Impact of a 12-wk physical conditioning program on the aerobic capacity of aviation cadets

BACKGROUND Flight cadets need to have good physical fitness to cope with the challenges of flying missions.The continuous development of science and technology has led to the constant upgrading of fighter jets and the improvement of their performance,which has resulted in new and higher requirements for the physical fitness of flight personnel.The traditional physical training mode,method,and assessment have been used for many years and do not meet current fitness needs.AIM To investigate the impact of a 12-wk comprehensive anti-G fitness training program on the aerobic capacity of aviation cadets and to evaluate its effectiveness.METHODS Fifty-five cadets were randomly assigned to control and experimental groups using a randomized,single-blind design.The control group maintained their existing training regimen,while the experimental group participated in a 12-wk comprehensive training intervention.The training program comprised strength training twice per week,high-intensity interval training three times per week,and supplemental nutritional and psychological support.Maximal oxygen uptake(VO2max),lower limb strength,and hemoglobin levels were measured at baseline,at 6 wk and 12 wk post-intervention.RESULTS Repeated measures analysis of variance revealed significant differences of both VO2max and relative VO2 in both groups across time points(P<0.05).However,no significant time-group interaction was observed(P>0.05).Paired t-tests comparing baseline and 12-wk results showed that VO2max and relative VO2 were significantly higher in the experimental group than the control group(P<0.05).This suggests that the training program effectively enhanced the aerobic capacity of the experimental group.Key indicators of aerobic capacity,bilateral lower limb strength and hemoglobin levels,were also significantly different over time and between groups(P<0.05).No significant differences were noted in heart-rate metrics(P>0.05).CONCLUSION A 12-wk comprehensive anti-G fitness training program significantly improved the aerobic capacity of aviation cadets,thereby enhancing their overall capacity and laying a physiological foundation for enduring high-G flights.

Exercise-induced adaptation of neurons in the vertebrate locomotor system

Vertebrate neurons are highly dynamic cells that undergo several alterations in their functioning and physiologies in adaptation to various external stimuli.In particular,how these neurons respond to physical exercise has long been an area of active research.Studies of the vertebrate locomotor system’s adaptability suggest multiple mechanisms are involved in the regulation of neuronal activity and properties during exercise.In this brief review,we highlight recent results and insights from the field with a focus on the following mechanisms:(a)alterations in neuronal excitability during acute exercise;(b)alterations in neuronal excitability after chronic exercise;(c)exercise-induced changes in neuronal membrane properties via modulation of ion channel activity;(d)exercise-enhanced dendritic plasticity;and(e)exercise-induced alterations in neuronal gene expression and protein synthesis.Our hope is to update the community with a cellular and molecular understanding of the recent mechanisms underlying the adaptability of the vertebrate locomotor system in response to both acute and chronic physical exercise.

Analysis of the Application of the Flipped Classroom in the Teaching of College Education Courses

The flipped classroom model is a method of educational reform that meets the needs of information technology development.On the one hand,it can promote the development of innovative and applicable human resources and improve the level of individual learning of university students.On the other hand,it can encourage the practice of teaching students using modern technologies and the need for teachers to master the use of the flipped classroom in higher education.Beginning with updating concepts and raising awareness,teachers need to change their learning habits and traditional teaching methods to facilitate the development of pedagogical reforms further.This paper introduces the concept and characteristics of the classroom.It proposes strategies for applying the flipped classroom,including organizing teaching activities,setting learning objectives,and micro-video design and production.

