Tracking handgrip strength in Kendo athletes from university to middle and older adulthood.

OBJECTIVE: This study aimed to compare the current handgrip strength (HGS) of Kendo athletes with their HGS when they were in university (up to 50 years). METHODS: Eighty male graduates who were Kendo club members during their university days performed anthropometric and HGS measurements, and these HGS were compared with those measured during their university days (mean age of 19.5 years old). RESULTS: There was no evidence of a statistical difference in HGS between the current measurement and the measurement taken during university [-0.64 (-1.9, 0.67) kg, p = .336]. There was, however, evidence that the difference in HGS depended upon the current age of the individual (t = -6.43, p < .001). When probing the interaction, there were statistical differences between the ages of 24.6 and 38.2 years and between the ages of 47.4 and 69.9 years. Strength increased across time in the younger participants and decreased for those who were older. Between the ages of 38.9 and 46.1 years, there was no evidence of a statistical difference indicating a maintenance of strength. CONCLUSION: The HGS of Kendo club graduates, which they acquired during their formative years, continued to increase even after they graduated from university and entered their 30s. However, their HGS decreased from age 50, even though they practiced Kendo.

Pre-heating stress associated with acute oral leucine supplementation effects in rat gastrocnemius muscle: Implications for protein synthesis signaling pathways.

Skeletal muscle is a highly plastic tissue. The role of heat shock protein 72 (Hsp72) in heat stress-induced skeletal muscle hypertrophy has been well demonstrated; however, the precise mechanisms remain unclear. Essential amino acids, such as leucine, mainly mediate muscle protein synthesis. We investigated the effects of pre-heating and increased Hsp72 expression on the mechanistic target of rapamycin (mTOR) signaling and protein synthesis following leucine administration in rat gastrocnemius muscle. To ensure increased Hsp72 expression in both the red and white portions of the muscle, one leg of male Wistar rats (10-week-old, n = 23) was heat-stressed in 43 °C water for 30 min twice at a 48-h-interval (heat-stressed leg, HS leg). The contralateral leg served as a non-heated internal control (CT leg). After the recovery period (48 h), rats were divided into the pre-administration or oral leucine administration groups. We harvested the gastrocnemius muscle (red and white parts) prior to administration and 30 and 90 min after leucine treatment (n = 7-8 per group) and intramuscular signaling responses to leucine ingestion were determined using western blotting. Heat stress significantly upregulated the expression of Hsp72 and was not altered by leucine administration. Although the phosphorylation levels of mTOR/S6K1 and ERK were similar regardless of heating, 4E-BP1 was less phosphorylated in the HS legs than the CT legs after leucine administration in the red portion of the muscles (P < 0.05). Moreover, c-Myc expression differed significantly after leucine administration in both the red and white portions of the muscles. Our findings indicate that following oral leucine administration, pre-heating partially blunted the muscle protein synthesis signaling response in the rat gastrocnemius muscle.

Effects of preconditioning with heat stress on acute exercise-induced intracellular signaling in male rat gastrocnemius muscle.

Heat stress (HS) induces Akt/mTOR phosphorylation and FoxO3a signaling; however, whether a prior increase in heat shock protein 72 (HSP72) expression affects intracellular signaling following eccentric exercise remains unclear. We analyzed the effects of HS pretreatment on intramuscular signaling in response to acute exercise in 10-week-old male Wistar rats (n = 24). One leg of each rat was exposed to HS and the other served as an internal control (CT). Post-HS, rats were either rested or subjected to downhill treadmill running. Intramuscular signaling responses in the red and white regions of the gastrocnemius muscle were analyzed before, immediately after, or 1 h after exercise (n = 8/group). HS significantly increased HSP72 levels in both deep red and superficial white regions. Although HS did not affect exercise-induced mTOR signaling (S6K1/ERK) responses in the red region, mTOR phosphorylation in the white region was significantly higher in CT legs than in HS legs after exercise. Thr308 phosphorylation of Akt showed region-specific alteration with a decrease in the red region and an increase in the white region immediately after downhill running. Overall, a prior increase in HSP72 expression elicits fiber type-specific changes in exercise-induced Akt and mTOR phosphorylation in rat gastrocnemius muscle.

