Fitness Components Research Articles

Prediction of central Augmentation Index in healthy adults.

Central Augmentation Index (AIx) is a surrogate marker of large artery stiffness that may provide valuable insight to cardiovascular health. The aim of this study was to evaluate the relationship between AIx and components of physical fitness. One hundred eighty-five healthy men and women (aged 20-79 years) underwent non-invasive assessment of arterial wave reflection to determine AIx, which was corrected to a heart rate of 75 beats per minute (AI×75). Body composition was evaluated using dual energy X-ray absorptiometry (DXA) and aerobic capacity (VO<inf>2max</inf>) was derived from expired gas analysis during a symptom limited exercise test on a treadmill. A multiple linear regression revealed age and VO<inf>2max</inf> as significant predictors of AI×75 [AI×75=32.055 + (0.252×age) - (0.722×VO<inf>2max</inf>)]. Upon removal of VO<inf>2max</inf> from regression analysis, resting heart rate (RHR) and % body fat (BF%) were revealed to be significant predictors of AI×75: AI×75=-61.316 + (0.481×age) + (0.565×BF%) + (0.56×RHR). Our findings demonstrate that central Augmentation Index can be reliably predicted in healthy adults who undergo a maximal exercise or body composition assessment. These prediction equations may be applied in non-medical settings to assist in creating comprehensive health and fitness profiles for healthy clientele.

The joint evolution of separate sexes and sexual dimorphism.

Dioecious plants are frequently sexually dimorphic. Such dimorphism, which reflects responses to selection acting in opposite directions for male and female components of fitness, is commonly thought to emerge after separate sexes evolved from hermaphroditism. But associations between allocation to male and female function and traits under sexual conflict may well also develop in hermaphroditic ancestors. Here, we show that variation in sex allocation and a trait under sexual conflict inevitably generates an advantage to sexual specialisation, fueling the transition to dioecy. In the absence of constraints, this leads to the joint evolution of separate sexes and sexual dimorphism through the build-up of an association between sex allocation and the conflict trait, such that eventually the population consists of unisexuals expressing their sex-specific optima. We then investigate how such association might materialise genetically, either via recombination suppression or via sex-dependent expression, and show that the genetic architecture of sex alloca- tion and the conflict trait readily evolves to produce the association favoured by selection. Finally and in agreement with previous theory, we demonstrate that limited dispersal and self-fertilisation, which are pervasive ecological char- acteristics of flowering plants, can offset the advantage of sexual specialisation generated by sexual conflict and thus maintain hermaphroditism. Taken together, our results indicate that advantages to sexual specialisation are inevitable when there is conflict between sexual functions in hermaphrodites, but these advantages can be counterbalanced by ecological benefits of hermaphroditism.

MHC Class II Supertypes Affect Survival and Lifetime Reproductive Success in a Migratory Songbird.

The major histocompatibility complex (MHC) plays a critical role in the immune response against pathogens. Its high polymorphism is thought to be mainly the consequence of host-pathogen co-evolution, but elucidating the mechanism(s) driving MHC evolution remains challenging for natural populations. We investigated the diversity of MHC class II genes in a wild population of pied flycatchers Ficedula hypoleuca and tested its associations with two key components of individual fitness: lifetime reproductive success and survival. Among 180 breeding adults in our study population, we found 182 unique MHC class II exon 2 alleles. The alleles showed a strong signal of positive selection and grouped into nine functional supertypes based on physicochemical properties at the inferred antigen-binding sites. Three supertypes were found in > 98% of the sampled individuals, indicating that they are nearly fixed in the population. We found no rare supertypes in the population, as all supertypes were present in > 70% of individuals. Three supertypes were related to different components of individual fitness: two were associated with lower offspring production over time, while the third was positively associated with survival. Overall, the substantial allelic and functional diversity and the relationship between specific supertypes and fitness are in accordance with the notion that balancing selection maintains MHC class II diversity in the study population, possibly with fluctuating selection as the underlying mechanism. The absence of rare supertypes in the population suggests that the balancing selection is not driven by rare-allele advantage.