Impact of built environment on physical activity and obesity among children and adolescents in China:A narrative systematic review

Background: Neighborhood built environment may profoundly influence children's physical activity(PA) and body weight. This study systematically reviewed scientific evidence regarding the impact of built environment on PA and obesity among children and adolescents in China.Methods: A keyword and reference search was conducted in Active Living Research, Cochrane Library, PubMed, and Web of Science. Studies that met all of the following criteria were included in the review:(1) study designs—experimental studies, observational studies, and qualitative studies;(2) study subjects—Chinese children and/or adolescents aged 17 years;(3) exposures—neighborhood built environment;(4)outcomes—PA and/or body weight status;(5) article type—peer-reviewed publications;(6) time window of search—from the inception of an electronic bibliographic database to May 31, 2018;(7) country—China; and(8) language—articles written in English.Results: A total of 20 studies, including 16 cross-sectional studies, 3 longitudinal studies, and 1 descriptive study, met the predetermined selection criteria and were included in the review. A total of 13 studies adopted subjective built environment measures reported by parents and/or children, 2 adopted objective measures(e.g., geographical information system, field observations), and 5 adopted both objective and subjective measures. PA behaviors included PA, physical inactivity, sedentary behavior, active/passive commuting from/to school, and park visits. Among the 16 studies that provided some quantitative estimates of the influence of built environment on PA and body weight status, all reported a statistically significant relationship in the expected direction. Availability and accessibility in proximity to greenspaces, parks, recreational facilities,and sidewalks were found to be associated with increased PA levels, reduced sedentary behaviors, and/or active commuting among Chinese children and adolescents. In contrast, the absence of bike lanes and living in higher density residential areas were associated with increased likelihood of childhood overweight and obesity.Conclusion: Neighborhood built environment plays an important role in Chinese children's PA engagement and weight outcomes. Building new exercise facilities and enhancing the accessibility of existing facilities hold the potential to enhance PA engagement among Chinese children and adolescents. In addition, urban designs that incorporate sidewalks, bike lanes, walking paths, less motorized traffic, and lower residential density are likely to promote PA and prevent childhood obesity in China.

Physical exercise may exert its therapeutic influence on Alzheimer’s disease through the reversal of mitochondrial dysfunction via SIRT1-FOXO1/3-PINK1-Parkin-mediated mitophagy

Alzheimer’s disease(AD)is the most common form of agerelated neurodegenerative disease.Importantly,the prevalence of AD is expected to increase as the population ages,and it will place a huge burden on health care in the future.AD is clinically characterized by confusion,disorientation,and progressive memory and language decline.Diagnosis is confirmed histologically by the accumulation of extracellular b-amyloid(Ab)plaques,intracellular tangles of abnormally phosphorylated tau protein,and progressive neuronal loss in the brain.1 Current treatment focuses on symptom alleviation since there is not yet a cure for AD,despite the wealth of research on the mechanisms underlying the disease and its pathophysiology.

Associations between meeting 24-hour movement guidelines and quality of life among children and adolescents with autism spectrum disorder

Background:The Canadian 24-hour movement behavior(24-HMB)guidelines suggest that a limited amount of screen time use,an adequate level of physical activity(PA),and sufficient sleep duration are beneficial for ensuring and optimizing the health and quality of life(QoL)of children and adolescents.However,this topic has yet to be examined for children and adolescents with autism spectrum disorder(ASD)specifically.The aim of this cross-sectional observational study was to examine the associations between meeting 24-HMB guidelines and several QoLrelated indicators among a national sample of American children and adolescents with ASD.Methods:Data were taken from the 2020 U.S.National Survey of Children’s Health dataset.Participants(n=956)aged 617 years and currently diagnosed with ASD were included.The exposure of interest was adherence to the 24-HMB guidelines.Outcomes were QoL indicators,including learning interest/curiosity,repeating grades,adaptive ability,victimization by bullying,and behavioral problems.Categorical variables were described with unweighted sample counts and weighted percentages.Age,sex,race,preterm birth status,medication,behavioral treatment,household poverty level,and the educational level of the primary caregivers were included as covariates.Odds ratio(OR)and 95%confidence interval(95%CI)were used to present the strength of association between adherence to 24-HMB guidelines and QoL-related indicators.Results:Overall,452 participants(45.34%)met 1 of the 3 recommendations,216(22.65%)met 2 recommendations,whereas only 39 participants(5.04%)met all 3 recommendations.Compared with meeting none of the recommendations,meeting both sleep duration and PA recommendations(OR=3.92,95%CI:1.639.48,p<0.001)or all 3 recommendations(OR=2.11,95%CI:1.034.35,p=0.04)was associated with higher odds of showing learning interest/curiosity.Meeting both screen time and PA recommendations(OR=0.15,95%CI:0.040.61,p<0.05)or both sleep duration and PA recommendations(OR=0.24,95%CI:0.070.87,p<0.05)was associated with lower odds of repeating any grades.With respect to adaptive ability,participants who met only the PA recommendation of the 24-HMB were less likely to have difficulties dressing or bathing(OR=0.11,95%CI:0.020.66,p<0.05)than those who did not.For participants who met all 3 recommendations(OR=0.38,95%CI:0.150.99,p=0.05),the odds of being victimized by bullying was lower.Participants who adhered to both sleep duration and PA recommendations were less likely to present with severe behavioral problems(OR=0.17,95%CI:0.040.71,p<0.05)than those who did not meet those guidelines.Conclusion:Significant associations were found between adhering to 24-HMB guidelines and selected QoL indicators.These findings highlight the importance of maintaining a healthy lifestyle as a key factor in promoting and preserving the QoL of children with ASD.

