Search

Abstract:Introduction: Kendo, a Japanese martial art, requires rigorous physical and mental training. Kendo practitioners who engage in daily mental training may experience a disparity between their subjective perception of exertion and the actual physiological load on their bodies. Methods: Fifteen healthy adult female kendo practitioners were recruited as participants. Participants were asked to report levels of exertion using the Ratings of Perceived Exertion (RPE) during a progressive, load-incremented stress test. The participants' heart rate at the time of reporting RPE13, which is considered a "somewhat hard" level of exertion, as well as heart rate at the anaerobic threshold (AT) to measure actual load, were compared to the maximum heart rate measurement obtained during the test. Results: The participants' heart rates at RPE13 were found to be higher than those at AT, based on their values as percentages of maximum heart rates. Conclusion: This study discovered that kendo practitioners engaged in regular mental training exhibited a higher heart rate at "somewhat hard" exertion (RPE13) compared to the anaerobic threshold (AT), indicating a relative increase in RPE. Additional research is necessary to determine if this effect is attributable to mental training. [ABSTRACT FROM AUTHOR]

The study explores the relationship between phase angle (PhA), an indicator of cellular health, and metabolic health parameters among junior sumo wrestlers in Japan. Given the demanding lifestyle and high‐energy diets of sumo wrestlers that predispose them to metabolic syndrome post‐retirement, this study focuses on a younger cohort. The primary aim is to evaluate if PhA could serve as an early indicator of metabolic health issues within this unique demographic. A total of 14 sumo wrestlers aged 9–17 years were assessed to determine the relationship between PhA and various metabolic markers, including glycated hemoglobin (HbA1c), using a TANITA MC‐780A‐N body composition analyzer and standard blood tests. Bivariate regression analysis and Pearson's correlation revealed a negative relationship between PhA and HbA1c even after adjusting for age and weight (ß = −0.496, r2 = 0.776, r = −0.756, p = 0.004). The results indicate a significant negative relationship between PhA and HbA1c levels, suggesting that lower PhA values, which indicate poorer cellular integrity, are associated with higher HbA1c levels, signifying impaired glycemic control. These findings underscore the potential of PhA as a valuable biomarker for monitoring metabolic health in young sumo wrestlers, with implications for early intervention and management strategies. [ABSTRACT FROM AUTHOR]

Simple Summary: The present study aims to establish a method of whole mitochondrial DNA (mtDNA) sequencing for domestic dogs. Prior to proceeding with the experiment, the collection of relevant DNA samples was essential. Therefore, we decided to use oral mucosa DNA, which can be collected non-invasively. A polymerase chain reaction (PCR) was performed using the DNA collected from six dogs raised in Japan and four primer pairs as specific to the mtDNA, after which the amplified products were sequenced using next-generation sequencing. As a result, the whole mtDNA obtained from all dogs was correctly sequenced. Thus, we determined that the method we used in our study may be useful for future research on dog-related medical care and welfare. In human beings, whole mitochondrial DNA (mtDNA) sequencing has been widely used in many research fields, including medicine, forensics, and genetics. With respect to the domestic dog (Canis lupus familiaris), which is commonly recognized as being an additional member of the traditional human family structure, research studies on mtDNA should be developed to expand and improve our collective knowledge of dog medicine and welfare as it seems that there is still room for further development in these areas. Moreover, a simple and robust method for sequencing whole mtDNA that can be applied to various dog breeds has not yet been described in the literature. In the present study, we aim to establish such a method for the whole mtDNA sequencing of the domestic dog. In the experiments we conducted, oral mucosa DNA samples obtained from six Japanese domestic dogs were used as a template. We designed four primer pairs that could amplify approximately 5 kbp from each region of the mtDNA and validated several PCR conditions. Subsequently, the PCR amplicons were pooled and subjected to library preparation. The sequencing of the libraries was performed using next-generation sequencing (NGS), followed by bioinformatics analysis. Our results demonstrate that the proposed method can be used to perform highly accurate resequencing. We believe that this method may be useful for future research conducted to better understand dog medicine and welfare. [ABSTRACT FROM AUTHOR]