Blood biomarkers for estimating energy intake in Japanese male collegiate athletes: a pilot study.

BACKGROUND: Athletes should be informed of their required energy intake in preparation for sports competitions. However, the environment in which dietary surveys can be conducted to determine the required energy intake for sports competitions is limited, and such survey will require a substantial amount of time and effort from athletes and dietitians. If certain biomarkers for estimating the energy intake can be identified, they may compensate for the shortcomings of these dietary surveys. We aimed to identify the blood biomarkers to estimate the energy intake/basal metabolic rate ratio of male athletes. METHODS: Twenty-six male athletes from a university physical education department were included and underwent measurements of height, weight, and body composition, as well as blood sampling. The dietary assessment included a 3-day dietary recall and collection of meal photographs. The basal metabolic rate was estimated using the lean body mass, while the daily energy intake/basal metabolic rate ratio was used as an index to determine the energy intake. From the 36 selected blood biomarkers, we identified the independent biomarkers for inclusion in the multiple regression analysis by assessing for pairwise correlations and multicollinearity. A formula for estimating the energy intake/basal metabolic rate was then developed using the stepwise method. A p-value of < 0.05 was considered significant. RESULTS: Overall, 18 of the 36 blood biomarkers were selected, and multiple regression analysis revealed that triiodothyronine, white blood cell count, and triglyceride level were significant factors that can be used to estimate the energy intake/basal metabolic rate, accounting for 60.4% of the variance. No systematic errors were observed in the estimated values, calculated using the estimation formula and dietary assessment results. CONCLUSIONS: A combination of free triiodothyronine level, white blood cell count, and triglyceride level can be used for estimating the energy intake/basal metabolic rate of male athletes, thus compensating for the shortcomings of dietary surveys.

The association between subjective anti-doping knowledge and objective knowledge among Japanese university athletes: a cross-sectional study.

Introduction: This study aimed to assess the association between subjective anti-doping knowledge (subjective ADK) and objective anti-doping knowledge (objective ADK) among Japanese university athletes, framed within the context of the Theory of Planned Behavior (TPB). Methods: Eligible participants were 486 university athletes [320 men (65.8%), 166 women; mean age of 18.9 ± 1.0 years]. The participants categorized themselves in terms of the quality of their anti-doping knowledge. This assessment resulted in an independent variable coded as "(1) substantial lack of adequate knowledge," "(2) some lack of adequate knowledge," "(3) fair amount of knowledge" or "(4) good amount of knowledge." Objective ADK was assessed using the Athlete Learning Program about Health and Anti-Doping (ALPHA) test, a set of questions derived from the ALPHA-a former World Anti-Doping Agency e-learning program. The test comprises 12 questions (four choices each; passing index: ≧10 points or 80% correct answer rate). ANCOVA was conducted using subjective ADK as an independent variable and ALPHA scores as a dependent variable, adjusting for confounding factors (anti-doping experience). Results: The ALPHA corrected answer rate across subjective ADK levels for the group were 73.10% for "(1) substantial lack of adequate knowledge," 71.97% for "(2) some lack of adequate knowledge," 75.18% for "(3) fair amount of knowledge" and 72.86% for "(4) good amount of knowledge." Comparison between different levels of subjective ADK revealed no significant differences in ALPHA score considering the main effects or any of their interactions. Discussion: The present results revealed that Japanese university athletes' subjective ADK did not match their objective ADK. In the context of the TPB, there may be limitations in the perceived behavioral control in anti-doping knowledge. Even if athletes view doping as a wrongful act and have formed attitudes and subjective norms to comply with the rules, the results suggest that errors may occur in the composition of behavioral intentions due to a lack of knowledge. This could lead to the possibility of facing the risk of unintentional anti-doping rule violations. It highlights the need for targeted educational interventions to align subjective ADK of athletes with their objective ADK.

Associations of Morphological Changes in Skeletal Muscles of Preschool Children in China Following Physical Activity.

