三种强度运动对脑电地形图影响的比较研究

采用实验研究方法，对体育系男学生(20名)在安静状态、小于通气阈强度、通气阈强度、大于通气阈强度负荷后即刻1min的脑电变化进行测试。结论：通气阈强度运动在一定程度上对大脑皮质产生影响，增进了大脑细胞新陈代谢强度，可改善大脑皮质神经元代谢能力，使其产生复杂的生理效应和训练效应，对脑皮层神经细胞工作能力的改善和提高很显著；大于通气阈强度运动后易使中枢神经细胞产生疲劳。     

太极拳对女大学生脑电α波影响的实验研究

采用常规脑电检测法,研究不同运动量的24式简化太极拳对女大学生脑电α波的影响。结果发现,经过9周太极拳运动后,对照组女大学生心理调节呼吸、3分钟过度换气后的α频段功率值均显著低于运动组女大学生,而意念表象中的α频段功率值未见显著性差异。结果表明,太极拳训练对中枢神经的刺激能引起神经细胞产生良好的生理适应,可以在一定程度上影响中枢神经系统,使大脑皮质神经元代谢强度增加,可改善大脑皮质神经元代谢能力。     

运动生理学

G804.2 小于通气阈强度运动对脑电地形图影响的研究=A stu- dy on the effect of the less ventilatory threshold intensity on brain electrical activity mapping[刊, 中,I]/律海涛(南通师范学院体育系)∥湖北体育科技. -2003,22(3).-303-305,311图5表2参11(XH) 通气阈∥脑电图∥功率 对体育系男学生(20名)在安静中状态、小于通 气阈强度负荷运动后即刻1min的脑电变化进行测试得     

L-肉毒碱对足球运动员训练过程中生理机能的影响研究

以足球专项大学生为对象,采用双盲法分别口服Ｌ－肉毒碱和安慰剂３０天,观察训练前后身体机能及运动能力的变化。结果显示：大强度运动训练后对照组各项有氧能力指标均显著下降,呈明显的疲劳状态,而实验组最大摄氧量仍保持原水平,通气阈略上升,尤其是代表单纯有氧能力的通气阈时作功显著增大。研究表明,实验组有氧能力的改善主要是由于组织内脂肪供能的加强所致,而适当补充Ｌ－肉毒碱可能正是改善脂肪代谢的关键。     

男子散打运动员血液流变性与通气阈关系的实验研究

通过对男子散打运动员和普通男子大学生递增负荷运动过程中气体代谢与通气阈关系的实验研究，发现散打运动训练可有效改善血液的流变性，提高红细胞的变形性，降低红细胞的聚集性和血液的粘度，减小内环境变化对血液流变性造成的不良影响，且通气阈摄氧量与血液流变性密切相关，其相关关系与运动训练水平有关。     

乳酸阈强度运动对超重女大学生心肺机能和身体成分的影响

该研究旨在观察乳酸阈强度训练提升超重女大学生心肺机能和改善身体成分的效果。方法：通过递增负荷实验测定超重女大学生个体乳酸阈，绘制血乳酸-走跑强度动力曲线，依此确定运动干预强度及设计运动方案；受试者进行12周乳酸阈强度运动训练；测定实验前后身体成分、肺活量、最大摄氧量、超声心动等指标进行与对照组的对比分析。结果显示：超重女大学生个体乳酸阈为3.75±0.91mmol/L，乳酸阈强度为6.91±0.88km/h，乳酸阈强度训练靶心率为137±12.2次/min；实验组训练后，体脂%、腹部脂肪含量等非常显著的下降，最大摄氧量、肺活量、每博输出量、射血分数显著性提升；对照组无明显变化。结论：12周乳酸阈强度运动锻炼可显著改善超重女大学生的心肺机能和身体成分；本研究得出的乳酸阈强度可作为超重女大学生有氧健身的参考强度。     

不同无氧阈测定方法比较及其在中长跑训练中的应用

本文比较了各种无氧阈测值:通气阈(VT),4mmol乳酸阈(LT_4),血乳酸开始升高(LT_(OBLA)),个体无氧阈(IAT),血乳酸最大稳态(maxLass)和心率拐点(HRd)。发现各测值之间高度相关,但是maxLass与其它测值之间存在不同程度的差异,为AT在训练中的应用提供了有价值的生理依据。继而探讨了LT_4百分比强度对控制中长跑训练,改善运动员肌肉氧化代射能力,提高运动成绩的意义。     

