Objective: We aimed to establish a novel approach that enables the prediction of behavioral effects of lesions using neuroimaging data, which is applicable to sportological analyses, particularly in identifying the links between brain activity and behavior related to sports.
Materials and Methods: Experimental details are described in our previous reports (Miyamoto et al., 2013; Osada et al., 2015). Four monkeys (M. mulatta and M. fuscata) were used. All experimental protocols, animal welfare, and steps for minimizing suffering were in full compliance with the Guidelines for Proper Conduct of Animal Experiments by Science Council of Japan.
Functional images were acquired using a 4.7-T MRI scanner (Biospec47/40, Bruker) during a recognition or temporal-order judgment task. Monkeys performed the tasks while sitting in an MRI-compatible chair. Group analyses of image data were conducted using SPM5.
Results: A task-evoked connectivity network was identified based on data from the functional imaging conducted during recognition tasks (Miyamoto et al., 2013) and temporal-order judgment tasks (Osada et al., 2015). A significant positive correlation was observed between the predicted impact on performance and the betweenness centrality based on task-evoked connectivity network, whereas no correlation was observed between the predicted impact on performance and the betweenness centrality based on anatomical connectivity network.
Conclusions: Severity of impairment arising from local brain damage was predicted by network “hubness” of the damaged area in the task-evoked connectivity network. These findings will form the basis for future research that aims to predict the functional brain center for watching or partaking in sports.
Participation in sports by children in the United States over the past 3 decades has seen a move from spontaneous and fun activity by children and adolescents to a more organized and competitive activity largely governed by adults and sports governing organizations. With this shift we have also seen a trend in participation in organized sports at younger age, increase in intensity in activity level, and specialization in a single sport from an early age. These and other factors contribute to an increased incidence of sport related overuse injuries in children and adolescents. Another area of intense debate and scrutiny is the long term neurocognitive impact in adolescents of sport-related concussions. Recognition of adverse long term impact of sport related concussions on developing brain has resulted in increased education efforts, prevention strategies, and legislative activity. Screening of young athletes for cardiovascular disease to prevent sudden cardiac death also continues to be a subject of ongoing intense debate in the United States.
A number of familial and twin studies have assessed the relative contribution of genetic and environmental factors to physical performance or its-related traits, and a significant genetic component has been predicted to affect phenotypes. A twin study indicated that the heritability of athletic status is 66%. Thus, genetic factors appear to be important for determining elite sporting performance. To date, over 200 genes in both nuclear DNA and mitochondrial DNA (mtDNA) have been reported to be associated with physical performance and health-related fitness. However, most studies have been reported in European populations. In the Asian population, only 3 genetic loci have been linked to physical performance, including angiotensin I-converting enzyme and α-actinin-3 genetic polymorphisms and mtDNA polymorphisms (mitochondrial haplogroups). In this review, we discuss the genetics of elite sporting performance, particularly in Asian populations, and their effects on lifestyle-related diseases such as type 2 diabetes and age-related muscle wasting (i.e., sarcopenia).
The prevalence of coronary artery disease (CAD) has increased over the last several decades in Japanese population. Recent epidemiological studies have indicated that the incidence of acute myocardial infarction (MI) has increased, particularly in the urban areas of Japan. Previous data have strongly supported the important role of lifestyle intervention, including physical activity and dietary modification to improve glucose and insulin homeostasis, lipid profiles, and other risk factors for the prevention of CAD. Cardiac rehabilitation (CR) is a comprehensive intervention that includes supervised exercise training, risk factor control, patient education, and psychosocial counseling. CR has been reported to be effective in reducing the risk of cardiovascular events through intensive lifestyle modification. However, the implementation of CR is still low even in academic cardiovascular institutes. In this review, we will discuss the recent status and problems regarding the safety and efficacy of CR and will discuss the future directions of CR in patients with CAD in Japan.
Obesity and its associated metabolic disorders are rapidly disseminating all over the world. While they became serious health problem, such diseases in Asians shows different features from those in other races such as Caucasian and African. One of the important features is a susceptibility to develop to type 2 diabetes even without excess body mass index. To search for the mechanism underlying this feature is important to find the suitable therapeutic strategy for Asian obesity. Thus, as a core study of the Sportology Center of Juntendo University Graduate School of Medicine, we assessed tissue-specific insulin resistance in Japanese non-obese subjects. In this study, we recruited non-obese and non-diabetic Japanese subjects and measured insulin sensitivity in muscle and liver by a 2-step hyperinsulinemiceuglycemic clamp with glucose tracer and ectopic fat content in muscle and liver by proton magnetic resonance spectroscopy. So far, our data suggests that muscle insulin resistance may play a central role in future onset of the diseases that could make the healthy people to disable people.
“Locomotive syndrome” is defined as a condition associated with being restricted in one’s ability to walk or lead a normal life owing to a dysfunction in one or more of the parts of the locomotion system, including the muscles, bones, joints, cartilage or the intervertebral discs. This syndrome especially refers to those elderly who have come to need nursing care services because of problems with the locomotive organs, or who have conditions which may require them to have such services in the near future. The recent epidemiological studies revealed that the one fourth of the reasons for requiring special assistance or nursing care in elderlies is currently the locomotive disorders. Osteoarthritis of the knee (knee OA) or hip and the spinal canal stenosis due to spondylosis are the three major locomotive disorders those are related to the requiring special assistance or nursing care in elderlies. We are trying to elucidate the mechanistic insight into the pathophysiology of knee OA and osteoporosis by receiving several supports, such as the COI program by a MEXT and the Juntendo Sportology Center under the concept of “Sportology”, as we believe to be able to contribute directly the concept of “locomotive syndrome” by these actions.
Mechanical stresses play various different roles in regulating organismal functions, depending on the situation when and where they are borne. Cell signaling related to ‘straining’ mechanical stresses, such as cell stretching, pressurizing, cytoskeletal tensioning, adhesion to stiff substrate, and high traction force generation, is imperative in the ‘constructive’ phase of tissues and organs, including development, regeneration and repair. However, once steady state is reached upon completion of tissue/organ formation, straining mechanical stress often causes failure of organismal homeostasis, such as inflammation and cancer. In contrast to such ‘detrimental’ aspect of straining stress, relaxing mechanical stress contributes to maintenance of homeostasis. Collectively, balance and integration between straining and relaxing mechanical stresses is vital, whose disruption gives rise to diseases, particularly those related to ageing or physical inactivity (Figure-1).
In obesity, plasma adiponectin is reduced, which causes insulin resistance and atherosclerosis. We identified its receptors AdipoR1 and R2, and showed that they exert antiaging effects via activation of AMPK/SIRT1 and PPAR-α pathways, respectively, leading to increased mitochondria as well as decreased ectopic fat accumulation, oxidative stress and inflammation. Recently, we identified orally active small-molecule AdipoR agonist AdipoRon, which bound to AdipoR, showed very similar effects to adiponectin in muscle and liver, such as increased exercise endurance and energy expenditure, and ameliorated insulin resistance via AdipoR in obese mice, leading to healthy longevity. Most recently, we determined and reported the crystal structures of human AdipoR, which will facilitate the understanding of novel structure-function relationships and the optimization of AdipoRon as exercise mimetics.
Objective: Lipid droplets (LDs) are cytoplasmic inclusions that have a neutral lipid core with a single phospholipid layer, while excess free fatty acids and glucose in plasma are converted to triacylglycerol (TAG) and stored as LDs. However, the mechanism for the generation and growth of LDs in cells is largely unknown. This review will explain the relationship between LD formation and autophagy.
Results: LD formation accompanied by accumulation of TAG induced by starvation was largely suppressed in the hepatocytes and cardiac myocytes that cannot execute autophagy. Under starvation conditions, LDs in addition to autophagosomes were abundantly formed in the cytoplasm of these tissue cells, although autophagosomes did not appear in wild-type and autophagy-unable cardiac myocytes. Moreover, LC3 was localized on the surface of LDs and LC3-II (lipidation form) was fractionated to a perilipin-positive lipid fraction from the starved liver.
Conclusion: Taken together, these results indicate that the LC3 conjugation system is critically involved in lipid metabolism via LD formation.
The hypothalamus contains several sub-nuclei that regulate autonomic functions such as hunger and thirst. The hypothalamus is a small structure of less than 1 cubic centimeter in each hemisphere of the human brain, and very little is known about precise anatomical organization and functional properties of the hypothalamus in the human brain. In this study, in collaboration with departments of endocrinology and radiology, high-resolution fMRI was conducted, while blood glucose level was monitored (Figure-1). Cubic voxels of 1.25 mm were employed, rather than standard high-resolution fMRI of 2 mm cubic voxels, which allowed us to divide the human hypothalamus into several sub-regions using a boundary mapping method based on the resting-state functional connectivity. The defined sub-regions were used to track fMRI signal time-courses when the blood glucose level was manipulated by OGTT. Our preliminary results showed prominent signal changes after OGTT in specific sub-regions in the hypothalamus, and promise future studies of mapping autonomic functions in the human hypothalamus.
