Search Results (21)

The rapid development of wearable electronics requires multifunctional, transient electronic devices to reduce the ecological footprint and ensure data security. Unfortunately, existing transient electronic materials need to be degraded in chemical solvents or body fluids. Here, we report green luminescent, water-soluble, and biocompatible piezoelectric nanofibers developed by electrospinning green carbon quantum dots (G-CQDs), mulberry silk fibroin (SF), and polyvinyl alcohol (PVA). The introduction of G-CQDs significantly enhances the piezoelectric output of silk fibroin-based fiber materials. Meanwhile, the silk fibroin-based hybrid fibers maintain the photoluminescent response of G-CQDs without sacrificing valuable biocompatibility. Notably, the piezoelectric output of a G-CQD/PVA/SF fiber-based nanogenerator is more than three times higher than that of a PVA/SF fiber-based nanogenerator. This is one of the highest levels of state-of-the-art piezoelectric devices based on biological organic materials. As a proof of concept, in the actual scenario of a rope skipping exercise, the G-CQD/PVA/SF fiber-based nanogenerator is further employed as a self-powered wearable sensor for real-time sensing of athletic motions. It demonstrates high portability, good flexibility, and stable piezoresponse for smart sports applications. This class of water-disposable, piezo/photoactive biological materials could be compelling building blocks for applications in a new generation of versatile, transient, wearable/implantable devices. Full article

Background: Previous studies have shown that a high body mass index (BMI) is detrimental to executive function (EF) in children and elderly populations but may be improved by physical activity (PA). However, research on adolescents aged 12–14 is lacking. This study explores two parts: Part 1: cross-sectional correlation between BMI and EF; Part 2: the effect of an 8-week rope skipping intervention. Methods: Recruit 166 adolescents to participate in EF tasks. Screen and select 96 adolescents to be assigned to the normal weight control group (N-C, n = 23) and the normal weight exercise group (N-E, n = 23), the overweight control group (OV-C, n = 13), and the overweight exercise group (OV-E, n = 14), the obese control group (OB-C, n = 12), and the obese exercise group (OB-E, n = 11). Exercise program: moderate-to-high-intensity rope skipping training. Control program: Self-directed reading. Data were recorded for BMI and EF tasks. Results: Part 1, EF and BMI exhibit a negative linear correlation. Part 2, the reaction time of EF tasks in N-E, OV-E and OB-E decreased about 9, 14, 13% (p < 0.05), respectively, while the average BMI in OV-E and OB-E decreased about 10% and 11% (p < 0.05), suggesting a potential correlation between the reduction in BMI and the improvement in EF, which means that the exercise intervention significantly improved EF performance. Conclusions: Among adolescents aged 12–14, overweight and obese individuals exhibit weaker EF compared with normal weight individuals. An 8-week moderate-to-high-intensity rope skipping exercise program can improve EF in adolescents aged 12–14 with different BMIs, and the improvement is greater in overweight and obese individuals. Full article

Adolescent obesity is a growing global health problem all around the world. We reviewed the use of complementary and alternative medicine (CAM) for adolescent obesity, examining improvements in BMI or any metabolic indices of obesity. We performed a PubMed and Scopus search for articles on CAM treatments in adolescents aged 12–17 years, and included all studies with subjects in that age range. Out of 226 PubMed articles and 14 Scopus articles, 28 articles from PubMed and 1 article from Scopus fit our criteria. Most CAM studies that showed some improvement in BMI were acupuncture- or yoga-based. Yoga-based interventions showed a BMI reduction of 1–2 points, which is similar to results achieved in studies based on physical activity and Orlistat, a weak anti-obesity medication; meanwhile, acupuncture-based studies showed a slightly higher BMI reduction of 2–4 points, similar to that achieved with Liraglutide, a GLP-1 agonist that is a good anti-obesity medication. Herbs and supplements showed improvement in metabolic markers of obesity. Stress interventions in mind–body interventions, music skip-rope exercise, and creative drama in physical activity-based interventions also showed improvement in BMI. Although many of the studies reviewed were RCTs, the small sample size of those RCTs is a limiting factor. There may be a role for investigating this topic in larger populations to generate more effective conclusions. Full article

Objectives: This study aims to examine the geographical variation in physical fitness levels among Chinese children and adolescents in Shaanxi province. Methods: A total of 19,175 children from Shaanxi province with physical fitness data in 2019, participated in the study. Physical fitness was assessed using body mass index, force vital capacity, 50 m sprint, sit and reach, 1 min rope skipping, sit-ups, 50 m × 8 round-trip running, standing long jump, pull-ups, 800 m, and 1000 m running, and their standardized scores were aggregated to form a summary score. The total score is used to classify the physical fitness levels into four grades (excellence to failure). Results: The Guanzhong (GZ) region scored the highest, while Northern Shaanxi (NS) scored the lowest. The excellence rate for physical fitness was highest in GZ and lowest in NS, while the failure rate was highest in NS and lowest in GZ. Notably, children and adolescents in NS demonstrated the best endurance levels despite their overall lower fitness scores. The comprehensive physical fitness among Chinese children and adolescents in Shaanxi province showed significant regional disparities. GZ region exhibited the highest physical fitness levels, while Northern Shaanxi had the lowest. Conclusions: Region-specific interventions and targeted health policies are essential to address these disparities and improve the overall physical health status of children and adolescents in Shaanxi province. Full article