Effects of soccer instruction on the executive functions and agility of children in early childhood.

Studies have shown that in open-skill sports the executive function of high-performing players is significantly higher than that of the control group. However, whether participation in soccer effectively improves executive function is unclear because previous studies lacked baseline measurements of executive function. Furthermore, agility, mostly developed in early childhood, is the most demanding component of physical fitness in open-skill sports, requiring sudden changes in body direction while running at full speed. However, no studies have examined the improvement in agility of young children participating in open-skill sports through comparison with a control group. This study aimed to clarify whether instruction in soccer, an open-skill sport, can effectively improve the executive function and agility of kindergarteners compared to a control group. In April 2020, 31 five-year-old children enrolled in kindergarten K in H prefecture in Japan were targeted as the intervention group and received soccer instruction for 12 weeks. In April 2020, a control group was established, consisting of 39 five-year-old children enrolled at the same kindergarten. Participants in both groups were measured for agility, inhibition, and working memory before and after (pre-post) soccer instruction for the intervention group. For each item, a two-way ANOVA of the group (intervention group・control group) x measurement period (pre-post) was performed, showing no significant interactions for working memory and agility. Because only the inhibition effect was significant, simple main effects were tested. Regarding inhibition, although the intervention group (M = 0.18, SD = 0.01) and the control group (M = 0.17, SD = 0.01) did not differ significantly in performance pre-intervention, the intervention group (M = 0.23, SD = 0.01) showed significantly better performance post-intervention compared to the control group (M = 0.19, SD = 0.01) (p < .01). Thus, soccer instruction improved kindergarteners' inhibition, to a level significantly higher than that of the control group. Still, no differences were found between groups regarding working memory and agility.

Inbreeding accelerates reproductive senescence, but not survival senescence, in a precocial bird.

Inbreeding depression is predicted to increase with age, because natural selection is less efficient at purging deleterious alleles that are only expressed later in life. However, empirical results are scarce, and equivocal between studies. Here we performed controlled matings between related and unrelated individuals of domesticated Japanese quail (Coturnix japonica), and monitored the performance of their offspring for all fitness components over their complete life course. We found rapid senescence in adult survival and egg laying performance, and inbreeding depression at all life stages (reduced embryo viability, increased age at maturity, as well as reduced adult survival and reproduction). Inbreeding depression did not increase at later ages for survival, but did so for egg laying, thereby accelerating reproductive senescence. Moreover, the effect of inbreeding on egg laying persisted after correcting for lifespan, indicating that both survival and reproduction were independently affected by inbreeding. We suggest that in heterogeneous populations intra-generational purging may at earlier ages already select out the individuals that are homozygous for the specific alleles responsible for depressed survival, preventing the appearance of increased inbreeding depression in survival with age. Given that inbreeding affects reproduction independent of survival this should not apply to reproductive senescence or homogeneous populations, which may explain equivocal results between traits and studies.

Incidental Physical Activity and Physical Fitness Associate with Sustained Attention and Impulse Control in Older Adults

Age-related changes have been observed in sustained attention and impulse control. Deficits in these functions are related to pathological aging. However, research suggests that an active lifestyle may exert a protective effect on cognition in aging. While the association between physical activity and cognitive functioning in older adults has been previously described, few studies have explored the relationship between incidental physical activity and fitness with sustained attention and impulse control in this population. Therefore, this study aimed to evaluate the association between incidental physical activity and various components of fitness and sustained attention and impulsivity in older adults. Fifty-four older adults were recruited (41 females and 13 males) with a mean age of 76.76 years (SD = 8.94). Physical activity levels were assessed using the Yale Physical Activity Survey (YPAS), physical function in healthy older adults was evaluated with the Senior Fitness Test, and sustained attention and impulsivity were measured using a computerized continuous performance task. Significant correlations were found between higher energy expenditure during housework and yardwork activities, and fewer commission errors and shorter reaction times during sustained attention task, and higher sensitivity during impulse control task (rho between 0.35 and 0.40, p < .01, β = 0.80). Additionally, higher scores between agility and balance were associated with better accuracy during the sustained attention task, and faster speed processing correlated to better performance impulse control task (rho between 0.33 and 0.36, p < .05, β = 0.80). Our study highlights the importance of incidental physical activity and various components of fitness on sustained attention and impulse control in aging.

