Validation of a single-stage submaximal treadmill walking test     

Lindsey Waddoups  Jennifer Fallon  Edward Heath 《Journal of sports sciences》2013,31(5):491-497

Abstract

The single-stage treadmill walking test of Ebbeling et al. is commonly used to predict maximal oxygen consumption ([Vdot]O_2max) from a submaximal effort between 50% and 70% of the participant's age-predicted maximum heart rate. The purpose of this study was to determine if this submaximal test correctly predicts [Vdot]O_2max at the low (50% of maximum heart rate) and high (70% of maximum heart rate) ends of the specified heart rate range for males and females aged 18 – 55 years. Each of the 34 participants completed one low-intensity and one high-intensity trial. The two trials resulted in significantly different estimates of [Vdot]O_2max (low-intensity trial: mean 40.5 ml · kg^?1 · min^?1, s = 9.3; high-intensity trial: 47.5 ml · kg^?1 · min^?1, s = 8.8; P < 0.01). A subset of 22 participants concluded their second trial with a [Vdot]O_2max test (mean 47.9 ml · kg^?1 · min^?1, s = 8.9). The low-intensity trial underestimated (mean difference = ?3.5 ml · kg^?1 · min^?1; 95% CI = ?6.4 to ?0.6 ml · kg^?1 · min^?1; P = 0.02) and the high-intensity trial overestimated (mean difference = 3.5 ml · kg^?1 · min^?1; 95% CI = 1.1 to 6.0 ml · kg^?1 · min^?1; P = 0.01) the measured [Vdot]O_2max. The predictive validity of Ebbeling and colleagues' single-stage submaximal treadmill walking test is diminished when performed at the extremes of the specified heart rate range.  相似文献   

High-intensity interval running is perceived to be more enjoyable than moderate-intensity continuous exercise: Implications for exercise adherence     

Jonathan D. Bartlett  Graeme L. Close  Don P. M. MacLaren  Warren Gregson  Barry Drust 《Journal of sports sciences》2013,31(6):547-553

Abstract

The aim of this study was to objectively quantify ratings of perceived enjoyment using the Physical Activity Enjoyment Scale following high-intensity interval running versus moderate-intensity continuous running. Eight recreationally active men performed two running protocols consisting of high-intensity interval running (6×3 min at 90% [Vdot]O_2max interspersed with 6×3 min active recovery at 50% [Vdot]O_2max with a 7-min warm-up and cool down at 70% [Vdot]O_2max) or 50 min moderate-intensity continuous running at 70% [Vdot]O_2max. Ratings of perceived enjoyment after exercise were higher (P < 0.05) following interval running compared with continuous running (88 ± 6 vs. 61 ± 12) despite higher (P < 0.05) ratings of perceived exertion (14 ± 1 vs. 13 ± 1). There was no difference (P < 0.05) in average heart rate (88 ± 3 vs. 87 ± 3% maximum heart rate), average [Vdot]O₂ (71 ± 6 vs. 73 ± 4%[Vdot]O_2max), total [Vdot]O₂ (162 ± 16 vs. 166 ± 27 L) or energy expenditure (811 ± 83 vs. 832 ± 136 kcal) between protocols. The greater enjoyment associated with high-intensity interval running may be relevant for improving exercise adherence, since running is a low-cost exercise intervention requiring no exercise equipment and similar relative exercise intensities have previously induced health benefits in patient populations.  相似文献   

Effect of 6 weeks of endurance training on the lactate minimum speed     

Helen Carte  Andrew M. Jones  Jonathan H. Doust 《Journal of sports sciences》2013,31(12):957-967

The aim of this study was to assess the sensitivity of the lactate minimum speed test to changes in endurance fitness resulting from a 6 week training intervention. Sixteen participants (mean +/- s :age 23 +/- 4 years;body mass 69.7 +/- 9.1 kg) completed 6 weeks of endurance training. Another eight participants (age 23 +/- 4 years; body mass 72.7 +/-12.5 kg) acted as non-training controls. Before and after the training intervention, all participants completed: (1) a standard multi-stage treadmill test for the assessment of VO 2max , running speed at the lactate threshold and running speed at a reference blood lactate concentration of 3 mmol.l -1 ; and (2) the lactate minimum speed test, which involved two supramaximal exercise bouts and an 8 min walking recovery period to increase blood lactate concentration before the completion of an incremental treadmill test. Additionally, a subgroup of eight participants from the training intervention completed a series of constant-speed runs for determination of running speed at the maximal lactate steady state. The test protocols were identical before and after the 6 week intervention. The control group showed no significant changes in VO 2max , running speed at the lactate threshold, running speed at a blood lactate concentration of 3 mmol.l -1 or the lactate minimum speed.In the training group, there was a significant increase in VO 2max (from 47.9 +/- 8.4 to 52.2 +/- 2.7 ml.kg -1 .min -1 ), running speed at the maximal lactate steady state (from 13.3 +/- 1.7 to 13.9 +/- 1.6 km.h -1 ), running speed at the lactate threshold (from 11.2 +/- 1.8 to 11.9 +/- 1.8 km.h -1 ) and running speed at a blood lactate concentration of 3 mmol.l -1 (from 12.5 +/- 2.2 to 13.2 +/- 2.1 km.h -1 ) (all P ? 0.05). Despite these clear improvements in aerobic fitness, there was no significant difference in lactate minimum speed after the training intervention (from 11.0 +/- 0.7 to 10.9 +/- 1.7 km.h -1 ). The results demonstrate that the lactate minimum speed,when assessed using the same exercise protocol before and after 6 weeks of aerobic exercise training, is not sensitive to changes in endurance capacity.  相似文献   