Self-oscillatory systems have great utility in energy harvesting, engines, and actuators due to their ability to convert ambient energy directly into mechanical work. This characteristic makes their design and implementation highly valuable. Due to the complexity of the motion process and the simultaneous influence of multiple parameters, computing self-oscillatory systems proves to be challenging, especially when conducting inverse parameter design. To simplify the computational process, a combined approach o0f Random Forest (RF) and Backpropagation Neural Network (BPNN) algorithms is employed. The example used is a self-rotating skipping rope made of liquid crystal elastomer (LCE) fiber and a mass block under illumination. Numerically solving the governing equations yields precise solutions for the rotation frequency of the LCE skipping rope under various system parameters. A database containing 138,240 sets of parameter conditions and their corresponding rotation frequencies is constructed to train the RF and BPNN models. The training outcomes indicate that RF and BPNN can accurately predict the self-rotating skipping rope frequency under various parameters, demonstrating high stability and computational efficiency. This approach allows us to discover the influences of distinct parameters on the rotation frequency as well. Moreover, it is capable of inverse design, meaning it can derive the corresponding desired parameter combination from a given rotation frequency. Through this study, a deeper understanding of the dynamic behavior of self-oscillatory systems is achieved, offering a new approach and theoretical foundation for their implementation and construction. Full article

Purpose: To explore the difference in the biomechanics of the lower extremity during alternating jump rope skipping (AJRS) under barefoot and shod conditions. Methods: Fourteen experienced AJRS participants were randomly assigned to wear jump rope shoes or be barefoot (BF) during the AJRS at a self-selected speed. The Qualisys motion capture system and Kistler force platform were used to synchronously collect the ground reaction forces and trajectory data of the hip, knee, ankle, and metatarsophalangeal (MTP) joints. One-dimensional statistical parameter mapping was used to analyze the kinematics and kinetics of the lower extremity under both conditions using paired t-tests. Results: Wearing shoes resulted in a significant decrease in the ROM (p < 0.001) and peak angular velocity (p < 0.001) of the MTP joint during the landing phase. In addition, the MTP joint power (p < 0.001) was significantly larger under shod condition at 92–100% of the landing phase. Moreover, wearing shoes reduced the peak loading rate (p = 0.002). Conclusion: The findings suggest that wearing shoes during AJRS could provide better propulsion during push-off by increasing the MTP plantarflexion joint power. In addition, our results emphasize the significance of the ankle and MTP joint by controlling the ankle and MTP joint angle. Full article

Rope skipping has been well documented for eliciting positive effects on various health outcomes and contributing to overall physical activity levels. However, the specific health benefits may depend on the duration and intensity of the exercise bouts. This study aimed to compare the (1) metabolic and (2) perceptual responses between short (30 s) and long (3 min) bouts of all-out rope skipping, and to (3) evaluate the reliability and validity of a newly invented electronic rope (E-rope). A total of 23 young adults (13 males and 10 females; aged 23.23 ± 2.62 y) repeated short and long skipping bouts on two testing days. The oxygen consumption ($\stackrel{·}{\mathrm{V}}$O₂), peak respiratory exchange ratio (RER), heart rate (HR), rate of perceived exertion (RPE), and post-exercise muscle soreness were assessed during each trial. Longer skipping bouts (148.33 skips·min⁻¹) resulted in significantly greater metabolic responses (p < 0.01, d = 1.00–3.27), higher rates of perceived exertion (p < 0.01, d = 2.28), and more post-exercise muscle soreness (p < 0.01, d = 0.66–1.49) compared to shorter bouts (165.83 skips·min⁻¹). The E-rope demonstrated sufficient concurrent validity (r > 0.9) and between-day reliability (ICC_3,1 = 0.89–0.95) but slightly overestimated the number of skips. Both long and short all-out skipping bouts were considered moderate-to-vigorous exercise, but longer bouts resulted in higher metabolic and perceptual demands. These findings may be useful for practitioners to strategically apply different skipping bouts to improve physical activity levels and facilitate training adaptation. The E-rope could serve as a self-monitoring and self-evaluating tool. Full article

