Background:In a sprint cross-country(XC)ski competition,the difference in recovery times separating the first and the second semi-final(SF)heats from the final(F)may affect performance.The aim of the current study was...Background:In a sprint cross-country(XC)ski competition,the difference in recovery times separating the first and the second semi-final(SF)heats from the final(F)may affect performance.The aim of the current study was to compare the effects of longer vs.shorter recovery periods prescribed between the 3 knock-out races of a simulated sprint XC ski competition involving a prologue(P),quarter-final(QF),SF,and F.Methods:Eleven well-trained XC ski athletes completed 2 simulated sprint XC ski competitions on a treadmill involving 4×883-m roller-ski bouts at a 4°incline using the gear 3 ski-skating sub-technique.The first 3 bouts were completed at a fixed speed(PFIX,QFFIX,and SFFIX)corresponding to~96%of each individual’s previously determined maximal effort.The final bout was performed as a self-paced sprint time trial(FSTT).Test conditions differed by the time durations prescribed between the QFFIX,SFFIX,and FSTT,which simulated real-world XC ski competition conditions using maximum(MAX-REC)or minimum(MIN-REC)recovery periods.Results:The FSTT was completed 5.4±5.5 s faster(p=0.009)during MAX-REC(179.2±18.1 s)compared to MIN-REC(184.6±20.0 s),and this was linked to a significantly higher power output(p=0.010)and total metabolic rate(p=0.009).The pre FSTT blood lactate(BLa)concentration was significantly lower during MAX-REC compared to MIN-REC(2.5±0.8 mmol/L vs.3.6±1.6 mmol/L,respectively;p=0.027),and the pre-to-post FSTT increase in BLa was greater(8.8±2.1 mmol/L vs.7.1±2.3 mmol/L,respectively;p=0.024).No other differences for MAX-REC vs.MIN-REC reached significance(p>0.05).Conclusion:Performance in a group of well-trained XC skiers is negatively affected when recovery times between sprint heats are minimized which,in competition conditions,would occur when selecting the last QF heat.This result is combined with a higher pre-race BLa concentration and a reduced rise in BLa concentration under shorter recovery conditions.These findings may help inform decision making when XC skiers are faced with selecting a QF heat within a sprint competition.展开更多
Background/Purpose: The skin protects against external factors and this skin function can be affected by environmental conditions, including low temperature, low humidity, and high altitude. Therefore, it is important...Background/Purpose: The skin protects against external factors and this skin function can be affected by environmental conditions, including low temperature, low humidity, and high altitude. Therefore, it is important to study the relationship between the environment and the skin. The purpose of this study is to determine how the skin barrier functions change at low temperatures. Methods: This study was performed at a Korean ski resort on January 2015 and evaluated 10 subjects skin condition during skiing. Skin properties were examined at 2 sites (cheeks and dorsal hands) and four time points (indoor;baseline, outdoor;after first skiing and after second skiing, indoor;after taking a shower). Results: The skin hydration on the cheek decreased after the second skiing session and the erythema decreased only after the first skiing while this value on dorsal hand was not changed by skiing. The brightness and yellowness of cheek skin increased and redness decreased therefore, skin color became pale during skiing. The extensibility of cheeks and dorsal hands decreased after skiing. We found positive correlation between skin temperature and redness (r2 = 0.707, p Conclusions: Low temperatures can affect human skin color so that the skin color becomes pale because capillary blood vessels shrink when skin is exposed to cold environment. The cheek skin tends to change easily than dorsal hand during ambient temperature change.展开更多
In recent years, a new type of leisure sport—grass skiing, has been introduced from abroad. However, there is no standard design system for this type of turf. This paper, based on climatic characteristics of western ...In recent years, a new type of leisure sport—grass skiing, has been introduced from abroad. However, there is no standard design system for this type of turf. This paper, based on climatic characteristics of western Sichuan, introduced the requirements of the construction of grass skiing resort turf in western Sichuan as well as its maintenance management mode, and tried to explore the standard system of turf establishment and maintenance management of grass skiing resort in western Sichuan.展开更多
Alpine skiing is a popular sport in the northern region. Every winter, a large number of students sign up for alpine skiing training. There are also various groups of students in alpine skiing training. Some students ...Alpine skiing is a popular sport in the northern region. Every winter, a large number of students sign up for alpine skiing training. There are also various groups of students in alpine skiing training. Some students who lack physical training quality or have poor psychological quality will have fear of alpine skiing training, which leads to their poor performance and affects the training effect. From the coach's point of view, it is necessary to find out the specific factors of students' fear, and to arrange some effective measures to eliminate the college's fear combined with the specific procedures of alpine skiing training, so as to improve the effect of skiing training.展开更多
