Interval exercise has been evaluated as more effective than continuous exercise in improving cardiovascular function in individuals with cardiovascular disease. Previous research has confirmed that interval exercise leads to increased vascular shear stress related to endothelial function compared to continuous exercise. However, it is unclear whether interval exercise truly improves cerebral endothelial function and reduces the risk of cerebrovascular disease. This study aimed to investigate whether interval exercise do not only increase cerebral vascular shear rate（SR）but also improves cerebral endothelial function compared to continuous exercise. Seven healthy men（mean age 21±0.6 years）participated in the experiment, performing 32 minutes of interval cycling exercise and an equal amount of continuous exercise using a semi-recumbent exercise bike. Cerebral endothelial function（cFMD）was measured and evaluated before exercise（pre），15 minutes after exercise, and 40 minutes after exercise. cFMD was assessed by ultrasound, calculating the maximum dilation rate（Δ%） of the internal carotid artery diameter in response to a 30-second hypercapnic exposure with a partial pressure of carbon dioxide increase of approximately 9 mmHg from baseline. The results showed that cFMD did not change from baseline after both interval and continuous exercise trials, with no significant differences observed between conditions （15 minutes post-exercise, 7.47±4.92% vs. 5.66±4.21%; 40 minutes post-exercise, 5.91±4.01% vs. 6.16±2.26%; p = 0.442）．This study did not find evidence for the beneficial effects of interval exercise on cerebral endothelial function.

Teeth clenching greatly impacts athletic performance, but the optimal occlusal force and balance between the left and right sides remain unclear. Therefore, the present study aimed to investigate the effect of imbalanced occlusal pressure on remote facilitation, focusing on spinal function and locus coeruleus activation. Fourteen healthy adults with normal occlusion were enrolled; those with malocclusion were excluded from the analyses. Occlusal pressure measurements included maximum occlusal force and balance of occlusal pressure between the left and right sides. The sides with higher and lower occlusal pressures were referred to as the Hyper and Hypo sides, respectively. Electromyography electrodes were attached to the bilateral masseter, anterior temporal, and soleus muscles. The occlusion conditions were as follows: no-bite condition（no contact of the dental arches）， contact condition（contact of the dental arches without clenching）， and conditions of 12.5%, 25%, and 50% of the maximum voluntary contraction（MVC） of the right masseter muscle, as well as a max condition. Spinal excitability was evaluated using the H-re?ex, which was measured by electrically stimulating the tibial nerve in both lower limbs, with the stimulus intensity set so that the soleus H-wave amplitude was 20% of the maximum M-wave amplitude. Additionally, the pupil diameter on both sides was measured as an indicator of locus coeruleus activity. We analyzed the muscle activity of each muscle under each occlusion condition, H-wave amplitude values on both sides, and pupil diameter on both sides. Statistical processing included two-way repeated measures analysis of variance, and post hoc tests involved t-tests between conditions. The signi?cance level was set at 5%. The masseter and anterior temporal muscle activities were signi?cantly higher on the hyper side than on the hypo side in the 12.5%, 25%, 50% MVC, and max conditions （p< 0.05）．Spinal excitability and pupil diameter were significantly higher in the 12.5%, 25%, 50% MVC, and max conditions than in the no-bite condition（p < 0.05）． Furthermore, spinal excitability was signi?cantly higher on the hyper side than on the hypo side in the max condition（p < 0.05）．Pupil diameter was signi?cantly higher on the hyper side than on the hypo side in the 12.5%, 25%, 50% MVC, and max conditions （p< 0.05）． Our results suggest that imbalanced occlusal pressure leads to imbalances in locus coeruleus and spinal excitability activities. Given that such imbalances in the locus coeruleus and spinal excitability negatively affect cognitive and motor functions, the correction of occlusal pressure balance may be important.

