Insights into genetic diversity and phenotypic variations in domestic geese through comprehensive population and pan-genome analysis

Background Domestic goose breeds are descended from either the Swan goose(Anser cygnoides)or the Greylag goose(Anser anser),exhibiting variations in body size,reproductive performance,egg production,feather color,and other phenotypic traits.Constructing a pan-genome facilitates a thorough identification of genetic variations,thereby deepening our comprehension of the molecular mechanisms underlying genetic diversity and phenotypic variability.Results To comprehensively facilitate population genomic and pan-genomic analyses in geese,we embarked on the task of 659 geese whole genome resequencing data and compiling a database of 155 RNA-seq samples.By constructing the pan-genome for geese,we generated non-reference contigs totaling 612 Mb,unveiling a collection of 2,813 novel genes and pinpointing 15,567 core genes,1,324 softcore genes,2,734 shell genes,and 878 cloud genes in goose genomes.Furthermore,we detected an 81.97 Mb genomic region showing signs of genome selection,encompassing the TGFBR2 gene correlated with variations in body weight among geese.Genome-wide association studies utilizing single nucleotide polymorphisms(SNPs)and presence-absence variation revealed significant genomic associations with various goose meat quality,reproductive,and body composition traits.For instance,a gene encoding the SVEP1 protein was linked to carcass oblique length,and a distinct gene-CDS haplotype of the SVEP1 gene exhibited an association with carcass oblique length.Notably,the pan-genome analysis revealed enrichment of variable genes in the“hair follicle maturation”Gene Ontology term,potentially linked to the selection of feather-related traits in geese.A gene presence-absence variation analysis suggested a reduced frequency of genes associated with“regulation of heart contraction”in domesticated geese compared to their wild counterparts.Our study provided novel insights into gene expression features and functions by integrating gene expression patterns across multiple organs and tissues in geese and analyzing population variation.Conclusion This accomplishment originates from the discernment of a multitude of selection signals and candidate genes associated with a wide array of traits,thereby markedly enhancing our understanding of the processes underlying domestication and breeding in geese.Moreover,assembling the pan-genome for geese has yielded a comprehensive apprehension of the goose genome,establishing it as an indispensable asset poised to offer innovative viewpoints and make substantial contributions to future geese breeding initiatives.

Reabsorption of intervertebral disc prolapse after conservative treatment with traditional Chinese medicine:A case report

BACKGROUND Conservative treatments have been reported to diminish or resolve clinical symptoms of lumbar intervertebral disc herniation(LIDH)within a few weeks.CASE SUMMARY Computed tomography and magnetic resonance imaging(MRI)of the lumbar region of a 25-yearold male diagnosed with LIDH showed prolapse of the L5/S2 disc.The disc extended 1.0 cm beyond the vertebral edge and hung along the posterior vertebral edge.The patient elected a conservative treatment regimen that included traditional Chinese medicine(TCM),acupuncture,and massage.During a follow-up period of more than 12 mo,good improvement in pain was reported without complications.MRI of the lumbar region after 12 mo showed obvious reabsorption of the herniation.CONCLUSION A conservative treatment regimen of TCM,acupuncture,and massage promoted reabsorption of a prolapsed disc.

Is changing footstrike pattern beneficial to runners?

Some researchers, running instructors, and coaches have suggested that the "optimal" footstrike pattern to improve performance and reduce running injuries is to land using a mid-or forefoot strike. Thus, it has been recommended that runners who use a rearfoot strike would benefit by changing their footstrike although there is little scientific evidence for suggesting such a change. The rearfoot strike is clearly more prevalent. The major reasons often given for changing to a mid-or forefoot strike are(1) it is more economical;(2) there is a reduction in the impact peak and loading rate of the vertical component of the ground reaction force; and(3) there is a reduction in the risk of a running-related injuries. In this paper,we critique these 3 suggestions and provide alternate explanations that may provide contradictory evidence for altering one's footstrike pattern.We have concluded, based on examining the research literature, that changing to a mid-or forefoot strike does not improve running economy, does not eliminate an impact at the foot-ground contact, and does not reduce the risk of running-related injuries.