This paper presents a new study on modeling and optimization of trajectory and posture for the super-giant(SG)slalom of alpine skiing.It is the first time that a Three-Rigid-Body-Particle model based on rigorous deriv...This paper presents a new study on modeling and optimization of trajectory and posture for the super-giant(SG)slalom of alpine skiing.It is the first time that a Three-Rigid-Body-Particle model based on rigorous derivations and stability analysis is established to represent skiers trajectory and posture characteristics,as it is more accurate than the single-rigid-body model which is commonly used in existing studies.In addition,the Radau pseudospectral method is applied to solve the trajectory and posture optimization problem in order to obtain better skiing trajectory,skiing posture,and some key kinematic parameters of skiers.Moreover,this paper analyzes the effects of different body types,minimum turning radii,and flexor and extensor strength of knees and hip joint on skiing performance.Finally,based on the findings of the study,some advice about how to improve the performance of the SG slalom in view of science and technology is given to skiers and coaches for reference.展开更多
Purpose Pacing profiles differ substantially in endurance sports with short competition duration(2-4 min).Herein,we investigated the effect of a fast start(FS)versus a conservative start(CS)pacing strategy on sprint t...Purpose Pacing profiles differ substantially in endurance sports with short competition duration(2-4 min).Herein,we investigated the effect of a fast start(FS)versus a conservative start(CS)pacing strategy on sprint time-trial performance in competitive junior cross-country skiers.Methods Sixteen females(~17 years old)performed two individual self-paced 1.4 km time-trials(TT)in free technique on roller skis separated by 40 min of recovery.Skiers were instructed to perform a FS and CS pacing strategy the first~400-m(~1 min)in a randomized order.Split and finish time was determined using radio-based photocells,while speed characteris-tics were collected with GNSS/IMU sensors.1-10 Rate of perceived exertion(RPE)was collected retrospectively for 3 points during the TT.Based on mean FS and CS performance,skiers were divided into a Low-(n=8)and High performers(n=8).Results Overall,the FS strategy induced a faster~400-m time(56.0±3.8 s)than CS(58.7±3.4 s)(P<0.05),but no differ-ences in finish times were found between strategies for the group as a whole(FS:213.3±12.0 s;CS,212.9±10.3 s,P=0.68).However,High performers skied faster with FS than CS(203.4±7.4 s vs.205.1±7.1 s;0.8%±0.7%,P<0.05),whereas the Low performers skied faster with CS than FS(220.7±6.1 s vs.223.1±5.0 s;1.1%±1.0%,P<0.05).Independent of performance level,summated RPE during the TT was higher with FS versus CS(23±2 vs.22±2,P<0.05).Conclusion Optimal pacing strategy for TT sprint skiing appears dependent of performance level.A“fast start”strategy was accompanied by higher discomfort during the time-trial.展开更多
Purpose To examine the micro-pacing(within-lap)strategies during biathlon skiing with and without the biathlon rifle.Methods Twenty biathletes(7 women,13 men)performed two cross-country skiing time-trials on a≈2300 m...Purpose To examine the micro-pacing(within-lap)strategies during biathlon skiing with and without the biathlon rifle.Methods Twenty biathletes(7 women,13 men)performed two cross-country skiing time-trials on a≈2300 m course,once with and once without the biathlon rifle.During time-trials,biathletes wore a sensor that recorded position,distance and skiing-speed.A trajectory correction and statistical parametric mapping procedure determined the course positions(clusters)where instantaneous skiing-speed was significantly related to time-trial performance.The time differences between the fastest and slowest skier in these clusters were calculated.Results The fastest biathletes skied with greater instantaneous speeds in specific clusters,which included both uphill and downhill sections.The clusters represented time gains for the fastest skier over the slowest skier of between 16.1 and 25.8 s for the women and between 18.9 and 21.9 s for the men.The largest time gains between the fastest and slowest biathletes were observed in a downhill section that was preceded by a 180°turn,where time gains were between 2.9 and 4.1 s in clusters of between just 12 to 62 m.In biathlon skiing with-rifle,there were more clusters that were not present during without-rifle.When skiing with-rifle,there were additional clusters in the uphill sections that represented time gains of 5.2 s and 2.3 s for the women and men,respectively.Conclusions Statistical parametric mapping can be used in biathlon to provide pacing and performance feedback to athletes and coaches.展开更多
This is an in-depth journey to experience the ice and snow of Changbai Mountain.In these few days,you will explore Changbai Mountain and enjoy powder skiing;gallop on the ski trail;watch the stunning wonders of snow r...This is an in-depth journey to experience the ice and snow of Changbai Mountain.In these few days,you will explore Changbai Mountain and enjoy powder skiing;gallop on the ski trail;watch the stunning wonders of snow rime on thousands of trees;conquer the ice and snow wilderness on a snowmobile and start an in depth magical mystery tour in lilin Province.展开更多