Exploring the Role of Dietary Calcium Intake in Muscle and Cardiovascular Performance Among Young Athletes

The importance of dietary calcium intake in bone metabolism has been well established; however, it is still less investigated in health-related components, especially addressing muscle performance. This study aims to compare dietary calcium intake and its relationship with cardiovascular and muscular performance in young athletes (lacrosse, Baseball, and soccer players). In this cross-sectional study, 95 participants (ages 18 to 30) participated during two visits to the Human Performance Laboratory. Participants completed body composition, lower and upper body muscle performance, cardiorespiratory protocol, and questionnaires related to dietary calcium intake. One-way ANOVA was used to determine the difference in the calcium intake between groups. The Pearson Correlation Coefficient was used to investigate the relationship between dietary calcium intake and muscle performance variables. Further, linear regression was used to assess the predictive value of calcium variables on overall muscle performance. Lacrosse players had significantly higher calcium intake than Baseball and soccer players (p &lt; 0.05). There was a significant positive correlation between dietary calcium intake and the number of push-ups (r = 0.28; p = 0.03). CIBW and CI explained 4.3% and nearly 25% of the change in MPI, respectively (p &lt; 0.001). This suggests the possible role of dietary calcium intake in enhancing health-related fitness components and highlights the need to explore its involvement in muscle-bone crosstalk.

Features of the construction of the training program dragon boat rowing at the initial stage of preparation

The article reveals ways to improve the physical training of rowing athletes at the stage of initial training in the preparatory period for rowing on Dragonboats. Training in rowing at the stage of initial training is aimed at the harmonious development of all the main motor qualities of the athlete. At the same time, the training of rowers at this stage should ensure the versatile development of physical qualities. It should be noted that the physical fitness of rowers is the main component of general fitness. It is also known that physical fitness is characterized by the level of functional capabilities of various body systems - cardiovascular, respiratory and muscular. Therefore, the fact that it is necessary to pay more attention to the development of physical qualities, which in turn will be aimed at improving the types of training necessary for an athlete, is so important. The purpose of the study: To analyze the activities of the State University of Secondary Education in rowing on the "Dragon" boats and the peculiarities of the construction of the training program on rowing on the Dragonboats at the initial stage of preparation. Methodology. An analysis of sports training was conducted on the basis of the Irpin State University of Dragonboat, in the period from May to July 2024, the work of coaches with groups of initial training, analysis of plans and documents was analyzed. In the experiment, 2 groups of primary training, approximately 20 children, were accepted to learn. The training plans, standards, and working programs of the coaches were analyzed. Conclusions: Methodically and correctly organized training sessions effectively improve the physical and functional readiness of young rowers, which not only contributes to the improvement of sports results, but also creates opportunities for a successful transition to training at the next stage of multi-year training. The use of training without taking into account the level of physical and functional fitness of athletes at the stage of preliminary basic training not only negatively affects the dynamics of sports results, but also the state of health of young men.

Life history in Caenorhabditis elegans: from molecular genetics to evolutionary ecology.

