Cold stress and freezing tolerance negatively affect the fitness of Arabidopsis thaliana accessions under field and controlled conditions

Main conclusion Higher acclimated freezing tolerance improved winter survival, but reduced reproductive fitness of Arabidopsis thaliana accessions under field and controlled conditions. Abstract Low temperature is one of the most important abiotic factors influencing plant fitness and geographical distribution. In addition, cold stress is known to influence crop yield and is therefore of great economic importance. Increased freezing tolerance can be acquired by the process of cold acclimation, but this may be associated with a fitness cost. To assess the influence of cold stress on the fitness of plants, long-term field trials over 5 years were performed with six natural accessions of Arabidopsis thaliana ranging from very tolerant to very sensitive to freezing. Fitness parameters, as seed yield and 1000 seed mass, were measured and correlation analyses with temperature and freezing tolerance data performed. The results were compared with fitness parameters from controlled chamber experiments over 3 years with application of cold priming and triggering conditions. Winter survival and seed yield per plant were positively correlated with temperature in field experiments. In addition, winter survival and 1000 seed mass were correlated with the cold-acclimated freezing tolerance of the selected Arabidopsis accessions. The results provide strong evidence for a trade-off between higher freezing tolerance and reproductive fitness in A. thaliana, which might have ecological impacts in the context of global warming.

The Effects of a Five-Month Lockdown Due to COVID-19 on Physical Fitness Parameters in Adolescent Students: A Comparison between Cohorts

Background: This study examined the effects of a five-month lockdown due to COVID-19 pandemic on physical fitness parameters in urban adolescent male and female students. Methods: Two hundred and ninety-three male and female students (age: 15.8 ± 0.3 years) who attended the fourth grade of the same high school during the years 2016–2017 (first control group), 2018–2019 (second control group) and 2020–2021 (lockdown group) took part in the present study. Results: The percentage of overweight and obese students, according to body mass index, increased in males from 16.0% (2016–2017) and 14.6% (2018–2019), to 36.7% in 2020–2021 (p < 0.01), and in females from 8.6% (2016–2017) and 7.0% (2016–2017), to 25.6% in 2020–2021 (p < 0.01). Lower body fitness, as assessed by jumping, sprinting and agility tests, was impaired for both males and females after the lockdown compared with the 2016–2017 and 2018–2019 cohorts (vertical jumps: 10.4–15.1%; p < 0.01; d = 0.58–1.01, 30 m sprint: 3.7–4.9%; p < 0.01; d = 0.62–0.74; 505 agility test: from 6.1% to 9.4%; p < 0.01; d = 0.80–1.04). However, flexibility and performance in upper-body fitness tests (handgrip maximum isometric strength and medicine ball throws with different loads) was significantly reduced only in males after the lockdown (p < 0.05 to 0.01). Conclusions: These results suggest that a five-month lockdown negative influenced the physical fitness of adolescent students. Notably, greater reductions were observed in upper body strength, power and flexibility in males than in females. These results highlight the need to maintain strength, power and body mass during long periods of inactivity in adolescent populations.

Compensatory Phenolic Induction Dynamics in Aspen After Aphid Infestation

Condensed tannins (CTs) are polyphenolics and part of the total phenolic (TP) pool that shape resistance in aspen (Populus tremula). CTs negatively associate with pathogens, but their resistance properties against herbivores are less understood. Piercing, sucking arthropods, such as aphids, share similar defence pathways with pathogens suggesting that CTs could also shape resistance to aphids, potentially together with other phenolics. Being highly variable it can further be questioned whether CT-shaped resistance is better described by constitutive levels, by the induced response potential, or by both. Here, aspen genotypes were propagated and selected to represent a range of inherent abilities to produce and store foliar CTs; the plantlets were then exposed to Chaitophorus aphid infestation and to mechanical (leaf rupture) damage, and the relative abundance of constitutive and induced CTs was related to aphid fitness parameters. As expected, aphid fecundity was negatively related to CT-concentrations of the aphid infested plants although more consistently related to TPs. While TPs increased in response to damage, CT induction was generally low and it even dropped below constitutive levels in more CT-rich genotypes, suggesting that constitutive CTs are more relevant measurements of resistance compared to induced CT-levels. Relating CT and TP dynamics with phenolic low molecular compounds further suggested that catechin (the building block of CTs) increased in response to aphid damage in amounts that correlated negatively with CT-induction and positively with constitutive CT-levels and aphid fecundity. Our study portrays dynamic phenolic responses to two kinds of damage detailed for major phenylpropanoid classes and suggests that the ability of a genotype to produce and store CTs may be a measurement of resistance, caused by other, more reactive, phenolic compounds such as catechin. Rupture damage however appeared to induce catechin levels oppositely supporting that CTs may respond differently to different kinds of damage.