Injury rate,mechanism,and risk factors of hamstring strain injuries in sports:A review of the literature

Hamstring strains are one of most common sports injuries.The purpose of this literature review is to summarize studies on hamstring strain injury rate,mechanism,and risk factors in the last several decades with a focus on the prevention and rehabilitation of this injury.Hamstring injury commonly occurs in sporting events in which high speed sprinting and kicking are frequently performed,such as Australian football. English rugby,American football,and soccer.Basic science studies have demonstrated that a muscle strain injury occurs due to excessive strain in eccentric contraction instead of force,and that elongation speed and duration of activation before eccentric contraction affect the severity of the injury.Hamstring strain injury is likely to occur during the late swing phase and late stance phase of sprint running.Shortened optimum muscle length,lack of muscle flexibility,strength imbalance,insufficient warm-up,fatigue,lower back injury,poor lumbar posture,and increased muscle neural tension have been identified as modifiable risk factors while muscle compositions,age,race,and previous injuries are non-modifiable risk factors.The theoretical basis of some of these risk factors,however,is lacking,and the results of clinical studies on these risk factors are inconsistent.Future studies are needed to establish the cause-and-effect relationships between those proposed risk factors and the injury.

Mechanism of hamstring muscle strain injury in sprinting

Hamstring muscle strain injury is one of the most common injuries in sports involving sprinting and kicking.Hamstring muscle strain injuries occur at a high rate and have a high re-injury rate,which results in loss of training and competition time,which has a significant impact on the quality of life of the injured athletes.~1Preventing and rehabilitating hamstring muscle strain injury is an important task for clinicians and scientists in sports medicine.Understanding the mechanisms underlying hamstring injury is critical for developing appropriate strategies to prevent and rehabilitate hamstring injuries.Understanding the

Relationships among hamstring muscle optimal length and hamstring flexibility and strength

Background:Hamstring muscle strain injury(hamstring injury) due to excessive muscle strain is one of the most common injuries in sports.The relationships among hamstring muscle optimal lengths and hamstring flexibility and strength were unknown,which limited our understanding of risk factors for hamstring injury.This study was aimed at examining the relationships among hamstring muscle optimal length and flexibility and strength.Methods:Hamstring flexibility and isokinetic strength data and three-dimensional kinematic data for hamstring isokinetic tests were collected for11 male and 10 female recreational athletes.The maximal hamstring muscle forces,optimal lengths,and muscle lengths in standing were determined for each participant.Results:Hamstring muscle optimal lengths were significantly correlated to hamstring flexibility score and gender,but not to hamstring strength.The greater the flexibility score,the longer the hamstring muscle optimal length.With the same flexibility score,females tend to have shorter hamstring optimal muscle lengths compared to males.Hamstring flexibility score and hamstring strength were not correlated.Hamstring muscle optimal lengths were longer than but not significantly correlated to corresponding hamstring muscle lengths in standing.Conclusion:Hamstring flexibility may affect hamstring muscle maximum strain in movements.With similar hamstring flexibility,hamstring muscle maximal strain in a given movement may be different between genders.Hamstring muscle lengths in standing should not be used as an approximation of their optimal lengths in calculation of hamstring muscle strain in musculoskeletal system modeling.