PURPOSE: Physical activity (PA) is likely to be the most important modifiable factor in skeletal muscle development. However, the influence of PA on the skeletal muscle of preschool children has not been thoroughly investigated. The main objective of this study was to quantitatively measure PA, and then, to assess whether associations exist between site-specific muscle changes and PA in relation to sex and weight statuses in preschool children aged 3 to 4 years. METHODS: A total of 86 healthy preschool children, aged 3-4 years, were instructed to wear an accelerometer for seven consecutive days. The number of steps taken daily, and minutes spent in moderate-vigorous PA (MVPA) and total PA (TPA) were recorded. Muscle thickness was measured by B-mode ultrasonography using a 5-18 MHz scanning head. Muscle thickness was measured at seven sites: the lateral forearm, upper arm, abdomen, anterior and posterior thigh, and anterior and posterior lower leg. RESULTS: There was no significant difference between boys and girls in terms of MVPA and TPA on weekdays and weekends. According to the linear regression models, after adjusting for daylight duration, the muscle of the posterior thigh was significantly positively associated (p < 0.05) with daily steps and MVPA on weekdays for boys and girls, respectively. CONCLUSIONS: We found that the muscle thickness of the posterior thigh in preschool children was significantly positively associated with PA, as measured by daily steps and MVPA. We suggest that for the overall health and well-being of preschool children, the levels of PA should be maintained and/or increased, and preferably transformed into a regular part of daily living.

Correction: Ishihara et al. Association between Daily Physical Activity and Locomotive Syndrome in Community-Dwelling Japanese Older Adults: A Cross-Sectional Study. Int. J. Environ. Res. Public Health 2022, 19, 8164.

There was an error in the "d-value of the first paragraph in Section 3 (Results)" in the original publication (Page 5, Line 41) [...].

Qualitative study of the association between psychosocial health and physical activity/sleep quality in toddlers.

Physical activity and sleep are important factors of mental and physical health in children, with some reports indicating that their effects can persist into adulthood. However, there is limited research on the qualitative aspects of physical activity and sleep in preschool children, particularly in those aged < 3 years. Therefore, to elucidate the association between psychosocial health and physical activity/sleep in early childhood in terms of qualitative aspects, we conducted a retrospective cohort study in 2985 3-year-old children (37.2 ± 0.75 months) in Shanghai, China. An analysis using structural equation modeling indicated that current physical activity had a direct and moderate impact on current psychosocial health evaluated using the Strength and Difficulties Questionnaire. In particular, past physical activity had an indirect and mild effect on current psychosocial health via current physical activity in girls. However, regardless of sex, past sleep quality had slight impact on current psychosocial health, not only indirectly via current sleep quality, but also directly. These findings highlight the importance of considering the qualitative aspects of physical activity and sleep quality as significant factors influencing the current and future psychosocial health of children, even at a very early age (< 3 years).

Longitudinal changes of grip strength and forearm muscle thickness in young children.

Background: Grip strength is a marker of future health conditions and is mainly generated by the extrinsic flexor muscles of the fingers. Therefore, whether or not there is a relationship between grip strength and forearm muscle size is vital in considering strategies for grip strength development during growth. Thus, this study aimed to examine the association between changes in grip strength and forearm muscle thickness in young children. Methods: Two hundred eighteen young children (104 boys and 114 girls) performed maximum voluntary grip strength and ultrasound-measured muscle thickness measurements in the right hand. Two muscle thicknesses were measured as the perpendicular distance between the adipose tissue-muscle interface and muscle-bone interface of the radius (MT-radius) and ulna (MT-ulna). All participants completed the first measurement and underwent a second measurement one year after the first one. Results: There were significant (P < 0.001) within-subject correlations between MT-ulna and grip strength [r = 0.50 (0.40, 0.60)] and MT-radius and grip strength [r = 0.59 (0.49, 0.67)]. There was no significant between-subject correlation between MT-ulna and grip strength [r = 0.07 (-0.05, 0.20)], but there was a statistically significant (P < 0.001) between-subject relationship between MT-radius and grip strength [r = 0.27 (0.14, 0.39)]. Conclusion: Although we cannot infer causation from the present study, our findings suggest that as muscle size increases within a child, so does muscle strength. Our between-subject analysis, however, suggests that those who observed the greatest change in muscle size did not necessarily get the strongest.