Approximately 30% of Japanese citizens will be aged 65 or older in 2020, and this ratio will be the highest worldwide. An estimated 4.6 million individuals in Japan and 44 million individuals globally have been diagnosed with dementia. Exercise has been identified as a potential means of preventing or delaying cognitive decline. Several epidemiological studies on older adults demonstrated that gait speed was associated with cognitive function. Randomized control studies on physical exercise interventions also indicated that aerobic exercise is beneficial for cognitive function. In order to determine the effects of short-term treadmill exercise on tau protein modifications, we employed a 3-week treadmill treatment using tau model mice. The results obtained showed increases in oxidative stress, microglial cell proliferation, and C-terminal tau phosphorylation. Previous studies reported that long-term treadmill treatments were beneficial. Therefore, positive compensatory changes may occur with the continuation of treadmill training in mice. The molecular mechanisms underlying the relationship between physical exercise and cognitive function still remain unknown; however, their elucidation may lead to the identification of a novel molecule, which may ultimately result in a cure for dementia.
Recent advances of MR imaging allow us to visualize the functional and structural changes of the brain not only in the patients with neurological disorders, but also in normal subjects. Sophisticated MR techniques, such as resting-state functional MR and diffusion MR imaging, can depict subtle brain changes in normal subjects before metabolic syndrome as well as brain changes after a few weeks muscle training. Minimal structural changes in the brain after repeated minor head trauma during sports are now highlighted, because advanced MR techniques can be used to show substantial changes in the brain before neurological decline.
By diffusion tensor imaging (DTI), we can explore microstructure of the tissue in vivo through analysis of water diffusion direction and restriction. DTI was developed mainly in the central nervous system to visualize the white matter tracts and their networks. Plasticity of the brain white matter has been reconfirmed with this technique. Skeletal muscles also have the direction and restriction of water diffusion and can be analyzed by DTI as well.
Recent advances of MR techniques for sportology, especially diffusion MR imaging, will be presented in this paper.
Purpose: Alzheimer disease (AD), involved the abnormal metabolism of β-amyloid and tau, is the major cause of dementia among elderly. Diabetes mellitus (DM) has been identified as a risk factor of AD. Two pathological lesions of AD, Aβ plaques and neurofibrillary tangles, are linked to neuroinflammation and lipid peroxidation, are also induced by abnormal glucose metabolism. Here, we examined the effects of experimental DM in tau transgenic mice Tg601 (overexpressing wild-type human tau) and analyzed the brain regional difference occurred due to DM in AD.
Methods: Hippocampus, midbrain and cerebellum were analyzed from streptozotocin (STZ) injected of Tg601 and non-transgenic (NTg) mice. Immunoblotting and immunohistochemistry (IHC) were performed to assess tau hyperphosphorylation, and IHC to evaluate Ionized calcium binding adaptor molecule-1 (Iba-1) and CD68 positive microglia. Inflammatory cytokines including IL-1β, IL-6, and IL-10 were assayed using multiplexed bead based immunoassay. IL-18 was measured by enzyme linked immunosorbent assay (ELISA) and lipid peroxidation products 4-hydroxy-trans-2-noneal (HNE) and malondialdehyde (MDA) by ELISA and thiobarbituric acid reactive substances assay, respectively.
Results: STZ injection induced tau hyperphosphorylation, as detected by AT8 and AT180 antibodies, in the hippocampus, but not in the cerebellum or midbrain of Tg601 and NTg mice. STZ treatment also elevated the number of Iba1-positive microglial cells, levels of IL-1β, IL-6, IL-10 and IL-18, and lipid peroxidation markers MDA or HNE in the hippocampus of the brain.
Conclusions: These results indicated that hyperglycemia-induced tau hyperphosphorylation, neuroinflammation and oxidative stress occurred more severely in the hippocampus than other parts of the brain and could contribute to selective neurodegeneration in human AD.
Background: Physical exercise has been reported as a preventive measure of Alzheimer's disease, one of the neuropathological hallmarks of which, neurofibrillary tangles, consist of hyperphosphorylated insoluble tau. Long-term treadmill exercise reduced tau hyperphosphorylation: however, it remains unknown whether short-term treadmill exercise alters tau modifications.
Aim: Here we attempted to characterize the effects of short-term treadmill exercise on tau solubility and determine its relationship with neuroinflammation using tauopathy model mice (Tg601).
Results: 3 weeks of non-shock treadmill exercise in Tg601 and non-transgenic mice markedly increased insoluble tau by increasing the phosphorylation at the tau C-terminal end, particularly at Ser396. The results of immunohistochemical analyses revealed that short-term treadmill exercise increased the number of Ionized calcium binding adaptor molecule-1 (Iba-1) positive microglia in the hippocampus. Elevations in the levels of the lipid peroxidation markers 4-hydroxy-trans-2-noneal and malondialdehyde indicated the presence of oxidative stress.
Conclusion: Our results suggested that short-term forced exercise was harmful rather than beneficial to Alzheimer’s pathology.
Purpose: Eye movements are important factors for dynamic visual acuity (DVA) that refers to the ability to perceive fine details of a moving object. When tracking a moving visual stimulus, we often combine smooth eye movements with catch-up saccades. The velocity of saccade eye movements (up to 500-600 deg/s) is much faster than smooth pursuit (usually less than 50 deg/s). Even though a tracking ability using these two kinds of eye movements is thought to play a critical role in DVA, it is still uncertain whether better DVA is associated with an ability of catch-up saccades. The first purpose of this study was to quantitatively clarify the effects of vision training on DVA and eye movements. Therefore, we repetitively measured the eye movements during DVA training and attempted to determine the effects of visual training on saccade eye movements. The second purpose was to assess the concentration of serum and plasma brain-derived neurotrophic factor (BDNF) level before and after vision training. BDNF is a member of the neurotrophin family of growth factors, which are related to the canonical Nerve Growth Factor. Previous studies have reported that moderate intensity exercise leads to increase in BDNF. However it is unknown whether BDNF level is correlated with eye movements. Therefore, we examined the correlation between BDNF level and eye movement parameters.
Methods: DVA was evaluated by a moving visual target (Landolt ring) that was projected on the front screen (HI-10; Kowa, Japan). Eye movements were detected using a video based eye tracking system (Eye Link1000; SR research, Canada). We have performed measuring DVA in five subjects (mean age; 19.0±2.6, age range; 19 to 21 years old) and analyzed saccades eye movements quantitatively using custom analytical software (Matlab; Mathworks Inc., USA). Subjects were seated in front of a screen and put their jaw on a chin supporter of our device to stabilize the head. The subjects were asked to follow the Landolt ring moving across in front of their visual field and judge the direction of the slit. We analyzed saccade latency (msec), peak velocity (deg/sec), error (deg) and a correct response rate (%). The Landolt ring moved either from right to left or left to right with constant speed of 300 deg/s. A total of eight measurements were performed for each subject. We took blood samples from each subject before and after vision training and checked serum and plasma level of BDNF.
Results: Our results demonstrated that saccade latency and error showed significant decreases and the correct response rate increased after training for five subjects. Especially for the result of correlation analysis, the correct response rate showed a correlation coefficient of 0.63 (p=0.021), indicating a stronger correlation than the other three parameters. In contrast, saccade peak velocity showed different results among subjects. For three subjects, the velocity increased while two subjects showed a decrease in velocity after training. The results of the analysis showed a significant positive correlation of the concentration of plasma BDNF level with velocity and the correct response rate. However, the results showed a significant negative correlation of the concentration of plasma BDNF level with latency and error. It was also revealed that the results of plasma and serum BDNF level were contrary to each other.
Conclusion: Our study provided several lines of evidence showing that saccade eye movements, such as latency, error and peak velocity changed after vision training. Since our results showed that visual training improved DVA, better DVA could be associated with the tracking ability using catch-up saccades. We were also able to clarify that the plasma and serum BDNF possibly affected actual eye movements.
Although it is widely accepted that cerebrovascular events associated with diabetes mellitus adversely affect the brain, it is less well known that diabetes mellitus itself or even prediabetes can also do so. In this presentation, we focus on this issue by using evidence from recent diffusion tensor neuroimaging studies of patients with diabetes mellitus or metabolic syndrome.