不同无氧阈评价方法的比较研究

通过不同的无氧阈检测方法检测无氧阈指标出现的时间顺序,并对出现无氧阈时各相关指标进行相关性分析,以探讨不同无氧阈之间的关系。让8名赛艇运动员在ConceptⅡ风轮式赛艇测功仪上进行递增负荷测试,每级负荷3 min,直至力竭,同时测试每级负荷后的血乳酸,全程记录肌电以及气体代谢量,并做相关分析。结果表明：1）肌电阈、通气阈和乳酸阈3种无氧阈指标出现的时间依次为8 min 58 s、9 min 22 s和9 min 48 s;2）肌电阈、通气阈和乳酸阈依次出现的时间差均不超过30 s,并且通气阈和乳酸阈之间无显著性差异（P〉0.05）。3种无氧阈依次出现的原因是快肌纤维的快速动员引起了乳酸急剧增加,进而在转运到血液中时首先引起酸碱缓冲对的中和,当强度进一步增加时,产生的乳酸大大超过了乳酸的清除能力,进而引起血乳酸急剧增加。     

摄氧量动力学的指数函数方程及对工作能力的影响

摄氧量动力学反映的是运动开始后摄氧量逐渐增加至稳定状态过程的变化情况，其曲线在小于无氧阈强度时呈单因素指数函数方程特征，在大于无氧阈强度时呈双因素指数函数方程特征，即包含了乳酸成分。     

以心率转折点间接确定无氧阈

无氧阈(通气阈V_(AT))较最大摄氧量(Vo_(2max))对耐力性项目运动员的成绩影响更大(Scott等人,1983),而且依照个体无氧阈安排训练强度可以有效地改善运动员的有氧能力(Mclellan和Skinner,1981)。然而,由于无氧阈的测定始终限制在实验室内,所以在实际应用中尚未受到应有重视。1982年意大利学者Francesco、Conloni等人提出:在田径场上用逐增跑速而获得的心率转折点(Brp)可间接确定无氧阈。以后,另一些学者在自行车渐增负荷运动中也发现了心率转折点与无氧阈的关系(杨静宜,1984,Ribeiro等人1985)。值得注意的是:文献中所报导的实验对象多为有训练或无训练的成年人。而初次接受系统     

肌氧含量测定--一种测试无氧阈的新方法

阐述了无氧阈的形成机制及传统的测试方法,结合国内外的研究,提出了一种新的测试无氧阈的方法:肌氧含量的测定,并对其在无氧阈时的变化及与血乳酸的关系作一介绍,最后指出这一方法的可行性,但目前尚存在许多问题。     

间歇性低氧刺激对人体最大摄氧量及通气阈值的影响

目的:通过对体育学院大学生进行为期一周的间歇性低氧刺激,观察刺激前后递增负荷运动心率、通气量、摄氧量及定量负荷时血乳酸的变化,探讨间歇性低氧刺激对人体最大摄氧量及通气阈的影响。方法:本实验分两个阶段,每阶段做两次运动负荷。12名体育系男生在实验室常氧条件下在跑台上采用Bruce方法进行递增负荷运动至力竭。间隔3天后进行75%最大摄氧量的定量负荷运动,运动时间为9min,定量负荷后立即进行连续7天,每天1h的12%~10%O2的常压间歇性低氧刺激。低氧刺激完成后第二天再次进行上述两种运动方案。在极限递增负荷至力竭运动前后分别测定心率(HR)、递增负荷至力竭时间(t)、最大摄氧量(VO2max%)、血乳酸(Bla)及定量负荷时Bla等指标。结果:(1)低氧刺激后,递增负荷至力竭运动时HRmax增加(P0.01),VEmax上升(P0.01),呼吸商(R)增加(P0.05),t明显延长(P0.05),Bla明显增加(P0.05),定量负荷运动Bla显著降低(P0.05);(2)间歇性低氧刺激后通气阈时,HR、VE、VO2max%、HRmax%均显著性变化(P0.05),其中VE、VO2max%低氧刺激前后差异非常显著(P0.01)。结论:经过间歇性低氧刺激,受试者在进行递增负荷的力竭性运动时运动时间明显延长,心率在运动后增加,人体通气阈时相对应的心率百分数、最大摄氧量百分比、肺通气量均明显提高,这表明人体有氧耐力和极限负荷运动能力均得到增强。     

Effect of biological maturation on maximal oxygen uptake and ventilatory thresholds in soccer players: An allometric approach

Abstract

In this study, we investigated the effect of biological maturation on maximal oxygen uptake ([Vdot]O_2max) and ventilatory thresholds (VT₁ and VT₂) in 110 young soccer players separated into pubescent and post-pubescent groups.. Maximal oxygen uptake and [Vdot]O₂ corresponding to VT₁ and VT₂ were expressed as absolute values, ratio standards, theoretical exponents, and experimentally observed exponents. Absolute [Vdot]O₂ (ml · min^?1) was different between groups for VT₁, VT₂, and [Vdot]O_2max. Ratio standards (ml · kg^?1 · min^?1) were not significantly different between groups for VT₁, VT₂, and [Vdot]O_2max. Theoretical exponents (ml · kg^?0.67 · min^?1 and ml · kg^?0.75 · min^?1) were not properly adjusted for the body mass effects on VT₁, VT₂, and [Vdot]O_2max. When the data were correctly adjusted using experimentally observed exponents, VT₁ (ml · kg^?0.94 · min^?1) and VT₂ (ml · kg^?0.95 · min^?1) were not different between groups. The experimentally observed exponent for [Vdot]O_2max (ml · kg^?0.90 · min^?1) was different between groups (P = 0.048); however, this difference could not be attributed to biological maturation. In conclusion, biological maturation had no effect on VT₁, VT₂ or [Vdot]O_2max when the effect of body mass was adjusted by experimentally observed exponents. Thus, when evaluating the physiological performance of young soccer players, allometric scaling needs to be taken into account instead of using theoretical approaches.     

