与青少年有氧能力相关的10个问题

峰值摄氧量（pVO2）是国际公认的青少年有氧能力评估标准,尽管有近八十年的青少年数据,但对它的解释以及它与青少年儿童成长和成熟过程中其他健康相关变量的关系,仍存在争议。有关青少年有氧能力可训练性的争论从未停止,仍然需要解决训练导致变化的因果机制以及根据年龄、生物性成熟、性别等因素进行调整。青少年日常体育活动的特点是间歇性进行和强度的迅速变化,但大多数青少年很少进行用来确定峰值摄氧量的强度和持续时间的体育活动。在这个背景下,肺部摄氧量的瞬态动力学就可以最好地反映青少年的有氧能力。对不同强度运动开始时青少年肺部摄氧量动力学的严格研究非常少,而在运动强度的阶跃变化中,实足年龄、生物性成熟和性别因素的影响并没有得到充分证实。了解青少年肺部摄氧量动力学参数的可训练性主要基于对运动员和非运动员的少量比较研究,对训练导致变化的根本机制仍需进一步探索。文章的目标是对成长和成熟过程中的有氧能力提供简要概述,提高对其评估和解释争议的认识,找出知识差距,提出10个相关的研究问题,并指出未来研究的潜在领域。     

极限负荷时β-内啡肽、睾酮、皮质醇对心肺功能的影响

极限负荷时运动持续时间和运动水平密切相关。研究发现运动后睾酮（T）水平与耗氧平台（VO2maxPD）显著相关,β－内啡肽（β－EP）分泌水平与最大耗氧量,耗氧平台,呼吸频率显著相关。揭示耗氧平台的维系,可能有垂体—性腺轴的参与。而β－内啡肽对呼吸频率及耗氧平台的维系也存在着调控作用。耗氧平台时心率和通气量较之安静时大辐度增长,间接说明儿茶酚胺在极限负荷时对循环系统的支持。     

A new footwear technology to promote non-heelstrike landing and enhance running performance: Fact or fad?

This study sought to compare the kinetics and kinematics data in a group of habitual shod runners when running in traditional running shoes and newly designed minimalist shoes with lug platform. This novel footwear design claims to simulate barefoot running and reduce energy loss during impact. We compared footstrike angle (FSA), vertical average (VALR) and instantaneous (VILR) loading rates, energy loss and initial vertical stiffness between two shoe conditions. Runners demonstrated a decreased FSA while running in minimalist shoes with lug platform than traditional shoes (P = 0.003; Cohen’s d = 0.918). However, we did not observe a landing pattern transition. VALR and VILR between two footwear conditions showed no significant difference (P = 0.191–0.258; Cohen’s d = 0.304–0.460). Initial vertical stiffness (P = 0.032; Cohen’s d = 0.671) and energy loss (P = 0.044; Cohen’s d = 0.578) were greater when running in minimalist shoes with lug platform. The results show that minimalist shoes with lug platform reduce the FSA but may not lead to a landing pattern switch or lower vertical loading rates. Interestingly, the new shoe design leads to a greater energy loss than traditional running shoes, which could be explained by a higher initial vertical stiffness.     

Does moderate-intensity continuous training result in greater total energy expenditure compared to high-intensity interval training?

Recently in the Journal of Sports Sciences, Schaun et al. published a study on the comparison of energy expenditure between high-intensity interval training and moderate continuous training performed in water. With this Letter to the Editor, we would like to comment on the methodological aspects that should be considered to analyze the results presented, as well as the conclusions.

Abbreviations: CONT, moderate-intensity continuous training; EPOC, excess post-exercise oxygen consumption; HIIT, high-intensity interval training; VO2max, maximal oxygen consumption.     

最大吸氧量间接测算全新通用方程及其应用

作者论证了最大吸氧量间接测算全新通用议程组男VO2m,Ka;女,VO2mKa.式中：P,运动强度,单位,瓦;f,运动心率,次／分;n＝0.16－0．21,人机效率;Ka＝1．25~0．01A,A,年龄系数。在A＝25、P＝50~200瓦、f＝120~170次／分之间,方程组VO2m测算范围（1．6~6．0）升／分,包括体力弱者及世界级马拉松运动员,与奥斯特兰德实测数序表偏差不大于3％。     

评定有氧工作能力指标的探讨

对不同训练水平、不同性别的６０名受试者进行了摄氧量、心率及氧脉搏的测定,其目的是通过比较优选评定有氧工作能力的指标。结果显示：在此方面,由于公斤体重的氧脉搏可同时消除体重和心率等因素的影响,故它比最大摄氧量更为客观。     

Comparison of lower limb muscle architecture and geometry in distance runners with rearfoot and forefoot strike pattern