Investigating the Effects of Am rap and Classic Cross-fit Training in Freestyle Wrestlers on Physical Fitness Parameters

This study aims to investigate anaerobic strength alterations of wrestlers who perform AMRAP (As many reps as possible) and Classic CrossFit pieces of training. The research was implemented on 32 male wrestlers who were challenged in the Turkish Wrestling 1st League in the season of 2018-2019. The volunteer participants taken part in test groups performed CrossFit models in the preseason for 8-weeks; Group I (Classic CrossFit) and Group II (CrossFit AMRAP). Bodyweight, height, and age values were recorded respectively by creating measuring parkour and arranged on MS Excel spreadsheet program. Two-factor variance analysis was used in repetitive measurements for identifying the differences between pre and final measuring anaerobic strength values of the participants. As findings, it was observed there was a significant difference in terms of group x time interaction dimension in back squat movement, 1 min on behalf of AMRAP. According to the simple effect test results, there were significant values in both groups. The numerical increase in some performance values of the AMRAP CrossFit training group after 8-weeks of training was more prominent than the classic CrossFit training group. In addition, AMRAP CrossFit training was effective in reducing body weight. Both models were found to have a positive effect on their physical capacities effectively. Although there are studies on CrossFit in the literature, there is no significant study on AMRAP and thus this study might be the pioneer in terms of contributions to the literature and lead to further comments on sports science as well. Thus, this study is significant to reveal the effectiveness of Amrap and CrossFit training on physical fitness parameters.

The effect of sports participation in obese boys on some obesity indicators and physical fitness parameters

Background. To examine the effects of sports participation in obese boys on body mass index (BMI), waist circumference, hip circumference, muscle strength, muscular endurance, balance and agility. Materials and methods. Sixty-three obese children with a mean age of 10.80 ± 0.58 were included in the study. Participants participated in sports, including judo, table tennis and basketball, for three months at their schools. Body weight, waist circumference and hip circumference of the participants were measured before and after participating in sports. Before and after participating in sports, grip strength, bent arm hanging, single-leg stance balance and plate tapping tests were applied to the participants. Results. While before participating in sports, BMI, waist and hip circumference outcomes of the participants were 23.04 ± 2.89 cm/m2, 81.61 ± 8.56 cm and 87.69 ± 6.52 cm, respectively; after participating in sports, BMI, waist circumference and hip circumference outcomes were 22.51 ± 2.88 cm/m2, 79.38 ± 8.74 cm and 85.73 ± 6.65 cm, respectively. The results of the single leg balance and bent arm-hanging tests after participation in sports increased compared to the results which before participating in sports (p < 0.05). However, the results of plate tapping test results that after participation in sports were less than the results which before participating in sports (p < 0.05). The result obtained from the grip strength after participation in sports was not different from the result obtained before participating in sports (p > 0.05). Conclusions. Participation in regular sports in obese children has positive effects on BMI, waist circumfe­rence and hip circumference, which are associated with chronic diseases. Additionally, the participation of obese children in regular sports contributes to the development of physical fitness parameters, which are indicators of health.

Relationship Between Physical Fitness, Anthropometric Measurement, and Bone Health in Adult Men

The aim of this study was to assess the relationship between physical fitness, anthropometric measurement, and bone health in adult men. Ninety-six adult men participated in this cross-sectional study. Anthropometric measures, including height, weight, chest, waist and hip circumference, and physical fitness parameters reflecting muscular strength, agility, flexibility, power, balance, and cardiopulmonary fitness were assessed. Whole-body bone mineral density (BMD) and bone mineral content (BMC) were measured with a dual-energy X-ray absorptiometry scanner. The results showed bone health outcomes to have a significant correlation with anthropometric and physical fitness parameters. Stepwise regression analysis proved physical fitness parameters explaining significant variance in bone health such as BMD and BMC to be focused on muscular strength, flexibility, and pulmonary function. Furthermore, anthropometric parameters including hip circumference can help explain BMC. The findings suggest that anthropometry and physical fitness can be used for the prediction of bone health in adult men.

