Recent studies suggest that electrical muscle stimulation （EMS） has the potential to be an alternative modality to voluntary exercise. However, the effects of EMS on human body are not well understood. Thus, the purpose of this study was to examine the effects of EMS training on quadriceps muscle hypertrophy and strength, vascular endothelial function, autonomic nervous system function, and cognitive function. Methods: Thirty heathy male participants were divided into EMS training, resistance exercise training, and control groups. In the EMS training group, the participants performed EMS three times per week for 8 weeks. In the resistance exercise training group performed leg-press three times per week for 8 weeks. Cross-sectional area （CSA） of the quadriceps muscle was assessed at mid-thigh （50% of the femur） and distal （70%） regions using magnetic resonance imaging. At mid-thigh and distal regions, muscle CSA increased after both EMS and resistance exercise trainings. Isometric knee extension strength increased in the EMS group. The EMS training also increased vascular endothelial function. Both training did not affect autonomic nervous system activation and cognitive function. These results indicate that EMS potentially induces muscle hypertrophy, increases muscle strength, and improves vascular endothelial function. The present findings suggest that EMS can be an alternative to voluntary exercise.

This study aimed to measure and analyze ground reaction force （GRF） using MEMS 6-axis force sensors mounted in the insoles. The force sensors were placed on the thenar, hypothenar, and heel and measured vertical （Fz）， anterior-posterior （Fy）， and mediolateral （Fx） forces with a sampling frequency of 50 Hz. Measurements were taken in four events: walking, jogging, wind sprint, and sprint, and a 60 m run from a crouching start. The subject had 8 years of track and field experience. Running speed was maximal at sprint, and the stride was maximal at wind sprint. The time between the peak heel reaction force and the peak thenar reaction force confirmed that the center of gravity movement speed during ground contact was maximum at the sprint. During the wind sprint and sprint, the vertical reaction force and forward shear force at the thenar increased, while the outward and propulsive forces at the hypothenar increased. The vertical force at the heel was smaller than that of the other sensors due to the forefoot strike form. During the 60 m run, strong propulsive forces were measured from the hypothenar during the acceleration phase, and the values gradually decreased with time. On the other hand, the sensor on the thenar outputs a braking force, which gradually increases with acceleration. These research results suggest that the measurement of GRF using MEMS sensors is easier and more location-independent than force plates’ measurement. In this method, the trajectory of the leg can be inferred from the difference in sensor output between the thenar and the hypothenar, suggesting that the data can be used to improve the sprinter’s running form.

To investigate the evaluation criteria of the surface texture of sports clothing in 3D wearing simulation compared to actual clothing, a comparison was conducted on the similarity and difference between the simulated and the actual clothing images and those impression. We also tracked the eye movements of the evaluators during impression evaluation using a gaze-tracking device to investigate the parts of the garments they paid attention to. We prepared eight sportswear pieces with different materials and colors and created simulated and actual images worn on a mannequin. The evaluators were 20 university students in their twenties. As a result, the evaluators gazed at the garment's chest, hip, and leg curved parts in the simulated and actual image. There were less significant differences in the overall impression of a garment, such as gaudiness and elegance, between the simulated and the actual images. However, the simulated images of bright-colored or glossy fabrics tended to be evaluated as thicker and heavier than actual ones. The impression of smoothness also tended to differ in both. For dark and mat fabrics, there was no significant difference between the simulated and actual images. When evaluating the texture of sportswear in 3D wearing simulation, the evaluation items that cause differences from the actual image are "thickness," "weight," "smoothness," and "glossiness." Those are considered as the evaluation points of the difference between the simulated and the actual clothing. In electronic commerce, simulation images can convey the overall impression of a garment. Simulation images can be used more effectively as product images considering the evaluation points of this research result.