The effect of hamstring flexibility on peak hamstring muscle strain in sprinting

Background:The effect of hamstring flexibility on the peak hamstring muscle strains in sprinting,until now,remained unknown,which limited our understanding of risk factors of hamstring muscle strain injury(hamstring injury).As a continuation of our previous study,this study was aimed to examine the relationship between hamstring flexibility and peak hamstring muscle strains in sprinting.Methods:Ten male and 10 female college students participated in this study.Hamstring flexibility,isokinetic strength data,three-dimensional(3D)kinematic data in a hamstring isokinetic test,and kinematic data in a sprinting test were collected for each participant.The optimal hamstring muscle lengths and peak hamstring muscle strains in sprinting were determined for each participant.Results:The muscle strain of each of the 3 biarticulated hamstring muscles reached a peak during the late swing phase.Peak hamstring muscle strains were negatively correlated to hamstring flexibility(0.1179 ≤ R2≤ 0.4519,p = 0.001) but not to hip and knee joint positions at the time of peak hamstring muscle strains.Peak hamstring muscle strains were not different for different genders.Peak muscle strains of biceps long head(0.071 ± 0.059) and semitendinosus(0.070 ± 0.055) were significantly greater than that of semimembranosus(0.064 ± 0.054).Conclusion:A potential for hamstring injury exists during the late swing phase of sprinting.Peak hamstring muscle strains in sprinting are negatively correlated to hamstring flexibility across individuals.The magnitude of peak muscle strains is different among hamstring muscles in sprinting,which may explain the different injury rate among hamstring muscles.

Effects of flexibility and strength training on peak hamstring musculotendinous strains during sprinting

Background:Hamstring injury is one of the most common injuries in sports involving sprinting.Hamstring flexibility and strength are often considered to be modifiable risk factors in hamstring injury.Understanding the effects of hamstring flexibility or strength training on the biomechanics of the hamstring muscles during sprinting could assist in improving prevention strategies and rehabilitation related to these injuries.The purpose of this study was to determine the effects of altering hamstring flexibility or strength on peak hamstring musculotendinous strain during sprinting.Methods:A total of 20 male college students(aged 18-24 years)participated and were randomly assigned to either a flexibility intervention group or a strength intervention group.Each participant executed exercise training 3 times a week for 8 weeks.Flexibility,sprinting,and isokinetic strength testing were performed before and after the 2 interventions.Paired t tests were performed to determine hamstring flexibility or strength intervention effects on optimal hamstring musculotendinous lengths and peak hamstring musculotendinous strains during sprinting.Results:Participants in the flexibility intervention group significantly increased the optimal musculotendinous lengths of the semimembranosus and biceps long head(p<0.026)and decreased peak musculotendinous strains in all 3 bi-articulate hamstring muscles(p<0.004).Participants in the strength-intervention group significantly increased the optimal musculotendinous lengths of all 3 hamstring muscles(p<0.041)and significantly decreased their peak musculotendinous strain during sprinting(p<0.017).Conclusion:Increasing hamstring flexibility or strength through exercise training may assist in reducing the risk of hamstring injury during sprinting for recreational male athletes.

动态系统理论的概念与技术在生物力学分析中的应用（英文）

Traditional biomechanical analyses of human movement are generally derived from linear mathematics.While these methods can be useful in many situations,they do not describe behaviors in human systems that are predominately nonlinear.For this reason,nonlinear analysis methods based on a dynamical systems approach have become more prevalent in recent literature.These analysis techniques have provided new insights into how systems(1) maintain pattern stability,(2) transition into new states,and(3) are governed by short-and long-term(fractal) correlational processes at different spatio-temporal scales.These different aspects of system dynamics are typically investigated using concepts related to variability,stability,complexity,and adaptability.The purpose of this paper is to compare and contrast these different concepts and demonstrate that,although related,these terms represent fundamentally different aspects of system dynamics.In particular,we argue that variability should not uniformly be equated with stability or complexity of movement.In addition,current dynamic stability measures based on nonlinear analysis methods(such as the finite maximal Lyapunov exponent) can reveal local instabilities in movement dynamics,but the degree to which these local instabilities relate to global postural and gait stability and the ability to resist external perturbations remains to be explored.Finally,systematic studies are needed to relate observed reductions in complexity with aging and disease to the adaptive capabilities of the movement system and how complexity changes as a function of different task constraints.