Developing Statistical Modellings to Investigate the Internal Drivers for the Trend of Output Values in the Manufacturing Industry: Evidence from Chinese Enterprises

The manufacturing industry is an important pillar of the national economy. It is of vital importance to develop statistical modellings in order to quantify the relationship between potential internal drivers and the trend of output values in the manufacturing industry. However, only a few statistical modellings have been established to investigate such associations. This study developed the correlation coefficient model and generalized linear model (GLM) to measure the single and interactive effects of the internal drivers on the changes of the output values. For the GLM, different predictive variables were developed to fit into the dataset, and the performance of the models were compared using fitness parameters. Furthermore, an industry survey dataset for 1,180 manufacturing enterprises in 2020 was used to validate the models. The use of the GLM combining land area, number of employees, scientific research input, and labor productivity may have a great potential to bolster capacity in monitoring and predicting the trend of output values in the manufacture industry.

Effects of Thelytokous Parthenogenesis-Inducing Wolbachia on the Fitness of Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae) in Superparasitised and Single-Parasitised Hosts

Thelytokous Wolbachia-infected Trichogramma species have long been considered as biological control agents against lepidopteran pests in agriculture and forestry. Wolbachia has been suggested to increase the probability of the superparasitism of Trichogramma, but the fate of infected offspring in the superparasitised host is still unknown. The present study aimed to evaluate the fitness of thelytokous Wolbachia-infected (TDW) and bisexual Wolbachia-free (TD) Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae) lines in superparasitised or single-parasitised hosts. The results showed that irrespective of whether Trichogramma wasps were developed from superparasitised or single-parasitised hosts, the TDW line was characterized by reduced fitness, including lower fecundity, shorter longevity, and smaller body size of F1 offspring, and lower emergence rate of F2 offspring than the TD line. This was not true for the survival rate and developmental time of F1 offspring. Additionally, the fitness parameters of T. dendrolimi that developed from superparasitised hosts were lower compared with that of T. dendrolimi that developed from single-parasitised hosts. Interestingly, Wolbachia-infected females had higher dispersal capacity than bisexual females when they developed from superparasitised hosts. The results indicated that Wolbachia negatively affects fitness of T. dendrolimi, but enhance dispersal capacity of T. dendrolimi females in superparasitism condition. Further studies need to be carried out to select the best line that will allow Wolbachia and their host Trichogramma to be better adapted to one another.

Influence of 2D:4D ratio on fitness parameters and accumulated training load in elite youth soccer players

Background Digit ratio (2D:4D) characterized by the length of the second digit (2D) divided by the length of the fourth digit (4D), is a powerful marker of athletic performance. Some studies showed a negative correlation between 2D:4D ratio and sports performances. Objectives The purpose of the present study was three-fold: (1) to analyze the influence of anthropometric and 2D:4D ratio on variations of accumulated training load (ATL) and fitness parameters: maximal oxygen uptake (V̇O2max), countermovement jump (CMJ), isometric muscular strength of the knee extensor for hamstring (ISH) and flexor for quadriceps (ISQ) muscles; along three stages of evaluation of soccer players based on playing positions; (2) to analyze the correlations between 2D:4D ratio and aforementioned parameters; and (3) to investigate if variance in fitness levels and ATL can explain the 2D:4D ratio. Methods Twenty-four elite players under 17 years were daily monitored for their rating perceived exertion and ATL across 24 weeks over the season. Soccer players have also measured in three stages for anthropometric traits and fitness parameters. Results Significant differences were observed between playing positions for body mass, goalkeepers had higher body mass compared to centre-midfielder and winger players. Moreover, there were significant differences in ATL between early-season to mid-season in goalkeepers (P = 0.032). The 2D:4D ratio (left and right) shown largely and negatively association with muscular strength (ISQ: r = − 0.80; r = − 0.78, P ≤ 0.001, ISH: r = − 0.63; r = − 0.62, P = 0.001, respectively) and VO2max changes (r = − 0.55, P = 0.005; r = − 0.50, P = 0.013, respectively); lastly, both 2D:4D ratio significantly predicted changes in muscular strength and VO2max in young soccer players. Conclusions Goalkeepers tended to have higher body mass compared to centre-midfielder and winger players; and 2D:4D ratio revealed a mighty predictor of physical fitness changes in soccer players. Evidence should be helpful to professionals to highlight the usefulness of the 2D:4D into the identification of talent, but also to optimize young players' performance.