First, through the Sportology project, we explored the regional patterns of white matter alteration in subjects with metabolic syndrome. We also investigated whether the degree of white matter alteration was correlated with BMI. Seven middle-aged men with metabolic syndrome and seven without metabolic syndrome underwent diffusion tensor imaging. MRI scans were performed with a 3.0-T unit (Achieva; Philips Medical Systems, Best, the Netherlands). We analyzed the resultant fractional anisotropy (FA) values by using a tractbased spatial statistics technique. We subsequently measured the mean FA values of the right inferior fronto-occipital fasciculus (IFOF) in all subjects by using a tract-specific analysis. We used Pearson’s correlation coefficient to evaluate the relationship between BMI and the mean FA value in the right IFOF. In the whole-brain analysis, subjects with metabolic syndrome had significantly lower FA values than control subjects in part of the right external capsule (which is part of the right IFOF), the entire corpus callosum, and part of the deep white matter of the right frontal lobe. In the regional brain analysis, the mean FA value of the right IFOF was 0.41±0.03 in subjects with metabolic syndrome and 0.44±0.05 in control subjects. A significant negative correlation was observed between BMI and FA values in the right IFOF (r=-0.56, p<0.04). These results suggest that there are microstructural changes in the white matter of middle-aged individuals with metabolic syndrome. Our findings add to the increasing body of neuroimaging evidence on white matter alteration in patients with hypertension, diabetes, or metabolic syndrome. Microstructural alterations in the white matter of younger obese individuals may precede brain atrophy or cognitive impairment, or both, in advanced metabolic syndrome.
Second, again through the Sportology project, we explored the regional patterns of white matter alteration in 15 hypertensive middle-aged male participants and 11 normotensive controls by using diffusion kurtosis imaging (DKI)-based whole-brain analysis. DKI data were acquired by use of a single-shot, spin-echo planar imaging sequence. Mean diffusional kurtosis (MDK) values in many brain regions were higher in subjects with hypertension than in control subjects, indicating that there were widespread microstructural changes in the white matter, whereas the conventional diffusion metrics of FA did not differ significantly between subjects with hypertension and normal controls. Moreover, MDK values over the whole brain were significantly and positively correlated with systolic and diastolic blood pressure. This finding suggests that microstructural white matter changes occur in middle-aged men with hypertension, even before the onset of cerebrovascular disease. DKI might therefore be useful as a screening tool for risk of cerebrovascular disease.
DTI is completely noninvasive and is sensitive to white matter pathology in a number of disorders, including metabolic syndrome, in the human brain in vivo. Accumulated evidence highlights the need to further elucidate the relationship between metabolic syndrome and other neuronal mechanisms. A clear understanding of these relationships is crucial for managing patients with metabolic syndrome.
Background: Dilated cardiomyopathy (DCM) is one of major causes of heart failure (HF), characterized by ventricular dilatation and contractile dysfunction. In addition to HF, about 30-40% of patients with DCM die from premature death with lethal arrhythmia. To date, the exercise is considered to be one of therapy for HF as shown in the guideline for chronic HF (Japanese Society of Cardiology in 2010). However, the effects of exercise on DCM patients are still unclear, because evaluation of exercise therapy in DCM patients is associated with risks of worsening of HF or sudden cardiac death. Investigations with animal models of inherited DCM are necessary. Previously, we have established the method to evaluate the severity of HF using a mouse model of DCM (Sugihara et al. PLoS One, 2013). In the course of these studies, we found that voluntary exercise started at young age significantly prolongs survival rate of DCM mice. In this study, we investigated the effects of voluntary exercise on the cardiac function and arrhythmogenesity in DCM model mice.
Methods: We used a knock-in mouse model having one of human inherited DCM mutation, TNNT2 ΔK210, which decreases Ca2+ sensitivity of myofilaments (Du et al. Circ Res, 2007). Homozygous ΔK210 (below are called DCM mice) and wild type (WT) mice at 1 month-old were housed with a running wheel (diameter=12 cm) every 48 hours or all day long, and daily voluntary running activity was recorded. At 2 month-old, end-diastolic dimension and ejection fraction (EF) were measured by echocardiography. Heart, lung and lower extremity muscle (soleus, plantaris and gastrocnemius muscles) were excised and their weights were measured together with body weight. Gene expressions of major ion channels (Kv1.5, Kv4.2, KChiP2, Nav1.5, Cav1.2, etc.,) were quantified by real time PCR analysis.
Results and Discussion: DCM mice died with t1/2 of approximately 70 days as reported previously (Du et al, 2007). The average lifespan of the DCM mice who continued running exercise every 48 hours was about 20 days longer than that without exercise. Moreover, systolic cardiac function defined by the average EF was higher in DCM mice with exercise than in those without exercise [0.47±0.10 (n=7) vs. 0.31±0.10 (n=4), p<0.05] at 3 month-old. On the other hand, electrical remodeling such as down-regulation of multiple types of K+ channels and accessory subunits has been reported in the DCM mice and closely related to the arrhythmogenesity in them (Suzuki et al. PLoS One, 2012). Some of these expression in DCM mice starting exercise at young age were relatively preserved (n=6). We further discuss the relationship between cardiac function, electrical remodeling and leg muscle weights as a measure of exercise intensity.
Purpose: Regular bouts of endurance exercise can protect the heart against ischemia/reperfusion (I/R) injury. However, the effects of acute exercise immediately before I/R events on myocardial dysfunction remain unclear. This study examined (1) whether a single session of acute exercise reduced cardiac dysfunction after I/R, and (2) whether a single exercise session up-regulated the intracellular signaling pathways involved in cardioprotection in the rat heart.
Methods: Male Sprague-Dawley rats were divided into a sedentary control (CON) group and an exercise (EX) group. Rats in the EX group underwent one 30-min session of treadmill running. Following exercise, hearts were excised and subjected to Langendorff perfusion. To evaluate cardiac function during I/R, hearts from both groups were exposed to global ischemia (20 min) followed by reperfusion (45 min). Using western blotting, phosphorylation of Akt, protein kinase C-ε (PKCε) and glycogen synthase kinase 3-β (GSK-3β) in the hearts were analyzed.
Results: Cardiac function was significantly higher in the EX group compared with the CON group for 5-20 min after reperfusion (p<0.05). Phosphorylation of Akt, PKCε and GSK-3β in hearts of EX rats showed significant increases compared with CON rats (p<0.05). Exercise did not change expression levels of heat shock protein 72 in the heart.
Conclusions: Acute exercise prior to I/R attenuated cardiac dysfunction in the isolated rat heart. The attenuation might be due to exercise-induced activation of cardioprotective intracellular signaling.
A single bout of exercise induces a moderate increase in arterial pressure with marked tachycardia as a result of sympathoexcitation. However, the brain mechanisms underlying cardiovascular regulation during exercise still remain unknown. In this proceeding, we introduce our hypothesis that the brain histaminergic system plays an important role in regulating the cardiovascular system during exercise. The nucleus of the solitary tract (NTS) is one of the ideal brain sites for generating cardiovascular controls during exercise because it is known as a pivotal region which integrates the baroreceptor sensory information with other inputs such as muscle afferents and descending signals from the hypothalamic area. We found that activation of histamine receptor H1 expressed in the NTS neurons induced pressor and tachycardiac responses, and that the pressor response exhibited functional plasticity after long-term daily exercise. These findings suggest that H1 receptors in the NTS are involved in cardiovascular regulation during exercise. Since the NTS receives axons of histaminergic neurons located in the tuberomammillary nucleus (TMN) in the hypothalamus, the functional roles of TMN-NTS pathway have also been investigated. We electrically stimulated the TMN and found pressor and tachycardiac responses. Notably the pressor responses were partially inhibited by cetirizine, a H1 receptor antagonist, microinjected into the NTS whereas we failed to see the inhibitory effects on the heart rate response. Based on all these findings, we postulate that the TMN-NTS pathway has an important role in a central feed forward mechanism underlying pressor responses to exercise.
Objective: It has been reported that psychological triggers such as emotional stress, increase the incidence of cardiovascular events. The association between soccer championships and the risk of cardiovascular events is still unclear. World Cup Soccer (WCS) involving the national team might be a strong enough trigger to induce cardiac arrhythmia. However, there are no reports which investigated the relationship between WCS and cardiac arrhythmia in the Japanese population.
Design: A multi-center retrospective observational study.
Methods: We assessed 25 patients who were evaluated ischemic changes and/or arrhythmia by 24-h Holter electrocardiography in 4 Cardiology Divisions during WCS 2014. The patients were divided into two groups [Watching group (n=7): patients who watched WCS on live-TV on June 20 (Japan vs. Greece) or July 25, 2014 (Japan vs. Colombia), and No-watching group (18 patients)]. Heart rates, arrhythmia, and ischemic changes were evaluated.
Results: There were no significant differences of clinical characteristics, frequency of premature atrial contractions, and ischemic changes between the two groups. Although there were no differences in total premature ventricular contractions (PVCs), the frequency of PVCs during matches (p<0.05) were significantly higher during live-TV in the Watching group than in the No-watching group. No sustained ventricular tachycardia or fibrillation was observed.