Physical exercise protects muscle from accelerated aging induced by high-salt intake and muscle CG2196(salt)gene overexpression in Drosophila

Aging decreases muscle mass,strength,and functional capacity.High-salt stress seems to promote muscle aging and decrease lifespan.However,exercise delays muscle aging and increases longevity,and it may protect muscle from rapid aging induced by high-salt intake(HSI),but the molecular mechanisms are poorly understood.In this study,the flies were fed a high-salt diet and trained to exercise.Muscle CG2196(salt)gene and dSir2 gene were over-expressed by building mef2-gal4/UAS system.The results showed that both physical exercise and muscle dSir2 gene overexpression prevented HSI-induced and muscle salt overexpression-induced accelerated age-related decline of climbing index,climbing endurance,muscle NAD^(+)level,SOD activity level,dSir2 expression,and dFOXO expression,and they also prevented HSI-induced and muscle salt overexpression-induced accelerated age-related increase in muscle ROS level,MDA level,and salt gene expression.Physical exercise improved lifespan decrease induced by HSI and muscle salt overexpression.Therefore,current results indicated that high-salt stress accelerated muscle aging by decreasing muscular NAD^(+)/dSir2/dFOXO pathway activity and increasing oxidative stress.Physical exercise protected muscle from accelerated aging induced by high-salt stress through activating muscle NAD^(+)/dSir2/dFOXO pathway and enhancing muscle oxidation resistance.The combination of exercise and muscle dSir2 overexpression had the best protective effect on muscle aging and lifespan in flies.

A Study on the Chess Culture of Ethnic Minority Groups in Gansu Province

As a region inhabited by large populations of ethnic minority groups, Gansu province boasts rich ethnic cultural resources which reflect traditional culture and intangible cultural heritage that had taken shape thousands of years ago. Among these are various ethnic folk chess games. They are time-honored with many types such as the “Fang” chess of the Hui ethnic group, the “Jiu” chess of the Tibetans, the “King and Ministers” chess, the Mongolian chess, the Mongolian military chess, etc. These games embody distinctive ethnic and regional characteristics, as well as the cultural elements of a particular ethnic minority group. It is of great significance, therefore, to study the ethnic chess by collecting, documenting and comparing different types of related chess. The paper explores ways to standardize, protect and promote them scientifically in joint efforts, and draws a conclusion that examining their significance in the present era and the ethnic characteristics is the key to understanding the profound culture behind the chess.

体教融合视域下高校健身健美发展困境与路径研究

研究体教融合背景下高校健身健美教学的现状和实践方法,以提高高校教学质量.体教融合是当前体育教育发展的必然趋势,也是提高大学生综合素质的途径之一.文章针对目前高校健身健美存在问题、揭示健身健美有效开展的困境,提出健身健美体教融合的必要性及发展路径,从而为高校教学质量与学生身体素质的提升提供思路.