ABSTRACT

We examined the association between footfall pattern and characteristics of lower limb muscle function and compared lower limb muscle function between forefoot and rearfoot runners. Fifteen rearfoot and 16 forefoot runners were evaluated using ultrasonography of the gastrocnemii and tibialis anterior while strike index and heel strike angle quantified footfall pattern. Higher strike index was associated with lower medial gastrocnemius echo intensity (p = 0.05), lower lateral gastrocnemius echo intensity (p = 0.04), smaller tibialis anterior pennation angle (p = 0.05), and longer lateral gastrocnemius fascicle length (p = 0.04). Larger heel strike angle was associated with smaller medial gastrocnemius cross-sectional area (p = 0.04), shorter lateral gastrocnemius fascicle length (p < 0.01), and lower plantar flexion moment (p < 0.01). Larger plantar flexion moment was associated with lesser medial gastrocnemius echo intensity (p = 0.04), lesser lateral gastrocnemius echo intensity (p = 0.03), and greater lateral gastrocnemius fascicle length (p = 0.02). A smaller plantar flexion moment, larger heel strike angle, lower tibialis anterior echo intensity, larger tibialis anterior pennation angle, and smaller lateral gastrocnemius pennation angle were observed in rearfoot compared to forefoot runners (p < 0.05). Lower limb muscle architecture is associated with footfall pattern and ankle mechanics during running.

Abbreviation: EMG: electromyographic; MG: medial gastrocnemius; LG: lateral gastrocnemius; TA: tibialis anterior; EI: echo intensity; CSA: cross-sectional area; PA: pennation angle; FL: fascicle length; FT: fat thickness     

游泳运动员最大吸氧量与成绩关系的研究

通过对游泳运动员水中最大吸氧量的测试,探讨游泳运动员最大吸氧量与运动成绩的关系。表明ＶＯ２ｍａｘ相对值与４００米、１５００米相关系数密切,并具依从关系。     

The Relationship Between Running Economy and Biomechanical Variables in Distance Runners

In this study, we analyzed the relationship between running economy (RE) and biomechanical parameters in a group running at the same relative intensity and same absolute velocity. Sixteen homogeneous male long-distance runners performed a test to determine RE at 4.4 m.s^-1, corresponding to 11.1% below velocity at the ventilatory threshold. We found significant correlations between RE and biomechanical variables (vertical oscillation of the center of mass, stride frequency, stride length, balance time, relative stride length, range of elbow motion, internal knee, ankle angles at foot strike, and electromyographic activity of the semitendinosus and rectus femoris muscles). In conclusion, changes in running technique can influence RE and lead to improved running performance.     

Aerobic Demand of Running Shoes Designed to Exploit Energy Storage and Return

This qualitative case study used tenets of critical race theory and a single focus group and individual interviews with 4 African American football athletes at a predominantly White institution of higher education (PWIHE) in an effort to bring the voices of this marginalized group into the dialogue on issues concerning institutional integrity in college sport. Institutional integrity involves an athletic program's actual commitment to the educational interests of college athletes as expressed through their structures, functions, and activities. Three themes emerged from the data: (a) there is a need for more African American role models in leadership positions within the athletic departments of these PWIHE; (b) there is a need for more financial support for athletes; and (c) African American athletes should be given a platform to voice concerns. These findings have implications for those educational stakeholders and researchers who are genuinely concerned with institutional integrity in college sport.     

健身健美操对大学生最大摄氧量的影响研究——以武汉科技大学为例

运用抽样调查、实验和比较研究法研究武汉科技大学学生的最大摄氧量。结论显示:健身健美操能显著改善大学生的心血管机能;足球、篮球、羽毛球和网球项目相比,改善效果更显著;对女生心血管机能的改善程度大于男生。     

Effects of footwear midsole thickness on running biomechanics

Shoe manufacturers launch running shoes with increased (e.g., maximalists) or decreased (e.g., minimalists) midsole thickness and claim that they may prevent running injury. Previous studies tested footwear models with different midsole thicknesses on the market but the shoe construct was not strictly comparable. Therefore, in the present study, we examined the effect of midsole thickness, from 1-mm to 29-mm, in a standard test shoe prototype on the vertical loading rates, footstrike angle and temporal spatial parameters in distance runners. Fifteen male habitual rearfoot strikers were recruited from local running clubs. They were asked to run on an instrumented treadmill in shoes with different midsole thicknesses. We found significant interactions between midsole thickness with vertical loading rates (p < 0.001), footstrike angle (p = 0.013), contact time (p < 0.001), cadence (p = 0.003), and stride length (p = 0.004). Specifically, shoes with thinner midsole (1- and 5-mm) significantly increased the vertical loading rates and shortened the contact time, when compared with thicker midsole shoes (25- and 29-mm). However, we did not observe any substantial differences in the footstrike angle, cadence and stride length between other shod conditions. The present study provides biomechanical data regarding the relationship between full spectrum midsole thicknesses and running biomechanics in a group of rearfoot strikers.     