The 9th Asian Winter Games were successfully held in Harbin,Heilongjiang Province,China,from February 7 to February 14,2025.This exciting event brought together athletes from all over Asia.They showed their great skil...The 9th Asian Winter Games were successfully held in Harbin,Heilongjiang Province,China,from February 7 to February 14,2025.This exciting event brought together athletes from all over Asia.They showed their great skills and strong will in different kinds of winter sports,such as skiing,skating and ice hockey.展开更多
Purpose:The rapid development of winter sports requires investigation on injuries in Chongli district,Zhangjiakou city,one of the ski sites of the 2022 Winter Olympics.Careful evaluation is required to observe which i...Purpose:The rapid development of winter sports requires investigation on injuries in Chongli district,Zhangjiakou city,one of the ski sites of the 2022 Winter Olympics.Careful evaluation is required to observe which injuries are caused under what circumstances,and then we can make corresponding preventive measures and recommendations based on the results.Methods:In this retrospective study,the data of injury cases at ski resorts in China(Chongli district)and Japan were analyzed to provide a reference for the ongoing injury prevention at ski resorts.We collected data on injuries at Wanlong and Fulong ski resorts in Chongli district during the 2017–2018 and 2018-2019 ski seasons.We referred to the skiing injury report issued in February 2020 of a nationwide ski safety statistical service–Japan Ski Safety Association.The causes of injury and specific injured body parts were analyzed based on the data of Chinese and Japanese ski resorts.Statistical significance has been calculated using the Chi-square test.Results:During the 2019–2020 ski season in Japanese ski resorts,the number of reported injuries per 10,000 skiers was 0.93,of which 457(17.3%)were over 50 years old,accounting for a large proportion of injuries,meanwhile in Chongli ski resort,the injury rate of skiers aged 50 and over was 7.1%.The knee joint(23.7%at Wanlong ski resort and 28.4%in Japanese ski resorts)was the most injured body part among Chongli and Japanese skiers.Among snowboarders,shoulder joint injury(17.7%in Japanese ski resorts)was the most common,and injury on hands and fingers(16.3%in Wanlong ski resorts)was the most common.Head injury rates are similar in Chongli,China and Japanese ski resorts(8.2%and 8.7%,respectively).Conclusion:Our analysis demonstrated that injury data recorded among young skiers was higher in Chinese ski resorts(Chongli district)than that in Japanese ski resorts,and elderly skiers made up a larger proportion of skiing injuries in Japanese resorts.Thus,according to our research,the protection of knee joints,shoulder joints,and hands and fingers should be taken seriously.It should pay attention to the teaching of ski poles(for finger protection),and use protective devices such as knee pads,helmets,etc.展开更多
Purpose The purpose was to investigate whether an increased amount of training while carrying the rifle affects skiing in well-trained biathletes at submaximal and maximal workloads during a pre-season period lasting ...Purpose The purpose was to investigate whether an increased amount of training while carrying the rifle affects skiing in well-trained biathletes at submaximal and maximal workloads during a pre-season period lasting a minimum of 12 weeks.Methods Seventeen well-trained biathletes(9 females,8 males)were assigned to an intervention(IG,n=10)or control(CG,n=7)group.Before(T1)and after(T2)the training intervention all participants performed,using treadmill roller-skiing,a submaximal test without the rifle on one day and two submaximal workloads and a maximal time trial(TT)with the rifle on a subsequent day.Between T1 and T2 all participants performed a minimum of 12 weeks of normal training,the only difference between groups being that IG performed more of their training sessions carrying the rifle.Results IG performed more training compared to CG(15.4±1.1 vs.11.2±2.6 h/week,P<0.05),including a higher amount of training with the rifle(3.1±0.6 vs.1.1±0.3 h/week,P<0.001).Speed at 4 mmol/L of blood lactate increased significantly for CG from T1 to T2(P=0.028),while only tended to increase for IG(P=0.058).Performance during the TT,VO2max and the aerobic metabolic rate increased significantly from T1 to T2,although the differences disappeared when including the speed at baseline as a covariate.Conclusion According to the present results,increasing training while carrying the rifle by 2 h/week does not appear to improve skiing performance in well-trained biathletes.In addition,physiological markers at submaximal and maximal intensities while carrying the rifle were not affected after the training intervention.展开更多
To address the contradiction between the rapid development of ski tourism and effective protection of the ecological environment,this study constructed the DPSIR-EES(Drive-Pressures-State-Impact-Response-Environment-E...To address the contradiction between the rapid development of ski tourism and effective protection of the ecological environment,this study constructed the DPSIR-EES(Drive-Pressures-State-Impact-Response-Environment-Economy-Society)model and Ski Tourism Destination Ecological Security System(STDESS)framework system.They form an integrated methodology system based on the“entropy weighting-hierarchical analysis-gray correlation projection”composite weighting method that can be used to clarify the intrinsic mechanism of ecological security in ski tourism destinations.Taking Chongli as a case study,this study