In wearing clothes, passive contact between the clothes and the skin occurs accompanied with human movements. In this study, we first examined the contact between clothing and the skin on the trunk during the movement of upper extremity utilizing a pressure measurement film. It was clarified the neck, shoulder tip, and scapula are prominent contact sites. Next, we explored the possibility of skin vibration measurement in the vicinity of the protruding part of the scapula. Investigation of the vibration intensity and median frequency of the skin vibration caused by contact between the skin and clothing revealed that a site about 2 cm away from the contact area was suitable for measurements. In addition, from the skin vibration measurement in wearing several types of sportswear, it was clarified that the vibration intensity was greater in wearing sportswear than in not wearing it, and we found a certain tendency from the analyses of results of each sample. The relationship between the feeling of wearing and skin vibration is different from the active contact by tracing the clothing materials. In the passive contact between worn clothes and the skin, it was manifest that multiple factors, such as the looseness of the clothes and the characteristics materials, affect the skin vibration in contact.

The moisture-absorbing and heat-generating fibers are used in innerwear for winter sports. The moisture-absorbing and heat-generating fibers generate wet heat through reaction between insensible perspiration from the skin and the functional groups of the fibers. In this study, the parameters of thermal properties such as ΔTmax and heat retention index were measured using a device made according to the JIS method to measure the thermal properties of hygroscopic heat-generating fibers with different functional groups. It was found that these parameters of thermal properties depend on the types of functional groups, and that acrylate fibers had higher ΔTmax and heat retention index.The subjects were asked to wear inners made of moisture-absorbing heat-generating fibers, and evaluated the comfort of the inners with regard to the feeling of warmth and moisture during the time course of a series of rest and motion activities by monitoring the micro-climate between inner and skin. A correlation was observed between the temperature within the clothing and ΔTmax, heat retention index.

Among sports injuries caused by pitching motion, preventive measures for circulatory disorders have not been sufficiently established. Therefore, this study aimed to clarify the acute effects of icing performed after pitching on brachial hemodynamics in baseball pitchers. A pitching task consisting of 98 pitches was conducted with twelve university baseball pitchers, and two conditions were set: a control condition without icing treatment after pitching and an intervention condition with icing treatment. Subjective fatigue, shoulder external/internal rotation muscle strength, and brachial hemodynamic parameters were evaluated before and after pitching. The reactive hyperemia index （RHI） score, an indicator of endothelial function, was calculated to assess one of the brachial hemodynamics. No significant interaction between time and condition was observed for subjective fatigue and shoulder muscle strength. However, a significant interaction was found between the temporal changes in RHI scores and the presence or absence of icing treatment, with lower RHI scores on the following day observed in the condition with icing after pitching. The results of this study suggest the potential impact of icing after pitching on endothelial function. These findings are considered important fundamental insights for investigating cooling-down methods for preventing circulatory disorders in baseball pitchers.

The motion of the talonavicular joint in shoes is important for understanding the mechanism of sports injury, but there is no method for analysis under normal shoe stiffness. We examined the motion of the talonavicular joint using the stretch strain sensor （STR） that can measure the motion of the talonavicular joint with shoes on. Fourteen feet of 14 healthy adult males were included in the study. The talonavicular coverage angle （TNCA） was assessed in the sitting and standing positions using X-rays, and the arch strain （AS） was measured in the same postures using an STR. The AS was measured by four attachment methods and the correlation between the AS and changes in TNCA was analysed. The method with the highest correlation was used to examine the changes in the AS waveform of running motion in barefoot and shoe conditions. The AS condition with a line connecting the medial malleus and navicular, and an inclination of 50 degrees downwards to the floor correlated significantly with changes in TNCA （r = 0.60, p = 0.02） . There was no significant difference in AS during running between with the shoe and without shoe conditions. Therefore, AS measurement by STR might be able to assess the motion of the talonavicular joint during running.