The contribution of small and large sensory afferents to postural control in patients with peripheral neuropathy

Peripheral neuropathy(PN) is a multifarious disorder that is caused by damage to the peripheral nerves. Although the symptoms of PN vary with the etiology, most cases are characterized by impaired tactile and proprioceptive sensation that progresses in a distal to proximal manner. Balance also tends to deteriorate as the disorder becomes more severe, and those afflicted are substantially more likely to fall while walking compared with those who are healthy. Most patients with PN walk more cautiously and with greater stride variability than age-matched controls, but the majority of their falls occur when they must react to a perturbation such as a slippery or uneven surface. The purpose of this study was to first describe the role of somatosensory feedback in the control of posture and then discuss how that relationship is typically affected by the most common types of PN. A comprehensive review of the scientific literature was conducted using MEDLINE, and the relevant information was synthesized. The evidence indicates that the proprioceptive feedback that is conveyed primarily through larger type I afferents is important for postural control. However, the evidence indicates that the tactile feedback communicated through smaller type II afferents is particularly critical to the maintenance of balance. Many forms of PN often lead to chronic tactile desensitization in the soles of the feet and, although the central nervous system seems to adapt to this smaller type II afferent dysfunction by relying on more larger type I afferent reflex loops, the result is still decreased stability. We propose a model that is intended both to help explain the relationship between stability and the smaller type II afferent and the larger type I afferent feedback that may be impaired by PN and to assist in the development of pertinent rehabilitative interventions.

Effect of a specialized injury prevention program on static balance, dynamic balance and kicking accuracy of young soccer players

AIM To study the effect of balance intervention program using the "FIFA 11+" program on static and dynamic balance and kicking accuracy of young soccer players.METHODS Twenty young soccer players were allocated to experimental(n = 10) or control(n = 10) groups. The experimental group performed the "FIFA 11+" program three times a week for six weeks. The control group performed their normal warm-up routine. The primary outcomes were measured pre and post intervention, and assessed kicking accuracy, static balance and dynamic balance.RESULTS No differences were found in kicking accuracy following intervention, for both groups, however, static balance improved significantly among the experimental group with significant interaction with the control group, and with high effect size. In addition, the dynamic balance of the left leg of the experimental group, with medium effect size for interaction between groups.CONCLUSION The large effect size of balance improvement that was observed following six weeks of intervention sessions, implies that soccer trainers and coaches should consider the inclusion of "FIFA 11+" as components of programs aimed at improving balance ability/control in young soccer players, as improvement in balance abilities may prevent injuries.

Association of resting heart rate and hypertension stages on all-cause and car- diovascular mortality among elderly Koreans： the Kangwha Cohort Study

Background Elevated resting heart rate and hypertension independently increase the risk of mortality. However, their combined ef- fect on mortality in stages of hypertension according to updated clinical guidelines among dderly population is unclear. Methods We fol- lowed a cohort of 6100 residents （2600 males and 3500 females） of Kangwha County, Korea, ranging from 55 to 99 year-olds as of March 1985, for all-cause and cardiovascular mortality for 20.8 years until December 31, 2005. Mortality data were collected through telephone calls and visits （to 1991）, and were confirmed by death record matching with the National Statistical Office （1992-2005）. Hazard ratios were calculated for all-cause and cardiovascular mortality by resting heart rate and hypertension defined by Eighth Joint National Committee crite- ria using the Cox proportional hazard model after controlling for confounding factors. Results The hazard ratios associated with resting heart rate 〉 80 beats/min were higher in hypertensive men compared with normotensives with heart rate of 61-79 beats/rain, with hazard ratios values of 1.43 （95% CI： 1.00-1.92） on all-cause mortality for prehypertension, 3.01 （95% CI： 1.07-8.28） on cardiovascular mortality for prehypertension, and 8.34 （95% CI： 2.52-28.19） for stage 2 hypertension. Increased risk （HR： 3.54, 95% CI： 1.16-9.21） was observed among those with both a resting heart rate 〉 80 beats/rain and prehypertension on cardiovascular mortality in women. Conclusions Indi- viduals with coexisting elevated resting heart rate and hypertension, even in prehypertension, have a greater risk for all-cause and cardiovas- cular mortality compared to those with elevated resting heart rate or hypertension alone. These findings suggest that elevated resting heart rate should not be regarded as a less serious risk factor in elderly hypertensive patients.