evaluated the evolution of its ecological security from 1995 to 2023,predicted the ecological security early warning levels from 2024 to 2050,and analyzed the mechanism of influences on regional ecological security.The findings indicate that the ecological security of ski tourism destinations shows a significant“stepped leap–dynamic equilibrium”evolutionary path.The dynamic response mechanism of the subsystems is characterized by significant heterogeneity.The ecological security early warning system revealed the temporal and sequential differentiation of risk transmission.The factors influencing ecological security show the significant dual dominance of policy and climate.This paper enhances the applicability of ecological security systems within ski tourism contexts by analyzing their evolutionary characteristics,predicted future changes and impact factors,and it provides an effective case study for ecological improvement.展开更多
Ski resort abandonment is more frequent due to global warming,which progressively reduces snowpack and persistence.However,projects aiming for new resorts in the Apennines have proliferated.Such economic investments a...Ski resort abandonment is more frequent due to global warming,which progressively reduces snowpack and persistence.However,projects aiming for new resorts in the Apennines have proliferated.Such economic investments are risky,especially without long-term data on snow cover duration.Our aim,thus,is to provide the first census of abandoned ski resorts in the Apennines and compare them with the resorts currently open to understand the causes that led to their abandonment.Subsequently,we explore factors behind resort failure by analyzing the relationships between climatic,geomorphological,and economic variables.Overall,we found 101 ski resorts in the Apennines,of which 28 were open,41 closed and abandoned and 32 partially closed(i.e.,closed in more than at least 7 years in the last 10 years).The closed and partially closed resorts represent 358 km of ski slopes(44%of total available).The number of structures per resort(i.e.ski lifts,chair lifts)is higher for open compared to partially closed and closed ones.Notably,the maximum elevation reached by the resorts is higher for those open(1793 m a.s.l.)than for those partially closed(1687 m a.s.l.)and especially those closed(1577 m a.s.l.).Finally,the mean size of the resorts in terms of skiable track length is larger for open(15.7 km)than partially closed(7.1 km)and closed resorts(3.2 km).The average duration of operation for abandoned resorts is 29.5 years,varying from a maximum of 56 years to a minimum of 0 years for two sites that were never opened after reconstruction.The year of abandonment is positively associated with the maximum elevation,size,and duration of operation.Furthermore,the duration of operation is negatively correlated with the construction year.Our multivariate analysis confirms and strengthens the hypothesis for the causes that lead to abandonment are multi-factorial.Most of the closed resorts are located at low altitude and have small ski areas although some higher altitude sites have also been abandoned in recent years.This information can be useful for investors,policymakers,and stakeholders who should use it as a starting point when designing and planning new resorts to avoid future failures and the loss of public money.展开更多
Multinucleon transfer in low-energy heavy-ion collisions is increasingly considered a promising approach for generating exotic nuclei.Understanding the complex mechanisms involved in multinucleon transfer processes pr...Multinucleon transfer in low-energy heavy-ion collisions is increasingly considered a promising approach for generating exotic nuclei.Understanding the complex mechanisms involved in multinucleon transfer processes presents significant challenges for the theoretical investigation of nuclear reactions.A Langevin equation model was developed and employed to investigate multinucleon transfer processes.The^(40)Ar+^(232)Th reaction was simulated,and the calculated Wilczyński plot was used to verify the model.Additionally,to study the dynamics of multinucleon transfer reactions,the^(136)Xe+^(238)U and^(136)Xe+^(209)Bi reactions were simulated,and the corresponding TKE-mass and angular distributions were computed to analyze the energy dissipation and scattering angles.This investigation enhances our understanding of the dynamics involved in multinucleon transfer processes.展开更多
Purpose:This study aimed to compare biomechanical aspects of a novel"running"diagonal stride(DSRUN)with"conventional"diagonal stride(DSCONV)skiing techniques performed at high speed.Methods:Ten eli...Purpose:This study aimed to compare biomechanical aspects of a novel"running"diagonal stride(DSRUN)with"conventional"diagonal stride(DSCONV)skiing techniques performed at high speed.Methods:Ten elite Italian male junior cross-country skiers skied on a treadmill at 10 km/h and at a 10°incline utilizing both variants of the diagonal stride technique.The 3-dimensional kinematics of the body,poles,and roller skis;the force exerted through the poles and foot plantar surfaces;and the angular motion of the leg joints were determined.Results:Compared to DSCONV,DSRUN demonstrated shorter cycle times(1.05±0.05 s vs.0.75±0.03 s(mean±SD),p<0.001)due to a shorter rolling phase(0.40±0.04 s vs.0.09±0.04 s,p<0.001);greater force applied perpendicularly to the roller skis when they had stopped rolling forward(413±190 N vs.890±170 N,p<0.001),with peak force being attained earlier;prolonged knee extension,with a greater range of motion during the roller ski-stop phase(28°±40 vs.16°±3°,p=0.00014);and more pronounced hip and knee flexion during most of the forward leg swing.The mechanical work performed against friction during rolling was significantly less with DSRUN than with DSCONV(0.04±0.01 J/m/kg vs.0.10±0.02 J/m/kg,p<0.001).Conclusion:Our findings demonstrate that DSRUN is characterize by more rapid propulsion,earlier leg extension,and a greater range of motion of knee joint extension than DSCONV-Further investigations,preferably on snow,should reveal whether DSRUN results in higher acceleration and/or higher peak speed.展开更多