Life history is defined by traits that reflect key components of fitness, especially those relating to reproduction and survival. Research in life history seeks to unravel the relationships among these traits and understand how life history strategies evolve to maximize fitness. As such, life history research integrates the study of the genetic and developmental mechanisms underlying trait determination with the evolutionary and ecological context of Darwinian fitness. As a leading model organism for molecular and developmental genetics, Caenorhabditis elegans is unmatched in the characterization of life history-related processes, including developmental timing and plasticity, reproductive behaviors, sex determination, stress tolerance, and aging. Building on recent studies of natural populations and ecology, the combination of C. elegans' historical research strengths with new insights into trait variation now positions it as a uniquely valuable model for life history research. In this review, we summarize the contributions of C. elegans and related species to life history and its evolution. We begin by reviewing the key characteristics of C. elegans life history, with an emphasis on its distinctive reproductive strategies and notable life cycle plasticity. Next, we explore intraspecific variation in life history traits and its underlying genetic architecture. Finally, we provide an overview of how C. elegans has guided research on major life history transitions both within the genus Caenorhabditis and across the broader phylum Nematoda. While C. elegans is relatively new to life history research, significant progress has been made by leveraging its distinctive biological traits, establishing it as a highly cross-disciplinary system for life history studies.

Extreme positive epistasis for fitness in monosomic yeast strains.

The loss of a single chromosome in a diploid organism halves the dosage of many genes and is usually accompanied by a substantial decrease in fitness. We asked whether this decrease simply reflects the joint damage caused by individual gene dosage deficiencies. We measured the fitness effects of single heterozygous gene deletions in yeast and combined them for each chromosome. This predicted a negative growth rate, that is, lethality, for multiple monosomies. However, monosomic strains remained alive and grew as if much (often most) of the damage caused by single mutations had disappeared, revealing an exceptionally large and positive epistatic component of fitness. We looked for functional explanations by analyzing the transcriptomes. There was no evidence of increased (compensatory) gene expression on the monosomic chromosomes. Nor were there signs of the cellular stress response that would be expected if monosomy led to protein destabilization and thus cytotoxicity. Instead, all monosomic strains showed extensive upregulation of genes encoding ribosomal proteins, but in an indiscriminate manner that did not correspond to their altered dosage. This response did not restore the stoichiometry required for efficient biosynthesis, which probably became growth limiting, making all other mutation-induced metabolic defects much less important. In general, the modular structure of the cell leads to an effective fragmentation of the total mutational load. Defects outside the module(s) currently defining fitness lose at least some of their relevance, producing the epiphenomenon of positive interactions between individually negative effects.

Extreme positive epistasis for fitness in monosomic yeast strains

The loss of a single chromosome in a diploid organism halves the dosage of many genes and is usually accompanied by a substantial decrease in fitness. We asked whether this decrease simply reflects the joint damage caused by individual gene dosage deficiencies. We measured the fitness effects of single heterozygous gene deletions in yeast and combined them for each chromosome. This predicted a negative growth rate, that is, lethality, for multiple monosomies. However, monosomic strains remained alive and grew as if much (often most) of the damage caused by single mutations had disappeared, revealing an exceptionally large and positive epistatic component of fitness. We looked for functional explanations by analyzing the transcriptomes. There was no evidence of increased (compensatory) gene expression on the monosomic chromosomes. Nor were there signs of the cellular stress response that would be expected if monosomy led to protein destabilization and thus cytotoxicity. Instead, all monosomic strains showed extensive upregulation of genes encoding ribosomal proteins, but in an indiscriminate manner that did not correspond to their altered dosage. This response did not restore the stoichiometry required for efficient biosynthesis, which probably became growth limiting, making all other mutation-induced metabolic defects much less important. In general, the modular structure of the cell leads to an effective fragmentation of the total mutational load. Defects outside the module(s) currently defining fitness lose at least some of their relevance, producing the epiphenomenon of positive interactions between individually negative effects.