Cage restriction-induced physical inactivity promotes subsequent hepatic apoptosis during tail suspension in young male rats.

This study investigated the impact of long-term physical inactivity on hepatic cytoprotective- and inflammatory-related protein expressions in young rats and the subsequent apoptotic response during microgravity stress simulated by tail suspension. Four-week-old male Wistar rats were randomly assigned to the control (CT) and physical inactivity (IN) groups. The floor space of the cages provided to the IN group was reduced to half of that provided to the CT group. After 8 weeks, rats in both groups (n = 6-7) underwent tail suspension. Their livers were harvested immediately before (0 day) or 1, 3, and 7 days after tail suspension. Levels of hepatic heat shock protein 72 (HSP72), an anti-apoptotic protein, reduced over 7 days of tail suspension in the IN group than in the CT group (p < 0.01). Fragmented nucleosomes in the cytoplasmic fraction of the liver, an apoptotic index, were drastically increased by physical inactivity and tail suspension, and this change was significantly greater after 7 days of tail suspension in the IN group than in the CT group (p < 0.01). The apoptotic response was accompanied by the upregulation of pro-apoptotic proteins (cleaved caspase-3 and -7). Moreover, the levels of other pro-apoptotic proteins (tumor necrosis factor-1α and histone deacetylase 5) were also significantly higher in the IN than in the CT group (p < 0.05). Our results indicated that 8 weeks of physical inactivity decreased hepatic HSP72 levels and promoted hepatic apoptosis during the subsequent 7 days of tail suspension.

Effects of Ingesting Food Containing Heat-Killed Lactococcus lactis Strain Plasma on Fatigue and Immune-Related Indices after High Training Load: A Randomized, Double-Blind, Placebo-Controlled, and Parallel-Group Study.

Lactococcus lactis strain Plasma (LC-Plasma) is a unique lactic acid bacterium that activates plasmacytoid dendritic cells (pDCs). We evaluated the effect of LC-Plasma on fatigue indices and dendritic cells activity in athletes after 14 days' continuous exercise load. Thirty-seven participants were divided into two groups and consumed placebo (PL) or LC-Plasma capsules (containing 100 billion cells) daily for 14 days. Maturation markers on dendritic cells, blood parameters, physiological indices, and fatigue-related indices were recorded on days 1 and 15 (before and after exercise). Cumulative days of symptoms relating to physical conditions were also recorded during the continuous exercise period. We observed that CD86 as a maturation marker on pDCs was significantly higher and that cumulative days of fatigue were significantly fewer in the LC-Plasma group than in the Placebo group on day 15. We also conducted 2 h ergometer exercise on day 15 to evaluate fatigue. The results showed that autonomic fatigue parameters (LF/HF) were significantly lower in the LC-Plasma group. These results suggest that LC-Plasma supplementation alleviates fatigue accumulation and increases pDC activity caused by a continuous high training load.

Athletes in sporting events with upper-body gripping movements have greater handgrip strength than those in sporting events that prioritize the lower body.

OBJECTIVE: Evidence suggests that acquiring a high level of handgrip strength early in life and maintaining that strength throughout life may be important for health. In addition, it is thought that sports activities performed during the developmental period are effective in improving handgrip strength, but it is unknown what types of sports are more effective. As a first step, we conducted a cross-sectional study to compare handgrip strength across different sports (upper-body gripping sports vs. lower body) in early adulthood. METHODS: We used the Juntendo Fitness Plus Study data from 1973 to 2018 and selected two types of sporting events with matching physiques (soccer, baseball, and kendo) but different degrees of gripping. Data on 7344 male first-year sports university students included 1127 soccer, 297 Kendo, and 698 baseball players. RESULTS: Those in the lower body-only (soccer) sports had -3.78 (95% CI: -4.27, -3.29) kg lower handgrip strength than those in the lower + upper (kendo and baseball). Comparing each individual sport found that each sport was different from each other with Kendo > Baseball > Soccer (between each sport, p < .001). In addition, the difference between sports has become greater across time. CONCLUSIONS: In early adulthood, handgrip strength is greatest in those participating in sports with upper-body movements compared to those participating in sports that mainly involved lower-body movements. The three sports we selected are natural activities that do not directly train handgrip strength. Therefore, sport may be one potential method to improve low handgrip strength in children/adolescents during the developmental period.