Effects of different doses of metformin on bone mineral density and bone metabolism in elderly male patients with type 2 diabetes mellitus

BACKGROUND Diabetes is a chronic disease,which may cause various complications.Patients with diabetes are at high risk of bone and joint disorders,such as osteoporosis and bone fractures.In addition,it became widely accepted that diabetes has an important impact on bone metabolism.Metformin is a commonly used and effective first-line treatment for type 2 diabetes.Some glucose-lowering agents have been found to have an effect on bone metabolism.The present study explored if different doses of metformin have an effect on bone mineral density(BMD)and bone metabolism in type 2 diabetes.AIM To investigate the effects of different doses of metformin on BMD and bone metabolism in elderly male patients with type 2 diabetes mellitus.METHODS A total of 120 elderly male outpatients with type 2 diabetes mellitus who were admitted to our hospital were included in the study from July 2018 to June 2019.They were randomly assigned to an experimental group and a control group with 60 patients in each group.Patients in the experimental group were given high dose metformin four times a day 0.5 g each time for 12 wk.Patients in the control group were given low dose metformin orally twice a day 0.5 g each time for 12 wk.The changes in bone mineral density and bone metabolism before and after treatment and the efficacy rate of the treatment were compared between the two groups.RESULTS There was no significant difference in the efficacy rate between the two groups(P>0.05).Before the treatment,there was no significant difference in BMD and bone metabolism between the two groups(P>0.05).However,after the treatment,BMD and bone metabolism were improved in the two groups.Moreover,BMD and 25-hydroxyvitamin D were significantly higher in the experimental group than in the control group,and N-terminal/midregion andβ-isomerized Cterminal telopeptides were significantly lower in the experimental group than in the control group(all P<0.05).There was no significant difference in the incidence of adverse reactions between the two groups(P>0.05).CONCLUSION Both high and low dose metformin can effectively control the blood glucose levels in elderly male patients with type 2 diabetes mellitus.However,the benefits of high dose metformin in improving BMD and bone metabolism level was more obvious in patients with type 2 diabetes mellitus.

前脚掌着地和后脚跟着地跑步中的冲击震动频率成分及衰减（英文）

背景:研究显示,与脚后跟着地跑步模式相比,前脚掌着地跑步模式可通过降低冲击相关参数来降低引发跑步相关的过劳性损伤的风险。但现有研究仅比较了不同着地模式冲击参数的时域部分。由于冲击震动的频率成分和衰减度可能对损伤风险及预防非常重要,因此本研究旨在探究后脚跟着地和前脚掌着地跑步者的头部和胫骨加速信号功率以及冲击衰减方面的差别。方法:选取惯用后脚跟和前脚掌着地的跑步者各19名,让其按照各自习惯使用的着地模式,以3.5m/s的速度在跑步机上跑步,收集其胫骨和头部加速数据,计算第1和第2个头部加速峰值的量级和胫骨正向加速度峰值。计算各个信号的功率谱密度来转换头部加速度的频域部分,用相当于胫骨的头部信号的转换函数计算冲击衰减。结果:后脚跟着地时胫骨的正向加速度峰值和信号功率在较低和较高的范围内明显大于前脚掌着地(p<0.05)。第1和第2个头部加速度峰值和头部信号功率在两种跑步模式下均无明显差异(p>0.05)。后脚跟着地跑步模式下,由于胫骨加速度增大,冲击衰减度在较低和较高的范围内均会增大(p<0.05)。结论:不同跑步模式冲击震动频率成分不同,说明衰减的主要机制有差异。虽然冲击衰减机制和运动损伤间的关系尚不清晰,但因冲击成分不同,也许两种跑步模式都无法有效避免损伤,不同模式中的持续损伤类型各不相同。