The Impact of Sport-Specific Practice on Health-Related Physical Fitness Components in Young Water Polo and Volleyball Athletes

The Impact of Sport-Specific Practice on Health-Related Physical Fitness Components in Young Water Polo and Volleyball Athletes

Field-based physical fitness assessment in preschool children in China

BackgroundPhysical fitness in the preschool years is considered a marker of current and future health. Therefore, understanding physical fitness levels of preschool children is necessary. Furthermore, the use of field-based methods to measure physical fitness is essential for assessing children in authentic venues such as schools. Hence, the main purpose of this study was to describe the physical fitness of Chinese preschool children across field-based methods considering a statement of confidence intervals for reference in physical fitness in each age and genders.MethodsA total of 619 children (296 boys and 323 girls) aged 3–6 years old from China participated in the present study. Physical fitness was measured using the Chinese National Physical Fitness Measurement (CNPFM-Pre) battery, which included the tennis ball throw (upper-limb muscular strength), standing long jump (lower-limb muscular strength), shuttle run test (speed-agility), double-leg timed hop (coordination), sit-and-reach (flexibility), and balance beam test (dynamic balance).ResultsThe results revealed significant differences in gender for standing long jump (SLJ; η2 = 0.012, p = 0.007), tennis ball throw (TT; η2 = 0.081, p < 0.001), sit-and-reach (SR; η2 = 0.114, p < 0.001), and one-legged stance test (OST; η2 = 0.037, p < 0.001). Age had positive effects on all physical fitness performance tests, as the shuttle run test (η2 = 0.672, p < 0.001), SLJ (η2 = 0.513, p < 0.001), TT (η2 = 0.394, p < 0.001), double-legged timed hop test (DTH; η2 = 0.445, p < 0.001), SR (η2 = 0.069, p < 0.001), balance beam test (BBT; η2 = 0.367, p < 0.001), and OST (η2 = 0.336, p < 0.001). Older preschool children performed better than their younger counterparts in all the tests. No significant interactions between age groups and gender were found.ConclusionsThis study provided age- and gender-specific physical fitness performance data in Chinese preschool children. Gender differences in physical fitness tests performance already exists at the preschool age. All physical fitness component results increased with age in this cohort. These findings can help healthcare, physical education, and pediatric professionals understand the physical fitness development of preschool children at different ages and help design sports tasks for preschool boys and girls.

Association of body mass index with muscle strength and cardiorespiratory fitness: A cross-sectional study based on Chinese adolescents.

Muscle strength and cardiorespiratory fitness are important components of physical fitness and are important for the physical and mental health development of university students. However, obesity is also an important factor affecting physical fitness, and there are few studies on how body mass index (BMI), which reflects obesity, is associated with muscle strength and cardiorespiratory fitness among Chinese university students. Therefore, this study analyzed the association between BMI and muscle strength and cardiorespiratory fitness among Chinese university students in order to provide a reference and basis for promoting the development of physical fitness among Chinese university students. A stratified whole-group sampling method was used to test physical fitness items in 27 973 (15 527 boys, 55.51%) university students in 800 first- to fourth-year university classes in Anhui, Fujian, Xinjiang, Shanghai, and Jiangxi, China. The physical fitness items included height, weight, standing long jump, 1000 m running (boys), and 800 m running (girls) items. Curvilinear regression analysis was used to analyze the correlations that existed between BMI and standing long jump and VO2max. The BMI of Chinese 19-22 years old university students was (21.14 ± 2.92) kg/m2. The mean standing long jump score was (197.31 ± 34.07) cm. In general, the BMI reached the highest point of 207.92 cm when the BMI was 26.25 kg/m2, and then showed a decreasing trend with the increase of BMI. The overall relationship between BMI and vertical jump showed an inverted "U"-shaped curve. In terms of VO2max, the overall trend of VO2max increased gradually with the increase of BMI, and when BMI reached 40 kg/m2, VO2max was 4.34 L-kg-1-min-1. Chinese university students showed an inverted "U" curve relationship between BMI and standing long jump in general, while VO2max showed a gradual increase with increasing BMI. Compared with the cardiorespiratory fitness of Chinese university students, the effect of BMI changes on muscle strength was greater.

