Autonomic response to a short and long bout of high-intensity functional training

The evaluation of Autonomic Nervous System (ANS) recovery following exercise provides insight into the transient stress placed on the cardiovascular system. High-Intensity Functional Training (HIFT) is a form of intense exercise that is prescribed in various modalities and durations; however, little is known about the influence of HIFT duration on ANS recovery. Ten apparently healthy males (28.1 ± 5.4 yrs) performed two HIFT sessions (<5-minute and 15-minute) in a crossover fashion. ANS activity was measured using plasma Epinephrine (E) and Norepineprine (NE); Heart Rate Variability markers of the log transformed Root Mean Square of Successive Differences (lnRMSSD) and High-Frequency power (lnHF). No trial dependent differences were observed in lnRMSSD (p = 0.822), lnHF (p = 0.886), E (p = 0.078), or NE (p = 0.194). A significant main time effect was observed in both trials with a depression in lnRMSSD and lnHF following the trials (p < 0.05) and recovering by 2-hours post (p = 0.141, p > 0.999) respectively. A trial dependent increase in E and NE occurred immediately post (p < 0.05) and recovered by 1-hour post (p > 0.999, p > 0.999) respectively. The HIFT bouts examined within this study demonstrated similar transient strain of the ANS.     

关于最大摄氧量的限制因素

影响最大摄氧量的生理学因素有:氧运输系统被称为中枢因素,骨骼肌氧利用系统被称为外周因素。研究表明,运动形式不同,限制因素不同。心肺系统是人体在完成最大全身运动时最大摄氧量的限制因素,而骨骼肌内外周氧扩散梯度及线粒体容量是人体在完成局部肌肉活动或单侧肢体运动时起主要限制作用。而线粒体容量和氧运输能力在解释不同动物物种间的最大摄氧量差异时是很重要的。     

与最大摄氧量相关的单核苷酸多态性的研究进展

最大摄氧量是与运动成绩及心血管疾病发生密切相关的一个生理学指标。作为第三代DNA多态性标志,单核苷酸多态性能在一定程度上反映人类个体或群体的特异性。寻找并确认影响最大摄氧量的基因位点及单核苷酸多态性对耐力项目的科学选材及心肺功能的合理训练具有重要价值,对心血管疾病运动处方的制定和评价也有一定的参考价值。     

Alterations in autonomic cardiac modulation in response to normobaric hypoxia

Purpose: The present study aimed to determine if autonomic cardiac modulation was influenced by acute exposure to normobaric hypoxia. Method: Ten healthy male lowland dwellers completed five block-randomised single-blinded, crossed-over acute exposures to a normobaric hypoxic environment, each separated by 24 hours’ recovery (20.3%, 17.4%, 14.5%, 12.0% and 9.8% F_IO₂). Supine recordings were made of arterial oxygen saturation and electrocardiogram (ECG). RR intervals from the ECG trace were analysed for time (SDNN, lnrMSSD), frequency (lnVLF, lnLF, lnHF, lnTP, LFnu, and HFnu), and nonlinear (DFA-α1 and SampEn) heart rate variability components. Results: A significant reduction in arterial SaO₂ occurred with reduced F_IO₂, along with a rise in heart rate (Cohen’s d?=?1.16, 95% Confidence Interval [2.64–6.46]), significant at 9.8% F_IO₂. A decrease in autonomic cardiac modulation was also found as shown by a statistically significant (at 9.8% F_IO₂) decrease in lnTP (d?=?1.84 [1.74–1.94]), and SampEn (d?=?0.98 [0.83–1.12]) and an increase in DFA-α₁ (d?=?0.72 [0.60–0.84]) from normoxia at 9.8% F_IO₂. Conclusion: The decrease in variability indicated a reduction in autonomic cardiac modulation. There appears to be a threshold ～9.8% F_IO₂ (～6000?m equiv.), below which significant alterations in autonomic control occur.     

