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1.
Patrick B. Wilson Stacy J. Ingraham 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(3):270-282
Scarce research has examined the effects of carbohydrate composition on running stride characteristics. On two occasions, 14 males and 6 females completed a 120-min sub-maximal run followed by a 4-mile time trial. Participants consumed glucose (GLU) or glucose–fructose (GLU–FRU) beverages supplying 1.3 g/min carbohydrate. Substrate use, psychological affect [Feeling Scale (FS)], and stride characteristics (stride frequency, stride length, and contact time) were assessed. Effects were expressed as Cohen’s d (90% confidence limits [90% CL]). CLs for stride frequency differences at 53 min (90% CL = 0.04–0.21) and 113 min (90% CL = 0.02–0.24) did not cover 0, indicating a positive effect of GLU–FRU. However, effect sizes were small (d = 0.13) and likely-to-very-likely trivial. Energy expenditure differences at sub-maximal end were very likely trivial (d = 0.08; 90% CL = 0.00–0.17), while FS ratings were possibly higher for GLU–FRU at 50 (d = 0.19; 90% CL = ?0.10–0.48) and 110 min (d = 0.16; 90% CL = ?0.13–0.45). During the time trial, stride length was possibly higher with GLU–FRU (d = 0.13; 90% CL = ?0.08–0.33). Glucose–fructose co-ingestion has no significant effect on stride characteristics during constant-velocity running but may result in slightly higher stride length during self-paced running. 相似文献
2.
补充糖对运动员训练和竞技能力的影响 总被引：8，自引：0，他引：8
运动员饮食中含糖低于“最适宜的”量易诱发过早疲劳。在进行长时间运动时疲劳常因肌糖元排空,其含量低于临界值(50mM/kg湿肌)或血糖浓度降至临界值(3.3mM/L)以下引起,这时运动强度必将显著降低甚或被中止。因此,摄食高糖饮食可增加肌糖元及改善耐力,维持高的训练质量。摄食糖的数量、糖的类型和摄取时间三者都是改善运动后恢复速率的营养策略的组成部分。 相似文献
3.
《European Journal of Sport Science》2013,13(3):259-264
AbstractCarbohydrate (CHO) mouth rinse has been shown to improve time trial performance. Although the exact mechanism remains un-established, research postulates that there are oral cavity receptors which increase neural drive. Increasing the duration of the mouth rinse could potentially increase stimulation of these receptors. The aim of the current investigation was to determine whether the duration of mouth rinse with 6.4% CHO affected 30-min self-selected cycling performance. Eleven male participants (age =24.1±3.9 years) performed three 30-min self-paced trials. On one occasion water was given as a mouth rinse for 5 s without being ingested placebo (PLA), on the other two occasions a 6.4% CHO solution was given for 5 and 10 s. Distance cycled, heart rate, ratings of perceived exertion, cadence, speed and power were recorded throughout all trials. The main findings were that distance cycled during the 10-s mouth rinse trial (20.4±2.3 km) was significantly greater compared to the PLA trial (19.2±2.2 km; P<0.01). There was no difference between the 5- and 10-s trials (P=0.15). However, 10 out of 11 participants cycled further during the 5-s trial compared to PLA, and eight cycled further during the 10-s trial compared to the 5 s. In conclusion, although there was an improvement in distance cycled with the 5-s mouth rinse compared to the PLA it was only significant with 10 s suggesting a dose response to the duration of mouth rinse. 相似文献
4.
