Delong Chen

Objective:This study explores the biomechanical characteristics and potential sports injuries of reverse vertical jump (CMJ) in male firefighters of different grades based on spatiotemporal parameters, dynamic parameters, and kinematic parameters. Method:A total of 86 male firefighters were recruited (age: 29.01±5.11, height: 1.73±0.05, weight: 69.61±8.15, service years: 5.83±5.05, BMI: 23.36±2.31). The IMU insole was adopted as the measurement tool and the relevant index parameters were measured. SPSS29.0 was used for sorting and statistical analysis. Result:The results of some CMJ indicators of firefighters of different grades showed statistically significant differences. The right leg lift-off time of senior firefighters was lower than that of junior firefighters (P < 0.05). The flexion Angle of the left ankle landing of senior firefighters was lower than that of junior and intermediate firefighters (P < 0.05). The left leg propulsion speed of senior firefighters was lower than that of junior firefighters (P < 0.01), and also lower than that of intermediate firefighters (P < 0.05). Meanwhile, the right leg propulsion speed of senior firefighters was lower than that of junior firefighters (P < 0.05). There were statistically significant differences in the results of some CMH indicators among firefighters with different attributes. The right leg landing stability of the national team firefighters was higher than that of the professional team (P < 0.05). The commander's leg flight time, flight height, flexion Angle of the left ankle upon landing and the propulsion speed of the left leg were all lower than those of the firefighters (P < 0.05). Conclusion:As the rank of firefighters increases, their vertical jumping ability shows a declining trend. The decline of various indicators of senior firefighters (CMJ) is more obvious compared with that of junior firefighters, indicating that they have regressed in center of gravity control, strength level and joint range of motion, and have increased the potential risk of injury. The shock absorption capacity and stability of the right ankle joint of national team firefighters need to be improved more compared with those of professional team firefighters. Commanders have lower levels of center of gravity control, ankle range of motion and pushing force than firefighters, indicating a higher potential risk of injury for them during mission execution and strength and conditioning training.

Background: Physical literacy (PL) can positively affect the health of children, adolescents, and adults, and is closely related to cardiorespiratory fitness (CRF). Objective: To perform a systematic review and meta-analysis to examine the relationship between overall physical literacy (PL) and CRF in children and adolescents. Methods: Cross-sectional, cohort and experimental studies on the relationship between PL and CRF in children and adolescents were collected by searching the Web of Science Core Collection, PubMed, EBSCOhost, ScienceDirect, Cochrane Library and China National Knowledge Infrastructure (CNKI) databases. Based on the characteristics of the included literature, PL was divided into physical competence (PC), daily behavior (DB), knowledge and understanding (K&U), and motivation and confidence (M&C). R 4.3.6 was used to analyze the combined effect size of PL and the relationships of the four dimensions with CRF among children and adolescents. Results: A total of 21 articles were included, 42.9% of which were published after 2020, involving a total of 43,352 children and adolescents from 23 countries or regions. The characteristics of the included studies showed that, except for the K&U of children and adolescents aged 13–18 years, the K&U of other age groups and the PL, PC, DB, M&C of all age groups were significantly positively correlated with CRF. Furthermore, the results of male and female samples in all included studies were the same. The results of the meta-analysis indicated that PL (COR = 0.64, 95% CI 0.58, 0.70), PC (COR = 0.74, 95% CI 0.69, 0.79), DB (COR = 0.49, 95% CI 0.40, 0.57), K&U (COR = 0.41, 95% CI 0.23, 0.56), and M&C (COR = 0.45, 95% CI 0.41, 0.49) were significantly positively correlated with CRF. Regarding DB, total physical activity (TPA) was positively correlated with CRF (COR = 0.49, 95% CI = 0.40, 0.57). Moderate to vigorous physical activity (MVPA), vigorous physical activity (VPA) and high physical activity (HPA) were positively correlated with CRF (COR = 0.16, 95% CI 0.09, 0.22; COR = 0.33, 95% CI 0.22, 0.43; COR = 0.38, 95% CI 0.13, 0.58), but light physical activity (LPA) was negatively correlated with CRF (COR = − 0.20, 95% CI − 0.32, 0.06). Conclusion: PL and CRF are positively correlated among children and adolescents, suggesting that the development of physical literacy has a wide range of effects on children and adolescents’ cardiopulmonary health and that these effects are not limited by PL and its various dimensions or sex. In addition, to exert the positive effect of daily activities on cardiopulmonary health, the intensity of physical activity should reach a moderate level or above.