Relationship between Skeletal Muscle Thickness and Physical Activity in 4- to 6-Year-Olds in Japan.

PURPOSE: Physical activity (PA) is widely recognized as a key factor in promoting skeletal muscle growth, though little is known about the specific impact of PA on the skeletal muscle development of preschool children. The purpose of this study is to investigate whether there is a relationship between PA levels and skeletal muscle thickness in preschoolers. By exploring this relationship, we hope to gain a better understanding of how PA can be used to promote healthy skeletal muscle development in preschoolers. METHODS: In this study, a total of 275 healthy Japanese preschoolers, aged 4-6 years, from seven nursery schools in the town of Togo were recruited. Participants were asked to wear an accelerometer for four consecutive days to record their daily steps and the amount of time spent in moderate-to-vigorous PA and t total physical activity. Muscle thickness (MTs) was measured using B-mode ultrasonography at four sites: the anterior and posterior thigh (AT and PT, respectively) and the anterior and posterior lower leg (AL and PL, respectively). RESULTS: On weekdays, boys were found to be more physically active and engaged in significantly higher levels of total physical activity and moderate-to-vigorous PA than girls. Both boys and girls recorded more physical activity, daily steps, and higher levels of total physical activity and MVPA on weekdays compared to weekends. After adjusting for daylight duration, multivariable regression analyses revealed that increased total physical activity and moderate-to-vigorous PA were positively associated with greater muscle thickness size in the anterior tibialis (AT) and posterior lower leg (PL) muscles (ß = 1.11 and ß = 1.37 for AT, ß = 1.18 and ß = 0.94 for PL, p < 0.05) in Japanese preschoolers. CONCLUSIONS: The time spent involved in most of the different categories of moderate-to-vigorous PA was significantly higher for boys than for girls on the weekdays and weekends. Additionally, there was a positive correlation between time spent in moderate-to-vigorous PA and greater development of skeletal muscle in the lower body.

Development of a Core Body Thermometer Applicable for High-Temperature Environment Based on the Zero-Heat-Flux Method.

Monitoring core body temperature (CBT) allows observation of heat stress and thermal comfort in various environments. By introducing a Peltier element, we improved the zero-heat-flux core body thermometer for hot environments. In this study, we performed a theoretical analysis, designed a prototype probe, and evaluated its performance through simulator experiments with human subjects. The finite element analysis shows that our design can reduce the influence of external temperature variations by as much as 1%. In the simulator experiment, the prototype probe could measure deep temperatures within an error of less than 0.1 °C, regardless of outside temperature change. In the ergometer experiment with four subjects, the average difference between the prototype probe and a commercial zero-heat-flux probe was +0.1 °C, with a 95% LOA of -0.23 °C to +0.21 °C. In the dome sauna test, the results measured in six of the seven subjects exhibited the same trend as the reference temperature. These results show that the newly developed probe with the Peltier module can measure CBT accurately, even when the ambient temperature is higher than CBT up to 42 °C.

Estimability study on the age of toddlers' gait development based on gait parameters.

In the first few years of toddlers' locomotion, various gait parameters improve gradually and dynamically with gait development. Therefore, in this study, we hypothesized that the age of gait development, or the level of gait development with age as its indicator, can be estimated from several gait parameters related to gait development, and investigated its estimability. In total, 97 healthy toddlers aged about 1-3 years participated in the study. All five selected gait parameters showed a moderate or higher correlation with age, but the duration with a large change and the strength of the association with gait development varied for each gait parameter. Multiple regression analysis was performed using age as the objective variable and five selected gait parameters as explanatory variables, and an estimation model (R2 = 0.683, adjusted R2 = 0.665) was created. The estimation model was verified using a test dataset separate from the training dataset (R2 = 0.82, p < 0.001). It was suggested that the age of gait development could be estimated from gait alone. Gait analysis based on empirical observations may reduce the need for skilled observers and their potential variability.