A modified incremental shuttle run test for the determination of peak shuttle running speed and the prediction of maximal oxygen uptake     

DAVID M. WILKINSON  JOANNE L. FALLOWFIELD  STEPHEN D. MYERS 《Journal of sports sciences》2013,31(5):413-419

The aim of this study was to determine the incidence of subject drop-out on a multi-stage shuttle run test and a modified incremental shuttle run test in which speed was increased by 0.014m.s-1 every 20-m shuttle to avoid the need for verbal speed cues. Analysis of the multi-stage shuttle run test with 208 elite female netball players and 381 elite male lacrosse players found that 13 (+/-3) players stopped after the first shuttle of each new level, in comparison with 5 (+/-2) players on any other shuttle. No obvious drop-out pattern was observed on the incremental shuttle run test with 273 male and 79 female undergraduate students. The mean difference between a test-retest condition (n= 20) for peak shuttle running speed (-0.03+/- 0.01m.s-1) and maximal heart rate (0.4+/- 0.1 beats.min-1) on the incremental test showed no bias (P > 0.05). The 95% absolute confidence limits of agreement were 0.11m.s-1 for peak shuttle running speed and +/-5 beats.min-1 for maximal heart rate. The relationship (n= 27) between peak shuttle running speed on the incremental shuttle run test (4.22+/- 0.14m.s-1) and VO2max (59.0+/- 1.7ml.kg-1.min-1) was r=0.91 (P< 0.01), with a standard error of prediction of 2.6ml.kg-1.min-1. These results suggest verbal cues during the multi-stage shuttle run test may influence subject drop-out. The incremental shuttle run test shows no obvious drop-out patten and provides a valid estimate of VO2max.  相似文献   

几类规划问题最优解不存在的条件   总被引：1，自引：0，他引：1  

罗毅平  杨逢建 《湘潭师范学院学报(社会科学版)》1997,(3)

本文给出了几类线性约束条件下的非线性规划问题最优解不存在的条件，并把此结论推广到了非线性约束条件下的目标函数为线性的规划问题。  相似文献   

Seminal plasma levels of free 8-isoprostane and its relationship with sperm quality parameters     

Ali Khosrowbeygi  Nosratollah Zarghami 《Indian journal of clinical biochemistry : IJCB》2008,23(1):49-52

There is growing evidence that damage to spermatozoa by reactive oxygen species play a key role in male infertility. The aim of this study was to assess seminal plasma free 8-Isoprostane levels in men with asthenozoospermia, asthenoteratozoospermia and oligoasthenoteratozoospermia compared to normozoospermic males and its correlation with seminal parameters. The case group consisted of men with asthenozoospermia (n=15), asthenoteratozoospermia (n=16) and oligoasthenoteratozoospermia (n=15). The control group consisted of 16 males with normozoospermia. After Purification of Free 8-Isoprostane by affinity column, its concentration was measured by enzyme immunoassay method. Free 8-Isoprostane evaluation showed significantly greater values in the total case group (n=46) versus control group (18.23±3.56 vs 2.6±0.38 ng/ml). In each case group free 8-Isoprostane also showed a significant increasing compared to normozoospermic males. Free 8-Isoprostane showed an inversely significant correlation with sperm motility and sperm morphology. Lipid peroxidation could have significant role in etiology of sperm abnormalities. Measurement of 8-Isoprostane can be used as a specific biomarker for assessing lipid peoxidation in sperm.  相似文献   

求最大公因式的矩阵变换法     

吕效国 《南通职业大学学报》2000,14(2):37-39

求多项式的最大公因式教材中都是运用辗转相除法,运算的过程比较复杂。本介绍的矩阵变换法,使求解过程简洁明了,尤其对多于2个的多项式的最大公因式可一并求出,更显其优越性。  相似文献   

液态铜的结构及液态铜中氧和氢的性质     

时文中  李趁意 《天中学刊》1997,12(2):43-45

介绍了液态铜的几种热力学性质和结构特征，讨论了氧、氢在液态锡中的存在形式、溶解度、活度系数及杂质元素对液态铜中氢氧溶解度的影响.  相似文献   

青少年耐力训练及有氧适应     

张子超  张爱军  王松 《湖北广播电视大学学报》2008,28(12)

青少年进行体育锻炼有利于身体发展和身心健康。有氧耐力训练能够增加青少年对运动忍受能力,最终提高青少年的运动能力。有氧耐力训练可以提高峰值摄氧量,平均提高为5％～6％。青少年具有较高无氧阈值,训练强度超过80％最大心率可能是提高有氧适应所必须的。  相似文献   

氧弹头充氧电极接口连接转换器的设计     

周钢  杨坤  吴蕾  兰叶青  朱浩  陈禹衡 《中国现代教育装备》2011,(13):14-15

从实际生产及合理应用的角度出发,着重对氧弹头充氧电极接口连接转换器的设计进行了阐述。其中包括：接触电阻等对连接转换器性能的影响。连接转换器中内螺纹结构、连接口结构、导角结构、导入口结构以及滚花等的设计和各自所具有的功能,同时还介绍了具体实施方案和实施过程。还对传统的电气连接方式的特点进行了必要的分析。  相似文献