Purpose The aim of the present study was to evaluate the trunk strength capacity of alpine ski racers aged 10-18 years,who were tested during the last 15 years,to identify reference values for trunk flexor to extensor...Purpose The aim of the present study was to evaluate the trunk strength capacity of alpine ski racers aged 10-18 years,who were tested during the last 15 years,to identify reference values for trunk flexor to extensor strength ratios according to age and sex.Methods In total,2841 participants(1605 males,1236 females;10-18 years)were included,who were pupils of a famous skiing-specific secondary modern school or members of the provincial ski team between 2006 and 2020.The maximum isometric trunk flexion and extension strength was measured using the slightly modified Back Check.Sex-specific differ-ences were assessed with Student’s t test or Mann-Whitney-U test.Univariate analyses of variance or Kruskal-Wallis-H tests were used to assess differences between age groups.Descriptive sex-and age-specific reference values were calculated(norm area:mean±½standard deviation).Results Sex-specific differences were found for both flexion(starting at 11 years)and extension strength(starting at 12 years)(P<0.001).Lower flexion to extension strength ratios were identified for males(0.89±0.18)compared with females(0.82±0.15),but the ratios remained constant across age groups for both sexes.Conclusion The present study provides age-and sex-specific reference values for trunk flexion to extension strength ratios for 10-to 18-year old youth and adolescent ski racers.The data of the present study represent a large data pool of youth ski racers at a high-performance level;thus,coaches can use the reference values for comparing the ratios of their athletes.展开更多
Purpose:The purposes of this study were to examine the trajectories of athlete burnout across a 2-month period characterized by high physical,psychological,and social demands to explore(1)whether several subgroups of ...Purpose:The purposes of this study were to examine the trajectories of athlete burnout across a 2-month period characterized by high physical,psychological,and social demands to explore(1)whether several subgroups of athletes representing distinct burnout trajectories emerged from the analyses and(2)whether athlete burnout symptoms(reduced accomplishment,sport devaluation,and exhaustion)developed in tandem or whether some burnout dimensions predicted downstream changes in other dimensions(causal ordering model).Methods:One hundred and fifty-nine table tennis players in intensive training centers completed a self-reported athlete burnout measure across 3 time points within a 2-month period characterized by high demands.Data were analyzed through latent class growth analysis.Results:Results of latent class growth analysis showed 3 distinct trajectories for each athlete burnout dimension,indicating not only linear or quadratic change but also stability in longitudinal athlete burnout perceptions.Results also suggested that the 3 dimensions of athlete burnout did not develop in tandem.Rather,the likelihood of belonging to particular emerging trajectories of sport devaluation and physical/emotional exhaustion was significantly influenced by the athletes’perception of reduced accomplishment assessed at Time 1.Thus,reduced accomplishment predicted downstream changes in the 2 other athlete burnout dimensions.Conclusion:As a whole,these results highlighted that the multinomial heterogeneity in longitudinal athlete burnout symptoms needs to be accounted for in future research.展开更多
Background：Relatively few studies on the peripheral sweating mechanisms of trained tennis athletes have been conducted.The purpose of this study was to compare the sweating capacities of tennis athletes against untra...Background：Relatively few studies on the peripheral sweating mechanisms of trained tennis athletes have been conducted.The purpose of this study was to compare the sweating capacities of tennis athletes against untrained subjects（controls）.Methods：Thirty-fi e healthy male volunteers participated including 15 untrained subjects and 20 trained tennis athletes（nationally ranked）.Active heat generation was performed for 30 min（running at 60%VO2max） in a climate chamber（temperature,25.0°C ± 0.5°C;relative humidity,60% ± 3%,termed active heating）.Sweating data（local sweat onset time,local sweat volume,activated sweat glands,sweat output per gland,whole body sweat loss volume） were measured by the capacitance hygrometer-ventilated capsule method and starch-iodide paper.Mean body temperature was calculated from tympanic and skin temperatures.Results：Local sweat onset time was shorter for tennis athletes（p〈0.001）.Local sweat volume,activated sweat glands of the torso and limbs,sweat output per gland,and whole body sweat loss volume were significant y higher for tennis athletes than control subjects after active heating（p〈0.001）.Tympanic and mean body temperatures were lower among tennis athletes than controls（p〈0.05）.Conclusion：These results indicate that tennis athletes had increased regulatory capacity of their sweat gland function.展开更多
The exploitation and utilization of the tour resources of tournament athletics, including skiling, boat sailing, archery, ice engraving, snow engrav ing, has become a new trend of the development of Chinese tourism. D...The exploitation and utilization of the tour resources of tournament athletics, including skiling, boat sailing, archery, ice engraving, snow engrav ing, has become a new trend of the development of Chinese tourism. Due to the un ique cold climate and superior geographic location,Harbin is a promising city f or developing tour resources of tournament athletics. Based on the analysis of t he superiority and peculiarity of Harbin,the speculation on development of tour resources of tournament athletics in Harbin is proposed as follows:1) Harbin s hould develop its special tour resources of tournament athletics associated with needs of market; 2) Harbin should take the advantages of rich resources and dev elop ice and snow entertainment in winter and travel for sight-seeing and spend ing summer; 3) the adjustment of the layout of ice and snow resources should be based on the idea of taking Harbin as the center and all-side opening at the la rge scale in the way of radiation; 4) tourism should be developed by the combine d efforts of various departments to make feasible plan, and the organizers shoul d pay much attention to ensuring the safety of tourists.展开更多