Objective: Based on the decision tree model, to explore the key influencing factors of children’s physical fitness, rank the key influencing factors, and explain the complex interaction between the influencing factors.Methods: A cohort study design was adopted. 1,276 children (ages 3–6) from 23 kindergartens in Nanchang, China, were chosen for the study to measure the children’s physical fitness at baseline and a year later and to compare the physical fitness scores at the two stages. The study was conducted following the Chinese National Physical Fitness Testing Standard (Children Part); To identify the primary influencing factors of changes in physical fitness, a decision tree model was developed, and a questionnaire survey on birth information, feeding patterns, SB, PA, dietary nutrition, sleep, parental factors, and other relevant information was conducted.Results: The levels of physical fitness indicators among preschool children showed a significant increase after 1 year. The accuracy of the CHAID model is 84.17%. It showed that 7 variables were strongly correlated with the physical changes of children’s fitness, the order of importance of each variable was weekend PA, weekend MVPA, mother’s BMI, mother’s sports frequency, father’s education, mother’s education, and school day PA. Three factors are related to PA. Four factors are related to parental circumstances. In addition to the seven important variables mentioned, variables such as breakfast frequency on school day, puffed food, frequency of outing, school day MVPA, parental feeling of sports, father’s occupation, and weekend breakfast frequency are all statistically significant leaf node variables.Conclusion: PA, especially weekend PA, is the most critical factor in children’s physical fitness improvement and the weekend MVPA should be increased to more than 30 min/d based on the improvement of weekend PA. In addition, parental factors and school day PA are also important in making decisions about changes in fitness for children. The mother’s efforts to maintain a healthy BMI and engage in regular physical activity are crucial for enhancing the physical fitness of children. Additionally, other parental factors, such as the parents’ educational levels and the father’s occupation, can indirectly impact the level of physical fitness in children.

Objective: To evaluate the best option among traditional Chinese exercises for reducing oxidative stress in middle-aged and older adults, using a network meta-analysis. Methods: PubMed, Web of Science, and CNKI databases were used. We searched randomized controlled trials (RCTs) on middle-aged and older adults to influence oxidative stress by any traditional Chinese exercises from the beginning to 20 January 2022. A network meta-analysis of randomized control trials was performed comparing the changes in the concentration of glutathione peroxidase (GPX), malondialdehyde (MDA), and superoxide dismutase (SOD) as primary outcomes, following different therapeutic interventions with traditional Chinese exercises in middle-aged and older adults over 30 years old. Standardized mean differences (SMD) and 95% confidence intervals (CI) were used to assess the correlation between each group of interventions, and surface under the cumulative ranking (SUCRA) was used to rank the best interventions. Results: The meta-analysis comprised 15 trials with a total of 927 participants and six interventions: (Wuqinxi (WQX), Baduanjin (BDJ), Tai Ji Quan (TJQ), Yijinjing (YJJ), Mawangdui Daoyin (MWD), and no exercise intervention (NEI)). Regarding GPX: WQX [SMD = 2.79 (1.75, 3.83)], TJQ [SMD = 0.47 (0.23, 0.70)], YJJ [SMD = 1.78 (1.18, 2.37)], MWD [SMD = 1.89 (1.36, 2.43)] were superior in increasing GPX relative to NEI. Regarding MDA: WQX [SMD = 1.68 (0.94, 2.42)], YJJ [SMD = 0.99 (0.28, 1.69)] were superior in reducing MDA relative to NEI. Regarding SOD: WQX [SMD = 1.05 (0.10, 2.01)] were superior in increasing SOD relative to NEI. WQX topped the SUCRA with GPX: 0.97, MDA: 0.91, and SOD: 0.94. Furthermore, WQX was more effective than TJQ in interfering with GPX [SMD = 2.32 (1.26, 3.39)] and MDA [SMD = 1.47 (0.26, 2.67)], and a significantly better intervention effect on SOD than YJJ [SMD = 1.52 (0.80, 2.24)] and MWD [SMD = 0.89 (0.03, 1.75)]. Conclusion: Traditional Chinese exercise can help middle-aged and older adults reduce oxidative stress. WQX may be the best traditional Chinese exercise of the exercises evaluated for reducing oxidative stress in middle-aged and older adults.