Water molecule dynamics in vivo are important for heat stroke caused by exercise in high-temperature environments and its prevention. Water molecules in skeletal muscle and other living tissues can be broadly classified into “free water,” which can move freely without binding to other substances, and “bound water,” which is bound to other substances and whose molecular motion is constrained. However, the effects of hydration at the onset of heat stroke and afterward on water molecules of different properties, such as free water and bound water, are unclear. The present study examined the effects of running exercise-induced heat stroke caused in a high-temperature environment and subsequent hydration on water molecule properties and water transport mechanisms in skeletal muscle in rats. Running exercise at a running speed of 10 m/min was performed in a room maintained at a room temperature of31±2ﾟ and humidity of 45±5%. The exercise was terminated when the rats lost 3% of their body weight during the running exercise. Hydration was then provided ad libitum for 24 hours. As a result, it was demonstrated that muscle water content changes in response to changes in free water volume due to running exercise-induced heat stroke and subsequent hydration. On the other hand, there was no change in hyaluronan concentration, suggesting that changes in bound water may not be affected. Furthermore, no signi?cant changes were observed in the expression levels of AQP1 and AQP4, which are water molecule transport mechanisms. In the present study, it was suggested that running exercise induced heat stroke and subsequent hydration may affect the dynamics of free water, but not bound water. In addition, it was also indicated that the water molecule transport mechanism was hardly affected.

[Purpose] The present study aimed to investigate the effect ofβ-hydroxybutyrate（β HB）elevation via exogenous ketone supplementation on serum erythropoietin（EPO） and hepcidin concentrations in response to endurance exercise in young active women. [Methods] Eight young women（20 ± 1 years）performed two high-intensity interval cycling sessions（8 sets×3 min of cycling at 85% of peak oxygen consumption） followed by supplementation of 25.5g β HB（8.5 g/h, 3 times; β HB trial）or placebo（CON trial）．Both trials were conducted during the early follicular phase（day 1 to day 7 after the onset of menstruation）．Blood samples were taken before exercise, immediately, 30, 60, 120, and 180 min after exercise. Ketone and iron metabolism were assessed from the collected blood samples. [Results] Serum β HB concentrations in the β HB trial were signi-cantly increased from 30 min to 180 min after exercise（p < 0.01 at each time point），with higher β HB concentrations in the β HB trial compared to the CON trial（p < 0.05 at each time point）．The average blood glucose concentration in theβ HB trial was signi-cantly lower than in the CON trial（p = 0.012）．Serumferritin concentration at baseline did not vary between the trials（p = 0.474）．Serum hepcidin concentration did not change after exercise（interaction: p = 0.449），and changes in this concentration did not differ signi-cantly between the trials（p = 0.430）． Changes in serum EPO concentration 180 min after exercise significantly differed between the trials（p = 0.027）．[Conclusion] Serumβ HB elevation via exogenous ketone supplementation in active young women in-uenced EPO changes after exercise while not hepcidin changes in response to endurance exercise in young active women.

Exercise-Associated Muscle Cramps（EAMC）are sudden, involuntary muscle contractions that often occur during or after physical activity. Despite their commonality, the exact physiological mechanisms underlying EAMC remain elusive and are the subject of ongoing research. Two primary hypotheses have been proposed to explain their origin: the central nervous system origin hypothesis and the peripheral nervous system origin hypothesis. The central nervous system origin hypothesis suggests that muscle cramps may be triggered by abnormal neural activity originating from the brain or spinal cord. This theory posits that disruptions in motor neuron firing patterns, possibly due to fatigue or electrolyte imbalances, could lead to the involuntary contractions observed in EAMC. On the other hand, the peripheral nervous system origin hypothesis proposes that cramps arise from abnormalities in the nerves directly controlling the affected muscles, possibly due to compression, injury, or metabolic changes within the muscle fibers themselves. The aim of this study is to elucidate changes associated with EAMC. Matrix sEMG was used to monitor the muscle activity patterns in the lateral gastrocnemius muscle during repetitive plantar flexion exercises of the dominant foot. As the results, during the onset of muscle cramp precursors, the muscle activity patterns changed that the sEMG signals exhibited increased amplitude and had a high-frequency band at the localized site. Concurrently, the new innervation zones observed. These findings provide support for the central nervous system hypothesis by suggesting that muscle cramps occur due to a disruption of the size principle in conventional muscle contractions, leading to irregular firing of motor neurons.