基金supported by a general collaborative grant for winter sport research provided through Mid Sweden University and the?stersund municipality(reference number:2018/1758-500584)。
文摘Background:In a sprint cross-country(XC)ski competition,the difference in recovery times separating the first and the second semi-final(SF)heats from the final(F)may affect performance.The aim of the current study was to compare the effects of longer vs.shorter recovery periods prescribed between the 3 knock-out races of a simulated sprint XC ski competition involving a prologue(P),quarter-final(QF),SF,and F.Methods:Eleven well-trained XC ski athletes completed 2 simulated sprint XC ski competitions on a treadmill involving 4×883-m roller-ski bouts at a 4°incline using the gear 3 ski-skating sub-technique.The first 3 bouts were completed at a fixed speed(PFIX,QFFIX,and SFFIX)corresponding to~96%of each individual’s previously determined maximal effort.The final bout was performed as a self-paced sprint time trial(FSTT).Test conditions differed by the time durations prescribed between the QFFIX,SFFIX,and FSTT,which simulated real-world XC ski competition conditions using maximum(MAX-REC)or minimum(MIN-REC)recovery periods.Results:The FSTT was completed 5.4±5.5 s faster(p=0.009)during MAX-REC(179.2±18.1 s)compared to MIN-REC(184.6±20.0 s),and this was linked to a significantly higher power output(p=0.010)and total metabolic rate(p=0.009).The pre FSTT blood lactate(BLa)concentration was significantly lower during MAX-REC compared to MIN-REC(2.5±0.8 mmol/L vs.3.6±1.6 mmol/L,respectively;p=0.027),and the pre-to-post FSTT increase in BLa was greater(8.8±2.1 mmol/L vs.7.1±2.3 mmol/L,respectively;p=0.024).No other differences for MAX-REC vs.MIN-REC reached significance(p>0.05).Conclusion:Performance in a group of well-trained XC skiers is negatively affected when recovery times between sprint heats are minimized which,in competition conditions,would occur when selecting the last QF heat.This result is combined with a higher pre-race BLa concentration and a reduced rise in BLa concentration under shorter recovery conditions.These findings may help inform decision making when XC skiers are faced with selecting a QF heat within a sprint competition.
文摘Background/Purpose: The skin protects against external factors and this skin function can be affected by environmental conditions, including low temperature, low humidity, and high altitude. Therefore, it is important to study the relationship between the environment and the skin. The purpose of this study is to determine how the skin barrier functions change at low temperatures. Methods: This study was performed at a Korean ski resort on January 2015 and evaluated 10 subjects skin condition during skiing. Skin properties were examined at 2 sites (cheeks and dorsal hands) and four time points (indoor;baseline, outdoor;after first skiing and after second skiing, indoor;after taking a shower). Results: The skin hydration on the cheek decreased after the second skiing session and the erythema decreased only after the first skiing while this value on dorsal hand was not changed by skiing. The brightness and yellowness of cheek skin increased and redness decreased therefore, skin color became pale during skiing. The extensibility of cheeks and dorsal hands decreased after skiing. We found positive correlation between skin temperature and redness (r2 = 0.707, p Conclusions: Low temperatures can affect human skin color so that the skin color becomes pale because capillary blood vessels shrink when skin is exposed to cold environment. The cheek skin tends to change easily than dorsal hand during ambient temperature change.
文摘In recent years, a new type of leisure sport—grass skiing, has been introduced from abroad. However, there is no standard design system for this type of turf. This paper, based on climatic characteristics of western Sichuan, introduced the requirements of the construction of grass skiing resort turf in western Sichuan as well as its maintenance management mode, and tried to explore the standard system of turf establishment and maintenance management of grass skiing resort in western Sichuan.
文摘Alpine skiing is a popular sport in the northern region. Every winter, a large number of students sign up for alpine skiing training. There are also various groups of students in alpine skiing training. Some students who lack physical training quality or have poor psychological quality will have fear of alpine skiing training, which leads to their poor performance and affects the training effect. From the coach's point of view, it is necessary to find out the specific factors of students' fear, and to arrange some effective measures to eliminate the college's fear combined with the specific procedures of alpine skiing training, so as to improve the effect of skiing training.