MicroRNA expression profile and lipid metabolism characteristics in liver of rat undergoing high-fat diet

This study aimed to investigate the microRNA expression profile and the characteristics of lipid metabolism in the livers of rats undergoing a high-fat diet.Fifty male Sprague-Dawley(SD)rats were divided into a standard chow group(C group,N=10)and a high-fat diet group(H group,N=40).After 12 weeks,the rat body weight,body length,fat mass,and serum lipid concentration were measured.The expression profile of microRNAs and the gene and protein expression levels involved in lipid metabolism in rat liver were detected.Body fat and serum lipid concentrations were all significantly higher in the H group than those in the C group(p<0.05 or p<0.01).The expression of 10 microRNAs showed significant differences in the liver(p<0.05).In particular,the let-7 family expression levels significantly increased(p<0.05)in the H group compared with those in the C group.Compared with the C group,the high-fat diet resulted in low FAS,CPT1A,and ApoAI mRNA expression levels(p<0.05 or p<0.01)and high PPARαand FAT/CD36 mRNA expression levels in the H group rat liver(p<0.01).Meanwhile,the protein PPARα,FAS,CPT1A,FAT/CD36,and ApoAI expression levels were all significantly lower in the H group than those in the C group(p<0.05 or p<0.01).In conclusion,the high-fat diet increased the body fat and serum lipid levels and altered the 10 microRNA expression levels in the liver.The high-fat diet may affect hepatic carbohydrate metabolism and increase ectopic fat accumulation through let-7 family overexpression.The high-fat diet for 12 weeks decreased lipid metabolism level in the liver,thereby decreasing fatty acid synthesis,oxidation,and transport by down-regulating the PPARα,FAS,CPT1A,FAT/CD36,and ApoAI protein levels.

Effects of core and non-dominant arm strength training on drive distance in elite golfers

Background： Various training schemes have sought to improve golf-related athletic ability. In the golf swing motion, the muscle strengths of the core and arms play important roles, where a difference typically exists in the power of arm muscles between the dominant and non- dominant sides. The purposes of this study were to determine the effects of exercises strengthening the core and non-dominant arm muscles of elite golf players （handicap 〈 3） on the increase in drive distance, and to present a corresponding training scheme aimed at improving golf performance ability. Methods： Sixty elite golfers were randomized into the control group （CG, n = 20）, core exercise group （CEG, n = 20）, and group receiving a combination of muscle strengthening exercises of the non-dominant arm and the core （NCEG, n = 20）. The 3 groups conducted the corresponding exercises for 8 weeks, after which the changes in drive distances and isokinetic strength were measured. Results： Significant differences in the overall improvement of drive distance were observed among the groups （p 〈 0.001）. Enhancement of the drive distance of NCEG was greater than both CG （p 〈 0.001） and CEG （p = 0.001）. Except for trunk flexion, all variables of the measurements of isokinetic strength for NCEG also showed the highest values compared to the other groups. Examination of the correlation between drive distance and isokinetic strength revealed significant correlations of all variables except trunk flexion, wrist extension, and elbow extension. Conclusion： The combination of core and non-dominant arm strength exercises can provide a more effective specialized training program than core alone training for golfers to increase their drive distances.