he aim of the present study was to determine the effects of aerobic exercise with different pattern of blood flow restriction on endothelial function of the non-active limb. Six males （25±3 yr, 176.1±5.5 cm, 66.2±6.6 kg） completed 30 min of recumbent leg-cycling at 40% of V･O2peak in two trials: 1） exercise with continuous blood flow restriction （continuous trial） and 2） exercise with intermittent blood flow restriction （3 cycles of 5 min inflation/5 min deflation） （intermittent trial）．Cardiovascular hemodynamics and brachial shear rate were recorded every five min during exercise. Brachial artery flow-mediated dilation （FMD） was assessed before exercise and 10 and 60 min post-exercise. Both trials showed increases in arterial blood pressure during exercise, with the intermittent trial demonstrating lower values during the deflation phases （10, 20, and 30 min） compared to the continuous trial （p<0.001）．Changes in blood flow and shear rate during exercise did not differ between the trials （p>0.05）．FMD was decreased in both the continuous （7.7±1.2 to 3.7±1.4%） and intermittent （8.0±2.0 to 4.9±1.6%） trials at 10 min post-exercise （p<0.001）．However, the change in FMD from baseline to 60 min post-exercise was higher in the intermittent trial （+1.7±2.5%） than in the continuous trial （-3.1±1.0%, p = 0.047）．In conclusion, impaired vascular function following exercise with blood flow restriction can be restored with using intermittent blood flow restriction, independent of shear rate kinetics.

The present study examined the importance of hamstring muscle strength in female rugby players from the perspectives of athletic performance and occurrence of hamstring injuries. Twenty female rugby sevens players participated in this study. Participants were classified into regular and semi-regular groups based on their tournament participation. Measurements were taken for lean body mass, eccentric and concentric knee flexion torque, as well as 10-meter sprint times. Eccentric knee flexion torque was assessed using strength in the Nordic hamstring exercise. Measurements for lean body mass and muscle strength were repeated after three months. A significant positive correlation was found only between lean body mass and eccentric knee flexion torque. After three months of competitive training, eccentric knee flexion torque increased in the regular group, but no significant changes were observed in the semi-regular group or in concentric knee flexion torque in either group. Players who had experienced hamstring injuries in the past two years exhibited significantly lower eccentric torque compared to those without such history. These findings suggest that eccentric muscle strength exerted during the Nordic hamstring exercise may be related to athletic performance and the experience of hamstring injuries.

During dynamic exercise, blood flow to active muscles increases, while blood flow to inactive organs, such as inactive limbs and splanchnic organs, decreases. At resting conditions, the splanchnic region and renal receive about 50% of cardiac output, while this is reduced to 20-25% of basal values during maximal dynamic exercise. Differences in splanchnic blood flow during exercise have been observed between younger and older males. However, to our knowledge, no data exist on age-related differences in splanchnic blood flow during dynamic exercise in females. This study aimed to elucidate the effects of aging in females on arterial blood pressure and celiac artery blood flow responses during light-intensity dynamic exercise. Ten young females （YF; 20±2 yrs, mean±SD） and ten elderly females （EF; 71±5 yrs） performed dynamic knee-extension and -flexion for 4-min at 30% heart rate reserve. Heart rate （HR） , mean arterial blood pressure （MAP; automated sphygmomanometer） , and celiac artery mean blood flow （celMBF; Doppler ultrasound） were measured continuously during the experiment. HR increased in both groups at the onset of exercise and was maintained throughout the exercise. The increase in HR was larger in the YF than in EF as expected （+37.3±5.5 vs. +26.0±5.3 beats/min, P<0.001）．The rise in MAP during exercise was greater in the EF than in YF （+27.2±10.3 vs. +12.8±6.9 mmHg, P<0.001）．celMBF decreased during exercise in both groups, with no significant difference between YF and EF （-100.3±64.5 vs. -84.7±68.9 mL/min, P=0.61）．Similarly, vascular conductance （celVC; celMBF/MAP） decreased during exercise in both groups, with no significant difference in response between YF and EF （-1.8±1.0 vs. -1.5±0.7 mL/min/mmHg, P=0.33）．These results suggest that aging has minimal impact on changes in celiac artery blood flow during light-intensity dynamic exercise in females.

