Influence of upright versus time trial cycling position on determination of critical power and W′ in trained cyclists

Body position is known to alter power production and affect cycling performance. The aim of this study was to compare mechanical power output in two riding positions, and to calculate the effects on critical power (CP) and W′ estimates. Seven trained cyclists completed three peak power output efforts and three fixed-duration trial (3-, 5- and 12-min) riding with their hands on the brake lever hoods (BLH), or in a time trial position (TTP). A repeated-measures analysis of variance showed that mean power output during the 5-min trial was significantly different between BLH and TTP positions, resulting in a significantly lower estimate of CP, but not W′, for the TTP trial. In addition, TTP decreased the performance during each trial and increased the percentage difference between BLH and TTP with greater trial duration. There were no differences in pedal cadence or heart rate during the 3-min trial; however, TTP results for the 12-min trial showed a significant fall in pedal cadence and a significant rise in heart rate. The findings suggest that cycling position affects power output and influences consequent CP values. Therefore, cyclists and coaches should consider the cycling position used when calculating CP.     

Determination of peak cardiorespiratory fitness parameters in children: which averaging method should we use?

The purpose of this study was to identify which averaging methods most accurately measures peak cardiorespiratory fitness (CRF) parameters [peak O₂ uptake (VO₂), peak O₂pulse and peak respiratory exchange ratio (RER)] in a sample of healthy children and adolescents. In this cross-sectional multicenter study, we recruited 278 healthy children aged 12–17 years. We compared the mean peak value of three CRF parameters using the recommended averaging methods (30-second block average) with alternative averaging methods such as moving averages or shorter smoothing periods. We also assessed averaging methods for accuracy by individually reviewing breath-by-breath scatter plots. The 30-second block average method resulted in a lower mean peak VO₂ and in an increased proportion of underestimated peak values. Using a 30-second moving average significantly increased mean peak values which increased accuracy. Similar results were found for peak RER and peak O₂pulse. In conclusion, the currently recommended averaging method (30-second block average) increased the risk of misinterpretation of peak CRF values in children. Using a moving average approach decreased misinterpretation and increased accuracy.     

体育课堂运动干预对女大学生体质健康影响的实验研究

运用文献资料法、数理统计法、实验法,研究体育课堂运动干预对女大学生体质健康的影响,为高校的体育教学改革提供一定的理论依据.结果显示:体育课堂的运动干预对女大学生身体素质和身体机能的改善和提高效果明显.     

Maximal heart rate declines linearly with age independent of cardiorespiratory fitness levels

There have been many conflicting observations between the linear or curvilinear decline in maximal heart rate (HR_max) with age. The aim of this study was to determine if linear or curvilinear equations would better describe the decline in HR_max with age in individuals of differing cardiorespiratory fitness (CRF) levels. Treadmill cardiopulmonary exercise test (CPX) results from participants (1510 men and 1134 women; 18–76 years) free of overt cardiovascular disease were retrospectively examined using cross-sectional and longitudinal study designs. Participants completing ≥2 CPX with ≥1 year between test dates were included in the longitudinal analysis (325 men and 150 women). Linear and quadratic regressions were applied to age and HR_max for the whole cohort and respective CRF groups (high, moderate, and low, relative to age and gender normative values). To test for differences among linear, quadratic, and polynomial equations, the change in R² (cross-sectional analysis) and Bayesian information criterion (BIC) (longitudinal analysis) from the linear to the more complex models were calculated. The quadratic or polynomial regression in the cross-sectional analysis, marginally improved the variance in HR_max explained by age compared to the linear regression for the whole cohort (0.2%), moderate fit group (0.3%), and low fit group (0.8%). With no improvements in the high fit group. BIC did not improve for any CRF category in the longitudinal analysis. In conclusion, the minimal differences among linear, quadratic, and polynomial equations in the respective CRF groups, emphasizes the use of linear prediction equations to estimate HR_max.     