基金supported in part by the Key Technology Research and Demonstration of National Scientific Training Base Construction of China under Grant No.2018YFF0300800in part by the National Natural Science Foundation of China under Grant No.62173323in part by Beijing Institute of Technology Research Fund Program for Young Scholars.
文摘This paper presents a new study on modeling and optimization of trajectory and posture for the super-giant(SG)slalom of alpine skiing.It is the first time that a Three-Rigid-Body-Particle model based on rigorous derivations and stability analysis is established to represent skiers trajectory and posture characteristics,as it is more accurate than the single-rigid-body model which is commonly used in existing studies.In addition,the Radau pseudospectral method is applied to solve the trajectory and posture optimization problem in order to obtain better skiing trajectory,skiing posture,and some key kinematic parameters of skiers.Moreover,this paper analyzes the effects of different body types,minimum turning radii,and flexor and extensor strength of knees and hip joint on skiing performance.Finally,based on the findings of the study,some advice about how to improve the performance of the SG slalom in view of science and technology is given to skiers and coaches for reference.
文摘Purpose Pacing profiles differ substantially in endurance sports with short competition duration(2-4 min).Herein,we investigated the effect of a fast start(FS)versus a conservative start(CS)pacing strategy on sprint time-trial performance in competitive junior cross-country skiers.Methods Sixteen females(~17 years old)performed two individual self-paced 1.4 km time-trials(TT)in free technique on roller skis separated by 40 min of recovery.Skiers were instructed to perform a FS and CS pacing strategy the first~400-m(~1 min)in a randomized order.Split and finish time was determined using radio-based photocells,while speed characteris-tics were collected with GNSS/IMU sensors.1-10 Rate of perceived exertion(RPE)was collected retrospectively for 3 points during the TT.Based on mean FS and CS performance,skiers were divided into a Low-(n=8)and High performers(n=8).Results Overall,the FS strategy induced a faster~400-m time(56.0±3.8 s)than CS(58.7±3.4 s)(P<0.05),but no differ-ences in finish times were found between strategies for the group as a whole(FS:213.3±12.0 s;CS,212.9±10.3 s,P=0.68).However,High performers skied faster with FS than CS(203.4±7.4 s vs.205.1±7.1 s;0.8%±0.7%,P<0.05),whereas the Low performers skied faster with CS than FS(220.7±6.1 s vs.223.1±5.0 s;1.1%±1.0%,P<0.05).Independent of performance level,summated RPE during the TT was higher with FS versus CS(23±2 vs.22±2,P<0.05).Conclusion Optimal pacing strategy for TT sprint skiing appears dependent of performance level.A“fast start”strategy was accompanied by higher discomfort during the time-trial.
文摘Purpose To examine the micro-pacing(within-lap)strategies during biathlon skiing with and without the biathlon rifle.Methods Twenty biathletes(7 women,13 men)performed two cross-country skiing time-trials on a≈2300 m course,once with and once without the biathlon rifle.During time-trials,biathletes wore a sensor that recorded position,distance and skiing-speed.A trajectory correction and statistical parametric mapping procedure determined the course positions(clusters)where instantaneous skiing-speed was significantly related to time-trial performance.The time differences between the fastest and slowest skier in these clusters were calculated.Results The fastest biathletes skied with greater instantaneous speeds in specific clusters,which included both uphill and downhill sections.The clusters represented time gains for the fastest skier over the slowest skier of between 16.1 and 25.8 s for the women and between 18.9 and 21.9 s for the men.The largest time gains between the fastest and slowest biathletes were observed in a downhill section that was preceded by a 180°turn,where time gains were between 2.9 and 4.1 s in clusters of between just 12 to 62 m.In biathlon skiing with-rifle,there were more clusters that were not present during without-rifle.When skiing with-rifle,there were additional clusters in the uphill sections that represented time gains of 5.2 s and 2.3 s for the women and men,respectively.Conclusions Statistical parametric mapping can be used in biathlon to provide pacing and performance feedback to athletes and coaches.
文摘This is an in-depth journey to experience the ice and snow of Changbai Mountain.In these few days,you will explore Changbai Mountain and enjoy powder skiing;gallop on the ski trail;watch the stunning wonders of snow rime on thousands of trees;conquer the ice and snow wilderness on a snowmobile and start an in depth magical mystery tour in lilin Province.
文摘The 9th Asian Winter Games were successfully held in Harbin,Heilongjiang Province,China,from February 7 to February 14,2025.This exciting event brought together athletes from all over Asia.They showed their great skills and strong will in different kinds of winter sports,such as skiing,skating and ice hockey.
