Interval exercise induces milder respiratory responses compared to continuous exercise

ABSTRACT

The purpose of this study was to explore the respiratory response of acute interval and continuous exercise (CE) of low and high intensity. Fourteen recreational athletes (7 men and 7 women; VO₂max = 35.7 ± 6.1 mlkg^–1min^–1) performed a bout of continuous and a bout of interval exercise (IE) both consisted of 5-min cycling at low intensity [80% of the power output (W) of the predetermined gas exchange threshold (GET) (80%W_GET)] and 5-min cycling at high intensity {W_GET plus the work rate corresponding to 50% of the difference between peak power output (PPO) at oxygen uptake (VO₂max) test and the W_GET [W_GET + 0.50 Δ(PPO – W_GET)]}. CE compared to IE induced significant higher heart rate and ventilation as well as significant higher levels of mouth occlusion pressure for 0.1 s (P_0.1) (P < 0.05) during low and high intensities. Our results indicate that CE stimulates respiration more than IE when the exercise is performed at the same relative intensity.     

四肢伸展体操

腿部伸展二 动作要领 双脚自然分开与肩同宽,右手放在腰胯部,左腿向后伸出,用左手握住左脚尖。,尽量保持身体平衡。保持几秒后交换方向进行。     

Youth exercise intention and past exercise behavior: examining the moderating influences of sex and meeting exercise recommendations

The study purposes were to examine: (a) the determinants of exercise intention and past exercise behavior (PEB) using the theories of reasoned action and planned behavior, and (b) the moderating influences of sex and exercise group (meeting or not meeting exercise guidelines). Participants (n = 676 adolescents) completed self-reported measures of their exercise attitude, subjective norm, perceived behavioral control (PBC), intention, and PEB. We found that attitude, subjective norm, and PBC explained 55% of the variance in intention, and intention and PBC explained 51% of the variance in PEB. While we found sex and exercise group differences across the study measures, we did not find evidence of significant moderation. Thus, the theory constructs predicted intention and PEB similarly across sex and exercise groups.     

Explaining long-term exercise adherence in women who complete a structured exercise program

The purpose of this study was to qualitatively examine factors related to physical activity adherence to understand why women continue to participate in long-term exercise after completing a structured exercise program. Data were collected from focus groups, interviews, and e-mails, and analysis used grounded theory. The central category related to physical activity adherence was self-worth. Motivation, activity enjoyment, priorities, body image, ability to access support, and self-regulation skills had an impact on the self-worth of nonadherers and adherers. Women must value themselves enough to continue to participate in physical activity once they start. Exercise and fitness professionals are encouraged to use strategies to increase self-worth and long-term adherence to physical activity. Some recommended strategies include (a) increasing motivation and enjoyment relative to activity, (b) making activity a high priority in a woman's life, (c) improving or deemphasizing body image, (d) increasing a woman's ability to access support, and (e) facilitating the use of self-regulation strategies. This study is the first to examine qualitative perspectives of exercise adherence among women who completed a structured exercise program. Several concepts related to adherence presented in the quantitative literature are confirmed and enhanced in this study.     

企业职工锻炼动机对职工体育活动的影响

通过文献资料、问卷调查、访谈、数理统计等方法,分析了企业职工锻炼动机对职工体育活动的影响,结果表明：培养和激发企业职工参加体育锻炼的动机是当前职工体育一项重要的任务;在实际的工作中,应运用多种手段和方法来激发企业职工的体育锻炼动机;因人因时因地而异地营造各种体育氛围;加强对体育锻炼价值和体育文化的宣传;增加和改善体育锻炼设施与场所,开发趣味性和启发性强的体育项目激发企业职工参加体育锻炼的内、外部动机,使其能更好的参加体育锻炼活动,达到增强职工健康水平的目的。     

大学生锻炼态度与自我概念、锻炼行为的关系性研究

为了明确大学生锻炼态度及其下位因素与自我概念、锻炼行为之间的关系,采用<锻炼态度>与<自我概念>问卷对普通高校大学生进行问卷调查与分析,结果表明:1)锻炼态度与自我概念存在高度相关(r=0.623,P＜0.000),并存在6条显著路径,但只有4个因素能够非常好地对自我概念有预测作用(P＜0.001);2)锻炼态度各因素对锻炼行为的作用差异较大,五个因素对锻炼行为的直接作用达到显著水平.     