Prediction of Outcomes in Mini-Basketball Training Program for Preschool Children with Autism Using Machine Learning Models

In recent years evidence has emerged suggesting that Mini-basketball training program(MBTP)can be an effec-tive intervention method to improve social communication(SC)impairments and restricted and repetitive beha-viors(RRBs)in preschool children suffering from autism spectrum disorder(ASD).However,there is a considerable degree if interindividual variability concerning these social outcomes and thus not all preschool chil-dren with ASD profit from a MBTP intervention to the same extent.In order to make more accurate predictions which preschool children with ASD can benefit from an MBTP intervention or which preschool children with ASD need additional interventions to achieve behavioral improvements,further research is required.This study aimed to investigate which individual factors of preschool children with ASD can predict MBTP intervention out-comes concerning SC impairments and RRBs.Then,test the performance of machine learning models in predict-ing intervention outcomes based on these factors.Participants were 26 preschool children with ASD who enrolled in a quasi-experiment and received MBTP intervention.Baseline demographic variables(e.g.,age,body,mass index[BMI]),indicators of physicalfitness(e.g.,handgrip strength,balance performance),performance in execu-tive function,severity of ASD symptoms,level of SC impairments,and severity of RRBs were obtained to predict treatment outcomes after MBTP intervention.Machine learning models were established based on support vector machine algorithm were implemented.For comparison,we also employed multiple linear regression models in statistics.Ourfindings suggest that in preschool children with ASD symptomatic severity(r=0.712,p<0.001)and baseline SC impairments(r=0.713,p<0.001)are predictors for intervention outcomes of SC impair-ments.Furthermore,BMI(r=-0.430,p=0.028),symptomatic severity(r=0.656,p<0.001),baseline SC impair-ments(r=0.504,p=0.009)and baseline RRBs(r=0.647,p<0.001)can predict intervention outcomes of RRBs.Statistical models predicted 59.6%of variance in post-treatment SC impairments(MSE=0.455,RMSE=0.675,R2=0.596)and 58.9%of variance in post-treatment RRBs(MSE=0.464,RMSE=0.681,R2=0.589).Machine learning models predicted 83%of variance in post-treatment SC impairments(MSE=0.188,RMSE=0.434,R2=0.83)and 85.9%of variance in post-treatment RRBs(MSE=0.051,RMSE=0.226,R2=0.859),which were better than statistical models.Ourfindings suggest that baseline characteristics such as symptomatic severity of 144 IJMHP,2022,vol.24,no.2 ASD symptoms and SC impairments are important predictors determining MBTP intervention-induced improvements concerning SC impairments and RBBs.Furthermore,the current study revealed that machine learning models can successfully be applied to predict the MBTP intervention-related outcomes in preschool chil-dren with ASD,and performed better than statistical models.Ourfindings can help to inform which preschool children with ASD are most likely to benefit from an MBTP intervention,and they might provide a reference for the development of personalized intervention programs for preschool children with ASD.

Acylation of Quercetin with a Novel Thermophilic Esterase as Biocatalyst

The regioselective acylation of quercetin catalyzed by a novel thermophilic esterase（APE1547） from the archaeon Aeropyrum pernix K1 was successfully conducted in organic solvents.The effects of acyl donor,substrate ratio,organic solvent,temperature,and water activity were investigated.Under the optimum conditions,a yield of 74% for its mono ester could be achieved in the reaction for about 6 h.With the reaction time extending to about 30 h,the final conversion of quercetin was about 100% and three products were synthesized.

Analysis of health quotient and mood stability of students in Shaanxi nor mal school

AIM:To analyze relationship between hea lth quotient and mood stability of202cases of Department of Physical E ducation and 786cases of public cour se2000in Shaanxi Normal University.METHODS:Mood stability and health quotient were surveyed through questionnaire for 202students of physic al department of grade 1998-2001and 286of public lessons.RESULTS:Percent of students of physical departments with abnormal mood was lower than that of public lessons,more stu dents with high score of mood stability for physical departments compared with public students.CONCLUSION:Quo-tients index has close relation with mood stability for students of physical department and public lessons.

