Abstract:
NEW FINDINGS:What is the central question of this study? Does the magnitude of neuromuscular fatigue depend on the amount of work done (W') at task failure when cycling above critical power (CP)? What is the main finding and its importance? Creatine supplementation increases W' and enhances supra-CP performance, but induces similar magnitudes of neuromuscular fatigue at task failure compared to placebo. Increased W' does not lead to higher levels of neuromuscular fatigue. This supports the notion of a critical level of neuromuscular fatigue at task failure and challenges a direct causative link between W' depletion and neuromuscular fatigue. ABSTRACT:The present study examined the effect of creatine supplementation on neuromuscular fatigue and exercise tolerance when cycling above critical power (CP). Eleven males performed an incremental cycling test with four to five constant-load trials to task failure (TTF) to obtain asymptote (CP) and curvature constant (W') of the power-duration relationship, followed by three constant-load supra-CP trials: (1) one TTF following placebo supplementation (PLA); (2) one TTF following creatine supplementation (CRE); and (3) one trial of equal duration to PLA following creatine supplementation (ISO). Neuromuscular assessment of the right knee extensors was performed pre- and post-exercise to measure maximal voluntary contraction (MVC), twitch forces evoked by single (Qpot ) and paired high- (PS100) and low- (PS10) frequency stimulations and voluntary activation. Creatine supplementation increased TTF in CRE vs. PLA by ∼11% (P = 0.017) and work done above CP by ∼10% (P = 0.015), with no difference (P > 0.05) in reductions in MVC (-24 ± 8% vs. -20 ± 9%), Qpot (-39 ± 13% vs. -32 ± 14%), PS10 (-42 ± 14% vs. -36 ± 13%), PS100 (-25 ± 10% vs. -18 ± 12%) and voluntary activation (-7 ± 8% vs. -5 ± 7%). No significant difference was found between ISO and either PLA or CRE (P > 0.05). These findings suggest similar levels of neuromuscular fatigue can be found following supra-CP cycling despite increases in performance time and amount of work done above CP, supporting the notion of a critical level of neuromuscular fatigue and challenging a direct causative link between W' depletion and neuromuscular fatigue.
journal_name
Exp Physioljournal_title
Experimental physiologyauthors
Schäfer LU,Hayes M,Dekerle Jdoi
10.1113/EP087886subject
Has Abstractpub_date
2019-12-01 00:00:00pages
1881-1891issue
12eissn
0958-0670issn
1469-445Xjournal_volume
104pub_type
杂志文章,随机对照试验abstract::Chronic heart failure (CHF) impairs muscle O2 delivery (QO2) and, at a given O2 uptake (VO2), lowers microvascular O2 pressures (PmvO2: determined by the QO2-to-VO2 ratio), which may impair recovery of high-energy phosphates following exercise. Because CHF preferentially decreases QO2 to slow-twitch muscles, we hypoth...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2004.027367
更新日期:2004-07-01 00:00:00
abstract::An energy-rich diet leads to enhanced ruminal Na(+) absorption, which is associated with elevated plasma insulin-like growth factor 1 (IGF-1) levels and an increased number of IGF-1 receptors in rumen papillae. This study examined the in vitro effect of IGF-1 on Na(+) transport across the rumen epithelium of hay-fed s...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2011.061580
更新日期:2012-04-01 00:00:00
abstract::Appreciation for the role of aldosterone and mineralocorticoid receptors in cardiovascular disease is accelerating rapidly. Recent experimental work has unveiled a strong relationship between brain mineralocorticoid receptors and sympathetic drive, an important determinant of outcome in heart failure and hypertension....
journal_title:Experimental physiology
pub_type: 杂志文章,评审
doi:10.1113/expphysiol.2008.045948
更新日期:2010-01-01 00:00:00
abstract::Previously, we undertook simultaneous recording of ventilation and pulmonary gas exchange in mice and revealed that dopamine D(2) receptors participate in exercise hyperpnoea via behavioural control of ventilation with unchanged pulmonary gas exchange. Here, we examined the hypothesis that D(1) receptors also contribu...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2012.068312
更新日期:2013-02-01 00:00:00
abstract::Moderate-intensity endurance exercise training improves vascular endothelial vasomotor function; however, the impact of high-intensity exercise training has been equivocal. Thus, the effect of the physiological stress of the exercise remains poorly understood. Furthermore, enhanced vascular repair mediated by circulat...