血睾酮与运动

运动应激中下丘脑—垂体—性腺轴(HPG轴)功能低下或紊乱,使睾酮合成降低。其原因可能既有调节因素的变化,也有睾丸间质细胞内一些独立因素的变化。大强度运动早期血睾酮水平上升,随时间延长而下降,而皮质醇水平上升,有人提出用睾酮/皮质醇来评定机体的机能状况。血睾酮的作用机制以及运动引起的血睾酮变化的机制仍不完全清楚,尚待进一步研究。     

HMB与运动能力

HMB（β-羟基-β丁酸甲酯）是亮氨酸代谢的中间产物，能促进蛋白质合成和减少其分解，使机体力量增加，加快脂肪消耗，延缓肌肉疲劳，有助于提高耐力，是一种增加力量，增大肌肉体积，减少体脂的新型营养补剂。现从HMB的来源、作用和与运动训练的关系几方面作一论述，为HMB的合理使用提供参考。     

Carbohydrate feeding during exercise

Abstract

Carbohydrate ingestion can improve endurance capacity and performance. Since the 1980s, research has focused on optimizing the delivery strategies of these carbohydrates. The optimal dose of carbohydrate is still subject to debate, but recent evidence suggests that there may be a dose–response effect as long as the carbohydrate ingested is also oxidized and does not result in gastrointestinal distress. Oxidation rates of a single type of carbohydrate do not exceed 60 g·h^?1. However, when multiple transportable carbohydrates are ingested (i.e. glucose and fructose), these oxidation rates can be increased significantly (up to 105 g·h^?1). To achieve these high oxidation rates, carbohydrate needs to be ingested at high rates and this has often been associated with poor fluid delivery as well as gastrointestinal distress. However, it has been suggested that using multiple transportable carbohydrates may enhance fluid delivery compared with a single carbohydrate and may cause relatively little gastrointestinal distress. More research is needed to investigate the practical applications of some of the recent findings discussed in this review.     

Immune function and exercise

This review will examine the effects of exercise and training on immune func-tion and will discuss the methodological problems that limit the interpretation of many exercise immunology studies. Acute bouts of exercise cause a tempo-rary depression of various aspects of immune function, such as neutrophil oxidative burst, lymphocyte proliferation, monocyte MHC class II expression, and natural killer cell cytotoxic activity, that will usually last for approximately three to 24 hours after exercise, depending on the intensity and duration of the exercise bout. Post-exercise immune function depression is most pronounced when the exercise is continuous, prolonged (<1.5 hours), of moderate to high intensity (55-75% VO₂max), and performed without food intake. Periods of intensified training that result in overreaching have been shown to chronically depress immune function—i.e., immune cell functions measured at rest are still depressed 24 hours after the last exercise bout. Although elite athletes are not clinically immune deficient, it is possible that the combined effects of small changes in several immune parameters may compromise resistance to common minor illnesses such as upper respiratory tract infection. Protracted immune depression linked with prolonged training may determine susceptibility to infection, particularly at times of major competitions.     

Dietary antioxidants and exercise

Muscular exercise promotes the production of radicals and other reactive oxygen species in the working muscle. Growing evidence indicates that reactive oxygen species are responsible for exercise-induced protein oxidation and contribute to muscle fatigue. To protect against exercise-induced oxidative injury, muscle cells contain complex endogenous cellular defence mechanisms (enzymatic and non-enzymatic antioxidants) to eliminate reactive oxygen species. Furthermore, exogenous dietary antioxidants interact with endogenous antioxidants to form a cooperative network of cellular antioxidants. Knowledge that exercise-induced oxidant formation can contribute to muscle fatigue has resulted in numerous investigations examining the effects of antioxidant supplementation on human exercise performance. To date, there is limited evidence that dietary supplementation with antioxidants will improve human performance. Furthermore, it is currently unclear whether regular vigorous exercise increases the need for dietary intake of antioxidants. Clearly, additional research that analyses the antioxidant requirements of individual athletes is needed.     

维生素E与运动

堆生素E是具有抗氧化作用的脂溶性维生素。一些研究认为．急性运动或长期运动训练可能造成血液VE水平的低下，但也有不同结果的报导。VE与机体的抗氧化能力关系密切。但运动后和训练期如何正确补充VE仍是需要探讨的问题。     

Dietary antioxidants and exercise

Muscular exercise promotes the production of radicals and other reactive oxygen species in the working muscle. Growing evidence indicates that reactive oxygen species are responsible for exercise-induced protein oxidation and contribute to muscle fatigue. To protect against exercise-induced oxidative injury, muscle cells contain complex endogenous cellular defence mechanisms (enzymatic and non-enzymatic antioxidants) to eliminate reactive oxygen species. Furthermore, exogenous dietary antioxidants interact with endogenous antioxidants to form a cooperative network of cellular antioxidants. Knowledge that exercise-induced oxidant formation can contribute to muscle fatigue has resulted in numerous investigations examining the effects of antioxidant supplementation on human exercise performance. To date, there is limited evidence that dietary supplementation with antioxidants will improve human performance. Furthermore, it is currently unclear whether regular vigorous exercise increases the need for dietary intake of antioxidants. Clearly, additional research that analyses the antioxidant requirements of individual athletes is needed.     