Racial Differences In Health-related Components Of Physical Fitness In Professional Firefighters

Racial Differences In Health-related Components Of Physical Fitness In Professional Firefighters

Early Life History Divergence Mediates Elevational Adaptation in a Perennial Alpine Plant

ABSTRACTSpatially divergent natural selection can drive adaptation to contrasting environments and thus the evolution of ecotypes. In perennial plants, selection shapes life history traits by acting on subsequent life stages, each contributing to fitness. While evidence of adaptation in perennial plants is common, the expression of life history traits is rarely characterized, limiting our understanding of their role in adaptive evolution. We conducted a multi‐year reciprocal transplant experiment with seedlings from low and high elevation populations of the alpine carnation Dianthus carthusianorum to test for adaptation linked to contrasting climates and inferred specific contributions of early life stages to fitness. We assessed genotype by environment interactions in single fitness components, applied matrix population models to achieve an integrated estimate of fitness through population growth rates, and performed trade‐off analyses to investigate the advantage of alternate life history traits across environments. We found evidence of genotype by environment interactions consistent with elevational adaptation at multiple stages of the early life cycle. Estimates of population growth rates corroborated a strong advantage of the local genotype. Early reproduction and survival are alternate major contributors to adaptation at low and high elevation, respectively, and are linked by trade‐offs that underlie the evolution of divergent life history traits across environments. While these traits have a strong genetic basis, foreign populations express co‐gradient plasticity, reflecting the adaptive strategy of the local populations. Our study reveals that selection associated to climate has driven the evolution of divergent life histories and the formation of elevational ecotypes. While the high energy environment and strong competition favor investment in early reproduction at low elevation, limiting resources favor a more conservative strategy relying on self‐maintenance at high elevation. The co‐gradient plasticity expressed by high‐elevation populations may facilitate their persistence under warming climatic conditions.

Influence of Obesity and Sociodemographic Features on the Physical Fitness of Breast Cancer Survivors.

Obesity is a chronic, relapsing, and progressive disease. The issue of obesity affects 50 to 80% of patients who have been diagnosed with breast cancer. The aim of this study is to assess the scale of the problem of obesity among breast cancer survivors (BCS) older than 60 years, evaluate their physical fitness, and study the relationship between the occurrence of obesity and levels of fitness among breast cancer survivors. The relationship between fitness and sociodemographic factors has also been analyzed. This original epidemiological clinical study included a cohort of 88 female breast cancer survivors treated in 2022 in Holycross Cancer Center, Kielce, Poland. A questionnaire involving demographic information and medical data was utilized. The Senior Fitness Test (SFT) battery has been used to assess the physical fitness of the patients. Body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR) were also analyzed. More than 70% of the studied breast cancer survivors were classified as overweight or obese, according to BMI and WC indices. Depending on the SFT trial, the regression coefficients indicated worse results in participants who were older, lived in urban areas, were professionally active, less educated, and had higher obesity indices. The analysis of the relationship between obesity indices and fitness components revealed that all obesity indices were significantly associated with lower body flexibility (BMI p = 0.0118, WC p = 0.0092, WHR p = 0.0364, WHtR p = 0.0095). Upper body flexibility was significantly correlated with BMI indices (p = 0.0091, p = 0.0193) and WHtR (p = 0.0095). Agility and balance were significantly associated with WC (p = 0.0193), WHR (p = 0.098), and WHtR (p = 0.0095). Lower body strength was significantly correlated with the WHR index (p = 0.0487). Significant differences were found in upper body strength depending on the WHtR category. In the studied group of breast cancer survivors, there is a high prevalence of overweight and obesity. With increasing obesity rates, older age, and lower education levels, physical activity measured by the SFT decreases. Living in urban areas and being professionally active also predispose to lower physical activity levels. As obesity indices increase, physical fitness decreases in trials assessing upper and lower body strength, upper and lower body flexibility, as well as agility and dynamic balance.

Fitness consequences of depressive symptoms vary between generations: Evidence from a large cohort of women across the 20th century.