Conclusions: A significant association between watching WCS and the frequency of PVCs was observed. These data suggest that emotional stress while watching national team soccer matches may induce stress-related cardiovascular events.
Introduction: School athletic clubs serve as central sites of sports activities for many junior and senior high school students in Japan. School athletic clubs preserve the traditions of pre-war junior and senior high schools, and constitute a sports-education system unique to Japan. Although other countries maintain athletic clubs, only in Japan is there a system, an environment, and leaders (school teachers) under which school athletic clubs seek to win national championships. This system is characterized by the incorporation of sport within school-based education; this arrangement allows students to regularly perform athletic activities. Three million junior and senior high school students spend 700 hours each on athletic club activities annually. These facts indicate a large number of school athletic clubs performing extremely intensive physical training activities. The question thus arises: do school athletic clubs’ activities truly cultivate the minds and spirits of young athletes, given the current environment has these problems? In our study, we surveyed athletes belonging to school athletic clubs to examine relationships between concepts related to mental strength and ideas about sports. The authors specifically addressed sport commitment and resilience. Scanlan et al. proposed a theory of sport commitment, which describes athletes’ persistence in, connection with, and devotion to sports. Research has examined resilience since the 1990s; in Japan, resilience has been discussed in terms of ‘ability to recover’ and ‘restoration of strength’. Resilience has also been considered ‘mental strength’, which enables one to recover from stress or negative life events, and to recuperate after harm. Additionally, as students may experience a variety of stressors unique to school athletic clubs, stress measures specific to these clubs were used. This study aimed to investigate relationships among these factors.
Method: Anonymous questionnaire surveys were administered. Participants were students (n=203) attending private high schools in the Tokyo metropolitan district. Questionnaires were (1) Hagiwara et al.’s Commitment to Sports Scale, (2) the Resilience Scale developed by Yamagishi and revised by Oshio and Ishige et al., (3) Shibukura et al.’s Stressor Scale for High School Athletic Club Members, and (4) a face sheet inquiring whether the participant is a member of a school athletic club. For followup investigation, each participant was issued a password. Data were collected from the 11th to the 15th of May 2015.
Results: Factor analysis of Resilience Scale scores extracted five factors that differed slightly from factors reported in previous research: ‘positive future orientation and optimism’, ‘pursuit of novelty’, ‘emotional adjustment and optimism’, ‘relationship orientation’, and ‘metacognition orientation and emotional adjustment’. Factor analysis of scores on the Stressor Scale for High School Athletic Club Members extracted the same five factors as in previous research: ‘competitiveness’,‘coaches’, ‘practice time’, ‘comrades’, and ‘injury or illness’.(The rest of omitted)
The objective of this study was to examine the impact of parental support of physical activity and parents’ past levels of competitiveness in sports on parenting attitudes. The research subjects were 256 parents of freshman students in a university’s Health and Sports Science Department and Medical Department. The time period of this research was November 2014 to January 2015. Questionnaires included the Parental Support Scale, the past levels of competitiveness in sports, and the Parenting Attitude Scale. The exploratory actor analyses were conducted on the Parental Support Scale and the Parenting Attitude Scale, separately. The results revealed that the Parental Support Scale consisted of 3 factors with 4 items each (total of 12 items) and the Parenting Attitude Scale consisted of 2 factors with 4 items each (total of 12 items). The reliabilities and validities of these two scales were also assessed. In the multiple regression analyses, the Parental Support Scale was set as a dependent variable, and the Parenting Attitude Scale and the level of competitiveness in sports were set as independent variables. The analyses were conducted separately on fathers and mothers and separately on male and female children. The path models showed the gender difference between fathers and mothers and difference between male and female children, and both the parenting attitude and the level of competitiveness in sports distinctively influenced on the parental support of children’s physical activity. When we considered past levels of competitiveness in sports and parental support of physical activity as potential factors affecting parenting attitudes, the latter factor had an impact among both fathers and mothers, whereas the former factor was significant only among mothers. Parents should increase their emphasis on responsiveness when raising boys and on demandingness when raising girls to contribute to improvement in their parenting attitude.
We compared the level of physical activity, physical fitness, and obesity of adolescents among major metropolitan cities in East and Southeast Asia. A total of 12,588 valid adolescents’ data (age 12-15 years) were collected from eight major metropolitan cities in East and Southeast Asia. Analytic items included body mass index (BMI), self-reported moderate to vigorous physical activity (MVPA), and whether or not students engaged in sports club activity. Physical fitness tests included Sit-and-reach Test, Hand Grip test, 1 Minute Sit-up Test and 15 meters Progressive Aerobic Capacity Endurance Run (PACER) Test All measures of Japanese adolescents were significantly (p<0.05) greater than the other adolescents. In particular, the effect sizes relating to endurance fitness, and MVPA were much higher than the effect sizes on the other measures. These findings suggested that Japanese adolescents were the most physically fit and active in Asian adolescents.
Purpose: The purpose of this study was to validate for leg and vertical stiffness estimated by using Morin’s method.
Method: One hundred twenty seven children participated in this study. Each subject sprinted for 50 m. The motion through an interval from 30 m to 40 m was recorded with high-speed camera at 300 Hz from the sagittal plane. The running speed, contact time in stance phase and flight time were measured to estimate maximal force exerted on the foot (Fmax), vertical stiffness (k’vert) and leg stiffness (k’leg) by Morin’s method (2005). In gold standard method (MacMahon and Cheng, 1990), vertical excursion of center of mass and leg spring length variation was calculated from digitized landmarks and ratios of Fmax to vertical excursion of center of mass and to leg spring length variation were calculated as the vertical stiffness (kvert) and leg stiffness (kleg).
Result: All values are represented in mean value±standard deviation (SD). k’vert was 15.51±5.97 kN/m, whereas kvert was 17.92±6.59 kN/m. The mean difference of the k’vert between kvert was -2.41±2.62 kN/m. ICC between k’vert and kvert was 0.851 (p<0.001). Mean k’leg and kleg was 5.21±1.91 kN/m and 6.81±2.57 kN/m. ICC between k’leg and kleg was 0.642 (p<0.001), while k’leg was highly correlated with kleg (r=0.839). Additionally k’leg was underestimated (-23.6%) to kleg.
Conclusion: We could conclude that Morin’s method might be able to estimate vertical stiffness and leg stiffness in children, although vertical and leg stiffness tended to be underestimated.
Objective: The purpose of this study was to examine the relationship between birth month, physical size, motor ability, and physical activity evaluated by kindergarten teachers, of young Japanese children by using structural equation modeling.
Methods: We collected the data from 329 children (160 four-year-old children: 76 male and 84 female, and 169 five-year-old children: 85 male and 84 female). Ten teachers in charge of children’s classes in the kindergarten were administered questionnaires, and the children’s physical size, motor ability, and children’s physical activity, as determined by kindergarten teachers, were investigated. Structural equation modeling was used to examine the above-mentioned variables in each grade.
Results: The results showed significant goodness of fit in both 4- and 5-year-old children. Specifically, the model in 4-year-old children showed a significant scale, a good fit to the model according to the approximate fit indices (Goodness of Fit Index [GFI]=0.938, Adjusted Goodness of Fit Index [AGFI]=0.894, Comparative Fit Index [CFI]=0.967, and Root Mean Square Error of Approximation [RMSEA]=0.043). The model in 5-year-old children showed a significant scale and a good fit to the model according to the approximate fit indices (Goodness of Fit Index [GFI]=0.938, Adjusted Goodness of Fit Index [AGFI]=0.894, Comparative Fit Index [CFI]=0.936, and Root Mean Square Error of Approximation [RMSEA]=0.043). In both 4- and 5-year-old children, birth month influenced physical activity evaluated by kindergarten teachers, mediating physical size and motor ability.
Conclusions: We concluded that the birth months influenced children’s physical activity evaluated by kindergarten teachers through physical size and motor ability.
Objective: An important strategy for achieving healthier body compositions is to encourage lifetime physical activity (PA) participation in overweight or obese adolescents. The purpose was to compare the association between PA and obesity among adolescents in China, and to identify the factors that influence the PA and obesity.
Methods: In 2013, a cross-sectional study was involved 962 Chinese children and adolescents aged 12-16 years (mean age 14.9±0.9). The adolescents were classified as normal weight (NW), overweight (OW), and obese (OB), according to the BMI cut-offs that was determined by an obesity working in China. The adolescents were recruited for anthropometric measurements and to complete a standardized PA questionnaire. Other confounding variables such as the parents’ demographic information, and lifestyle factors were also collected through the questionnaire.