基金This study was supported by 2019 Nation Key Research and Development Program for"Science and Technology Winter Olympics"of China[grant numbers 2019YFF0302305]Integrated application of technology and comprehensive demonstration Project of Scientific and Technological Winter Olympics of Zhangjiakou in 2020[grant numbers 20110004D]Integrated application of technology and comprehensive demonstration Project of Scientific and Technological Winter Olympics of Zhangjiakou in 2021[grant numbers 21110006D].
文摘Purpose:The rapid development of winter sports requires investigation on injuries in Chongli district,Zhangjiakou city,one of the ski sites of the 2022 Winter Olympics.Careful evaluation is required to observe which injuries are caused under what circumstances,and then we can make corresponding preventive measures and recommendations based on the results.Methods:In this retrospective study,the data of injury cases at ski resorts in China(Chongli district)and Japan were analyzed to provide a reference for the ongoing injury prevention at ski resorts.We collected data on injuries at Wanlong and Fulong ski resorts in Chongli district during the 2017–2018 and 2018-2019 ski seasons.We referred to the skiing injury report issued in February 2020 of a nationwide ski safety statistical service–Japan Ski Safety Association.The causes of injury and specific injured body parts were analyzed based on the data of Chinese and Japanese ski resorts.Statistical significance has been calculated using the Chi-square test.Results:During the 2019–2020 ski season in Japanese ski resorts,the number of reported injuries per 10,000 skiers was 0.93,of which 457(17.3%)were over 50 years old,accounting for a large proportion of injuries,meanwhile in Chongli ski resort,the injury rate of skiers aged 50 and over was 7.1%.The knee joint(23.7%at Wanlong ski resort and 28.4%in Japanese ski resorts)was the most injured body part among Chongli and Japanese skiers.Among snowboarders,shoulder joint injury(17.7%in Japanese ski resorts)was the most common,and injury on hands and fingers(16.3%in Wanlong ski resorts)was the most common.Head injury rates are similar in Chongli,China and Japanese ski resorts(8.2%and 8.7%,respectively).Conclusion:Our analysis demonstrated that injury data recorded among young skiers was higher in Chinese ski resorts(Chongli district)than that in Japanese ski resorts,and elderly skiers made up a larger proportion of skiing injuries in Japanese resorts.Thus,according to our research,the protection of knee joints,shoulder joints,and hands and fingers should be taken seriously.It should pay attention to the teaching of ski poles(for finger protection),and use protective devices such as knee pads,helmets,etc.
文摘Purpose The purpose was to investigate whether an increased amount of training while carrying the rifle affects skiing in well-trained biathletes at submaximal and maximal workloads during a pre-season period lasting a minimum of 12 weeks.Methods Seventeen well-trained biathletes(9 females,8 males)were assigned to an intervention(IG,n=10)or control(CG,n=7)group.Before(T1)and after(T2)the training intervention all participants performed,using treadmill roller-skiing,a submaximal test without the rifle on one day and two submaximal workloads and a maximal time trial(TT)with the rifle on a subsequent day.Between T1 and T2 all participants performed a minimum of 12 weeks of normal training,the only difference between groups being that IG performed more of their training sessions carrying the rifle.Results IG performed more training compared to CG(15.4±1.1 vs.11.2±2.6 h/week,P<0.05),including a higher amount of training with the rifle(3.1±0.6 vs.1.1±0.3 h/week,P<0.001).Speed at 4 mmol/L of blood lactate increased significantly for CG from T1 to T2(P=0.028),while only tended to increase for IG(P=0.058).Performance during the TT,VO2max and the aerobic metabolic rate increased significantly from T1 to T2,although the differences disappeared when including the speed at baseline as a covariate.Conclusion According to the present results,increasing training while carrying the rifle by 2 h/week does not appear to improve skiing performance in well-trained biathletes.In addition,physiological markers at submaximal and maximal intensities while carrying the rifle were not affected after the training intervention.
基金National Natural Science Foundation of China,No.42471284,No.42071199Beijing Social Science Foundation,No.22GLB036。
文摘To address the contradiction between the rapid development of ski tourism and effective protection of the ecological environment,this study constructed the DPSIR-EES(Drive-Pressures-State-Impact-Response-Environment-Economy-Society)model and Ski Tourism Destination Ecological Security System(STDESS)framework system.They form an integrated methodology system based on the“entropy weighting-hierarchical analysis-gray correlation projection”composite weighting method that can be used to clarify the intrinsic mechanism of ecological security in ski tourism destinations.Taking Chongli as a case study,this study evaluated the evolution of its ecological security from 1995 to 2023,predicted the ecological security early warning levels from 2024 to 2050,and analyzed the mechanism of influences on regional ecological security.The findings indicate that the ecological security of ski tourism destinations shows a significant“stepped leap–dynamic equilibrium”evolutionary path.The dynamic response mechanism of the subsystems is characterized by significant heterogeneity.The ecological security early warning system revealed the temporal and sequential differentiation of risk transmission.The factors influencing ecological security show the significant dual dominance of policy and climate.This paper enhances the applicability of ecological security systems within ski tourism contexts by analyzing their evolutionary characteristics,predicted future changes and impact factors,and it provides an effective case study for ecological improvement.