Children have received much attention in recent years, as many studies have shown that their physical fitness level is on the decline. Physical education, as a compulsory curriculum, can play a monumental role in contributing to students’ participation in physical activities and the enhancement of their physical fitness. The aim of this study is to examine the effects of a 12-week physical functional training intervention program on students’ physical fitness. A total of 180 primary school students (7–12 years) were invited to participate in this study, 90 of whom participated in physical education classes that included 10 min of physical functional training, and the remaining 90 were in a control group that participated in traditional physical education classes. After 12 weeks, the 50-m sprint (F = 18.05, p < 0.001, ${\eta }_p^2$ = 0.09), timed rope skipping (F = 27.87, p < 0.001, ${\eta }_p^2$ = 0.14), agility T-test (F = 26.01, p < 0.001, ${\eta }_p^2$ = 0.13), and standing long jump (F = 16.43, p < 0.001, ${\eta }_p^2$ = 0.08) were all improved, but not the sit-and-reach (F = 0.70, p = 0.405). The results showed that physical education incorporating physical functional training can effectively promote some parameters of students’ physical fitness, while at the same time providing a new and alternative idea for improving students’ physical fitness in physical education. Full article

Body fat mass (FM) has advantages over body mass index (BMI) in terms of accuracy of fitness assessment and health monitoring. However, the relationship between FM and fitness in Chinese children has not yet been well studied. This study aimed to investigate the relationship between health-related physical fitness, BMI, and FM, which was estimated using a predictive model among elementary schoolchildren in China. This cross-sectional study included 2677 participants (boys, 53.6%; girls, 46.4%) who underwent anthropometric measurements (height, weight, BMI, and FM) and five health-related fitness tests: 50-m sprint (speed), sit and reach (flexibility), timed rope-skipping (coordination), timed sit-ups (muscular endurance), and 50-m × 8 shuttle run (endurance). In boys, BMI showed a positive correlation with speed (p < 0.001) and endurance (p < 0.006) tests and a negative correlation with flexibility (p < 0.004) and coordination (p < 0.001) tests. In girls, a positive correlation between speed (p < 0.001) and endurance (p < 0.036) tests was observed. Both BMI and FM (estimated using the predictive model) were strongly associated with the health-related physical fitness of elementary schoolchildren. Our findings indicate that health-related physical fitness was similarly affected by FM and BMI. As FM can be quantified, it could therefore be used to develop strategies and intervention programs for the prevention and management of obesity in children. Full article

Numerous studies have shown cognitive enhancement through sport and physical exercise. Despite the variety of studies, the extent to which physical activity before or after a cognitive learning session leads to more effective cognitive enhancement remains largely unresolved. Moreover, little attention has been paid to the dependence of the motor learning approach then applied. In this study, we compare the influence of differential with uniformly rope skipping directly succeeding an acquisition phase in arithmetic mathematics. For three weeks 26 pupils, 14 female, 12 male, and 13.9 ± 0.7 years old, completed nine 15 min exercises in arithmetic math, each followed by 3 min rope skipping with heart rate measurement. Arithmetic performance was tested in a pre-, post- and retention test design. The results showed a statistically significant difference between the differential and the control groups within the development of arithmetic performance, especially in the retention test. There was no statistical difference in heart rate. It is suggested that the results provide evidence for sustainable improvements of cognitive learning performance by means of highly variable rope skipping. Full article

Studies examining the effectiveness of rope skipping training to improve the body mass index (BMI) of school children are scarce. Hence, this study examined the effectiveness of nine-week skipping training on the BMI of primary six school-aged children (n = 77). The participants underwent 30 min of skipping training three days per week over a nine-week period. The participants’ BMI was measured at the baseline and during weeks 3, 6 and 9. The results from a one-way ANOVA with repeated measures indicated a statistically significant difference in the BMI for both males [F(3,111) = 9.42, p < 0.001, ηp² = 0.203] and females [F(3,114) = 7.35, p < 0.001, ηp² = 0.162], suggesting an improvement in BMI. Post hoc comparisons with a Bonferroni adjustment revealed significant differences in BMI after nine weeks of intervention for males between the pre-test (M = 21.47, SD = 4.94) and the 9-week post-test (M = 20.15, SD = 4.36), and for females between the pre-test (M = 21.56, SD = 5.80) and the 9-week post-test (M = 20.68, SD = 5.32). This study demonstrated that regular participation in vigorous physical activity such as skipping training could promote child health by preventing the likelihood of young children being overweight. This result has implications for the inclusion of skipping training into the school life of school-aged children to help manage their BMI levels. Full article