Results: Nine hundred thirty-seven valid data were collected from the adolescents. The prevalence of obesity was 8.8% (boys: 9.9%, girls: 7.5%) for junior high-school students (JS) and 7.8% (boys: 12.7%, girls: 4.3%) for high-school students (HS). Regardless of the sex and weight status, the probabilities for achieving PA for HS were less than JS. Moreover, the OW and OB groups had significantly less PA, watched more television, or used the computer more often than the NW groups (p<0.05).
Conclusion: The adolescents consistently failed to meet the established PA recommendations and supported the age-related declines in PA. In this study, we highlighted the importance of promoting PA to adolescents, especially those who are OW and OB.
Introduction: Toes are the only parts of the body connected to the ground, providing both tactile and pressure information through the plantar afferents, somatic sensation through these organs is also very important for various movements, including standing and walking. In particular, the toes control whole body posture and movement, and can generate propulsive force during walking and prevent forward falls. Toe function has been often represented as toe grip strength in various studies. Some investigators have found that low toe grip strength (TGS) is an important risk factor for falls among elderly individuals (Endo et al. 2002). The other side a decrease in children’s physical strength and athletic ability has become a problem in recent years. The present study was aimed to reveal the relationship between TGS and physical fitness in elementary school children.
Methods: From first to sixth grade 274 primary school children (men=133, women=141) were participated in this study. TGS was measured using a toe grip dynamometer (Takei Scientific Instruments, Japan). Physical performance was evaluated using MEXT’s physical fitness tests (Grip strength, sit-up, long seat type anteflexion measurement, sidesteps, multi-stage fitness test, 50-meter run, standing long jump, softball throw), manual muscle test (MMT)(Knee extension torque, knee flexion torque, hip extension torque and Hip flexion torque) and Jumping height (Rebound jump (RJ), squat jump (SQJ), counter movement jump (CMJ). The correlations for mean TGS between boys and girls were calculated using Peason’s correlation coefficient. To assess relationships between mean TGS and the selected parameters, we calculated Pearson’s correlation coefficient by sex and conducted a stepwise multiple regression analysis that included physical characteristics, physical fitness and muscle strength as explanatory valuables. For all tests, statistical significance was set at p<0.05.
Results and Discussion: Toe grip strength was significantly increased after the third grade in comparison to the first grade for both genders (p<0.01). It was observed that muscle strength of elementary school children increases with growth. It tended boys higher than girls, however, was not significant gender differences in all of grade. In both genders, TGS was significantly correlated with MEXT’s physical fitness tests (p<0.01), MMT (p<0.01) in all of the items and boys SQJ (p<0.01) and CMJ (p<0.01) and girls RJ (p<0.05). The stepwise multiple regression analysis revealed that boys height (p<0.01), knee extension torque (p<0.01) girls weight (p<0.01), hip flexion/extension torque (p<0.01) and both genders grip strength (p<0.01), knee flexion torque (p<0.01) were associated with TGS. TGS was increased with the growth particularly for the affected height and weight, therefore it was analyzed eliminate the effect of height and weight. The grades were not significantly correlated between the grades for both genders. The stepwise multiple regression analysis revealed that boys knee extension torque and softball throw, girls hip extension torque, standing long jump and grip strength have been selected as the independent variable were associated with both of body weight correction TGS and height correction TGS. Knee extensor strength and hip extensor strength are widening the stride, help to make a walking or running in a large stride. Toe grip strength has been reported to perform the functions push the body forward during walking or moving and by strengthening the power of the walking speed and the running speed to be improved. From these, the TGS stronger person is considered that it is possible to push out to a more forward body and to stabilize the waist.
Objective: The purpose of this study was to compare the physical fitness level of Taiwanese elementary and junior high school students in Japan with that of Japanese students.
Method: The subjects were Taiwanese school children (T, n=100); specifically, 10 to 14-year-old boys and girls. The evaluation consisted of height, weight, seated height, grip strength, 30-seconds of sit-ups, sit and reach, side steps, a 50 meter dash, standing long jump, softball or handball throw, and a 20 m shuttle run. These data are compared with a research report of physical fitness of children of Kanagawa Prefecture in 2013 (J).
Results: T was higher than J in sit-ups (10, 11, 14 years) in boys (p<0.05). T was lower than J in the 50 meter dash (12 years), and the 20 m shuttle run (11, 12, 14 years) in boys (p<0.05), but the total fitness composite score did not significantly differ between the T and J populations. T was higher than J in sit-ups (10 years) and side steps (10 years) in girls (p<0.05). T was lower than J in the 50 meter dash (14 years), standing long jump (14 years), handball throw (13, 14 years), and the 20 m shuttle run (13, 14 years) in girls (p<0.05). Furthermore, the total fitness composite score was significantly different between the T and J populations (14 years, p<0.05).
Conclusion: The physical fitness level of Taiwanese elementary school children is similar to that of Japanese boys and girls, but the physical fitness level of female Taiwanese junior high school students is lower than that of their Japanese counterparts.
Introduction: Ciliary neurotrophic factor (CNTF) is a protein that promotes the differentiation and survival of a wide range of neuronal cell types and signals through its receptor (CNTFR) thereby regulating neuronal and muscle growth.
Purpose: To examine the association between CNTFR gene polymorphism and elite Japanese endurance-athlete status.
Methods: 209 endurance/middle-power athletes: EMA (middle- and long-distance runners) and 814 Japanese controls were genotyped for C/T polymorphism of 3’-UTR of the CNTFR gene by use of TaqMan Genotyping Assay. All athletes were national (n=143) or international (n=66) level and the group included several medalists at the international competitions such as Olympic Games.
Result: Genotype distribution of C/T polymorphism in EMA (CC: 40, CT: 48, and TT: 12%) and controls (CC: 52, CT: 40, and TT: 8%) were in Hardy-Weinberg equilibrium. TT+CT genotype frequency was higher in EMA than controls under the T-allele-dominant model (p=0.0015, OR: 1.64 [95% CI: 1.21 - 2.24]). When EMAs were divided into 2 groups: national (N) and international (I) athletes, the TT+CT genotype frequency was higher than controls only in I-EMA under the T-allele-dominant model (p=6e-04, OR: 2.49 [95% CI: 1.45 - 4.28]).
Conclusion: The association found between the C/T polymorphism of 3’-UTR of the CNTFR gene and elite Japanese athlete status is of interest and worthy of further study in other elite athlete cohorts.
Muscle flexibility is a component of physical fitness. It is suggested that genetic factor affects individual muscle flexibility, however, the relationship between alpha-actinin-3 gene (ACTN3) R577X polymorphism and muscle flexibility is unclear. The purpose of this study was to investigate an association between ACTN3 R577X polymorphisms and muscle flexibility in Japanese.
In this study, 776 people (208 men and 568 women, 23-88 years old) were included. All subjects answered a questionnaire about exercise habits, and were subjected to a battery of tests to assess their fitness status (including grip strength and sit and reach). Genotyping was performed using the TaqMan approach for the ACTN3 R577X polymorphism (rs1815739).
The genotype frequencies of the ACTN3 R577X polymorphism in men (RR, 24.5%; RX, 52.9%; XX, 22.6%) and women (RR, 19.9%; RX, 52.6%; XX, 27.5%) were in the Hardy-Weinberg equilibrium (men, p=0.402; women, p=0.160). In men, there were no differences in age, height, weight, BMI, grip strength, and sit and reach among genotypes. In contrast, the sit and reach flexibility in the RR genotype (36.1±0.9 cm) was significantly lower than that in the RX and XX genotype (38.9±0.4 cm) even after statistically adjusted by age and exercise habit as covariates in women (p<0.01).
In conclusion, ACTN3 R577X genotype was associated with muscle flexibility assessed by sit and reach test in women. RR genotype had lower muscle flexibility than RX and XX genotype.
Objective: The purpose of this study was to investigate the association between the combination of insulin-like growth factor 2 (IGF2), alpha-actinin-3 (ACTN3), and angiotensin-converting enzyme (ACE) gene polymorphisms and judo status.
Methods: We recruited 156 male judo athletes from a top-level university in Japan. These athletes were divided into two groups based on their competitive history: international-level athletes and others. Genomic DNA was extracted from the saliva of each athlete. Genotyping by PCR or PCR-RFLP was used to detect IGF2 G/A (rs680), ACTN3 R577X (rs1815739), and ACE I/D (rs1799752) polymorphisms. The combined frequencies of the three gene polymorphisms were compared between all judo athletes and controls and between international-level athletes and others.
Results: There was a higher frequency of the IGF2 GG, ACTN3 RX, and ACE II genotype in all judo athletes (10.3%) compared to that of this genotype in the controls (1.2%). Moreover, there was a lower frequency of the IGF2 AA, ACTN3 RX, and ACE ID genotype in all judo athletes (1.9%) compared to that of this genotype in the controls (8.9%). Two of the 156 judo athletes exhibited the IGF2 GG, ACTN3 RX, and ACE DD genotype; both of them were international-level athletes.