Background: About 70% of children and adolescents worldwide do not meet the recommended level of physical activity (PA), which is closely associated with physical, psychological, and cognitive well-being. Nowadays, the use of technologies to change PA is of interest due to the need for novel, more effective intervention approaches. The previous meta-analyses have examined smartphone-based interventions and their impact on PA in adults, but evidence in children and adolescents still needs further research. Objective: This systematic review and meta-analysis aimed to determine the effectiveness of smartphone-based interventions for improving PA in children and adolescents. Methods: Five electronic databases (PubMed, Web of Science, OVID, Scopus, and the China National Knowledge Infrastructure) were searched up to June 29, 2020. Randomized controlled trials with a control group that examine the effect of smartphone interventions on PA among children and adolescents were included. Bias risks were assessed using the Cochrane collaboration tool. Meta-analysis was performed to assess the pooled effect on PA using a random effects model. Subgroup analyses were conducted to examine the potential modifying effects of different factors (eg, types of intervention, intervention duration, age, measurement, study quality). Results: A total of 9 studies were included in this review, including 4 mobile app interventions, 3 SMS text messaging interventions, and 2 app + SMS text messaging interventions. In general, the risk of bias of included studies was low. Compared with the control group, the use of smartphone intervention significantly improved PA (standardized mean difference [SMD] 0.44, 95% CI 0.11-0.77, P=.009), especially for total PA (TPA; weighted mean difference [WMD] 32.35, 95% CI 10.36-54.33, P=.004) and daily steps (WMD 1185, 95% CI 303-2068, P=.008), but not for moderate-to-vigorous PA (WMD 3.91, 95% CI –1.99 to 9.81, P=.19). High statistical heterogeneity was detected (I2=73.9%, P<.001) for PA. Meta-regression showed that duration (β=–.08, 95% CI –0.15 to –0.01, n=16) was a potential factor for high heterogeneity. The results of subgroup analyses indicated that app intervention (SMD 0.76, 95% CI 0.23-1.30, P=.005), children (SMD 0.64, 95% CI 0.10-1.18, P=.02), “≤8 weeks” (SMD 0.76, 95% CI 0.23-1.30, P=.005), objective measurement (SMD 0.50, 95% CI 0.09-0.91, P=.02), and low risk of bias (SMD 0.96, 95% CI 0.38-1.54, P=.001) can significantly improve PA. Conclusions: The evidence of meta-analysis shows that smartphone-based intervention may be a promising strategy to increase TPA and steps in children and adolescents. Currently, app intervention may be a more effective strategy among smartphone intervention technologies. To extend the promise of smartphone intervention, the future needs to design comparative trials among different smartphone technologies. Trial Registration: PROSPERO CRD42019148261; https://tinyurl.com/y5modsrd

BACKGROUND About 70% of children and adolescents worldwide do not meet the recommended level of physical activity (PA), which is closely associated with physical, psychological, and cognitive well-being. Nowadays, the use of technologies to change PA is of interest due to the need for novel, more effective intervention approaches. The previous meta-analyses have examined smartphone-based interventions and their impact on PA in adults, but evidence in children and adolescents still needs further research. OBJECTIVE This systematic review and meta-analysis aimed to determine the effectiveness of smartphone-based interventions for improving PA in children and adolescents. METHODS Five electronic databases (PubMed, Web of Science, OVID, Scopus, and the China National Knowledge Infrastructure) were searched up to June 29, 2020. Randomized controlled trials with a control group that examine the effect of smartphone interventions on PA among children and adolescents were included. Bias risks were assessed using the Cochrane collaboration tool. Meta-analysis was performed to assess the pooled effect on PA using a random effects model. Subgroup analyses were conducted to examine the potential modifying effects of different factors (eg, types of intervention, intervention duration, age, measurement, study quality). RESULTS A total of 9 studies were included in this review, including 4 mobile app interventions, 3 SMS text messaging interventions, and 2 app + SMS text messaging interventions. In general, the risk of bias of included studies was low. Compared with the control group, the use of smartphone intervention significantly improved PA (standardized mean difference [SMD] 0.44, 95% CI 0.11-0.77, P=.009), especially for total PA (TPA; weighted mean difference [WMD] 32.35, 95% CI 10.36-54.33, P=.004) and daily steps (WMD 1185, 95% CI 303-2068, P=.008), but not for moderate-to-vigorous PA (WMD 3.91, 95% CI –1.99 to 9.81, P=.19). High statistical heterogeneity was detected (I2=73.9%, P<.001) for PA. Meta-regression showed that duration (β=–.08, 95% CI –0.15 to –0.01, n=16) was a potential factor for high heterogeneity. The results of subgroup analyses indicated that app intervention (SMD 0.76, 95% CI 0.23-1.30, P=.005), children (SMD 0.64, 95% CI 0.10-1.18, P=.02), “≤8 weeks” (SMD 0.76, 95% CI 0.23-1.30, P=.005), objective measurement (SMD 0.50, 95% CI 0.09-0.91, P=.02), and low risk of bias (SMD 0.96, 95% CI 0.38-1.54, P=.001) can significantly improve PA. CONCLUSIONS The evidence of meta-analysis shows that smartphone-based intervention may be a promising strategy to increase TPA and steps in children and adolescents. Currently, app intervention may be a more effective strategy among smartphone intervention technologies. To extend the promise of smartphone intervention, the future needs to design comparative trials among different smartphone technologies. CLINICALTRIAL PROSPERO CRD42019148261; https://tinyurl.com/y5modsrd