To predict garment pressure accurately, it is essential to model the biaxial deformation behavior of textiles by considering yarn properties and weave structure. Yarn's mechanical properties are nonlinear, and assuming a Poisson's ratio of 0.5, we can employ a hyperelastic model to simulate large deformation behavior. In this study, we approximate the mechanical properties of spun yarn using an equivalent model of a homogeneous monofilament. We use CAE software, Abaqus, to simulate the biaxial tensile behavior of a plain weave.We estimate the stress-strain relationship by fitting the strain energy density function to the Mooney-Rivlin approximation, which is based on biaxial deformation in the course direction. This direction closely resembles the deformation experienced when wearing a garment. We also utilize CAD data for a general-purpose mannequin and a shirt. When we compared the results with the measured garment pressure of a T-shirt worn on a mannequin, we found that they were in good agreement with the measured garment pressure.

Biomarkers as indicators for the diagnosis of sports related concussion have not been established. The purpose of this study was to analyze saliva samples from student American football players for microRNA and protein expression before and after concussion injury and during recovery, and to identify biomarkers in saliva as indicators of concussion diagnosis and recovery.

Six samples were analyzed before concussion （Pre）， nine samples during concussion （Post）， and three samples during concussion recovery （Rec）．MicroRNA extraction and protein mass spectrometry were performed on these samples to analyze and identify biomarkers whose expression changed at each phase. The results showed that the expression of SPRR1A （small proline-rich repeat protein1A） protein, which is considered to be related to nerve regeneration, increased significantly from Pre to Post and decreased from Post to Rec, suggesting that it may be a biomarker in saliva in sports related concussion.

The purpose of this study was to observe the postural control strategy during the single-leg standing posture with knee joint extension fixation and clarify the pathogenesis of chronic ankle instability （CAI） specific to the ankle joint, which is obscured by the postural control governed by the hip joint. The subjects consisted of male basketball players, including 15 healthy individuals with no history of ankle sprain and 15 subjects with CAI. They maintained a double-leg standing posture for 10 seconds, followed by a single-leg standing posture for 20 seconds. In addition to comparing the healthy group and the CAI group, comparisons were made between the two groups with and without knee bracing to immobilize the knee joint in the extended position. The CAI group exhibited significantly higher center of pressure acceleration during the transition from bipedal to single-leg standing due to knee joint immobilization, suggesting a substantial contribution of the hip and ankle joint kinetic chain to the CAI group's ability to maintain the single-leg standing posture. The results revealed ankle dysfunction masked by the hip strategy, which could not be confirmed through previous examination of CAI pathology.

Resistance exercise with blood flow restriction （BFR） is a new training method providing significant training effects despite the use of low-intensity mechanical loads. It was previously demonstrated that BFR remarkably enhances muscular metabolic stress in resistance exercise and that the metabolic stress was effectively enhanced by increasing mechanical intensity but not BFR pressure. However, because of blocking the metabolic recovery by BFR, it is possible that even with low intensity, metabolic stress might gradually increase with respect to increased repetitions and reach sufficient level.

Therefore, in this study, the muscular metabolic stress during resistance exercise with BFR between light-long and hard-short protocols, adjusted by totally the same work volume （load × repetitions） were compared.

Twelve male university students were recruited and performed unilateral plantar-flexion at 30 repetitions/min in a whole body magnetic resonance system. The BFR exercise protocols were as follows: exercise with 10% of one repetition maximum （1-RM） for 360 sec （180 repetitions） , 15% 1-RM for 240 sec （120 repetitions） , 40% 1-RM for 90 sec （45 repetitions） . All protocols were same in total work volume （load × repetitions=1800） . In addition, a standard high-intensity protocol of 65% 1-RM without BFR （60 sec, 30 repetitions） was also performed for comparison. Muscular metabolic stress in the calf muscle, defined as phosphocreatine and intramuscular pH decrease were evaluated by using 31P-magnetic resonance spectroscopy.Phosphocreatine depletion and intramuscular pH decrease at the end of each exercise were statistically similar and equal to or greater than that in 65% 1-RM without BFR. In conclusion, if the total exercise volume calculated as a product of mechanical load multiplied by repetitions were equal, metabolic stress in exercising muscle might achieve the similar level at the end of exercise with BFR and could provide similar successful training effects.