Depression has strong negative impacts on how individuals function, leading to the assumption that there is strong negative selection on this trait that should deplete genetic variation and decrease its prevalence in human populations. Yet, depressive symptoms remain common. While there has been a large body of work trying to resolve this paradox by mapping genetic variation of this complex trait, there have been few direct empirical tests of the core assumption that there is consistent negative selection on depression in human populations. Here, we use a unique long-term dataset from the National Health and Nutrition Examination Survey that spans four generational cohorts (Silent Generation: 1928-1945, Baby Boomers: 1946-1964, Generation X: 1965-1980, and Millenials: 1981-1996) to measure both depression scores and fitness components (lifetime sexual partners, pregnancies, and live births) of women from the United States born between 1938-1994. We not only assess fitness consequences of depression across multiple generations to determine whether the strength and direction of selection on depression has changed over time, but we also pair these fitness measurements with mixed models to assess how several important covariates, including age, body mass, education, race/ethnicity, and income might influence this relationship. We found that, overall, selection on depression was positive and the strength of selection changed over time-women reporting higher depression had relatively more sexual partners, pregnancies, and births except during the Silent Generation when selection coefficients neared zero. We also found that depression scores and fitness components differed among generations-Baby Boomers showed the highest severity of depression and the most sexual partners. These results were not changed by the inclusion of covariates in our models. A limitation of this study is that for the Millenials, reproduction has not completed and data for this generation is interrupted by right censoring. Most importantly, our results undermine the common belief that there is consistent negative selection on depression and demonstrate that the relationship between depression and fitness changes between generations, which may explain its maintenance in human populations.

The Effect of Physical Education with a Humanistic Approach on the Physical Activity Level and Physical Fitness in Shy Children

Background: Shy children often avoid interacting with their peers, which can restrict their participation in physical activities and impact their physical fitness. Therefore, it is essential to offer specific support and strategies to assist these children in increasing their involvement and enhancing their physical fitness. Objectives: This study aimed to investigate how physical education, utilizing a humanistic approach, impacts the physical fitness and daily physical activity behavior of shy children. Methods: In order to achieve this, a quasi-experimental field study was planned with pre- and post-tests including a control group. Participants were 9 to 10-year-old elementary school girls from Tehran, selected based on the Chick-Briggs Shyness Scale Physical fitness was measured using tests for cardiorespiratory endurance, agility, muscular endurance, muscular strength, and flexibility. The physical Activity Questionnaire for Children (PAQ-C) was utilized in assessing children's attitude towards physical activity. The experimental group (n = 15) received a physical education course with a humanistic approach using the teaching physical and social responsibility (TPSR) model, while the control group (n = 15) maintained their usual daily routines. Results: The experimental group showed significant improvements in physical activity levels, muscular endurance, and flexibility compared to the control group. A humanistic, game-based educational approach using the TPSR model can effectively improve certain components of physical fitness and promote a positive attitude towards physical activity in shy children. Conclusions: This approach can help teachers and coaches better understand and assist this group of children in overcoming the negative relationship between shyness, sports participation, and physical fitness.

Genomic and fitness consequences of a near-extinction event in the northern elephant seal.

Understanding the genetic and fitness consequences of anthropogenic bottlenecks is crucial for biodiversity conservation. However, studies of bottlenecked populations combining genomic approaches with fitness data are rare. Theory predicts that severe bottlenecks deplete genetic diversity, exacerbate inbreeding depression and decrease population viability. However, actual outcomes are complex and depend on how a species' unique demography affects its genetic load. We used population genetic and veterinary pathology data, demographic modelling, whole-genome resequencing and forward genetic simulations to investigate the genomic and fitness consequences of a near-extinction event in the northern elephant seal. We found no evidence of inbreeding depression within the contemporary population for key fitness components, including body mass, blubber thickness and susceptibility to parasites and disease. However, we detected a genomic signature of a recent extreme bottleneck (effective population size = 6; 95% confidence interval = 5.0-7.5) that will have purged much of the genetic load, potentially leading to the lack of observed inbreeding depression in our study. Our results further suggest that deleterious genetic variation strongly impacted the post-bottleneck population dynamics of the northern elephant seal. Our study provides comprehensive empirical insights into the intricate dynamics underlying species-specific responses to anthropogenic bottlenecks.