文摘Ski resort abandonment is more frequent due to global warming,which progressively reduces snowpack and persistence.However,projects aiming for new resorts in the Apennines have proliferated.Such economic investments are risky,especially without long-term data on snow cover duration.Our aim,thus,is to provide the first census of abandoned ski resorts in the Apennines and compare them with the resorts currently open to understand the causes that led to their abandonment.Subsequently,we explore factors behind resort failure by analyzing the relationships between climatic,geomorphological,and economic variables.Overall,we found 101 ski resorts in the Apennines,of which 28 were open,41 closed and abandoned and 32 partially closed(i.e.,closed in more than at least 7 years in the last 10 years).The closed and partially closed resorts represent 358 km of ski slopes(44%of total available).The number of structures per resort(i.e.ski lifts,chair lifts)is higher for open compared to partially closed and closed ones.Notably,the maximum elevation reached by the resorts is higher for those open(1793 m a.s.l.)than for those partially closed(1687 m a.s.l.)and especially those closed(1577 m a.s.l.).Finally,the mean size of the resorts in terms of skiable track length is larger for open(15.7 km)than partially closed(7.1 km)and closed resorts(3.2 km).The average duration of operation for abandoned resorts is 29.5 years,varying from a maximum of 56 years to a minimum of 0 years for two sites that were never opened after reconstruction.The year of abandonment is positively associated with the maximum elevation,size,and duration of operation.Furthermore,the duration of operation is negatively correlated with the construction year.Our multivariate analysis confirms and strengthens the hypothesis for the causes that lead to abandonment are multi-factorial.Most of the closed resorts are located at low altitude and have small ski areas although some higher altitude sites have also been abandoned in recent years.This information can be useful for investors,policymakers,and stakeholders who should use it as a starting point when designing and planning new resorts to avoid future failures and the loss of public money.
基金supported by the National Key R&D Program of China(No.2023YFA1606401)the National Natural Science Foundation of China(Nos.12135004,11635003 and 11961141004)。
文摘Multinucleon transfer in low-energy heavy-ion collisions is increasingly considered a promising approach for generating exotic nuclei.Understanding the complex mechanisms involved in multinucleon transfer processes presents significant challenges for the theoretical investigation of nuclear reactions.A Langevin equation model was developed and employed to investigate multinucleon transfer processes.The^(40)Ar+^(232)Th reaction was simulated,and the calculated Wilczyński plot was used to verify the model.Additionally,to study the dynamics of multinucleon transfer reactions,the^(136)Xe+^(238)U and^(136)Xe+^(209)Bi reactions were simulated,and the corresponding TKE-mass and angular distributions were computed to analyze the energy dissipation and scattering angles.This investigation enhances our understanding of the dynamics involved in multinucleon transfer processes.
文摘Purpose:This study aimed to compare biomechanical aspects of a novel"running"diagonal stride(DSRUN)with"conventional"diagonal stride(DSCONV)skiing techniques performed at high speed.Methods:Ten elite Italian male junior cross-country skiers skied on a treadmill at 10 km/h and at a 10°incline utilizing both variants of the diagonal stride technique.The 3-dimensional kinematics of the body,poles,and roller skis;the force exerted through the poles and foot plantar surfaces;and the angular motion of the leg joints were determined.Results:Compared to DSCONV,DSRUN demonstrated shorter cycle times(1.05±0.05 s vs.0.75±0.03 s(mean±SD),p<0.001)due to a shorter rolling phase(0.40±0.04 s vs.0.09±0.04 s,p<0.001);greater force applied perpendicularly to the roller skis when they had stopped rolling forward(413±190 N vs.890±170 N,p<0.001),with peak force being attained earlier;prolonged knee extension,with a greater range of motion during the roller ski-stop phase(28°±40 vs.16°±3°,p=0.00014);and more pronounced hip and knee flexion during most of the forward leg swing.The mechanical work performed against friction during rolling was significantly less with DSRUN than with DSCONV(0.04±0.01 J/m/kg vs.0.10±0.02 J/m/kg,p<0.001).Conclusion:Our findings demonstrate that DSRUN is characterize by more rapid propulsion,earlier leg extension,and a greater range of motion of knee joint extension than DSCONV-Further investigations,preferably on snow,should reveal whether DSRUN results in higher acceleration and/or higher peak speed.