Effect of approach run velocity on the optimal performance of the triple jump

目的:确定三级跳远助跑最后一步着陆时水平和垂直速度对三级跳的远度和最佳阶段比的影响。方法:从比赛中获取13位高水平男子三级跳远运动员的三维运动学数据。通过计算机模拟方法,用三级跳远生物力学模型确定最长实际距离,即通过改变助跑最后一步着陆时的水平和垂直速度来获取最佳阶段比。结果:当助跑最后一步着陆时水平速度增加(p=0.001)相应的向下垂直速度降低(p=0.001)时,使用最佳阶段比获得的实际距离显著增加。增加助跑最后一步着陆时水平速度会降低最优单脚跳比率,并增加最优双脚跳比率(p=0.001);同时,降低相应的向下垂直速度则会增加最优单脚跳比率,但减少最优双脚跳比率(p=0.001)。结论:三级跳远助跑最后一步着陆时的速度对最佳阶段比的影响总体上很小,不会明显改变最佳技术。

The effects of total ankle replacement on ankle joint mechanics during walking

Background:End-stage ankle arthritis impairs joint function and patients' mobility.Total ankle replacement is a surgical procedure to treat severe ankle arthritis.Salto Talaris Anatomic Ankle^(TM)(STAA) was designed to mimic the normal ankle anatomy and flexion/extension of the ankle movement.The purpose of this study was to examine the effect of an STAA ankle replacement on ankle joint function and mechanics during gait.Methods:Five patients with end-stage unilateral ankle arthritis were recruited.Patients performed level walking in a laboratory setting on 2occasions,prior to and 3 months after the STAA ankle surgeries.American Orthopedic Foot and Ankle Society(AOFAS) hindfoot score was obtained.A 12-camera motion capture system was used to perform walking analysis.Gait temporo-spatial parameters and ankle joint mechanics were evaluated.Paired Student's t tests and non-parametric Wilcoxon matched tests were performed to examine the differences in biomechanical variables between the pre-and post-surgery walking conditions.Results:Compared to the pre-surgical condition,at 3 months of post-STAA surgery,patients experienced greater improvement in AOFAS hindfoot score(p = 0.0001);the STAA ankle demonstrated a 31% increase in ankle joint excursion(p = 0.045),a 22% increase in ankle plantarflexor moment(p = 0.075),a 60% increase in ankle power absorption(p = 0.023),and a 68% increase in ankle power production(p = 0.039).Patients also demonstrated a 26% increase in walking speed(p = 0.005),a 20% increase in stride length(p = 0.013),a 15% decrease in double support time(p = 0.043),and a 5% decrease in total stance time(p = 0.055).Conclusion:Three months after surgeries,the STAA patients experienced improvements in ankle function and gait parameters.The STAA ankle demonstrated improved ankle mechanics during daily activities such as walking.

Influences of load carriage and physical activity history on tibia bone strain

Background:Military recruits are often afflicted with stress fractures.The military’s strenuous training programs involving load carriage may contribute to the high incidence of tibia stress fractures in the army.The purpose of this study was to assess the influences of incremented load carriage and history of physical activity on tibia bone strain and strain rate during walking.Methods:Twenty recreational basketball players and 20 recreational runners performed 4 walking tasks while carrying 0 kg,15 kg,25 kg,and35 kg loads,respectively.Tibia bone strain and strain rate were obtained through subject-specific multibody dynamic simulations and finite element analyses.Mixed model repeated-measures analyses of variance were conducted.Results:The mean±SE of the runners’ bone strain(μs)during load carriages(0 kg,15 kg,25 kg,and 35 kg)were 658.11±1.61,804.41±1.96,924.49±2.23,and 1011.15±2.71,respectively,in compression and 458.33±1.45,562.11±1.81,669.82±2.05,and 733.40±2.52,respectively,in tension.For the basketball players,the incremented load carriages resulted in compressive strain of 634.30±1.56,746.87±1.90,842.18±2.16,and 958.24±2.63,respectively,and tensile strain of 440.04±1.41,518.86±1.75,597.63±1.99,and 700.15±2.47,respectively.A dose-response relationship exists between incremented load carriage and bone strain and strain rate.A history of regular basketball activity could result in reduced bone strain and reduced strain rate.Conclusion:Load carriage is a risk factor for tibia stress fracture during basic training.Preventative exercise programs,such as basketball,that involved multidirectional mechanical loading to the tibia bones can be implemented for military recruits before basic training commences.