超重和肥胖少年心肺功能下降及与身体成分的相关性

对12~14岁正常体重少年40名(男生22人,女生18人)与超重和肥胖少年84名(男生45人,女生39人)进行了最大耗氧量(V。O2max)、最大心率、身体成分、血压、脉搏、肺活量的测试。其中,V。O2max采用改良的Bruce方案,用电阻抗法(BIA)测身体成分。结果表明:12~14岁超重和肥胖少年心肺功能明显低于同龄正常体重少年,高正常血压者和高血压者占32.92%,但血压升高与身体成分变化相关性不明显;肥胖少年肺活量/体重显著下降,男性与体脂百分比呈中度负相关;肥胖少年V。O2max/BM显著下降,V。O2max/BM与身体成分的变化有一定相关性,但不是主要影响因素;肥胖对最大心率影响不明显,此年龄段肥胖少年和正常体重少年的最大心率平均值分别为194次/min和197次/min。     

The sensitivity of the alternative maximal accumulated oxygen deficit method to discriminate training status

The purpose of the study was to investigate the sensitivity of an alternative maximal accumulated oxygen deficit (MAOD_ALT) method to discriminate the “anaerobic” capacity while comparing: least trained (LT) participants (n = 12), moderately trained (MT) participants (n = 12), endurance trained (ET) participants (n = 16), and rugby (RG) players (n = 11). Participants underwent a graded exercise test on a treadmill and a supramaximal effort for assessing MAOD_ALT. MAOD_ALT was calculated as the sum of oxygen equivalents from the phosphagen and glycolytic metabolic pathways. MAOD_ALT was significantly higher (P < 0.05) in RG (64.4 ± 12.1 mL · kg^?1) than in ET (56.8 ± 5.4 mL · kg^?1; effect size [ES] = 0.77; +13.5%), MT (53.8 ± 5.3 mL · kg^?1; ES = 1.08; +19.8%), and LT (49.9 ± 4.5 mL · kg^?1; ES = 1.50; +36.4%). In addition, the magnitude-based inference analysis revealed that MAOD_ALT was likely (LT vs. MT), very likely (MT vs. RG, and ET vs. RG) and most likely (LT vs. ET, and LT vs. RG) different between all groups, except for MT and ET, which presented an unclear difference. In conclusion, MAOD_ALT was sensitive enough to distinguish the “anaerobic” capacity in individuals with different training status, especially for RG players compared with LT participants and MT participants.     

RPE6-20量表预测最 氧量的实验研究进展

基于运动过程中人体心、生理对运动负荷与强度的整体感知与反映,Rating of Perceived Exertion (RPE)量表用以预测机体最大摄氧量的信效度已得到众多实验研究的证实.但由于RPE值本身具有主观性,易受人群特征影响,因此,其利用RPE量表对最大摄氧量的预测结果存在争议性.采用文献综述的方法,对现有研究中采用的RPE量表模式、实验对象、RPE6-20量表区段值与临界值、运动形式与负荷以及运动器材等方面予以概述和总结.建议:在扩大群体样本量的基础上,统一实验环境与实验程序,针对某一个或几个相似性因素群进行研究与验证;在实际应用过程中则应因人而异地选择和利用相应的程序、方法,建议与其它预测指标(如心率)相结合,以提高预测最大摄氧量的准确性.     

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.     

跑节省化、无氧阈和最大摄氧量评价篮球运动员有氧能力的比较研究

以天津商务职业学院24名男篮球队员为研究对象,通过跑台测试、因子分析法等,采用跑节省化、无氧阈和最大摄氧量对篮球运动员进行评价分析。结果显示:篮球运动员跑节省化的修正值在第一公因子中载荷最大,在第二、第三公因子中跑节省化相关指标的载荷量处于相对重要位置,在第四公因子中只有跑节省化时通气量;跑节省化、无氧阈和最大摄氧量三指标在评价篮球运动员有氧耐力时,跑节省化指标优势明显。提示:跑节省化可以作为评价篮球运动员有氧耐力的首选指标。     

Prediction of maximal oxygen uptake from a 20-m shuttle run as measured directly in runners and squash players