Regular physical activity in early life is linked to lifelong cognitive health, whereas the effects of early-life physical inactivity on future cognitive function remain unknown. In this study, we examined the hypothesis that physical inactivity during childhood affects DNA methylation in the hippocampus, which is retained over time and leads to cognitive decline in adulthood. Four-week-old male Wistar rats were divided into two groups: a control group （CON） and a physical inactivity group （IN）． Rats in the IN group were housed in narrow cages with approximately half of the usual floor space to restrict their movement for 8 weeks until 12 weeks of age. After this period, all the rats were housed in standard-sized cages until 20 weeks of age. The object location task （OLT） was used to assess cognitive function at 19 weeks old. The dorsal hippocampus was collected immediately after the activity restriction intervention （12 weeks old） and 8 weeks after the intervention ended （20 weeks old） for analysis of genome-wide DNA methylation levels （RRBS）， RNA-seq, and protein expression levels. The IN group's physical activity decreased to about one-quarter that of the CON group between 4-12 weeks of age. In contrast, there were no significant differences in body weight or food intake throughout the experimental period. The IN group showed poor OLT performance and an increased expression of myelination-related genes and proteins in the hippocampus. However, the expression of these genes was not associated with the changes in DNA methylation induced by early-life physical inactivity. Instead, they are linked to DNA hypomethylation observed only in adulthood. These findings demonstrate that physical inactivity during the young period leads to cognitive decline in adulthood. This may be due to the dysregulation of myelination-related gene expression associated with DNA hypomethylation, a delayed consequence of physical inactivity in childhood.

Purpose: Measurement of serum cartilage oligomeric matrix protein （COMP） level isknown to be useful for detection and monitoring of cartilage degeneration. The present study examined the impact of physical activity in daily life on cartilage changes in patients with knee osteoarthritis （OA） by the measurement of serum COMP levels with 3D-MRI scanning. Method: Seven patients with knee OA participated in the present study. Blood sampling and knee MRI scanning were performed, and serum COMP levels were measured. Clinical scores of Tegner activity scale （TAS）， The International Knee Documentations Committee Rating System （IKDC）， Knee Injury and Osteoarthritis Outcome Score （KOOS）， and Locomo25 were obtained. Two-step test and measurement of knee extension strength were performed. All measurements above were performed at the start of the study and after the three months observation. During the observation, physical activity such as the daily steps and walking distance were recorded. Participants received treatment including outpatient rehabilitation by a physical therapist during the observation. Result: All cases involved low-impact sports, and the average number of steps per day was 11,579. While the change in serum COMP levels tended to be negatively correlated with the change in cartilage volume, no correlation was found with other parameters regarding daily living activities, clinical evaluation, or muscle strength. Conclusion: The present study showed the possibility that the serum COMP levels could be effective even in predicting only a minor change in cartilage degeneration as shown by 3DMRI.