Cryotherapy is one of the most common treatments for trauma or fatigue in the field of sports medicine. However, the molecular biological effects of acute cold exposure on skeletal muscle remain unclear. Therefore, we used zebrafish, which have recently been utilized as an animal model for skeletal muscle, to comprehensively investigate and selectively clarify the time-course changes induced by cryotherapy. Zebrafish were exposed intermittently to cold stimulation three times for 15 min each. Thereafter, skeletal muscle samples were collected after 15 min and 1, 2, 4, and 6 h. mRNA sequencing revealed the involvement of trim63a , fbxo32 , fbxo30a , and klhl38b in "protein ubiquitination" from the top 10 most upregulated genes. Subsequently, we examined the time-course changes of the four genes by quantitative PCR, and their expression peaked 2 h after cryotherapy and returned to baseline after 6 h. Moreover, the proteins encoded by trim63a and fbxo32 (muscle-specific RING finger protein 1 [MuRF1] and muscle atrophy F-box, respectively), which are known to be major genes encoding E3 ubiquitin ligases, were examined by western blotting, and MuRF1 expression displayed similar temporal changes as trim63a expression. These findings suggest that acute cold exposure transiently upregulates E3 ubiquitin ligases, especially MuRF1; thus, cryotherapy may contribute to the treatment of trauma or fatigue by promoting protein processing. • Acute cold stress affected the expression of multiple genes, mainly those related to E3 ubiquitin ligases. • The increase in gene expression was transiently induced, peaking at 2 h after cold exposure and returning to baseline by 6 h. • In particular, the protein expression of MuRF1 (encoded by trim63a) was significantly increased. • Cryotherapy may contribute to recovery from trauma or fatigue by promoting the processing of damaged or unfolded proteins. [ABSTRACT FROM AUTHOR]

Recently, fasting has been spotlighted from a healthcare perspective. However, the de-tailed biological mechanisms and significance by which the effects of fasting confer health benefits are not yet clear. Due to certain advantages of the zebrafish as a vertebrate model, it is widely utilized in biological studies. However, the biological responses to nutrient metabolism within zebrafish skeletal muscles have not yet been amply reported. Therefore, we aimed to reveal a gene expression profile in zebrafish skeletal muscles in response to fasting-refeeding. Accordingly, mRNA-sequencing and bioinformatics analysis were performed to examine comprehensive gene expression changes in skeletal muscle tissues during fasting-refeeding. Our results produced a novel set of nutrition-related genes under a fasting-refeeding protocol. Moreover, we found that five genes were dramatically upregulated in each fasting (for 24 h) and refeeding (after 3 h), exhibiting a rapid response to the provided conditional changes. The assessment of the gene length revealed that the gene set whose expression was elevated only after 3 h of refeeding had a shorter length, suggesting that nutrition-related gene function is associated with gene length. Taken together, our results from the bioinformatics analyses provide new insights into biological mechanisms induced by fasting-refeeding conditions within zebrafish skeletal muscle. [ABSTRACT FROM AUTHOR]

Despite the World Anti-Doping Agency (WADA) ban on gene doping in the context of advancements in gene therapy, the risk of EPO gene-based doping among athletes is still present. To address this and similar risks, gene-doping tests are being developed in doping control laboratories worldwide. In this regard, the present study was performed with two objectives: to develop a robust gene-doping mouse model with the human EPO gene (hEPO) transferred using recombinant adenovirus (rAdV) as a vector and to develop a detection method to identify gene doping by using this model. The rAdV including the hEPO gene was injected intravenously to transfer the gene to the liver. After injection, the mice showed significantly increased whole-blood red blood cell counts and increased expression of hematopoietic marker genes in the spleen, indicating successful development of the gene-doping model. Next, direct and potentially indirect proof of gene doping were evaluated in whole-blood DNA and RNA by using a quantitative PCR assay and RNA sequencing. Proof of doping could be detected in DNA and RNA samples from one drop of whole blood for approximately a month; furthermore, the overall RNA expression profiles showed significant changes, allowing advanced detection of hEPO gene doping. [ABSTRACT FROM AUTHOR]