Passive Muscle Stiffness of Biceps Femoris is Acutely Reduced after Eccentric Knee Flexion.

Eccentric hamstring exercises reportedly prevent hamstring strain injury in the biceps femoris long head (BFlh). However, information on the favorable adaptive responses in the BFlh to eccentric hamstring exercises is limited. We aimed to examine the acute effect of maximal isokinetic eccentric knee flexion on passive BFlh stiffness as a potential risk factor for the hamstring strain injury using ultrasound shear wave elastography. Ten young participants randomly performed both tasks involving five consecutive repetitions of isokinetic concentric and eccentric knee flexion with maximal effort on different legs. Passive BFlh shear modulus was taken before and 30, 60, 90, and 120 s after each task. Passive BFlh shear modulus was significantly reduced at all time points after eccentric knee flexion, whereas there was no significant change in passive BFlh shear modulus after the concentric task. The present findings indicate that passive BFlh stiffness would reduce specifically after low-volume, slow-velocity eccentric knee flexion exercise. The findings may help provide practitioners with a basis to develop more effective exercise programs for preventing HSI.

Exercise training improves obesity-induced inflammatory signaling in rat brown adipose tissue.

Chronic inflammation is considered as an etiology of obesity and type 2 diabetes. Brown adipose tissue (BAT) of obese animals shows increased inflammation. Regular exercise has anti-inflammatory effects; however, the effects of exercise training on BAT inflammation in obese animals remain unclear. Thus, this study aimed to investigate the effects of exercise training on inflammation-related signaling in the BAT of obese and diabetic rats. Male Otsuka Long-Evans Tokushima Fatty (OLETF) rats, an obese/diabetic rodent model, were randomly divided into either sedentary (n = 11) or exercise training (n = 8) groups. Long-Evans Tokushima Otsuka (LETO; n = 9) rats were used as the nondiabetic sedentary controls. Exercise training using a treadmill was conducted 4 days per week for 20 weeks, starting at 5 weeks old. As a result, exercise training attenuated the phosphorylation levels of p65 and mitogen-activated protein kinases in the BAT of OLETF rats, concurrently with the improvement of obesity and systemic glucose tolerance. Moreover, exercise training decreased oxidative stress and increased the antioxidant and anti-inflammatory protein levels in the BAT. Conversely, exercise training did not alter the expression levels of uncoupling protein-1 and oxidative phosphorylation-related proteins in the BAT, which were lower in the OLETF rats than the LETO rats. In conclusion, our data suggest that exercise training prevents the activation of inflammatory signaling in the BAT of obese/diabetic rats.

Genome-Wide Association Study Identifies CDKN1A as a Novel Locus Associated with Muscle Fiber Composition.

Muscle fiber composition is associated with physical performance, with endurance athletes having a high proportion of slow-twitch muscle fibers compared to power athletes. Approximately 45% of muscle fiber composition is heritable, however, single nucleotide polymorphisms (SNP) underlying inter-individual differences in muscle fiber types remain largely unknown. Based on three whole genome SNP datasets, we have shown that the rs236448 A allele located near the cyclin-dependent kinase inhibitor 1A (CDKN1A) gene was associated with an increased proportion of slow-twitch muscle fibers in Russian (n = 151; p = 0.039), Finnish (n = 287; p = 0.03), and Japanese (n = 207; p = 0.008) cohorts (meta-analysis: p = 7.9 × 10−5. Furthermore, the frequency of the rs236448 A allele was significantly higher in Russian (p = 0.045) and Japanese (p = 0.038) elite endurance athletes compared to ethnically matched power athletes. On the contrary, the C allele was associated with a greater proportion of fast-twitch muscle fibers and a predisposition to power sports. CDKN1A participates in cell cycle regulation and is suppressed by the miR-208b, which has a prominent role in the activation of the slow myofiber gene program. Bioinformatic analysis revealed that the rs236448 C allele was associated with increased CDKN1A expression in whole blood (p = 8.5 × 10−15) and with greater appendicular lean mass (p = 1.2 × 10−5), whereas the A allele was associated with longer durations of exercise (p = 0.044) reported amongst the UK Biobank cohort. Furthermore, the expression of CDKN1A increased in response to strength (p < 0.0001) or sprint (p = 0.00035) training. Accordingly, we found that CDKN1A expression is significantly (p = 0.002) higher in the m. vastus lateralis of strength athletes compared to endurance athletes and is positively correlated with the percentage of fast-twitch muscle fibers (p = 0.018). In conclusion, our data suggest that the CDKN1A rs236448 SNP may be implicated in the determination of muscle fiber composition and may affect athletic performance.