[INTRODUCTION] Studying sports injuries is crucial to their prevention and plays a role in the continuation and promotion of sports activities. However, few studies of sports injury have been conducted on sporting events for parasports athletes, especially deaf athletes. A clear understanding of the difference between sports injuries in deaf and hearing athletes is important for prevention of injuries in deaf athletes. The purpose of this study was to clarify the incidence and characteristics of sports injuries in deaf soccer players. [METHODS] Twenty-six participants （27.3±4.9 years old） who attended the Japanese national training camp for deaf soccer players in 2022-2023’s season were included in the study. The number of injuries, incidence （injuries/1000 player-hours [PH]），severity （number of days that the injured player can’t play），and injury burden （injury incidence×mean severity） were investigated over the one-year period. In addition, injury location, re-injury incidence, mode of onset, and injury mechanism were classified according to the definitions recommended by the International Olympic Committee and the Federation International de Football Association. [RESULTS] A total of 59 injuries occurred during the study period, with an incidence, severity, and injury burden of 10.1/1000 PH, 5.0 days, and 50.5 days/1000 PH, respectively. With respect to location, 89.8% of the injuries occurred in the lower extremity, with the ankle having the highest incidence and injury burden （2.7 injuries/1000 PH and 15.2 days/1000 PH）．The most common diagnosis was ankle sprain, 68.8% of which were re-injuries or aggravation. The mode of onset of ankle sprain was a 50:50 ratio of contact to non-contact injuries. [CONCLUSION] The incidence of sports injuries in deaf Japanese national soccer players were higher to those in hearing soccer players, with a high incidence in the lower extremity. The ankle sprain had the highest incidence in deaf soccer players.

Standing posture, which is fundamental to various movements and essential for daily life, can be destabilized by various factors, ultimately increasing the risk of falling. One of the factors that increases the risk of falling is the fear of falling. Besides, the activity of the lower limb muscles is crucial for maintaining postural balance, and this muscle activity is generated by the excitation of spinal motor neurons （spinal MNs）．Therefore, the purpose of this study was to investigate how fear of falling during standing posture influences the excitability of spinal MNs in the lower limb muscles. Eleven adult males participated in the experiment, performing a static standing task for 90 seconds while wearing a head-mounted display. The task was conducted under three conditions with different levels of induced fear of falling （Low-threat, Medium-threat, and High-threat conditions）．During each condition, transcutaneous spinal cord stimulation （tSCS） was applied to a lumber region 15 times. The motor-evoked responses from the vastus lateralis, biceps femoris, tibialis anterior, soleus, medial gastrocnemius, and lateral gastrocnemius muscles were recorded as spinal reflexes. The results showed that the spinal reflex amplitude of the tibialis anterior muscle was significantly increased in the High-threat condition compared to the Low-threat condition. In contrast, no significant differences in the spinal reflex amplitudes were observed in the other muscles among conditions. Our findings indicate that the fear of falling facilitates the excitability of spinal MNs in the tibialis anterior muscle during standing posture.

The objective of this study was to evaluate the effects of the decrease in physical activities due to voluntary or involuntary stay-at-home to prevent the spread of COVID-19 on fitness of elderly people after the pandemic. The subjects were 414 elderly people （74 males and 340 females） who participated in a fitness-assessment event in October 2023, in which they underwent fitness tests and answered a questionnaire about physical activities during the pandemic. There were no significant differences in the mean values of fitness test results between those who decreased and those who maintained the activity level during the pandemic. This suggests that the participants may have incurred a temporary decline in fitness due to voluntary restriction of outing during the pandemic but recovered half a year after the reclassification of COVID-19 as a Class V infectious disease.