Effect of time on biomechanics during exercise on the functional re-adaptive exercise device

ABSTRACT

Mechanistic studies of the Functional Re-adaptive Exercise Device (FRED) have shown it automatically recruits Lumbar Multifidus (LM) and Transversus Abdominis (TrA) – two deep-spinal muscles that are atrophied and show altered motor control in low back pain (LBP). No studies have investigated the time required to familiarise to FRED exercise, which is required to inform future FRED based clinical trial protocols. This study therefore determined the effect of time, during FRED exercise, on biomechanical outcome measures, to establish the familiarisation period, and assess for loss of technique throughout a ten minute trial. A cohort comparison study of 148 participants, 70 experiencing low back pain, had lumbopelvic kinematics, exercise frequency and movement variability measured during a 10 minute trial. Magnitude-based inference was used to assess for familiarisation, using plots of variation over time with familiarised reference ranges. The no pain group took 170 seconds, and the back pain group took 150 seconds, to familiarise. A familiarisation period of at least 170 seconds (2.8 minutes) is recommended. This justifies, and provides a familiarisation time for use of the FRED as a motor control intervention.     

膳食脂肪对运动能力的影响及运动时脂代谢的调节

就膳食脂肪对运动能力的影响以及脂肪代谢的调节作一综述。运动强度、时间不同，脂肪供能所占的比例不同，脂肪供能对运动成绩的影响也有所差异。运动时脂代谢的调节受多种因素的影响，激素敏感性甘油三酯脂肪酶(HSL)是酶解速度的主要控制因素。     

Social identification,exercise participation,and positive exercise experiences: Evidence from parkrun

Growing evidence suggests that social identities may have profound implications for physical activity participation. Real-world examinations of this relationship have, however, been lacking, with research predominantly examining intentions and hypothetical scenarios. To address this shortcoming and further advance understanding in this area, the present study tested relationships between group identification, participation, two exercise-specific outcomes (exercise-specific satisfaction and group cohesion), and a broad health indicator (life satisfaction) among individuals recruited from parkrun. Participants (N = 289) completed questionnaires measuring all variables except participants’ parkrun participation, which was objectively assessed. Structural equation modeling demonstrated that group identification was significantly associated with greater participation, exercise-specific satisfaction, group cohesion, and life satisfaction. Findings provide real-world evidence of the health-related benefits associated with forming strong social identities in exercise settings.     

锻炼行为和锻炼动机的性别差异——以高知人员为例的比较研究

对590名高级知识分子作问卷调查,对比分析了两性的健康状况、体育行为和锻炼动机。结果表明：①与男性相比,女性高知人员每次锻炼的时间短,锻炼强度小,两性体育锻炼频率和锻炼坚持差异不显著;②女性高知人员的外貌动机和乐趣动机明显强于男性,是她们参与体育锻炼的主要心理动力,这样的锻炼动机模式使她们选择参与轻松、对抗小和娱乐性强的体育锻炼项目;③高知人员健康状况不存在显著性性别差异,锻炼行为和动机存在的差异符合女性的身心特点,反映出在高知人员中性别平等程度较高。     

抗氧化剂的补充与运动

综述了运动性氧化应激的概念、产生及其与运动的关系，以及以抗氧化剂的研究现状，阐明补充抗氧化剂对运动性氧化应激的作用及运动能力的影响。     

Clinical implications of exercise immunology

Maintaining leanness and a physically active lifestyle during adulthood reduces systemic inflammation, an underlying factor in multiple chronic diseases. The anti-inflammatory influence of near-daily physical activity in lowering C-reactive protein, total blood leukocytes, interleukin-6, and other inflammatory cytokines may play a key role in lowering risk of cardiovascular disease, certain types of cancer, type 2 diabetes, sarcopenia, and dementia. Moderate exercise training causes favorable perturbations in immunity and a reduction in incidence of upper respiratory tract infection (URTI). During each bout of moderate exercise, an enhanced recirculation of immunoglobulins, neutrophils, and natural killer cells occurs that persists for up to 3-h post-exercise. This exercise-induced surge in immune cells from the innate immune system is transient but improves overall surveillance against pathogens. As moderate exercise continues on a near-daily basis for 12–15 weeks, the number of symptoms days with URTI is decreased 25%–50% compared to randomized sedentary controls. Epidemiologic and animal studies support this inverse relationship between URTI risk and increased physical activity.