文摘Purpose The aim of the present study was to evaluate the trunk strength capacity of alpine ski racers aged 10-18 years,who were tested during the last 15 years,to identify reference values for trunk flexor to extensor strength ratios according to age and sex.Methods In total,2841 participants(1605 males,1236 females;10-18 years)were included,who were pupils of a famous skiing-specific secondary modern school or members of the provincial ski team between 2006 and 2020.The maximum isometric trunk flexion and extension strength was measured using the slightly modified Back Check.Sex-specific differ-ences were assessed with Student’s t test or Mann-Whitney-U test.Univariate analyses of variance or Kruskal-Wallis-H tests were used to assess differences between age groups.Descriptive sex-and age-specific reference values were calculated(norm area:mean±½standard deviation).Results Sex-specific differences were found for both flexion(starting at 11 years)and extension strength(starting at 12 years)(P<0.001).Lower flexion to extension strength ratios were identified for males(0.89±0.18)compared with females(0.82±0.15),but the ratios remained constant across age groups for both sexes.Conclusion The present study provides age-and sex-specific reference values for trunk flexion to extension strength ratios for 10-to 18-year old youth and adolescent ski racers.The data of the present study represent a large data pool of youth ski racers at a high-performance level;thus,coaches can use the reference values for comparing the ratios of their athletes.
基金supported by the French Federation of Table Tennis.
文摘Purpose:The purposes of this study were to examine the trajectories of athlete burnout across a 2-month period characterized by high physical,psychological,and social demands to explore(1)whether several subgroups of athletes representing distinct burnout trajectories emerged from the analyses and(2)whether athlete burnout symptoms(reduced accomplishment,sport devaluation,and exhaustion)developed in tandem or whether some burnout dimensions predicted downstream changes in other dimensions(causal ordering model).Methods:One hundred and fifty-nine table tennis players in intensive training centers completed a self-reported athlete burnout measure across 3 time points within a 2-month period characterized by high demands.Data were analyzed through latent class growth analysis.Results:Results of latent class growth analysis showed 3 distinct trajectories for each athlete burnout dimension,indicating not only linear or quadratic change but also stability in longitudinal athlete burnout perceptions.Results also suggested that the 3 dimensions of athlete burnout did not develop in tandem.Rather,the likelihood of belonging to particular emerging trajectories of sport devaluation and physical/emotional exhaustion was significantly influenced by the athletes’perception of reduced accomplishment assessed at Time 1.Thus,reduced accomplishment predicted downstream changes in the 2 other athlete burnout dimensions.Conclusion:As a whole,these results highlighted that the multinomial heterogeneity in longitudinal athlete burnout symptoms needs to be accounted for in future research.
基金supported by the Soonchunhyang University Research Fund
文摘Background：Relatively few studies on the peripheral sweating mechanisms of trained tennis athletes have been conducted.The purpose of this study was to compare the sweating capacities of tennis athletes against untrained subjects（controls）.Methods：Thirty-fi e healthy male volunteers participated including 15 untrained subjects and 20 trained tennis athletes（nationally ranked）.Active heat generation was performed for 30 min（running at 60%VO2max） in a climate chamber（temperature,25.0°C ± 0.5°C;relative humidity,60% ± 3%,termed active heating）.Sweating data（local sweat onset time,local sweat volume,activated sweat glands,sweat output per gland,whole body sweat loss volume） were measured by the capacitance hygrometer-ventilated capsule method and starch-iodide paper.Mean body temperature was calculated from tympanic and skin temperatures.Results：Local sweat onset time was shorter for tennis athletes（p〈0.001）.Local sweat volume,activated sweat glands of the torso and limbs,sweat output per gland,and whole body sweat loss volume were significant y higher for tennis athletes than control subjects after active heating（p〈0.001）.Tympanic and mean body temperatures were lower among tennis athletes than controls（p〈0.05）.Conclusion：These results indicate that tennis athletes had increased regulatory capacity of their sweat gland function.
文摘The exploitation and utilization of the tour resources of tournament athletics, including skiling, boat sailing, archery, ice engraving, snow engrav ing, has become a new trend of the development of Chinese tourism. Due to the un ique cold climate and superior geographic location,Harbin is a promising city f or developing tour resources of tournament athletics. Based on the analysis of t he superiority and peculiarity of Harbin,the speculation on development of tour resources of tournament athletics in Harbin is proposed as follows:1) Harbin s hould develop its special tour resources of tournament athletics associated with needs of market; 2) Harbin should take the advantages of rich resources and dev elop ice and snow entertainment in winter and travel for sight-seeing and spend ing summer; 3) the adjustment of the layout of ice and snow resources should be based on the idea of taking Harbin as the center and all-side opening at the la rge scale in the way of radiation; 4) tourism should be developed by the combine d efforts of various departments to make feasible plan, and the organizers shoul d pay much attention to ensuring the safety of tourists.