Hamstring muscle strain injuries would occur during the late swing phase of high-speed running. Biceps femoris long head （BFlh） is the most common injured muscle among hamstring muscles. Here, we aimed to examine the influence of pelvic and lower limb joint kinematics on the BFlh muscle-tendon kinematics using an angle-driven simulation method. Forty male collegiate athletes performed maximal effort 50-60 m sprinting while capturing their motion with a three-dimensional motion capture system. Using this captured sprint data, we simulated the sprint motion that increased and decreased their BFlh muscle-tendon unit （MTU） length during the late swing phase of sprinting. This simulation revealed that the pelvic anterior-posterior and knee extension-flexion motions affect the BFlh MTU length, whereas hip extension-flexion motion has smaller contributions to the MTU length compared to the pelvic and knee joint motions. Thus, our result suggests that modifying the sagittal plane motions of the pelvis and knee joint would be beneficial for preventing hamstring muscle strain injuries. Hamstring muscle strain injuries would occur during the late swing phase of high-speed running. Biceps femoris long head （BFlh） is the most common injured muscle among hamstring muscles. Here, we aimed to examine the influence of pelvic and lower limb joint kinematics on the BFlh muscle-tendon kinematics using an angle-driven simulation method. Forty male collegiate athletes performed maximal effort 50-60 m sprinting while capturing their motion with a three-dimensional motion capture system. Using this captured sprint data, we simulated the sprint motion that increased and decreased their BFlh muscle-tendon unit （MTU） length during the late swing phase of sprinting. This simulation revealed that the pelvic anterior-posterior and knee extension-flexion motions affect the BFlh MTU length, whereas hip extension-flexion motion has smaller contributions to the MTU length compared to the pelvic and knee joint motions. Thus, our result suggests that modifying the sagittal plane motions of the pelvis and knee joint would be beneficial for preventing hamstring muscle strain injuries.

Managing the load on the Achilles tendon （AT） during jump landing is important in preventing AT injuries. Although foot kinematics may be associated with AT loading, these relationships are unclear during landing. The purpose of the present study was to determine the forefoot, midfoot, and rearfoot kinematics associated with AT force during a drop vertical jump （DVJ）．Thirty-five participants （25 males, age: 21.8±1.9 years old） performed the DVJ from a 30-cm high box. The landing phase was assessed using a three-dimensional motion analysis system. Dorsiflexion, eversion, and abduction of the forefoot, midfoot, and rearfoot were calculated using a multi-segment foot model. The AT force was estimated from the ankle flexion angle and plantarflexion moment. The relationship between the peak AT force and each foot angle was evaluated using correlation analysis and multivariate regression analysis. In correlation analysis, the AT force and rearfoot abduction were negatively correlated （ρ=-0.355, P=0.036）．No other significant correlations were found. In multivariate regression analysis, the variance inflation factors for forefoot dorsiflexion and abduction angles were large, so these variables were excluded due to multicollinearity. The rearfoot abduction （β=-0.523, P=0.004） and forefoot eversion （β=-0.445, P=0.012） were factors significantly associated with the AT force （R2=0.273, P=0.006）．The present study found that the increase in AT force during the landing task was associated with a decrease in rearfoot abduction and forefoot eversion. Foot orthoses that modify these kinematic characteristics may be useful in managing the AT loading during jump landings.

We investigated the effects of continuous vascular （static） stretching on flexibility, vascular endothelial function and arterial stiffness in latter-stage elderly people. Flexibility and vascular endothelial function and arterial stiffness significantly improved after three months of vascular stretching. After six months, further improvements were observed in flexibility, vascular endothelial function and arterial stiffness. However, six months after discontinuing vascular stretching, the flexibility, endothelial function, and arterial stiffness returned to the preintervention levels, thereby indicating that the effects of vascular stretching are reversible. These results suggest that vascular stretching may contribute as an anti-atherosclerotic exercise in latter-stage elderly people, as it improves flexibility, vascular endothelial function, and arterial stiffness.