Abstract

The aim of this study was to assess the validity of the multistage shuttle run test in predicting maximal oxygen uptake (VO ₂ max) in athletes trained in sports with different physical demands. Over a 14-day period, 10 male long-distance runners (continuous high-intensity exercise) and 10 male squash players (intermittent high-intensity exercise) performed, in random order, the multistage shuttle run test and a maximal treadmill protocol of increasing elevation which elicited VO ₂ max. Compared with direct measurement of VO ₂ max, the shuttle run test significantly underpredicted the VO ₂ max of the group of runners (n=10; P<0.01) and of the athletes as a whole (n=20; P<0.01). The correlation (r) between VO ₂ max determined by the shuttle run test and by the treadmill protocol was 0.61 (P<0.05) for the squash players, 0.71 (P<0.05) for the runners and 0.67 (P<0.01) for the athletes as a whole. As the subjects represented athletes trained specifically in sports with different physical demands, this may explain why the correlations between the shuttle run test and direct measurement of VO ₂ max are less robust than those reported in previous studies. Furthermore, our results indicate that there are sport-specific differences when predicting VO ₂ max from the multistage shuttle run test.     

有氧运动对大鼠心血管自主神经调节功能的影响

首先对心率变异性（HRV）和动脉压力反射敏感性（BRS）的测试分析方法进行了选取和改进,然后以正常大鼠为实验对象,观察比较尾动脉血压、脉搏、左室内压、心肌收缩力、心率变异性、动脉压力反射敏感性等指标在8周中等强度游泳运动组大鼠和和安静对照组大鼠之间的差异,旨在分析长期参加有氧运动对心血管自主神经调节功能的影响,为心血管自主神经平衡状态发生改变提供实验证据。研究发现,与对照组大鼠相比,运动组大鼠心肌出现肥大、心脏泵血功能增强、心交感神经介导的动脉压力反射敏感性升高、心迷走神经介导的动脉压力反射敏感性未受影响、心交感神经紧张性变异和心迷走神经紧张性变异程度均增加。研究结果提示,长期有氧运动可增强心血管自主神经的调节功能,使交感神经和副交感神经的协调与对抗关系在一个更高的功能层面上建立新的平衡。     

Six high-intensity interval training sessions over 5 days increases maximal oxygen uptake,endurance capacity,and sub-maximal exercise fat oxidation as much as 6 high-intensity interval training sessions over 2 weeks

BackgroundHigh-intensity interval training (HIIT) induces similar or even superior adaptations compared to continuous endurance training. Indeed, just 6 HIIT sessions over 2 weeks significantly improves maximal oxygen uptake (VO_2max), submaximal exercise fat oxidation, and endurance performance. Whether even faster adaptations can be achieved with HIIT is not known. Thus, we aimed to determine whether 2 sessions of HIIT per day, separated by 3 h, every other day for 5 days (double HIIT (HIIT-D), n = 15) could increase VO_2max, submaximal exercise fat oxidation, and endurance capacity as effectively as 6 sessions of HIIT over 2 weeks (single HIIT (HIIT-S), n = 13).MethodsEach training session consisted of 10 × 60 s of cycling at 100% of VO_2max interspersed with 75 s of low-intensity cycling at 60 watt (W). Pre- and post-training assessments included VO_2max, time to exhaustion at ∼80% of VO_2max, and 60-min cycling trials at ∼67% of VO_2max.ResultsSimilar increases (p < 0.05) in VO_2max (HIIT-D: 7.7% vs. HIIT-S: 6.0%, p > 0.05) and endurance capacity (HIIT-D: 80.1% vs. HIIT-S: 79.2%, p > 0.05) were observed. Submaximal exercise carbohydrate oxidation was reduced in the 2 groups after exercise training (HIIT-D: 9.2%, p = 0.014 vs. HIIT-S: 18.8%, p = 0.012) while submaximal exercise fat oxidation was significantly increased in HIIT-D (15.5%, p = 0.048) but not in HIIT-S (9.3%, p = 0.290).ConclusionSix HIIT sessions over 5 days was as effective in increasing VO_2max and endurance capacity and was more effective in improving submaximal exercise fat oxidation than 6 HIIT sessions over 2 weeks.     