Rapid and complete restoration of fluid balance after exercise is an important part of the recovery process, especially in hot, humid conditions, when sweat losses may be high. Rehydration after exercise can only be achieved if the electrolytes lost in sweat, as well as the lost water, are replaced. However, the amount of electrolytes lost in sweat is highly variable between individuals and although the optimum drink may be achieved by matching drink electrolyte intake with sweat electrolyte loss, this is virtually impossible in sport settings. The composition of sweat varies considerably not only between individuals, but also with time during exercise and it is further influenced by the state of acclimatization. A moderate excess of salt intake would appear to be beneficial as far as hydration status is concerned, without any detrimental effects on health, provided that fluid intake is in excess of sweat loss and that renal function is not impaired. To achieve effective rehydration following exercise in the heat, the rehydration beverage should contain moderately high levels of sodium (at least 50 mmol l -1 ), and possibly also some potassium. The addition of substrate is not necessary for rehydration, although a small amount of carbohydrate (< 2%) may improve the rate of intestinal uptake of sodium and water. The volume of beverage consumed should be greater than the volume of sweat lost to provide for the ongoing obligatory urine losses. Therefore, the palatability of the beverage is important. Many individuals may lose substantial amounts of sweat and will therefore have to consume large amounts of replacement fluids and this is more likely to be achieved if the taste is perceived as being pleasant. Water alone is adequate for rehydration purposes when solid food is consumed, as this replaces the electrolytes lost in sweat. However, there are many situations where intake of solid food is not possible or is deliberately avoided and, in these instances, the inclusion of electrolytes in rehydration beverages is essential. Where a second exercise bout has to be performed, replacement of sweat losses is an essential part of the recovery process. Exercise performance will be impaired if complete rehydration is not achieved. 相似文献
5.
Subir Kumar Das Prasunpriya Nayak D. M. Vasudevan 《Indian journal of clinical biochemistry : IJCB》2003,18(2):111-118
A variety of laboratory tests are available to assist in the diagnosis of alcohol consumption and related disorders. The levels
of intake at which laboratory results become abnormal vary from person to person. Laboratory tests are particularly useful
in settings where cooperativeness is suspected or when a history is not available. Several biochemical and hematological tests,
such as γ-glutamyltransferase (GGT) activity, aspartate aminotransferase (AST) activity, high-density lipoprotein cholesterol
(HDL-C) content of serum, and erythrocyte mean corpuscular volume (MCV) are established markers of alcohol intake. Their validity
as markers is based largely on correlations with recent intake at a single time point and on decreases in elevated values
when heavy drinkers abstain from alcohol. These readily available laboratory tests provide important prognostic information
and should be integral part of the assessment of persons with hazardous alcohol consumption. There are several other markers
with considerable potential for more accurate reflection of recent alcohol intake. These include carbohydrate deficient transferrin,
β-hexosaminidase, acetaldehyde adducts and the urinary ratio of serotonin metabolites, 5-hydroxytryptophol and 5-hydroxyindoleacetic
acid. These markers provide hope for more sensitive and specific aids to diagnosis and improved monitoring for intake. 相似文献
6.
Carbohydrate deficient transferrin (CDT) is one of the conventional markers for chronic alcohol consumption, is used by researchers
and clinicians. A number of enzymes are affected by ethanol intake. The induction or inhibition of sialyl transferase and
plasma sialidase may be involved in the CDT level elevation. An alteration of protein transport during post-translational
modification could be a primary mechanism in the impairment of protein metabolism associated with chronic alcohol abuse. Transferrin
being a steroid responsive protein, sex-based hormonal variations might contribute to the lower sensitivity of CDT. Varying
hormonal statuses such as pregnancy, use of contraceptives, menopause/ menstrual cycle can alter iron homeostasis in women.
CDT levels are markedly affected by iron homeostasis. Several CDT assay methods appeared promising, but it is not readily
apparent which technique is the most accurate. Moreover, false-positive results of CDT have been reported in non-alcohol related
hepatic failure and in rare conditions. Therefore clinical interpretation of CDT needs careful assessment in patients with
alcohol-related or non-alcohol-related health disorders. 相似文献
7.