We have previously shown that high-frequency （daily six maximal eccentric contractions x 5 times per week） training at maximal load and eccentric contraction training could increase muscle strength and muscle thickness of elbow flexors. In the present study, we aimed to extend this knowledge and clarify the effects of high-frequency training using a submaximal load, i.e., 2/3 and 1/3 of the maximal eccentric contraction strength. Thirty-six healthy university students were randomly divided into three groups: 2/3 group （n=12）， 1/3 group （n=12）， and control group （n=12）： The 2/3 and 1/3 groups that performed six eccentric contractions with 2/3 or 1/3 maximal eccentric contraction torque using a dumbbell 5 days a week for 4 weeks or control group that did not perform any training. We measured muscle strength and muscle thickness of elbow flexors before and after the 4 weeks intervention period. The results showed a significant （p<0.05） increase in muscle strength and thickness in only the 2/3 group but no significant change in the 1/3 group nor the control group. Also, there were no significant differences in muscle strength and thickness increases between the 2/3 group and maximal eccentric contraction training group shown in the previous study. Therefore, using more than 2/3 of the maximal eccentric contraction torque for high-frequency, eccentric contraction resistance training is necessary.

The purpose of the present study is to clarify the effects of heat stress added by layered clothing during 3 days of endurance training on thermoregulatory during exercise in a hot environment among long-distance runners. Nine male long-distance runners conducted three consecutive days of endurance （cycling） training at 50% V･O2max for 90 min/day at 15℃ with layered clothing （WEAR condition） or short-sleeve shirts and short （CON condition）．Each condition was separated six weeks between conditions. Before and after training period, heat stress test （HST）， consisting of 40 min of endurance （cycling） exercise in a hot environment （35℃, 50%RH）， were conducted. During HST, core temperature, plasm volume, heart rate, sweat rate, sweat sodium concentration, score of thermal sensation and rate of perceived exertion were evaluated. Peak core temperature during training session was 38.39℃ in WEAR and 38.31℃ in CON, with no significant difference between conditions. The mean heart rate during training session was 126 bpm in WEAR and 120 bpm in CON （P>0.05 between conditions）．The average sweat rate during training sessions was significantly higher in WEAR （2.45%） vs. CON （1.31%） （P<0.001 between conditions）．The absolute changes in resting core temperature before and after training period were -0.97% （from 37.22℃ to 36.85℃） in WEAR and -0.82% （from 37.19℃ to 36.88℃） in CON, with no significant difference between conditions. The relative change in sweat rate after HST was 0.01% （from 1.01% to 1.03%） in WEAR and 8.87% （from 1.03% to 1.12%） in CON, with no significant difference between conditions. In conclusion, three consecutive days of endurance training adding heat stress by wearing layers didn’t improve thermoregulatory ability in a hot environment.

We present here a case study of the characteristics of the running form in a para-athlete with hemiplegia （track and field, standing, cerebral palsy） to provide relevant information to para-athletes and coaches. The participant performed a multistep progressive load running test on a treadmill. Oxygen uptake, carbon dioxide output, respiratory rate, expired gas volume, heart rate, and blood lactate concentration were measured to determine running speeds equivalent to 2 mmol/L （LT speed） and 4 mmol/L （OBLA speed） blood lactate concentrations. The participant ran at determined speeds, and foot pressure measurements and 3-D motion analysis were performed. Differences in foot pressure were observed between left and right feet, revealing a bimodal foot pressure curve on the paralyzed side. The 3D motion analyses also revealed disparities in left and right trunk rotation in response to arm swinging. The findings of this study imply that hemiplegic para-athletes develop high levels of motor control over asymmetric movements and rotations by modifying and/or repressing the influence of the paralyzed side.

Real-time visualization of the flexion and extension status in joints of athletes is of prime importance for improving their performance and skill. Furthermore, when the injured athletes or elderly person carry out rehabilitation, the visualization of joint flexion status by color changes would motivate them to overcome their injuries and illnesses too. In this report, we designed and synthesized the cellulose-based liquid crystal materials （hereinafter called “cellulose liquid crystal elastomers”）， which exhibit both reflection colors and lithe elasticity in order to produce the sustainable strain-visualizable sheets. For example, when a cellulose liquid crystalline elastomer film with red reflection was compressed by a transparent plastic spoon, the reflection color in only the compressed area changed from red to yellowish green. Although this yellowish green reflection was maintained as long as the pressure remained constant, the reflection color immediately recovered to the original red by releasing the compressed pressure. This happened from because the elasticity of cellulose liquid crystalline elastomer film. Such pressure-induced color changes of cellulose liquid crystalline elastomer films exhibited the correlation between pressure and reflection color change. Therefore, the reflection color of cellulose liquid crystalline elastomer films allows us to quantitatively visualize the degree of pressure or strain at a glance.