The Effect of Adding External Weight on the Aerobic Requirement of Bench Stepping

Purpose

As there is little research that investigates the experiences of minority boys participating in youth development programs (Fashola, 2003), the current research focused on a sport-based youth development program for early adolescent Black and Latino boys in Hartford, CT. Specifically, the present study explored (a) what attracted minority boys to participate in youth development programs, (b) what kept them involved, and (c) whether their involvement translated into positive developmental outcomes.

Method

The study used semistructured individual interviews to collect data from 8 participants and their parents. The research team deductively coded interviews in accordance with the a-priori framework of the Five Cs and Sixth C of youth development (i.e., competence, character, caring, confidence, connection, and contribution; Roth &; Brooks-Gunn, 2003). In addition, interviews were deductively coded to investigate why participants became involved in the program and why they continued participation.

Results

Findings from the study indicated that participants became involved with the Sport Hartford Boys (SHB) program mainly due to its emphasis on sport-related activities. Moreover, findings related to the youths' continued involvement revealed their value for the SHB program as a safe place that kept them out of trouble and provided experiences that led to positive personal development. Furthermore, results indicated that participation in the program facilitated the development of each “C” of youth development.

Conclusion

By promoting positive relationships and providing opportunities for self-exploration in a safe and trusting environment, afterschool programs can cultivate positive youth development in minority boys, at least in the short term.     

广播体操锻炼对女大学生心脏自主神经调节功能影响的实验研究

目的:采用HRV时域和频域分析指标对第八套广播体操锻炼对心脏自主神经的调节作用进行新的评价。方法:选取女大学生志愿者34名作为受试对象,随机分为三组:对照组(n=12)、实验一组(n=11)及实验二组(n=11)。实验一组和实验二组进行为期8周的第八套广播体操锻炼(每周5天,每天1次,其中实验一组每次连续做2遍广播操,实验二组每次做4遍),对照组不进行任何相关锻炼。用polar心率表(S810i,芬兰)记录了做广播操前、中、后即刻、后5分钟的心率及锻炼开始前、锻炼4周后、锻炼8周后安静状态下的心率,并采用专门软件对5分钟间期的心率变异性进行时域和频域分析。结果:①做第八套广播体操运动时RMSSD和HFnorm较运动前呈显著性降低,运动后5分钟仍未恢复至正常水平。而SD和LFnorm较运动前呈显著性升高,运动后5分钟仍未恢复至正常水平。LF/HF运动中及运动后即刻均较运动前显著增加,运动后5分钟恢复。②无论是实验一组还是实验二组经过8周的广播体操锻炼,可使安静时SD均呈现显著降低。结论:广播体操锻炼时表现为心交感神经紧张性增强、迷走神经紧张性降低,总体效应可持续至运动后5分钟。8周广播体操锻炼可以显著降低安静状态下心交感神经的紧张度。     

Energy expenditure and EPOC between water-based high-intensity interval training and moderate-intensity continuous training sessions in healthy women

The present study compared the energy expenditure (EE) during and after two water aerobics protocols, high-intensity interval training (HIIT) and moderate continuous training (CONT). A crossover randomized design was employed comprising 11 healthy young women. HIIT consisted of eight 20s bouts at 130% of the cadence associated with the maximal oxygen consumption (measured in the aquatic environment) with 10s passive rest. CONT corresponded to 30 min at a heart rate equivalent to 90–95% of the second ventilatory threshold. EE was measured during and 30 min before and after the protocols and excess post-exercise oxygen consumption (EPOC) was calculated. Total EE during session was higher in CONT (227.62 ± 31.69 kcal) compared to HIIT (39.91 ± 4.24 kcal), while EE per minute was greater in HIIT (9.98 ± 1.06 kcal) than in CONT (7.58 ± 1.07 kcal). Post-exercise EE (64.48 ± 3.50 vs. 63.65 ± 10.39 kcal) and EPOC (22.53 ± 4.98 vs.22.10 ± 8.00 kcal) were not different between HIIT and CONT, respectively. Additionally, oxygen uptake had already returned to baseline fifteen minutes post-exercise. These suggest that a water aerobics CONT session results in post-exercise EE and EPOC comparable to HIIT despite the latter supramaximal nature. Still, CONT results in higher total EE.     