Nanoindentation of Teeth-A Review

This paper reviews some of the nanoindentation research that has been done on teeth and discusses the usefulness of this technique in studying the structure-property-function relationship at the micro and nanometer scale. In particular, examples on the use of nanoindentation technique in investigating the effects of cleansing and bleaching agents as well as drinks on the micro- and nanostructures and mechanical properties of teeth are highlighted. Although nanoindentation on teeth is a relatively new area of research, it provides an excellent way of probing and relating the structures and mechanical properties of teeth at the submicron and nanometer scales that were previously not possible but which can now greatly benefit dental research. For example, a nanoindenter with a high resolution imaging capability can help to elucidate the mechanisms with which certain diseases can damage and compromise the structural integrity of teeth at the micro- and nanometer scale. With this information, clinicians and researchers can then work towards how best to tackle these problems or even preventing them.

Numerical simulation of pulsatile non-Newtonian flow in the carotid artery bifurcation

Both clinical and post mortem studies indicate that, in humans, the carotid sinus of the carotid artery bifurcation is one of the favored sites for the genesis and development of atherosclerotic lesions. Hemodynamic factors have been suggested to be important in atherogenesis. To understand the correlation between atherogenesis and fluid dynamics in the carotid sinus, the blood flow in artery was simulated numerically. In those studies, the property of blood was treated as an incompressible, Newtonian fluid. In fact, however, the blood is a complicated non-Newtonian fluid with shear thinning and viscoelastic properties, especially when the shear rate is low. A variety of non-Newtonian models have been applied in the numerical studies. Among them, the Casson equation was widely used. However, the Casson equation agrees well only when the shear rate is less than 10 s-1. The flow field of the carotid bifurcation usually covers a wide range of shear rate. We therefore believe that it may not be sufficient to describe the property of blood only using the Casson equation in the whole flow field of the carotid bifurcation. In the present study, three different blood constitutive models, namely, the Newtonian, the Casson and the hybrid fluid constitutive models were used in the flow simulation of the human carotid bifurcation. The results were compared among the three models. The results showed that the Newtonian model and the hybrid model had verysimilar distributions of the axial velocity, secondary flow and wall shear stress, but the Casson model resulted in significant differences in these distributions from the other two models. This study suggests that it is not appropriate to only use the Casson equation to simulate the whole flow field of the carotid bifurcation, and on the other hand, Newtonian fluid is a good approximation to blood for flow simulations in the carotid artery bifurcation.

Mechanobiology:A new frontier for human pluripotent stem cells

Our understanding of the molecular and cellular mechanisms that control self-renewal,pluripotency and differentiation of human pluripotent stem cells(hPSCs)and our progress toward harnessing the regenerative potential of these cells to treat human diseases are advancing at a rapid rate.Human pluripotent stem cells(hPSCs)include human embryonic stem cells(hESCs)and human induced pluripotent stem cells(hiPSCs).Their unique capacity for indefinite self-renewal(unlimited proliferation)in vitro coupled with their ability to differentiate into almost any cell type present in the adult body(pluripotency)provide a potentially

Effect of acid etching on marginal adaptation of mineral trioxide aggregate to apical dentin:microcomputed tomography and scanning electron microscopy analysis