In open water swimming （OWS） in cold water （water temperature:16-18℃）， swimmers are allowed to wear a wetsuit. Given that wetsuits retain heat, the wearing a wetsuit during OWS in cold water is considered to have a significant effect on the swimmer's body core temperature and thermal sensation. However, it is unclear how wearing a wetsuit affects body core temperature during OWS in cold water. Therefore, in the present study, we examined （1） the local skin thermal sensitivity of OWS swimmers, and （2） the effect wetsuit on body core temperature during OWS in cold water. In experiment 1, local skin warm and cool sensitivities were measured in 8 OWS swimmers （OWS group） and 15 healthy adults （Control group）．Although local skin warm sensitivity did not differ between groups, the OWS group tended to be less cold-sensitive than the Control group （P = 0.075）．In experiment 2, four OWS swimmers performed two 2-hour OWS trials in cold water （water temperature:15-16℃） with （wetsuit trial） and without wetsuits （swimsuit trial）．Body core temperature was measured during OWS by ingestible thermometer. Body core temperature during OWS was higher in wetsuit trial than swimsuit trial （P = 0.046）．These results suggest that OWS swimmers tend to be more tolerant of cold than non-swimmers. In addition, wearing a wetsuit can prevent decrease in body core temperature during OWS in cold water.

Developing a device that can easily evaluate the intra-clothing microenvironment is important for developing new garments to prevent heat-related illness in summer periods. We evaluated the effectiveness of an originally developed fixture assessing the intra-clothing microenvironments during outdoor exercise on summer days. Eleven long- and middle-distance runners participated in a two-day summer experiment on the same schedule. The originally developed fixture was attached to participants on their chest and back skin sites using collodion to measure the temperature and humidity inside their clothing. The experiment consisted of two bouts of 30-minute moderate-intensity running, with the first bout wearing a conventional polyester fabric T-shirt （CON） on both experimental days. The second bout was conducted by wearing a commercially available T-shirt with high breathability （Dry Aero Flow, DAF） or CON. We showed that the intra-clothing temperature and relative humidity were successfully measured using the developed fixture in all participants. We also found that although there was no difference in intra-clothing temperature and relative humidity between conditions during the first bout of exercise, the DAF attenuated intra-clothing humidity than the CON in the second bout. These results suggest that the fixture developed in the present study is effective to assess the intra-clothing environment during outdoor exercise in summer periods.

The fan cooling garments are coming into very common use by Japanese outdoor manual workers. This study investigated the effects of the fan cooling vest use on endurance performance and prevention of heat-related illnesses in high school athletes during high-intensity training sessions under the clear sky in the summer heat. Ten male soccer players in high school conducted two high-intensity soccer training sessions for 2-h with （VEST） or without （CON） a commercially available fan cooling vest on a soccer uniform. These sessions commenced at 9 a.m. on separate days in late August. Increases in mean skin temperature, heart rate and thermal sensation were attenuated （all P<0.05） in VEST than CON during exercise. Rating of perceived exertion was lower （P<0.05） in VEST than CON during exercise. Total distance measured with a global positioning system was lower （both P<0.05） in VEST than CON. Body fluid responses were not different between trials （all P>0.05）．This study indicates that the use of the fan cooling vest would alleviate thermal strain and risks of heat-related illnesses in high school athletes during high-intensity training sessions under the clear sky in the summer heat. Meanwhile, it is likely that endurance performance is limited by using the fan cooling vest under our experimental conditions compared to when no vest is used.