Effects of carbohydrate supplements on exercise-induced menstrual dysfunction and ovarian subcellular structural changes in rats

Background： Exercise-associated menstrual dysfunction （EAMD） is a common health problem in female athletes as a part of female athlete triad （FAT）, a condition related to low energy availability. In this study, we explored the possibility that carbohydrate supplements can improve the status of EAMD and prevent exercise-induced ovarian injury in a FAT rat model. This research aimed to provide experimental evidence with regard to the relationship of energy intervention and EAMD. Methods： Forty-five female Sprague-Dawley rats （2 months old） were randomly divided into five experimental groups： control group （C）, 9-week exercise as model for EAMD （E）, post-EAMD recovery group （R）, oligosaccharide intervention group （O）, and glucose intervention group （G）. All rats were sacrificed at the end of 9 weeks. Serum samples were collected for measuring gonadotropin releasing hormone, follicle stimulating hormone, luteinizing hormone, 1713-estradiol and progesterone levels. The ovaries were taken for investigation of exercise- and carbohydrate-induced follicular subcellular structure changes. Results： Exercise induced irregular menstrual cycles and ovary subcellular structural damages, such as swollenness of mitochondria in rats from groups E and R. Both glucose and oligosaccharide supplements restored well-differentiated mitochondria in the ovarian follicular cells, and a significant improvement of endoplasmic reticulum and Golgi in swollenness in theca cells in groups O and G compared to groups C, E, and R. There was no difference in mitochondria subcellular structural changes between groups O and G. Group E showed attenuation of serum levels of 17β-estradiol and progesterone compared to C. There were no differences of 17β-estradiol serum levels among groups O, G, and R, while group G showed a lower level of progesterone than C. Conclusion： Female adult rats with 9-week continuous exercise can cause menstrual dysregulation as a model for EAMD. Post-EAMD intervention with glucose and oligosaccharide intake can normalize the menstrual cycle, restore the follicular subcellular structure, and reverse the exercise-induced reduction of ovary sex hormones. It suggests a positive feedback of hypothalamus-pituitary-ovary axis might be involved in the molecular mechanisms of energy intake in treating EAMD.

Trunk Kinematics and Centre of Pressure Displacement during Lateral Lifting and Lowering

Lateral bending of the trunk has been specifically identified as a high risk factor for lower back disorders. However, few studies have presented in vivo kinematic data of the trunk while performing functional lateral bending tasks. Five healthy male subjects performed lateral lifting and lowering tasks under loading condition ranging from light (2kg) to 100 % of a maximum (ML) at a controlled velocity. Single lowering tasks were also performed at 125% and 150% of ML. Video based movement analysis was used to determine kinematics of the trunk, pelvis, shoulders and neck in the frontal plane. Centre of pressure (COP) data was also obtained from a force platform on which the subjects stood when performing the lifting and lowering tasks. Kinematics of the trunk revealed a smooth and relatively large change in angular displacement (between 69°to 55°) toward the unloaded side during the lifting phase. Trunk angular displacement significantly decreased with increasing lifting load. The trunk was additionally divided into four segments representing the lower and upper lumbar regions and the lower and upper thoracic regions. The greatest displacement in these segments took place at the upper lumbar and lower thoracic regions (ranging from 29°to 22°and 23°to 17°, respectively) with the least displacement occurring in the lower lumbar and upper thoracic regions (approx. 6° and 5°, respectively). Both the upper lumbar and lower thoracic segments showed significant decreases in angular displacement with increasing load. During the single lowering trials the trunk rotated toward the loaded side with slightly less magnitude to that recorded during the lowering phase of the heaviest lifting and lowering conditions. Angular displacements of the upper lumbar and lower thoracic segments also decreased with increasing load in single lowering. Identified changes in the COP displacement were also correlated to increasing lifting and lowering load. The main findings of this study indicate that it is the central sections of the trunk that have the greatest motion

Training and Recommendations on the Lower Limbs Explosive Force of Juvenile Amateur Men Sprinters

Based on the characteristics of physiological development of China's juvenile men sprinters,combined with the training mechanism of explosive force,and taking the track- and- field team of Jianshan High School in Chongqing as experimental object,this article selects the combination of one leg training methods and the combination of two legs training methods to carry out group control experiment. The result shows: each index score of the two groups of athletes is improved after training,but the characteristics of employing forces and the way of muscle work in one leg jumping exercises such as the one leg jump and step are much closer to sprint techniques. And using this kind of methods can effectively develop the special quality of juvenile sprinter.