Chronic kidney disease is a serious health problem, and the effectiveness of exercise and training as prevention and treatment has not been fully verified particularly in terms of basic molecular biology and physiology. In this study, we employed a mouse model in which albuminuria induced by a high-fat diet is reduced by treadmill exercise as previously reported. We performed RNA sequencing combined with cluster enrichment analysis of mouse renal tissue with different diets and training programs, and found a group of genes related to inflammatory responses and stress responses that were upregulated by a high-fat diet and then downregulated by exercise. These genes include Cxcl2, which encodes chemoattractive chemokines which mainly affect neutrophils in inflammatory response. Therefore, we focus on their physiological effects and then performed immunohistological evaluation of neutrophil infiltration in kidney tissues obtained from mice with high fat diet and/or exercise. However, unfortunately, no changes in cellular infiltration were observed in response to a high-fat diet or exercise. This does not deny other biological of the chemokine effect than we anticipated. Indeed, in chronic inflammation, the role of neutrophils is less well understood and has been described as either beneficial or detrimental, causing tissue damage and enhancing the immune response. Based on the results of this comprehensive study, we intend to further elucidate the renal receptor mechanisms associated with exercise and aim to provide basic scientific insights into the effects of training and exercise in chronic kidney disease.

Muscle soreness is subjective muscle pain that occurs after high-intensity exercise, and the disappearance of muscle soreness is often used as an indicator of recovery from muscle damage. However, due to methodological limitations, it has not been clear whether muscle soreness reflects structural damage of muscles. The purpose of the present study was to clarify changes in muscle damage/inflammation and muscle soreness after endurance running using the magnetic resonance imaging （diffusion tensor imaging）， and to examine whether muscle soreness is an indicator of recovery from muscle damage. We measured subjective delayed onset muscle soreness （DOMS）， T2 relaxation time and diffusion parameters for each of 12 muscles of the lower limb using MR before and after a 20 km race including up-hill and down-hill in 16 male and female recreational runners. The results showed that the peaks of the DOMS and T2 relaxation time were on 1-2 days after the race, and recovered 3-4 days after the race. On the other hand, the mean diffusivity （MD） of some of the thigh muscles increased until 3-4 days after the race. In conclusion, even after the recovery of muscle soreness after the 20 km race, it is likely that muscle structural changes due to muscle damage or inflammatory reactions are still occurring, and it is not appropriate to use muscle soreness as an index for resume of exercise.

Motor imagery is a cognitive process that involves the mental simulation of motor actions without actual physical movements, and it is widely used as a training technique to enhance sports performance. Although previous studies have reported the positive effect of motor imagery training on motor function and motor learning, the underlying neurophysiological mechanisms of motor imagery have yet to be fully elucidated. Therefore, the purpose of our study was to investigate the effect of pinch motor imagery on sensorimotor integration, specifically assessed using the short-latency afferent inhibition （SAI） paradigm. Thirteen able-bodied male participants were recruited in this study. The assessments were conducted under two distinct conditions: Control and Motor imagery conditions. In the Control condition, participants were instructed to relax without engaging in any motor imagery, whereas in the Motor imagery condition, they performed maximum pinch imagery while observing a pinch image displayed on the monitor. During each condition, fifteen SAI responses were measured, which represent the inhibition of motor-evoked potentials elicited through transcranial magnetic stimulation following median nerve electrical stimulation. SAI responses were measured from the first dorsal interosseous muscle. The results showed that there was no significant difference in the magnitude of SAI between the Control and Motor imagery conditions, suggesting that motor imagery has no effect on sensorimotor integration assessed by SAI.