Active recovery effects by previously inactive muscles on 40-s exhaustive cycling

Abstract

The effects of active recovery using previously active and inactive muscle groups on power output and respiratory responses were examined. Ten male volunteers underwent two exhaustive 40-s bouts of leg cycling (1st Ex and 2nd Ex), separated by a 20-min recovery period. The recovery conditions were leg (Leg-Active) or arm (Arm-Active) cranking at 50% ventilatory threshold (VT), or sedentary control (Passive). The total output work (Total work) during the 2nd Ex in the Leg-Active condition was significantly higher than that in the Passive (299 vs. 282 J · kg body mass^?1 (J · BM^?1)). The values of Total work, peak [Vdot]O₂ and peak heart rate during the 2nd Ex were significantly higher than those during the 1st Ex in both Leg- and Arm-Active. Total CO₂excess after the 1st Ex was significantly higher than that after the 2nd Ex (67.6 vs. 26.0 ml · BM^?1) in Passive. After the 2nd Ex, the Total CO₂excess in the Leg-Active (51.5 ml · BM^?1) was significantly higher than that in both the Passive (26.0) and Arm-Active (36.5), with Arm-Active being significantly higher than Passive. The recovery exercise using previously inactive muscles improved respiratory compensation ability related to performance enhancement.     

Ventilatory Threshold,Running Economy and Distance Running Performance of Trained Athletes

Abstract

The purpose of this study was to assess the relationships among ventilatory threshold T(vent), running economy and distance running performance in a group (N=9) of trained experienced male runners with comparable maximum oxygen uptake ([Vdot]O₂ max). Maximal oxygen uptake and submaximal steady state oxygen uptake were measured using open circuit spirometry during treadmill exercise. Ventilatory threshold was determined during graded treadmill exercise using non-invasive techniques, while distance running performance was assessed by the best finish time in two 10-kilometer (km) road races. The subjects averaged 33.8 minutes on the 10km runs, 68.6 ml · kg ^-1 · min ^-1 for [Vdot]O₂ max, and 48.1 ml · kg ^-1 · min ^-1 for steady state [Vdot]O₂ running at 243 meters · min ^-1. The T(vent) (first deviation from linearity of [Vdot]_E, [Vdot]CO ₂ ) occurred at an oxygen consumption of 41.9 ml · kg ^-1 · min ^-1. The relationship between running economy and performance was r = .51 (p>0.15) and the relationship between T(vent) and performance was r = .94 (p < 0.001). Applying stepwise multiple linear regression, the multiple R did not increase significantly with the addition of variables to the T(vent); however, the combination of [Vdot]O₂ max, running economy and T(vent) was determined to account for the greatest amount of total variance (89%). These data suggest that among trained and experienced runners with similar [Vdot]O₂ max, T(vent) can account for a large portion of the variance in performance during a 10km race.     

Expert-level classification of ventilatory thresholds from cardiopulmonary exercising test data with recurrent neural networks

Abstract

First and second ventilatory thresholds (VT₁ and VT₂) represent the boundaries of the moderate-heavy and heavy-severe exercise intensity. Currently, VTs are primarily detected visually from cardiopulmonary exercise test (CPET) data, beginning with an initial data screening followed by data processing and statistical analysis. Automated VT detection is a challenging task owing to the high signal to noise ratio typical of CPET data. Recurrent neural networks describe a machine learning form of Artificial Intelligence that can be used to uncover complex non-linear relationships between input and output variables. Here we proposed detection of VTs using a single neural network classifier, trained with a database of 228 laboratory CPET data. We tested the neural network performance against the judgement of 7 couples of board-certified exercise-physiologists on 25 CPET tests. The neural network achieved expert-level performances across the tasks (mean absolute error was 9.5% (r?=?0.79) and 4.2% (r?=?0.94) for VT₁ and VT₂, respectively). Estimation errors are compatible with the typical error of the current gold standard visual methodology. The neural network demonstrated VT detecting and exercise intensity level classifying at a high competence level. Neural networks could potentially be embedded in CPET hardware/software to extend the reach of exercise physiologists beyond their laboratories.