The present study was to test the hypothesis that the plant growth retardants chlorocholine chloride (CCC) and paclobutrazol
(PBZ) could improve the carbohydrate accumulation in lily bulbs by enhancing photosynthetic capacity and changing endogenous
hormones. Plants of Lilium Oriental hybrids ‘Sorbonne’ were treated with a foliar spray of CCC or PBZ (both at 300 mg/L) solution, at six weeks after
planting (6 WAP). The morphological parameters, endogenous hormone contents (gibberellic acid (GA), abscisic acid (ABA), and
indole-3-acetic acid (IAA)), and carbohydrate contents were measured from 6 to 18 WAP, at 2-week intervals. The results showed
that CCC increased the biomass of leaves and stems which might produce more photoassimilates available for transportation
and utilization. However, PBZ treatment suppressed vegetative growth and favored photoassimilate transportation into bulbs.
A slight delay of bud and anthesis formation was observed in both treated plants. CCC and PBZ treatments substantially enhanced
the sucrose contents in leaves probably due to the increase of chlorophyll contents. Treatment with CCC or PBZ decreased GA
but increased IAA contents in lily bulbs which might stimulate starch accumulation and formation of new scales. Our experiment
suggested that CCC or PBZ treatment is an effective method to promote carbohydrate accumulation in lily bulbs. 相似文献
8.
The purpose of this study was to assess the effect of carbohydrate (CHO) feeding during different periods of two 90-min cycling bouts (the first bout began at 09:00?h and the second bout began at 13:30?h) at 60% maximal oxygen uptake ([Vdot]O2max) on saliva flow rate and saliva immunoglobulin A (sIgA) responses to the second exercise bout. The study consisted of three investigations: carbohydrate supplementation during (1) the first hour of the recovery interval (CHO-REC), (2) during the first bout of exercise and (3) during the second bout of exercise. Each investigation included two trials completed in a counterbalanced order and separated by at least 4 days. Participants consumed a lemon-flavoured 10% w/v carbohydrate beverage or placebo (22?ml?·?kg?1 body mass) in the first hour of the recovery interval (n = 8) and 500?ml just before exercise, followed by 250?ml every 20?min during exercise in the first (n = 9) and second exercise bouts (n = 9). Timed unstimulated saliva samples were collected at 10?min before exercise, after 48?–?50?min of exercise and during the last 2?min of exercise, at 1?h post exercise, 2?h post exercise (first exercise bout only), and 18?h post exercise (second exercise bout only). Venous blood samples were taken 5?min before exercise and immediately after exercise for both exercise bouts in all trials. The main findings of the present study were as follows. First, carbohydrate ingestion during both exercise bouts, but not during the recovery interval, better maintained plasma glucose concentrations and attenuated the increase in plasma adrenaline and cortisol concentrations after the second exercise bout compared with placebo. Second, carbohydrate feeding had no effect on saliva flow rate and sIgA secretion rate compared with placebo. Third, saliva flow rate and sIgA concentration returned to pre-exercise bout 1 values within 2?h in all trials. Fourth, there was no delayed effect of exercise on oral immunity. These findings suggest that carbohydrate ingestion during the first or second bout of exercise, but not during the recovery interval, is likely to better maintain plasma glucose concentrations and attenuate the responses of plasma stress hormones to a second exercise bout than ingestion of fluid alone. Two bouts of 90?min cycling at 60% [Vdot]O2max on the same day appears to inhibit saliva flow rate during the second exercise bout but does not alter sIgA transcytosis. Our results show that carbohydrate ingestion during any period of two prolonged exercise bouts does not induce different effects on oral immunity compared with placebo. 相似文献
9.
朱小平 《武汉体育学院学报》1999,(3)
我国运动员在膳食结构中长期地存在着不合理现象,且有随着年代的推进日趋严重的趋势。据此提出若干改进意见,以便使我国运动员在膳食结构中,三大热源质摄入比例合理化 相似文献
10.
脂肪酸的从头合成主要发生在肝脏和脂肪组织,肝脏脂肪酸的合成受到多种因素的调节,文章重点介绍调节脂肪酸合成的核转录因子:肝脏X受体固醇调节元件结合蛋白、碳水化合物反应元件结合蛋白。 相似文献