Regular exercise is effective treatment for the improvement of mental illness. However, the duration of exercise effects and the impact on future mood-related behaviors, such as anxiety and depression, remain unclear. Therefore, we determined the long-term impacts of regular exercise on mood behaviors after cessation of exercise. Moreover, we focused on epigenetics, which is one of the mechanisms for the regulation of gene expression independent of DNA sequences, in hippocampal BDNF as its underlying mechanisms. Anxiety-like behaviors as a mood-related behaviors were measured by Elevated Plus Maze test. After 4 weeks of exercise training, the anxiolytic effects were lasting after 2 weeks of exercise cessation. Meanwhile, after 4 weeks of exercise cessation, anxiety-like behaviors were increased on the contrary. In contrast to our hypothesis, hippocampal Bdnf mRNA and DNA methylation levels were unchanged after 2 and 4 weeks of exercise cessation. These results suggest that the beneficial effects on mood-related behaviors after cessation of exercise are maintained in the short term. However, over a more extended withdrawal period, they can lead to an increase in anxiety.

The accuracy of force production in children is recognized to be less than that of adults, yet the motor unit （MU） activation pattern, the smallest unit of the neural system and muscle fiber, remains incompletely understood. This research aimed to clarify the accuracy of force production and MU activity in children. Eighteen children aged 6 to 12 and 18 healthy young adults performed the maximal voluntary isometric contraction （MViC） and ramp-up contraction to 50 %MViC in knee extension. High-density surface electromyography was recorded from the vastus lateralis and decomposed into individual MU activity. Children exhibited significantly lower accuracy of force production during the ramp-up phase compared to adults （p<0.001）． Regarding MU activity, children demonstrated a significantly higher MU firing rate （FR） compared to adults （p<0.05）． The increase in FR was significantly greater for the lower-threshold MUs in children during the initial recruitment phase （p<0.05）， whereas adults displayed a greater increase in FR for higher-threshold MUs during the later phase of ramp-up contraction （p<0.05）． These findings suggest that children not only regulate MUs at a high FR but also show a tendency to rapidly increase FR during the initial recruitment phase. Differences in force production accuracy between children and adults could be linked to the characteristics of MU activity.

The present study examined the effects of different half-time strategies on repeated-sprint ability （RSA）． In a randomized cross-over design, ten male soccer players completed two RSA tests （6, 6-s sprints separated by 24 s of passive rest, first and second halves） separated by a 15-min half-time. During the half-time, the participants were assigned to a 15-min seated rest （CON）， a 7.5-min passive heating （wearing a jacket at 5 to 12.5 min during the 15-min half-time, PAS）， a 1.5-min active heating before the end of the half-time （performing a re-warm up at 12.5 to 14 min during the 15-min half-time, ACT）， or a combination of both passive and active heating （COMB）． All trials were performed on a non-motorized treadmill in a thermoneutral environment （17.1±1.1℃， 52.2±8.1% relative humidity）． In CON, mean and maximum running speeds were significantly lower during the second half than during the first half （p<0.05）， but this difference was not observed in the other trials. In the half-time, PAS, ACT, and COMB did not decrease magnitudes of the drop in gastrointestinal temperature. Skin temperature at the start of the second half was significantly higher in COMB than in CON （p<0.05）． In the second half, there were no significant differences in gastrointestinal temperature, electromyography, or muscle oxygenation between trials. Herat rate during the second half was significantly higher in ACT and COMB than in CON and PAS （p<0.05）． In conclusion, PAS, ACT, and COMB improved RSA during the second half compared to CON.

