Purpose The fact that CrossFit^(®)is the best-known and rapidly growing concept for high-intensity interval training(HIIT)and high-intensity functional training(HIFT)results in a continuous increase of athletes p...Purpose The fact that CrossFit^(®)is the best-known and rapidly growing concept for high-intensity interval training(HIIT)and high-intensity functional training(HIFT)results in a continuous increase of athletes performing CrossFit^(®).In the more than 15,000 CrossFit^(®)Affiliates worldwide,the training concept is usually offered in 1-h training sessions containing the CrossFit^(®)-related workout of the day(WOD),as well as a general warm-up,movement demonstrations,and skill training.Here,we report how physiological parameters measured by heart rate(HR)values vary during four different 1-h CrossFit^(®)training sessions of non-elite athletes(n=27)in a local affiliated training center and what influencing factors may exist.Methods The duration of the 1-h training sessions were divided into a warm-up part(WU-part),a skill development part combined with strength exercises(A-part),followed by the WOD part(B-part).Results Analysis of HR values shows high training intensity(≥91%HR_(max))not throughout the duration of each training session,only during B-part.The mean HR values in B-part differ significantly compared to the remaining training parts(P<0.001)for all four training sessions.Comparison of different CrossFit^(®)experience levels revealed no significant differ-ence in acute physiological demands and training load between beginner and experienced CrossFit^(®)athletes.Conclusion Our results may suggest that practicing CrossFit^(®)in 1-h training sessions combined anaerobic and aerobic exercise intensities,with the training concept allows beginners and experienced athletes to be trained with the same cardio-vascular responses and training intensities.展开更多
课次主观疲劳度(Session Rating of Perceived Exertion,sRPE)是一种通过评价运动过程中的感知努力/疲劳程度来量化运动负荷的方法。尽管评分者一致信度不佳,但sRPE重测信度较高。sRPE在不同运动项目、性别、年龄中都有高的效度。采集...课次主观疲劳度(Session Rating of Perceived Exertion,sRPE)是一种通过评价运动过程中的感知努力/疲劳程度来量化运动负荷的方法。尽管评分者一致信度不佳,但sRPE重测信度较高。sRPE在不同运动项目、性别、年龄中都有高的效度。采集方式、训练分组的数量、咖啡因、环境温度、触觉、脑力疲劳和昼夜节律对sRPE都存在影响。建议在横向和纵向使用中,采用Category Ratio 10(CR 10)量表,固定运动后5~30 min内的某个时间采集运动员的主观疲劳度,并将准备活动、主课训练和整理活动全部纳入运动持续时间。对不能控制但存在影响的因素进行详细记录,并在后期分析过程中进行参考。未来研究将进一步发挥sRPE在损伤预防和表现提升中的价值。展开更多
The rise of high-speed railway induces an increased probability of serious derailment accidents of operating high-speed trains during earthquakes.A two-and-half-dimensional finite element model(2.5D FEM)was developed ...The rise of high-speed railway induces an increased probability of serious derailment accidents of operating high-speed trains during earthquakes.A two-and-half-dimensional finite element model(2.5D FEM)was developed to investigate the ground vibration under combined seismic and high-speed train loads.Numerical examples were demonstrated and the proposed method was turned out to provide an effective means for estimating ground vibration caused by high-speed train load during earthquakes.The dynamic ground displacement caused by combined seismic and high-speed train loads increases with the increase of the train speed,and decreases with the increase of the stiffness of ground soil.Compared with the seismic load alone,the coupling effect of the seismic and high-speed train loads results in the low-frequency amplification of ground vibration.The moving train load dominants the medium–high frequency contents of the ground vibration induced by combined loads.It is observed that the coupling effects are significant as the train speed is higher than a critical speed.The critical train speed increases with the increase of the ground stiffness and the intensity of the input earthquake motion.展开更多
基金Open Access funding enabled and organized by Projekt DEAL.
文摘Purpose The fact that CrossFit^(®)is the best-known and rapidly growing concept for high-intensity interval training(HIIT)and high-intensity functional training(HIFT)results in a continuous increase of athletes performing CrossFit^(®).In the more than 15,000 CrossFit^(®)Affiliates worldwide,the training concept is usually offered in 1-h training sessions containing the CrossFit^(®)-related workout of the day(WOD),as well as a general warm-up,movement demonstrations,and skill training.Here,we report how physiological parameters measured by heart rate(HR)values vary during four different 1-h CrossFit^(®)training sessions of non-elite athletes(n=27)in a local affiliated training center and what influencing factors may exist.Methods The duration of the 1-h training sessions were divided into a warm-up part(WU-part),a skill development part combined with strength exercises(A-part),followed by the WOD part(B-part).Results Analysis of HR values shows high training intensity(≥91%HR_(max))not throughout the duration of each training session,only during B-part.The mean HR values in B-part differ significantly compared to the remaining training parts(P<0.001)for all four training sessions.Comparison of different CrossFit^(®)experience levels revealed no significant differ-ence in acute physiological demands and training load between beginner and experienced CrossFit^(®)athletes.Conclusion Our results may suggest that practicing CrossFit^(®)in 1-h training sessions combined anaerobic and aerobic exercise intensities,with the training concept allows beginners and experienced athletes to be trained with the same cardio-vascular responses and training intensities.
文摘课次主观疲劳度(Session Rating of Perceived Exertion,sRPE)是一种通过评价运动过程中的感知努力/疲劳程度来量化运动负荷的方法。尽管评分者一致信度不佳,但sRPE重测信度较高。sRPE在不同运动项目、性别、年龄中都有高的效度。采集方式、训练分组的数量、咖啡因、环境温度、触觉、脑力疲劳和昼夜节律对sRPE都存在影响。建议在横向和纵向使用中,采用Category Ratio 10(CR 10)量表,固定运动后5~30 min内的某个时间采集运动员的主观疲劳度,并将准备活动、主课训练和整理活动全部纳入运动持续时间。对不能控制但存在影响的因素进行详细记录,并在后期分析过程中进行参考。未来研究将进一步发挥sRPE在损伤预防和表现提升中的价值。
基金supported by National Natural Science Foundation of China(Grant Nos:41372271 and 51978510).
文摘The rise of high-speed railway induces an increased probability of serious derailment accidents of operating high-speed trains during earthquakes.A two-and-half-dimensional finite element model(2.5D FEM)was developed to investigate the ground vibration under combined seismic and high-speed train loads.Numerical examples were demonstrated and the proposed method was turned out to provide an effective means for estimating ground vibration caused by high-speed train load during earthquakes.The dynamic ground displacement caused by combined seismic and high-speed train loads increases with the increase of the train speed,and decreases with the increase of the stiffness of ground soil.Compared with the seismic load alone,the coupling effect of the seismic and high-speed train loads results in the low-frequency amplification of ground vibration.The moving train load dominants the medium–high frequency contents of the ground vibration induced by combined loads.It is observed that the coupling effects are significant as the train speed is higher than a critical speed.The critical train speed increases with the increase of the ground stiffness and the intensity of the input earthquake motion.