Conclusions: The combination of IGF2, ACTN3, and ACE gene polymorphisms may be associated with the judo status.
In Japan, although the prevalence of overweight (BMI≥25), the strongest predisposing factor for type 2 diabetes, is low compared with that in Europe and the United States, the prevalence of type 2 diabetes has increased over the last 15 years. In epidemiological studies of both Japanese and Caucasian population, a high level of cardiorespiratory fitness has been shown to be a protective factor against type 2 diabetes. However, there are no reports focused specifically on athletes that investigate whether high cardiorespiratory fitness at a young age can prevent disease later in life. Therefore, the present study examined the relationship between cardiorespiratory fitness at a young age and the development of type 2 diabetes in Japanese male college athletes using a cohort study.
Between 2007 and 2009, 3,539 male alumni who graduated at the physical education department, were mailed a follow-up questionnaire about their diabetes background and 1,385 male alumni returned it. The cardiorespiratory fitness of male alumni, as measured by 1,500-m endurance run in college (1971-1991) was available for 41% of the respondents. In the present study, we analyzed for 570 male alumni by Cox’s proportional hazards models and adjusted for age, year of graduation, BMI, smoking, and sports club participation at college age.
This study covered a 26-year follow-up period (Interquartile Range: IQR: 23-29 years), and median age at the follow-up questionnaire was 49 years (IQR: 45-52 years). At follow-up, 22 men had developed type 2 diabetes. The incidence of type 2 diabetes was inversely correlated with cardiorespiratory fitness, and the low cardiorespiratory fitness level increased the cumulative incidence rate of type 2 diabetes. There were progressively lower age-adjusted relative risks of type 2 diabetes across cardiorespiratory fitness levels (p=0.01 for trend). After adjustment for age, year of graduation, BMI, smoking, and sports participation, hazards ratio and 95% CI by category (low, medium, and high) were 1.00 (reference), 0.40 (0.14-1.13) and 0.26 (0.07-1.00) (p=0.03 for trend).
We conclude that cardiorespiratory fitness at a young age can predict type 2 diabetes later in life among Japanese male athletes.
＊ This data was already published at BMC Public Health. And this report was extracted from Someya Y, et al: Cardiorespiratory fitness and the incidence of type 2 diabetes: a cohort study of Japanese male athletes. BMC Public Health, 2014; 14: 493.
To assess the association between physical activity during pregnancy and mood changes after delivery, we surveyed 107 pregnant women who had a normal vaginal delivery in the Gynecological Department of Juntendo University Hospital. The study participants completed a structured questionnaire four times, viz. at 12, 25, and 36 weeks’ gestation and at 1 month after delivery. The first three questionnaires focused on physical exercise activity in the most recent 4 weeks. The forth questionnaire focused on mood changes, assessed by the Edinburgh Postnatal Depression Scale (EPDS), Profile of Mood States (POMS), and Visual Analog Scale fatigue score (VAS). In total, 12.9%, 29.8%, and 34.6% of the participants engaged in physical activity at 12, 25, and 36 weeks’ gestation, respectively. By contrast to the observation of decrease in women exercising from the second to third trimester1), the proportion of participants exercising increased from the 12th to 36th week of gestation in the present study. This discrepancy was probably due to the differences in socio-demographic characteristics of participants in the two studies. There were no differences in EPDS and VAS between women who had been physically active and inactive at 12, 25, or 36 weeks’ gestation. The results of the POMS showed that although there were no differences between women who were active and inactive at 12 and 25 weeks’ gestation, the “Vigor” scale was significantly higher (p<0.05) and the “Fatigue” scale was significantly lower (p<0.05) in women who were physically active at 36 weeks’ gestation than in women who were inactive at the same time. These results suggest that even if women do not engage in physical activity during the first or second trimester, physical activity during the third trimester may improve the mood after delivery.
Objective: Managing people from different backgrounds has brought great benefits to companies, sport teams, and surgical teams. However, previous research has shown that diversity may have negative effects on performance because of diversity “faultlines”, hypothetical dividing lines that may split a group into subgroups. We conducted an empirical study on faultlines for the first time in Japan to investigate the present status of faultlines and to assess the degree to which workers perceive that (certain) attributes (e.g. age, personality, attitude) may have an impact on the emergence of faultlines in Japanese work organizations.
Participants: Participants included 132 workers (122 males and 10 females; ages 20-59 years, M=48.1 years SD=±16.2).
Methods: The questionnaire consisted of three sections, the first of which was a face sheet. The second was a newly developed set of items designed to assess the degree to which participants perceived that (certain) attributes might have an impact on the emergence of faultlines. The third explored participant’s perception of faultlines at their present workplace.
Results: We found that task-related attributes such as specialty and ability/knowledge were great factors affecting faultlines, and that every participant perceived faultlines based on such attributes as specialty, personality, and attitude.
Conclusion: These findings provided the first step towards bridging faultlines in diverse teams. However, they also suggested faultlines are more detrimental than previously thought to individuals as well as organizations. Further research is now being conducted with the cooperation of more than 1,000 participants to examine the relationship between faultlines and individual outcomes, such as occupational stress and work-life conflict.
The purpose of this study is to obtain a perspective of the communication objectively and analyze the relationship between assertion types and interpersonal communications in a nursing organization of a university hospital. To promote the communications, assertive communication which enables self-expression attracts attention recently. However, in the previous studies of the assertion and communication in the context of nursing organization, it cannot be regarded that the study of this field was clarified scientifically although a few studies exist to clarify the relation with practical communication. Therefore, this study visualizes the communication channels scientifically with electronic sensors and is to clarify how the index influences them with the type of assertion. Participants of this study were 26 nurses in a maternity ward of a university hospital. Measures of this study were electronic sensors and questionnaires. The electronic badges, developed by MIT and applied by Health High-Technologies Corporation in Japan, are used for measuring the communication channels and social signaling behavior of nursing organizations in university hospitals. The results were the communication time of the nurses who had high assertive scores was concentrated in the middle area and the communication time of the nurses who had high passive aggressive scores was relatively low. In the communication signaling, one characteristic was if we analyze the communication time of connecting each nurse, we can see that the nurses with high assertive scores and the nurses with low assertive scores spend a lot of time communicating within their own group. The results of these characteristics show that there is a connection between assertion types and the amount of communication time and the connection of communication channels.
The purpose of this study was to develop guidelines for promoting, collecting and using client’s feedback in Japanese fitness clubs. Discussions were conducted to develop the guidelines with three business people belonging to three major fitness clubs. Good practices were collected using an interview survey, the guidelines were developed based on good practices. As a result, 7 items and phrases were created for promoting to collect and use client’s feedback. The guidelines included 2 concepts. One was to be able to work on immediately and adapt to each work place. The other was to be simple and low cost.
Existing systems of each club to collect client’s feedback had a few problems, and was difficult to collect positive feedback. Moreover, each club depended on accidents to collect client’s feedback without intention. The guidelines support internationally collecting client’s feedback. In addition, each item was decided considering the service record in the fitness industry. Positive feedback was effective for encouraging those who have a short service record. Negative feedback was effective for promoting growth of veterans having a long service record.
The guideline based on good practices was led. The guidelines include, 7 items and phrases considering adjustment for each workplace, ease, and low cost.
Purpose: Skeletal muscle cell lines such as mouse C2C12 cells and rat L6 cells often show abnormal characteristics because of repeated-passage cultures and artificial culture conditions. Primary myotubes are considered to retain their in vivo properties. Here, satellite cells originating from the extensor digitorum longus (EDL) or soleus muscle were differentiated into primary myotubes and used for an in vitro contraction model.
Materials and Methods: Satellite cells from the mouse EDL or soleus were isolated by a single-fiber isolation method. We examined the formation of the sarcomere assemblies by α-actininimmunostaining in the differentiated myotubes. We also investigated the contractile characteristics of myotubes stimulated with an electric pulse and insulin induced-glucose uptake. C2C12 myotubes were used for comparison with the primary myotubes.
Results and Discussion: The sarcomere assemblies were observed in the primary myotubes but hardly observed in the C2C12 myotubes. The number of myotubes responding to stimulation by the electric pulse was increased in both the C2C12 and primary myotubes, although the movement in the primary myotubes was larger than that in C2C12 myotubes. The glucose uptake stimulated by insulin was significantly increased compared to the basal uptake in the primary myotubes and the C2C12 myotubes. These data suggest that the mouse primary myotubes, with their greater number of sarcomere assemblies and higher level of contractive activity, will be valuable as an in vitro contraction model that can be used in place of cell lines or human primary myotubes.