The prevalence of nonalcoholic fatty liver disease (NAFLD) has been rapidly increasing worldwide. A choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) has been used to create a mouse model of nonalcoholic steatohepatitis (NASH). There are some reports on the effects on mice of being fed a CDAHFD for long periods of 1 to 3 months. However, the effect of this diet over a short period is unknown. Therefore, we examined the effect of 1-week CDAHFD feeding on the mouse liver. Feeding a CDAHFD diet for only 1-week induced lipid droplet deposition in the liver with increasing activity of liver-derived enzymes in the plasma. On the other hand, it did not induce fibrosis or cirrhosis. Additionally, it was demonstrated that CDAHFD significantly impaired mitochondrial respiration with severe oxidative stress to the liver, which is associated with a decreasing mitochondrial DNA copy number and complex proteins. In the gene expression analysis of the liver, inflammatory and oxidative stress markers were significantly increased by CDAHFD. These results demonstrated that 1 week of feeding CDAHFD to mice induces steatohepatitis with mitochondrial dysfunction and severe oxidative stress, without fibrosis, which can partially mimic the early stage of NASH in humans. [ABSTRACT FROM AUTHOR]

Background Sumo is a sport that requires wrestlers to develop their physique from childhood for athletic advantage. However, the energy expenditure and energy balance required for the growth of junior Sumo wrestlers remain unclear. This study aimed to determine the energy balance of junior Sumo wrestlers over six months using doubly labeled water (DLW) and bioelectrical impedance analysis (BIA). Methodology A total of 12 male Sumo wrestlers were affiliated with a local Sumo club (average age = 15 ± 1 years). The total energy expenditure (TEE) was measured using DLW, whereas body composition was evaluated using BIA. Daily physical activity was quantified using a tri-accelerometer (Active style Pro HJA-750C). Results The TEE was 4,194 ± 734 kcal/day, while daily physical activity without training was 786 ± 50 minutes. Within six months, the body weight increased by 2.0 ± 3.2 kg, fat-free mass (FFM) was augmented by 2.1 kg, while fat mass did not change significantly. The surplus energy accumulated was 5.6 ± 213 kcal/day. Conclusions The excess energy of junior Sumo wrestlers predominantly increases their FFM. To increase their physical prowess, wrestlers adhere to a lifestyle characterized by high-intensity training and attenuated daily physical activity., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Institutional Review Board of the University of Tsukuba, Institutes of Health and Sports Sciences issued approval Ref.Tai 019-156. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: This work was supported by Research Fellowships from JSPS KAKENHI awarded to HS (18K17882 and 23H03279) and KW (23K10738), as well as the Tanuma Green House Foundation awarded to HS. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Ogawa et al.)

Wrestlers have a risk of relative energy deficiency in sports because they believe that they can gain an advantage over their opponents by temporarily adopting weight-making strategies even women. However, precise methods of making weight and the effect of manipulating body mass (BM) on health and performance in female wrestlers have not been reported. Our study aimed to report a case of weight making in a world-class female wrestler, who won the world competition seven times in 5-y and had oligomenorrhea. We obtained the BM, blood, urine, and saliva samples, hand grip strength, subjective condition a month before the match (baseline), and 3-d before the match (day-3), and food and physical activity records during baseline and 10 d before the competition. The wrestler lost 4.7% of BM from baseline to day-3 and 7.6% of BM to the match by method to reduce energy intake and enhance dehydration. Hand grip strength did not change by weight loss. After weigh-in, the wrestler took the recovery food containing 4.9 g/kg BM of carbohydrate. Although these weight strategies may at least contribute to the success of wrestlers, the impact on health needs to be clarified in future studies.