3-min all-out effort on cycle ergometer is valid to estimate the anaerobic capacity by measurement of blood lactate and excess post-exercise oxygen consumption

The purpose of this study was to investigate the use of a single 3-min all-out maximal effort to estimate anaerobic capacity (AC) through the lactate and excess post-exercise oxygen consumption (EPOC) response methods (AC_{[La^?]+EPOCfast}) on a cycle ergometer. Eleven physically active men (age?=?28.1?±?4.0?yrs, height?=?175.1?±?4.2?cm, body mass?=?74.8?±?11.9?kg and ?O_2max?=?40.7?±?7.3?mL?kg^?1?min^?1), participated in the study and performed: i) five submaximal efforts, ii) a supramaximal effort at 115% of intensity of ?O_2max, and iii) a 3-min all-out maximal effort. Anaerobic capacity was estimated using the supramaximal effort through conventional maximal accumulated oxygen deficit (MAOD) and also through the sum of oxygen equivalents from the glycolytic (fast component of excess post-exercise oxygen consumption) and phosphagen pathways (blood lactate accumulation) (AC_{[La^?]+EPOCfast}), while during the 3-min all-out maximal effort the anaerobic capacity was estimated using the AC_{[La^?]+EPOCfast} procedure. There were no significant differences between the three methods (p?>?0.05). Additionally, the anaerobic capacity estimated during the 3-min all-out effort was significantly correlated with the MAOD (r?=?0.74; p?=?0.009) and AC_{[La^?]+EPOCfast} methods (r?=?0.65; p?=?0.029). Therefore, it is possible to conclude that the 3-min all-out effort is valid to estimate anaerobic capacity in physically active men during a single cycle ergometer effort.     

应用PWC_(170)、VU_(2max)及RPQ评价运动处方健身效果的研究

运动处方是健身锻炼科学化的要求,本文对28例大学生实施不同强度(男75％VO_(2max),女65％VO_(2max))和不同内容(篮球和健美操)的运动处方前后进行PWC_(170)、VO_(2max)、RPQ等生理指标的测定,评价运动处方健身效果,也为探讨应用PWC_(170)、VO_(2max)、RPQ指标对运动处方效果进行评价的可行性提供实验依据。     

Effect of asthma and six-months high-intensity interval training on heart rate variability during exercise in adolescents

ABSTRACT

Little is known regarding the influence of asthma and exercise, and their interaction, on heart rate variability (HRV) in adolescents.

Thirty-one adolescents with asthma (13.7±0.9 years; 21.9±3.9 kg·m^?2; 19 boys, 12 girls) and thirty-three healthy adolescents (13.8±0.9 years; 20.3±3.2 kg·m^?2; 16 boys, 17 girls) completed an incremental ramp test and three heavy-intensity constant-work-rate cycle tests. Thirteen adolescents (7 boys, 6 girls; 6 asthma, 7 control) completed six-months high-intensity interval training (HIIT) and were compared to age- and sex-matched controls. Standard time-domain, frequency-domain and non-linear indices of HRV were derived at baseline, three- and six-months.

Asthma did not influence HRV at baseline or following HIIT. Total power, low frequency and normalised low frequency power, and sympathovagal balance increased at three-months in HIIT, subsequently declining towards baseline at six-months. Normalised high frequency power was reduced at three-months in both groups, which was sustained at six-months. No effects of HIIT were observed in the time-domain nor in the non-linear indices.

HRV was not influenced by asthma, potentially because such derangements are a function of disease progression, severity or duration. HIIT may be associated with a short-term shift towards greater sympathetic predominance during exercise, perhaps caused by physiological overload and fatigue.