Inadequate intake of fruits and vegetables (FV) and moderate-to-vigorous physical activity (MVPA) in children has become a global public health problem. Therefore, school-based gardening and cooking (SGC) and sports participation (SP) interventions may be effective in improving children’s FV intake and MVPA. The aim of this study is to develop and evaluate the effectiveness of SGC and SP interventions on FV intake and MVPA among Chinese children. In this cluster randomized controlled trial study, 237 children in grades 4–5 from six public primary schools from Changsha, Hunan Province, China will be randomly assigned to: (1) a SGC and SP combined intervention group; (2) a SP intervention group; (3) a regular practice group. The intervention clusters will be implemented for a period of 6 months and follow up will be carried out after 12 months. The outcome will be collected using a combination of self-reported and objective measures. Primary outcomes will include children’s FV intake and duration of MVPA per day, and secondary outcomes will included frequency and attitudes of FV intake and SP, in addition to other measures. Finally, a process evaluation will be used to analyze the facilitators and barriers to intervention implementation. Trial Registration: (Registration Number: ChiCTR2200064141). Full article

This study aimed to examine whether a single bout each of high-intensity interval exercise (HIIE) and high-intensity continuous exercise (HICE) could improve inhibitory functions of overweight and obese children, and which mode of exercise was more beneficial. Seventy-two overweight and obese children, with (26.02 ± 1.05 kg/m²), aged 10–14 years (11.56 ± 1.03 years), were randomly assigned to three groups. The HIIE group completed a 30-min treadmill exercise session (5-min warm up, 20-min HIIE, and 5-min cool-down). The HICE group performed 30 min of rope skipping, while the control (CON) group watched a designated cartoon on a tablet computer for the same duration. Reaction time and number of errors in the Stroop test were determined before and after the intervention. The difference between pre- and post-test reaction time scores was higher in the HIIE and HICE groups than in the CON group, while the pre- and post-test difference in the number of errors was similar between groups. Overall, it is likely that both acute HIIE and HICE were similarly efficient in facilitating cognitive and inhibitory functions of children with overweight and obesity conditions, supporting the benefits of acute high-intensity exercise probability for cognitive functions of children in general, as well as of the population with overweight and obesity conditions. Full article

Purpose: The current study is intended to assess the effects of a multicomponent social support intervention program on grip strength, sprinting, jumping, agility, flexibility, core strength and exercise attitude among children over a period of twelve weeks. Method: This study followed a randomized parallel design in which 366 children (age: 9.35 ± 1.12 years) in the 3rd–5th grade at an elementary school in China were allocated to an intervention group (n = 183) or a control group (n = 183). Participants were assessed twice (baseline and postintervention) for the following tests: (i) grip strength, (ii) 50 m dash, (iii) rope skipping, (iv) sit-ups, (v) sit-and-reach, and (vi) exercise attitude. The intervention group received the “Exercise Methods and Wellness Knowledge Guide (EMWKG)” leaflet three times a week. The control group was not required to make any changes. Results: Significant increases in pre–post left-hand grip strength (Cohen’s d = 0.10, p < 0.001), right-hand grip strength (Cohen’s d = 0.09, p < 0.001), and behavioral intention (Cohen’s d = 0.17, p < 0.01) were observed in the intervention group. Students in the control group showed significant decreases in three indicators: both 50 m (Cohen’s d = 0.19, p < 0.01) and sit-ups (Cohen’s d = 0.14, p < 0.05) as well as sit-and-reach (Cohen’s d = 0.46, p < 0.001). Significant differences (p < 0.001) were found between the two groups in right-hand grip strength (F = 7.109, η_p² = 0.020), sit-and-reach (F = 11.255, η_p² = 0.031), and subjective standards (F = 15.461, η_p² = 0.043). A comparison of the post hoc test results showed that the intervention group scored 0.519 kg (95% CI: 0.136–0.901, Cohen’s d = 0.27), 0.944 cm (95% CI: 0.0391–1.497, Cohen’s d = 0.35), and 2.535 points (95% CI: 1.267–3.803, Cohen’s d = 0.41) higher than the control group in right-hand grip strength, sit-and-reach, and subjective standards, respectively. Conclusion: This combined social support theory-based intervention was effective in improving exercise attitude and fitness among children in 12 weeks. Full article

The purpose of this study was to explore the utility of an 8-week rope skipping intervention in enhancing standing long jump performance was assessed by means of specific kinematic parameters acquired by 3-D space photography. The fifteen male college students from the physical education institute were randomly recruited as the research subjects. Participants first completed a standing long jump test without rope skipping intervention. Participants subsequently took part in a second standing long jump test after rope skipping training. Two high-speed digital cameras with 100 Hz sampling rate were synchronized to capture the movement. The captured images were processed using motion analysis suite, and the markers attached to joints on images were optical auto capture. Based on the results, the velocity of the center of gravity at take-off and landing were significantly improved. In addition, the study confirmed the requirement for forward tilt of the hip joint at landing to increase the velocity of the center of gravity and hence long jump distance. The detailed kinematic analysis described here provided further evidence of the benefits of integrating non-specialized and specialized training activities to enhance athletic performance and offers a contribution to movement theory and practice. Full article