Patients following anterior cruciate ligament （ACL） reconstruction suffer from dysfunction of the quadriceps femoris muscle （QF） for a long period of time due to neurophysiological abnormalities called arthrogenic muscle inhibition （AMI）， preventing the patients from returning to sport. Failure to reduce AMI at early phases following injury or surgery could lead chronic muscular impairments due to supraspinal dysfunction. Recently, a systematic review reported the effect of cryotherapy as a treatment for AMI of QF. However, the effect of intervention using cryotherapy in early postoperative period for a certain period of time has not been investigated. In cryotherapy, exercise intervention is performed while exercise efficiency is temporarily higher by focal cooling of joints. In the present study, to examine the effect of cryotherapy intervention in early postoperative period on QF strength, cryotherapy was applied immediately before starting each rehabilitation session for 4 weeks at early phase following ACL reconstruction. The knee extension strength of patients who received cryotherapy tended to be higher than that of patients who did not receive cryotherapy. This result suggests that AMI of QF following ACL reconstruction could be treated at an early phase as hospitalization using cryotherapy.

Nailfold capillaries are small hairpin-shaped blood vessels that aline the nailfold at the tips of fingers and toes. Those vessels can be repeatedly observed using relatively inexpensive and small microscopy without injecting needles or administering drugs. Nailfold capillary morphology is known to be altered by various diseases, and morphological abnormalities have been associated with type 2 diabetes and its complications. Though, there have been few reports of quantitative analysis of nailfold capillary morphology. The conventional semi-quantitative analysis could only analyze the presence or absence of diseases and complications, so by shifting to quantitative analysis, nailfold capillaroscopy would be a new examination method in the treatment of type 2 diabetes, as it will provide more accurate results and also enable the evaluation of disease severity. In this study, we quantitatively analyzed not only the morphology of nailfold capillaries but also the colors of the capillaries, and showed that capillary diameters in hospitalized patients with diabetes had a significantly positive correlation with HbA1c levels, a glycemic control index that indicates the disease status of diabetes （R2=0.21, p=0.027）．Additionally, obesity, associated with insulin resistance in diabetes, had a significantly negative correlation with delta E, a color contrast between the inside and outside of capillaries in obese and diabetic patients （R2=0.19, p=0.035）．

We constructed a wearable perspiration ratemeter to develop an informing system to users for the heatstroke risk. To decide the timing point for informing heatstroke risk, we conducted human experiments of 16 heathy subjects with the step up and down physical exercises In addition, a wearable self-identification and -information system of thirst response was developed with a smartphone. The blood and urine samples of the subjects was collected before and after the 30-min physical exercise. The concentrations of total protein （TP）， albumin （Alb）， and red blood cells （RBC） increased slightly with the exercise. In contrast, the concentrations of vasopressin in all subjects remarkably increased with exercise. Using the simultaneous recording of perspiration ratemeter, we decided that the timing point for informing heatstroke risk was to change from positive to negative on the second derivative of sweating curve. In almost subjects they identified their thirst response until several min after the informing for heatstroke risk. In conclusion, the wearable ratemeter and self-informing system of thirst response were suitable for informing system of heatstroke risk.

Objective: Although body weight is used for routine physical conditioning, it is desirable for athletes to be able to routinely measure total body water （TBW） content, which correlates with skeletal muscle mass. Body composition changes during pregnancy were documented in para-athletes who continued training during pregnancy in order to return to competition after childbirth.Methods: Body composition was measured once a month during an outpatient visit and compared with the TBW calculated using a body water meter （BWM） developed to easily calculated TBW on the upper arm.

Results: TBW showed an increase until 20 weeks gestation, then decreased once, and increased in the third trimester. TBW on BWM was almost constant and showed similar changes to the changes in body water content in the upper rim.Consideration: Because she continued to train throughout her pregnancy, her weight in the third trimester was considered to be almost constant, a pregnancy in which she was able to manage her weight properly. Weight gain in the first half of pregnancy showed an increase in intracellular water content, although an increase in fat mass was observed. A decrease in fat mass and an increase in TBW were observed in the third trimester. This was mainly an increase in extracellular body water content, which was thought to be an increase in amniotic fluid, and an increase in trunk water content.