raised and research designs are employed in efforts to refute the theory. The inability to falsify a theory is the most meaningful way to prove that it is likely to be correct. To support this development, the CGM needs to be more carefully worded to form a theory that clearly reveals key features that can be researched and potentially falsified. In addition, the wording of the CGM needs to allow scientists to make predictions that can then be tested in controlled experimental research studies. Until this happens for the CGM and all other pertinent paradigms within exercise physiology, the discipline will never rise out of the abyss of normal science to extraordinary science involving paradigm shifts and scientific revolutions.

Limited research and data has been published for the H⁺ coefficients for the metabolites and reactions involved in non-mitochondrial energy metabolism. The purpose of this investigation was to compute the fractional binding of H⁺, K⁺, Na⁺ and Mg²⁺ to 21 metabolites of skeletal muscle non-mitochondrial energy metabolism, resulting in 104 different metabolite-cation complexes. Fractional binding of H⁺ to these metabolite-cation complexes were applied to 17 reactions of skeletal muscle non-mitochondrial energy metabolism, and 8 conditions of the glycolytic pathway based on the source of substrate (glycogen vs. glucose), completeness of glycolytic flux, and the end-point of pyruvate vs. lactate. For pH conditions of 6.0 and 7.0, respectively, H⁺ coefficients (-‘ve values = H⁺ release) for the creatine kinase, adenylate kinase, AMP deaminase and ATPase reactions were 0.8 and 0.97, -0.13 and -0.02, 1.2 and 1.09, and -0.01 and -0.66, respectively. The glycolytic pathway is net H⁺ releasing, regardless of lactate production, which consumes 1 H⁺. For glycolysis fueled by glycogen and ending in either pyruvate or lactate, H⁺ coefficients for pH 6.0 and 7.0 were -3.97 and -2.01 (pyruvate), and -1.96 and -0.01 (lactate), respectively. When starting with glucose, the same conditions result in H⁺ coefficients of -3.98 and -2.67, and -1.97 and –0.67, respectively. The most H⁺ releasing reaction of glycolysis is the glyceraldehyde-3-phosphate dehydrogenase reaction, with H⁺ coefficients for pH 6.0 and 7.0 of -1.58 and -0.76, respectively. Incomplete flux of substrate through glycolysis would increase net H⁺ release due to the absence of the pyruvate kinase and lactate dehydrogenase reactions, which collectively result in H⁺ coefficients for pH 6.0 and 7.0 of 1.35 and 1.88, respectively. The data presented provide an extensive reference source for academics and researchers to accurately profile the balance of protons for all metabolites and reactions of non-mitochondrial energy metabolism, and reveal the greater role of glycolysis in net H⁺ release than previously assumed. The data can also be used to improve the understanding of the cause of metabolic acidosis, and reveal mechanistic connections between H⁺ release within and from muscle and the electrochemical neutrality concepts that further refine acid-base balance in biological solutions.

Introduction: Esports demand peak cognitive performance from esports athletes (e-athletes), yet their sedentary lifestyle raises concerns. This pilot study explores the effects of aerobic exercise on executive function, cerebral hemodynamics, and heart rate variability (HRV) during gameplay. Methods: Six high-ranking male e-athletes (20.8 ± 2.1 years old), ranking in the top 10% of their game, were recruited. Functional Near-Infrared Spectroscopy measured cerebral hemodynamics, cognitive tests assessed executive function, and electrocardiography measured HRV. Individualized exercise intensities were set through graded exercise testing, followed by a 10-week treadmill-based cardiovascular training program. Results: Postintervention, weight, and body mass index remained unchanged (p > .05), but the graded exercise test and heart rate deflection point significantly improved (p < .05). Executive function displayed faster reaction times in the Color Word Stroop Task, and notably more accurate responses in the Parametric Go/No-Go tasks (p < .05), with large effect sizes. Functional Near-Infrared Spectroscopy revealed decreased oxygenated hemoglobin levels during rest, with moderate to large effect sizes, while HRV variables showed significant increases with large effect sizes. Conclusions: This pilot study introduces a 10-week exercise regimen for e-athletes, suggesting positive impacts on cerebral hemodynamics, executive functions, and HRV, warranting further research.