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。     

Blood lactate recovery and respiratory responses during diagonal skiing of variable intensity

Abstract

The aims of the study were to investigate blood lactate recovery and respiratory variables during diagonal skiing of variable intensity in skiers at different performance levels. Twelve male cross-country skiers classified as elite (n=6; [Vdot]O_2max=73±3 ml · kg^?1 · min^?1) or moderately trained (n=6; [Vdot]O_2max=61±5 ml · kg^?1 · min^?1) performed a 48-min variable intensity protocol on a treadmill using the diagonal stride technique on roller skis, alternating between 3 min at 90% and 6 min at 70% of [Vdot]O_2max. None of the moderately trained skiers were able to complete the variable intensity protocol and there was a difference in time to exhaustion between the two groups (elite: 45.0±7.3 min; moderately trained: 31.4±10.4 min) (P<0.05). The elite skiers had lower blood lactate concentrations and higher blood base excess concentrations at all 70% workloads than the moderately trained skiers (all P<0.05). In contrast, [Vdot] _E/[Vdot]O₂ and [Vdot] _E/[Vdot]CO₂ at the 70% [Vdot]O_2max workloads decreased independently of group (P<0.05). Partial correlations showed that [Vdot]O_2max was related to blood lactate at the first and second intervals at 70% of [Vdot]O_2max (r=?0.81 and r=?0.82; both P<0.01) but not to [Vdot] _E/[Vdot]O₂, [Vdot] _E/[Vdot]CO₂ or the respiratory exchange ratio. Our results demonstrate that during diagonal skiing of variable intensity, (1) elite skiers have superior blood lactate recovery compared with moderately trained skiers, who did not show any lactate recovery at 70% of [Vdot]O_2max, suggesting it is an important characteristic for performance; and (2) the decreases in respiratory exchange ratio, [Vdot] _E/[Vdot]O₂, and [Vdot] _E/[Vdot]CO₂ do not differ between elite and moderately trained skiers.     

Within- and Between-Day Repeatability and Variability in Children's Physiological Responses During Submaximal Treadmill Exercise

The purpose of this study was to verify within- and between-day repeatability and variability in children's oxygen uptake (VO₂), gross economy (GE; VO₂ divided by speed) and heart rate (HR) during treadmill walking based on self-selected speed (SS). Fourteen children (10.1 ± 1.4 years) undertook three testing sessions over 2 days in which four walking speeds, including SS were tested. Within- and between-day repeatability were assessed using the Bland and Altman method, and coefficients of variability (CV) were determined for each child across exercise bouts and averaged to obtain a mean group CV value for VO₂, GE, and HR per speed. Repeated measures analysis of variance showed no statistically significant differences in within- or between-day CV for VO₂, GE, or HR at any speed. Repeatability within- and between-day for VO₂, GE, and HR for all speeds was verified. These results suggest that submaximal VO₂ during treadmill walking is stable and reproducible at a range of speeds based on children's SS.     

Peak aerobic power and paddling efficiency in recreational and competitive junior male surfers

Abstract

The purpose of the present study was to measure and compare peak oxygen uptake and paddling efficiency in recreational and competitive junior male surfers. Eight male recreational surfers (mean age 18 years, s=2; mass 66.8 kg, s=13.0; height 1.75 m, s=0.10) and eight male competitive surfers (mean age 18 years, s=1; mass 68.0 kg, s=11.7; height 1.72 m, s=0.10) performed an incremental paddling test consisting of four 3-min constant load work stages followed by a ramp increase in power output of 20 W · 30 s^?1 until exhaustion. The oxygen uptake–power output relationship of the four constant load work stages and peak values obtained during the incremental paddling test were used to calculate paddling efficiency. No differences (P>0.05) were observed between the recreational and competitive surfers for peak oxygen uptake (recreational: 2.52 litres · min^?1, s=0.5; competitive: 2.66 litres · min^?1, s=0.35) or efficiency (recreational: 24%, s=3; competitive: 21%, s=4). Blood lactate concentration was significantly greater in recreational (2.4 mmol · l^?1, s=0.9) than competitive surfers (1.6 mmol · l^?1, s=0.5) during submaximal paddling. There were no differences in peak oxygen uptake or paddling efficiency between recreational and competitive surfers suggesting that peak oxygen uptake and efficiency are not sensitive to differences in surfing ability. The increase in blood lactate concentration during submaximal paddling in recreational compared with competitive surfers suggests that other determinants of paddling endurance, such as blood lactate threshold, might be better at distinguishing surfers of differing ability.