In human beings, whole mitochondrial DNA (mtDNA) sequencing has been widely used in many research fields, including medicine, forensics, and genetics. With respect to the domestic dog ( Canis lupus familiaris ), which is commonly recognized as being an additional member of the traditional human family structure, research studies on mtDNA should be developed to expand and improve our collective knowledge of dog medicine and welfare as it seems that there is still room for further development in these areas. Moreover, a simple and robust method for sequencing whole mtDNA that can be applied to various dog breeds has not yet been described in the literature. In the present study, we aim to establish such a method for the whole mtDNA sequencing of the domestic dog. In the experiments we conducted, oral mucosa DNA samples obtained from six Japanese domestic dogs were used as a template. We designed four primer pairs that could amplify approximately 5 kbp from each region of the mtDNA and validated several PCR conditions. Subsequently, the PCR amplicons were pooled and subjected to library preparation. The sequencing of the libraries was performed using next-generation sequencing (NGS), followed by bioinformatics analysis. Our results demonstrate that the proposed method can be used to perform highly accurate resequencing. We believe that this method may be useful for future research conducted to better understand dog medicine and welfare.

Background: Rugby showed a high incidence of exertional heatstroke. Different physiques and running performances between the forward and back players (FW and BK) may result in different heatstroke risks. This study aimed to compare the hydration status, running performance, and perceived heatstroke symptoms (PHS) between cool and hot environment training (HT and CT) in university rugby union FW and BK., Methods: Thirteen university rugby players (seven forwards and six backs) participated in this study. During both conditions, players were allowed to drink water and sports drink, and the amount of fluid intake was recorded. Body mass was measured pre- and post-training, and weight loss was calculated. Sweat loss was calculated based on body mass and fluid intake. During training, running performance was measured using GPS. The presence of PHS was assessed using a questionnaire administered after training., Results: Fluid intake and sweat loss were higher in the HT as opposed to the CT, and FW showed higher fluid intake and dehydration than BK. However, there were no significant differences in weight loss observed during data collection. Running distance per minute and maximum speed were higher in BK than in FW, but there was no significant difference between conditions. Although a significant weight loss was not observed between conditions, the number of PHS was higher in the HT., Conclusions: Although BK had a higher running distance and maximum speed than FW during training, a higher cycle of fluid intake and sweat loss was observed in the FW than that in the BK.

Purpose: Exercise is a key factor in preventing obesity and metabolic syndrome. Sumo wrestlers increase their body size from childhood for athletic advantage; however, the risk of metabolic syndrome in junior sumo wrestlers is undetermined. Preventive measures against pediatric obesity should be initiated during childhood to prevent obesity in adulthood, considering its high global incidence. We comparatively evaluated the risk factors for metabolic syndrome in junior sumo wrestlers and children with obesity., Methods: We enrolled 70 male children (age 9-17 years [sumo group, n = 14] and 9-14 years [other sports and non-exercise groups, n = 28 each]) and evaluated their anthropometric parameters (height, weight, body mass index z-score, obesity rate, waist circumference, waist to height ratio) and hematological parameters (total, low-density, high-density, and non-high-density lipoprotein-cholesterol; triglycerides; plasma glucose, and glycated hemoglobin levels)., Results: The BMI z-score, obesity rate, waist circumference (p < 0.05, along with the non-exercise group), and systolic blood pressure were significantly higher and the high-density cholesterol level was lower in the sumo group than in the other sports group (p < 0.05). The waist to height ratio was significantly higher in the non-exercise group than in the other sports group (p < 0.05). No significant difference was found in other blood lipid, plasma glucose (significantly lower level than the reference range in the sumo group, p < 0.05), and glycated hemoglobin (within the reference range in all groups) levels among the three groups., Conclusion: Junior sumo wrestlers had a larger body size and higher blood pressure than children with obesity who exercised regularly. This provides direction for future research into targeted preventive interventions against metabolic syndrome for junior sumo wrestlers with large body size.