The present investigation assessed the effect of acid etching on marginal adaptation of white- and gray-colored mineral trioxide aggregate （MTA） to apical dentin using microcomputed tomography （micro-CT） and scanning electron microscopy （SEM）. Sixty-four extracted single-rooted human maxillary teeth were used. Following root-end resection and apical preparation, the teeth were equally divided into four groups according to the following root end filling materials： （i） white-colored MTA （WMTA）, （ii） etched WMTA （EWMTA）, （iii） gray-colored MTA （GMTA） and （iv） etched GMTA （EGMTA）. After 48 h, the interface between root-end filling materials and the dentinal walls was assessed using micro-CT and SEM. Data were statistically analyzed using the KruskaI-Wallis and Dunn tests. Micro-CT analysis revealed gap volumes between the apical cavity dentin walls and EGMTA, GMTA, EWMTA and WMTA of （0.007 1±0.004） mm3, （0.053±0.002） mm3, （0.003 6±0.001） mm3 and （0.005 9±0.002） mm3 respectively. SEM analysis revealed gap sizes for EGMTA, WMTA, EWMTA and GMTA to be （492.3±13.8） μm, （594.5±17.12）μm, （543.1±15.33） μm and （910.7±26.2）μm respectively. A significant difference in gap size between root end preparations filled with GMTA and EGMTA was found （P〈O.05）. No significance difference in gap size between WMTA and EWMTA were found in either SEM or micro-CT analysis. In conclusion, pre-etching of apical dentin can provide a better seal for GMTA but not for WMTA.

Energy expenditure and muscular activation patterns through active sitting on compliant surfaces

Purpose: To test the effectiveness of sitting surfaces with varied amounts of stability on muscle activity and energy expenditure.Methods: Using a within-participants repeated measures design, 11 healthy young-adult females(age = 20.0 ± 1.8 years) were measured using indirect calorimetry to assess energy expenditure, and electromyography to assess muscular activation in trunk and leg musculature under 3different sitting surfaces: flat-firm surface, air-filled cushion, and a stability ball. Data were analyzed using repeated measures analysis of variance with follow-up pairwise contrasts used to determine the specific effects of sitting surface on muscle activation and energy expenditure.Results: Significantly greater energy expenditure was recorded for the stability ball(p = 0.01) and the cushion(p = 0.03) over the flat surface(10.4% and 9.6% greater, respectively), with no differences between the ball and the cushion. Both the ball and the cushion produced higher tibialis anterior activation over the flat surface(1.09 and 0.63 root-mean-square millivolts(RMSmv), respectively), while the stability ball produced higher soleus activity over both cushion and flat surfaces(3.97 and 4.24 RMSmv, respectively). Additionally, the cushion elicited higher adductor longus activity over the ball and flat surfaces(1.76 and 1.81 RMSmv, respectively), but no trunk musculature differences were revealed.Conclusion: Compliant surfaces resulted in higher levels of muscular activation in the lower extremities facilitating increased caloric expenditure.Given the increasing trends in sedentary careers and the increases in obesity, this is an important finding to validate the merits of active sitting facilitating increased caloric expenditure and muscle activation.

专项运动对青年女运动员垂直蹲跳主成分结构的影响(英文)

目的:长期的专项训练被认为会影响运动员在评估力量和耐力能力测试中的表现。本研究旨在为现有的关于不同组的女运动员在蹲跳的力量/时间属性上可能存在的某些差异提供最新信息。方法:173名从事田径、排球、手球、篮球运动的女运动员和体育教育专业的学生在一块力板上极限蹲跳(年龄:20.1±2.8岁;身高:1 71±0.09 m;体重:65.6±10.3 kg)。皮尔森相关系数常被用来鉴别蹲跳表现、人体测量特征和生物力学参数。用方差分析法研究了不同小组生物力学参数的差异,用主要成分分析法分析了蹲跳的力量和时间。结果:蹲跳和身高无关,但是和体重十分相关(r=-0.26.p=0.001)。与其余小组相比,从事田径运动的人跳得更高,产生的身体输出功率峰值更高。所有运动员表现都优于体育教育专业的学生,在推进阶段,她们蹲起时的垂直身体质量中心轨迹(p<0.05)更长。主要成分分析法结果显示,从事田径运动的组比其他组明显更依赖于力量。结论:田径运动员在蹲跳上的优势有赖于更强的力量输出和力度,建议从事室内运动的女运动员采用田径运动员的跳跃技巧来进行跳跃练习。