Relationship between the level of willingness to learn about anti-doping and objective knowledge among Japanese university athletes: A cross-sectional study.

Previous studies have indicated that athletes' anti-doping knowledge is inadequate. Athletes' willingness to learn about anti-doping (willingness to learn) may influence their anti-doping knowledge, but the actual situation is unclear. This study aimed to determine the relationship between athletes' willingness to learn about anti-doping and their objective measurement knowledge and explore directions for educational interventions. The eligible participants were 971 male and 802 female university athletes. We used the ALPHA test (12 questions/four choices; passing index: ≥10 points/80% correct answer rate) to assess objective anti-doping knowledge. The willingness to learn question was, "Would you like to learn more about anti-doping?" Responses were given on a 4-point scale ranging from 1: strongly disagree to 4: strongly agree. An ANCOVA was conducted with four levels of willingness to learn as the independent variable and ALPHA correct answer rate as the dependent variable, adjusting for confounding factors (years of athletic experience and anti-doping education experience). The percentage of athletes (%) and each ALPHA correct answer rate (%) by the level of willingness to learn was 1: strongly disagree, n = 1.64%, 61.78%; 2: somewhat disagree, n = 13.14%, 62.38%; 3: somewhat agree, n = 62.94%, 64.08%; 4: strongly agree, n = 22.28%, 67.11%. The ALPHA correct answer rates showed significant differences in the main effect by the level of willingness to learn [F (3, 1767) = 2.873, p < 0.05, η2 = 0.01], although the effect size was small, and multiple comparisons showed no significant differences between the levels. The results indicated that the ALPHA correct answer rate did not reach 80% even for the "strongly agree" level of willingness to learn, suggesting that information on anti-doping may be inadequate. The need to provide sufficient educational content to improve knowledge was evident.

Effect of losartan treatment on Smad signaling and recovery from hindlimb unloading-induced soleus muscle atrophy in female rats.

Losartan, an angiotensin II type 1 receptor blocker, exerts protective effect on soleus muscle atrophy in female rats. Thus, we aimed to examine the effect of losartan treatment on the recovery of atrophied soleus muscles. Female Wistar rats were subjected to hindlimb unloading for 7 d and then reloading for 7 d with either phosphate-buffered saline (PBS; n = 9) or losartan (40 mg/kg/day; n = 9). The soleus muscles were removed at rest (sedentary control [SED]; n = 9), after 7 d of hindlimb unloading (HU; n = 9), and after 7 d of reloading (HUR-PBS or HUR-LOS; n = 9 each). The absolute and relative weights, and fiber cross-sectional area (CSA) of the soleus muscles of rats in the HU group were significantly reduced as compared to those of the rats in the SED group at 7 d post-hindlimb unloading. Seven days of reloading significantly increased the muscle weights of rats in the HUR-PBS and HUR-LOS groups, with the recovery rate of the absolute muscle weight and type I fiber CSA being significantly higher in the HUR-LOS group (6.1% and 10.1%, respectively) than in the HUR-PBS group (4.7% and 5.2%, respectively) (p < 0.05). Moreover, the absolute and relative muscle weight in HUR-PBS were lower than SED; however, no significant difference was observed between the SED and HUR-LOS groups. CSAs of type I and IIa fiber were significantly higher in the HUR-LOS group than in the HU group. Losartan administration during reloading resulted in increased Smad1/5/8 and mTOR signaling and decreased Smad2/3 signaling and protein ubiquitination, facilitating the recovery of atrophied soleus muscle. Therefore, losartan administration-induced muscle recovery may partially be attributed to enhanced Smad1/5/8 and mTOR signaling activation, and reduced activation of canonical TGF-ß signaling (Smad2/3) in the soleus muscle.