Insulin resistance in skeletal muscle is one of the main features of metabolic syndrome, and it has been associated with lifestyle factors including diet 1) 2). Whereas the mechanisms underlying the development of insulin resistance have not been fully elucidated, the accumulation of intramyocellular lipid (IMCL) is recognized as an important determinant of insulin resistance, and is increased by a high-fat diet (HFD) 3) 4). The fat content of food is a determinant of the accumulation of IMCL. The effects of HFD on IMCL and insulin sensitivity are highly variable, although, it had shown that a short term (3-day) high-fat diet (HFD) in human increases the IMCL level and impairs insulin sensitivity in skeletal muscle 3) 5).
The aim of this study was to identify the genes in muscle that are related to this inter-individual variation.
Fifty non-obese healthy men were recruited for this study. Before and after HFD for 3 days, IMCL levels in the tibialis anterior were measured by 1H-magnetic resonance spectroscopy, and peripheral insulin sensitivity was evaluated by glucose infusion rate (GIR) during the euglycemic-hyperinsulinemic clamp. We observed a significant increase in TA-IMCL by HFD. GIR was significantly decreased by HFD. We also observed a negative correlation between changes in TA-IMCL and GIR by HFD (r=-0.37, p<0.01), Subjects who showed a large increase in IMCL and a large decrease in GIR by HFD were classified as the high-responder (HR), and the subjects who showed a small increase in IMCL and a small decrease in GIR were classified as the low-responder (LR). In 5 subjects in each group, the gene expression profile of the vastus lateralis muscle was analyzed by DNA microarray analyses. Before HFD, gene expression profiles related to lipid metabolism were comparable between the 2 groups. Gene Set Enrichment Analysis demonstrated that 5 gene sets related to lipid metabolism were up-regulated by HFD in the HR group, but not in the LR group. Changes in gene expression patterns were confirmed by qRT-PCR using more samples (LR: n=9; HR: n=11). These results suggest that IMCL accumulation/impaired insulin sensitivity after HFD is closely associated with changes in the expression of genes related to lipid metabolism in muscle.
It is known that the increased intramyocellular lipid (IMCL) levels observed in obese subjects are closely associated with insulin resistance (IR) in muscle 1). Interestingly, some reports suggested low intensity exercise (LIE) decreased IMCL and improved IR 2). On the other hand, a few reports showed vigorous intensity exercise (VIE) improved IR, but increased IMCL level 3) 4). This phenomenon is a reminiscent of endurance-trained athletes, who possess a high oxidative capacity and enhanced insulin sensitivity, also have higher IMCL content known as athlete’s paradox (AP) 5) 6). From these findings, we hypothesized exercise intensity is one of the determinants of AP.
To test this hypothesis, we recruited 20 men with moderate insulin resistance (HOMA-R >1.6) and randomly assigned to LIE (40% VO2 peak) or VIE (70% VO2 peak) group. Each group performed with ergometer for 5 consecutive days. Before and 3-day after completion of protocol, IR was evaluated by glucose clamp. IMCL was measured by 1H-MRS. The IMCL was also evaluated immediately after the exercise at day 5. Our preliminary data showed that in VIE group IMCL level was not significantly changed after exercise at day 5. Although IMCL level was decreased at 3-day after last bout of exercise in LIE group, that in VIE group increased about 50% from baseline. Interestingly, insulin resistance was similarly improved in both groups. These data suggested exercise intensity is a determinant of change of IMCL.
Although, changes in IMCL level after exercise were opposite between LIE and VIE, the improvement of insulin resistance was similar. IMCL exists mostly as triacylglycerol (TAG), which may not impair insulin sensitivity in muscle. On the other hand, intramyocellular diacylglycerol (DAG) concentration is considered to induce insulin resistance, which is generally increased in parallel with the amount of intramyocellular TAG. It has been shown that one bout of aerobic exercise increased the expression level of diacylglycerol acyltransferase (DGAT)-1 in muscle and to prevent FFA-induced muscle DAG accumulation and insulin resistance in healthy humans. Thus, we speculated that DAGT1 expression and decreased DAG levels play roles in the mechanisms involved in the athlete’s paradox phenomenon seen in VIE group. Future analysis is clearly required to test this hypothesis.
A single bout of exercise induces transient increase in blood interleukin-6 (IL-6) level in human and rodents, however, the role of exercise-induced IL-6 is poorly understand. Prolonged, chronic increase in IL-6 reflects low-grade inflammation, which decrease insulin sensitivity in adipose tissue, liver and skeletal muscle. On the other hand, acute, short-period of IL-6 enhances insulin sensitivity. Because, the increase in IL-6 after exercise is transient, we hypothesized that transient increase in IL-6 after exercise enhances insulin sensitivity in skeletal muscle. C57BL6J mouse were i.v. injected normal IgG or IL-6 antibody before exercise. Twenty-four hours after a single bout of exercise (treadmill running: 20 m/min, 90 min with 10 degree incline), plantaris muscle was harvested and incubated in oxygenized KRB buffer to measure insulin-stimulated 2-deoxyglucose (2-DG) uptake. Compared with sedentary mouse, insulin-stimulated 2-DG uptake in plantaris muscle was increased 24 h after exercise in IgG-injected mouse, however, the increase induced by exercise was not observed in IL-6 antibody-injected mouse. Concomitant with this results, GLUT4 expression was increased 24 h after exercise in IgG-injected mouse, the increase was canceled in IL-6 antibody-injected mouse. Recombinant mouse IL-6 injection increased GLUT4 expression both fast-twitch plantaris muscle and slow-twitch soleus muscle in C57BL6J mouse. Furthermore, short period incubation of IL-6 (3-12 hours) increased GLUT4 expression in differentiated C2C12 myotubes, however long period (24 h) did not. These results suggests that exercise-induced transient increase in IL-6 affects skeletal muscle in autocrine/paracrine manner, which enhances GLUT4 expression leading to increase insulin sensitivity in skeletal muscle.
Despite low body mass index (BMI), Asian people often develop type 2 diabetes 1)-3). In addition to reduced insulin secretion, etiological difference of insulin resistance (IR) between Caucasian and Asian might be involved in this phenomenon 4) 5). Previous data demonstrated that non-obese Asians easily develop non-alcoholic fatty liver disease (NAFLD) 6)-8) which is considered as cause and result of IR 9)-14). As well as fat accumulation in liver, liver enzymes, such as alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT), are easily elevated by small increase in BMI within normal limits in Asians 15); however those are less observed in other ethnicities 16). In addition, both ALT and GGT were correlated to insulin resistance independent of measures of adiposity 17) 18). These data suggested that intrahepatic lipid (IHL) accumulation and liver dysfunction could be markers of IR in non-obese type 2 diabetes.
To test this hypothesis, we recruited 16 non-obese (BMI<25kg/m2) type 2 diabetes (BMI 21.9±2.0 kg/m2, HbA1C 6.8±0.5%, Diet and exercise or take α-glucosidase only). We measured IHL by 1H-magnetic resonance spectroscopy (MRS) at overnight fasting state. Total body fat content was measured by using the bioimpedance method. We also evaluated visceral fat and subcutaneous fat area by magnetic resonance imaging (MRI). Then, we performed euglycemic hyperinsulinemic clamp to measure insulin sensitivity (IS) in muscle and liver, respectively. We also measured serum liver function tests, such as AST, ALT and γ-GTP. Based on the upper limit of normal IHL level (4%) in general non-obese Japanese cohort, we divided the subjects into low IHL group (n=11; 1.3 (0.46-2.39) %) and high IHL group (n=5; 10.3 (6.26-12.7) %). Our preliminary data showed that compared with low IHL group, high IHL group showed lower muscle IS (6.79 (5.48-7.54) mg/kg/min vs 3.87 (3.84-5.66) mg/kg/min, p=0.06). Correlation analysis in all subjects revealed that IHL was not significantly correlated to IS in muscle and liver, however, all liver function tests are significantly correlated to both hepatic and muscle IS, respectively.
The present study demonstrated that IHL accumulation and elevated liver enzymes were associated with impaired insulin sensitivity in non-obese Japanese type 2 diabetes. These data suggested the usefulness of those hepatic parameters as marker of impaired insulin sensitivity in non-obese Japanese type 2 diabetes. However, this study is preliminary analysis in small number of subjects; further analysis is clearly required to confirm these relationships.
Decreased physical activity and increased obesity during childhood have recently emerged as significant social problems. Since long-term exposure to risk factors contributes to the development of lifestyle diseases, determining effective early-age prevention strategies is essential. Regular exercise and increased physical activity are well known to prevent obesity and insulin resistance in both animals and humans. However, although physical activity during childhood has a well-known direct effect on child health, the long-term consequences of childhood exercise on adult health and morbidity have not been well studied due to the difficulties of following subjects long-term. To address this, many researchers use rodents or other animal models. Previous studies have suggested that exercise has long-lasting effects on body weight after exercise cessation. In this review, studies examining the long-lasting effects of childhood exercise on obesity and metabolic diseases later in life using animal models are summarized, and the importance of exercise in childhood in preventing obesity and its related comorbidities is highlighted.