The effects of short versus long inter-set rest intervals in resistance training on measures of muscle hypertrophy: A systematic review

Although the effects of short versus long inter-set rest intervals in resistance training on measures of muscle hypertrophy have been investigated in several studies, the findings are equivocal and the practical implications remain unclear. In an attempt to provide clarity on the topic, we performed a systematic literature search of PubMed/MEDLINE, Scopus, Web of Science, Cochrane Library, and Physiotherapy Evidence Database (PEDro) electronic databases. Six studies were found to have met the inclusion criteria: (a) an experimental trial published in an English-language peer-reviewed journal; (b) the study compared the use of short (≤60?s) to long (>60?s) inter-set rest intervals in a traditional dynamic resistance exercise using both concentric and eccentric muscle actions, with the only difference in resistance training among groups being the inter-set rest interval duration; (c) at least one method of measuring changes in muscle mass was used in the study; (d) the study lasted for a minimum of four weeks, employed a training frequency of ≥2 resistance training days per week, and (e) used human participants without known chronic disease or injury. Current evidence indicates that both short and long inter-set rest intervals may be useful when training for achieving gains in muscle hypertrophy. Novel findings involving trained participants using measures sensitive to detect changes in muscle hypertrophy suggest a possible advantage for the use of long rest intervals to elicit hypertrophic effects. However, due to the paucity of studies with similar designs, further research is needed to provide a clear differentiation between these two approaches.     

加强体育院校课余活动引导 促进大学生综合素质提高

运动技术的教学和训练离不开对运动技术时空特征的研判。对不同训练水平的教学对象需根据其运动时的技术时空特征采用合适的教学和训练方法才能实现运动技术的最优化。     

耐力和抗阻运动对血脂代谢的影响

长期规律的体育运动均可有效地改善其不良的脂质结构,并能延缓因增龄而带来的不良影响,从而使冠心病的危险性显著降低。目前WHO已将体育运动过少列为冠心病的独立危险因素。因为运动训练对血脂水平的改善起到了至关重要的作用。本综述旨在阐明耐力运动和抗阻运动对血脂代谢的影响。     

当前我国运动训练实践的新思维

重视运动过程,深入研究动态的技术细节,已经成为准确把握项目运动特征的基础和前提条件。对运动能力的认识不能仅停留在静态的距离或时间上,而应该深入到运动的过程中,捕捉并把握关键指标的动态变化,了解运动的全过程。运动训练应转变训练理念,从传统的大运动量低强度训练转变到大运动量高强度的高负荷训练模式上来,这个训练模式称为“高负荷训练法”。无论是以体能为主导的项群,还是以技能为主导的项群,都需要“以赛代练”,但不能“重赛轻练”。运动员在获得“最高运动成绩”时,并不处于“最佳准备状态”。     

皮划艇激流回旋项目的力量测试与评价

我国的皮划艇激流项目力量训练的设备仍是杠铃一类的器械,杠铃虽然是一种行之有效的训练器械,但在训练学界被认为是不符合专项力量训练要求的训练器材。研究表明,只要有有效的测试监控手段,教练员同样能够正确地评价力量训练效果,提高力量训练效率。本文的研究目的是要通过自行研制简单实用的训练测试设备及其力量训练效果评价体系,对皮划艇激流国家队运动员进行力量训练的测试与评价。     

不同锻炼方式对湘西地区大学生心境的影响

采用文献资料法、心理测量法、实验法、逻辑分析法等方法,以健美操和太极拳作为不同锻炼方式,对湘西吉首大学部分大学生就不同锻炼方式对心境的不同影响进行了15周系统的实验研究。实验结果表明:15周健美操锻炼和太极拳锻炼对大学生身体心境及各维度都具有明显改善作用,但健美操锻炼对大学生心境的影响效应不如太极拳效果好,不同锻炼方式对湘西地区大学生的心境产生不同的效益,均可促进心境不同方面的发展。