Objective: 5’-adenosine monophosphate-activated protein kinase (AMPK) has been identified as a key mediator of contraction-stimulated insulin-independent glucose transport in skeletal muscle. Caffeine acutely stimulates AMPK in resting skeletal muscle, but it is unknown whether caffeine affects AMPK in contracting muscle. In this study, we examined the effect of caffeine stimulation on contraction-stimulated AMPK activity and glucose transport.
Materials and Methods: (1) Isolated rat epitrochlearis muscle was preincubated and then incubated in the absence or presence of 3 mM caffeine for 30 min. Electrical stimulation (ES) was used to evoke tetanic contractions during the last 10 min of the incubation period. (2) Rats were given an intraperitoneal injection of caffeine (60 mg/kg body weight) or saline, and the extensor digitorum longus muscle was dissected 15 min later. ES of the sciatic nerve was performed to evoke tetanic contractions for 5 min before dissection.
Results: (1) The combination of caffeine plus contraction had additive effects on AMPKα Thr 172 phosphorylation, α-isoform-specific AMPK activity, and 3-O-methylglucose (3MG) transport. Caffeine significantly delayed muscle fatigue during contraction, and the combination of caffeine and contraction additively decreased ATP and phosphocreatine contents. (2) Similar to the findings from isolated muscles incubated in vitro, the combination of caffeine plus contraction in vivo had additive effects on AMPK phosphorylation, AMPK activity, and 3MG transport.
Conclusions: These findings suggest that caffeine and contraction synergistically stimulate AMPK activity and insulin-independent glucose transport, at least in part by decreasing muscle fatigue and thereby promoting energy consumption during contraction.
Purpose: Exercise is one of the established treatment method for knee osteoarthritis (OA). However, the mechanisms of its action is not fully understood. Although exercise has a muscle strengthening effect that may improve the stability of the knee joint, it has been speculated that exercise may exert anti-inflammatory effect for the joint. The aim of this study was to examine whether exercise had the anti-inflammatory effects for the joint in clinical practice using biomarkers for inflammation.
Methods: This study was approved by the Ethics Committee of our university and conducted in accordance with the declaration of Helsinki. The written informed consent for this study participation was obtained from all subjects. A total of one-hundred twenty postmenopausal women with medial type of primary knee OA (K/L2-4) who first visited our outpatient clinic for knee pain were included in the study. Subjects were randomized to either the exercise therapy group or the control group. The patients in the exercise therapy group conducted three different kinds of home exercise and stretching. The patients in the control group took either the oral selective COX2 inhibitor (celecoxib, 200 mg/day for 12 weeks) or the intra-articular injection of hyaluronic acid (HA, high molecular weight 2,700 kDa HA, 5 times with one week interval). Age, body mass index (BMI), Japanese Knee Osteoarthritis Measure (JKOM) score, visual analog scale (VAS) for pain score and serum levels of biomarkers for inflammation (high-sensitivity C-reactive protein [hs-CRP] and interleukin [IL]-6) were evaluated at baseline and 12 weeks after treatment initiation. Values in each group were compared between baseline and 12 weeks using a paired t-test.
Results: The sixty-nine of 120 patients were assigned to either the exercise therapy group and the remaining fifty-one patients were to the control group. During the twelve weeks of examination, twelve patients in the exercise therapy group and the eight patients in the control group were withdrawn. No significant differences of the baseline characteristics were observed between the exercise therapy group and the control group. The JKOM score (p<0.001 and p<0.001, respectively) and VAS score (p<0.001 and p<0.001, respectively) at 12 weeks of the patients with both the exercise therapy and control groups were significantly reduced in comparison to those at baseline. The hs-CRP levels remained unchanged in patients with both groups (p=0.267 and p=0.137, respectively). The sIL-6 levels of the patients in the exercise therapy group were significantly decreased (p=0.021) in comparison to those of the patients at baseline, but sIL-6 levels of the patients in the control group were not.
Conclusions: The serum IL-6 levels in patients with OA were significantly reduced by the exercise therapy, while sIL-6 levels were unchanged by NSAID, suggesting that exercise therapy may exert anti-inflammatory effects in knee OA.
Two weeks of detraining produces 6.4% of muscle atrophy even after long-term strength training. Thus, to maintain the training effect, preventing the muscle weakness and muscle atrophy caused by detraining would be valuable. Exposure to cold stimulus by cold water inhibits muscular atrophy.
The purpose of this study was to investigate the effect of cooling by ice bag on muscle weakness and muscle atrophy caused by detraining.
Six healthy males (23.0±2.5 y/o) performed elbow flexion resistance training three times per week for 6 weeks. After the 6 weeks training, the subjects were instructed to limit upper arm activity within their activity of daily living level during three weeks of detraining period. During the de-training period, one of the arms was cooled at inside of upper arm by an ice bag for 30 min a day (ICE), and the other arms was control condition (CON). The measurements were elbow flexion torques at angular speeds of 60 and 120 deg/s under concentric contraction (CC60, CC120) and isometric contraction (IM), cross-sectional area (CSA) and circumference of the upper arm. The measurements were done, at pre-training (PRE), post-training (POST), after the first week (D1), second week (D2) and third week (D3) of detraining.
IM significantly increased after training in both conditions (p<0.05). Significant decreases of IM in CON was observed at D2 (66.6±17.4 N･m) compared to POST (78.8±24.8 N･m) (p<0.05). Circumference significantly increased after training in both conditions (CON: 102.1±1.0%, ICE: 101.4±0.7%) (p<0.05). Significant decreases of circumference in CON was observed at D3 (29.6±3.4 cm) compared to D2 (29.8±3.5 cm) (p<0.05). CSA significantly increased after training in both conditions (CON: 108.5±3.3%, ICE: 107.9±2.2%) (p<0.05). CSA significantly decreased after the detraining in both conditions. However, there was no significant difference in all of measurements between CON and ICE.
Only IM increased after the training. It may be because of the fact that the training was composed of isometric contraction. Even though increased the muscle force, circumference and CSA by the training decreased by the detraining. On the other hand, there was no decrease in IM and circumference in ICE during detraining period. This result suggests the possibility that the cooling prevents muscle weakness and muscle atrophy; however, there was no significant difference between both conditions, therefore we consider that the effect of cooling was weak. In conclusion, the cooling for 30 min a day shows possibility that the cooling prevents muscle weakness and muscle atrophy caused by detraining.
Introduction: Sport athletes often show event-related muscular profiles that are possibly associated with their competitive and training activities. Thus, investigation of the muscular profiles in athletes can enlighten the association between muscle-specific hypertrophy and sport-specific movement performance. With respect to the movement of the lower extremities, rowing and pedaling mainly consist of repetitive multi-joint leg extensions (simultaneous extensions of knee and hip joints), which are largely contributed by the quadriceps femoris. On the other hand, several types of joint motions are involved in field sports. It is hypothesized that the quantitative profiles of the quadriceps femoris are similar for the athletes who routinely repeat leg extensions (oarsmen and cyclists) but not for the athletes not regularly performing leg extensions (field sport athletes; such as lacrosse players). This study tested the hypothesis.
Methods: T1-weighted MR images of the whole right thigh were obtained from 14 varsity oarsmen, 8 male cyclists, 13 male lacrosse players and 10 untrained men. The anatomical cross-sectional areas (ACSAs) from the origin to insertion of each muscle of the quadriceps femoris (vastuslateralis, vastus medialis, vastus intermedius, and rectus femoris) were measured. The muscle volume of each muscle was determined by summing in-series ACSAs which were multiplied by the slice thickness (1 cm), and the relative muscle volume to body mass (normalized volume) was calculated.
Results and Discussion: The normalized total volumes of the quadriceps femoris were significantly greater in the oarsmen and cyclists than in the untrained men, and that of the cyclists was significantly greater than that of the lacrosse players. Likewise, the normalized vastus lateralis volumes of the oarsmen and cyclists were significantly greater than those of the lacrosse players and untrained men, and the normalized volumes of the vastus medialis and vastus intermedius were significantly greater in the oarsmen and cyclists than in the untrained men. In contrast, the normalized rectus femoris volume of the lacrosse players was greatest of the four groups, while no statistical differences were shown among the other three groups. It was made clear that the varsity oarsmen and cyclists had hypertrophied monoarticular vasti (lateralis, medialis, and intermedius), whereas the lacrosse players had hypertrophied biarticular rectus femoris. These results strongly suggest that the varsity athletes demonstrate muscle-specific hypertrophy among the synergistic muscles comprising a muscle group, depending on the sport-specific motions involved during competitive and training activities.