journal_title:Experimental physiology
pub_type: 临床试验,杂志文章
doi:10.1113/expphysiol.2011.062836
更新日期:2012-03-01 00:00:00
abstract::Power spectral analysis of heart rate variability has often been used to assess cardiac autonomic function; however, the relationship of low-frequency (LF) power of heart rate variability to cardiac sympathetic tone has been unclear. With or without adjustment for high-frequency (HF) power, total power or respiration,...
journal_title:Experimental physiology
pub_type: 杂志文章,评审
doi:10.1113/expphysiol.2010.056259
更新日期:2011-12-01 00:00:00
abstract::We have functionally expressed and identified a monocarboxylate transporter (MCT1) from rat jejunal enterocyte and we provide evidence for its basolateral localization. Poly(A)+ RNA isolated from rat jejunum was injected into Xenopus laevis oocytes and expression of a proton-lactate symporter was investigated by means...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:
更新日期:1999-11-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? We investigated whether 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) could prevent acute increases in body fat and changes in omental and subcutaneous adipose tissue following the sudden transition from physical activity to physical inactivity. ...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP086335
更新日期:2017-11-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? What mechanisms account for the hypotension observed during chronic elevations in circulating 5-hydroxytryptamine in rats? What is the main finding and its importance? Chronic 5-hydroxytryptamine-induced hypotension requires continued activation of the 5-HT7 rece...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP088919
更新日期:2020-10-14 00:00:00
abstract::Transport of a number of dipolar amino acids (and the orally active antibiotic D-cycloserine) across the apical membrane of human intestinal epithelial (Caco-2) cell monolayers is mediated by a Na+-independent, pH-dependent transport mechanism. Relatively little is known about the mode of action of this transport syst...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:
更新日期:1999-03-01 00:00:00
abstract::Mammalian cardiomyocytes have limited regenerative capacity, such that cell death can result in a net loss of viable contractile elements and a decrease in cardiac functional reserve, both during normal ageing and after insults to the myocardium leading to heart failure. At least four types of cell death have been des...
journal_title:Experimental physiology
pub_type: 杂志文章,评审
doi:10.1113/eph8802549
更新日期:2003-05-01 00:00:00
abstract::Plasticity of insulin secretion is essential to maintain the action of insulin during insulin resistance and to prevent diabetes. Investigation of the plasticity of insulin secretion and its regulation is challenging, and the objective of this study was to develop a novel large-animal-based model. The effect of chroni...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2011.063560
更新日期:2012-05-01 00:00:00
abstract::Chronically hypoxic (CH) and normoxic control rats were used to assess the action of S9581, a water-soluble analogue of almitrine bismesylate. S9581 increased ventilation (Ve) by 34% in control and 20% in CH rats. During acute hypoxia Ve was raised and S9581 caused a further increase of 20% in both groups. Low doses o...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1992.sp003648
更新日期:1992-11-01 00:00:00
abstract::Severe-intensity constant-work-rate exercise results in the attainment of maximal oxygen uptake, but the muscle metabolic milieu at the limit of tolerance (T(lim)) for such exercise remains to be elucidated. We hypothesized that T(lim) during severe-intensity exercise would be associated with the attainment of consist...
journal_title:Experimental physiology
pub_type: 杂志文章,随机对照试验
doi:10.1113/expphysiol.2009.050500
更新日期:2010-04-01 00:00:00
abstract::In order to investigate the effect of chronic sodium depletion on renal proximal tubular reabsorption, studies were performed in conscious, unrestrained Brattleboro rats. Since these animals lack circulating vasopressin, fractional water reabsorption in the distal nephron can be assumed to be constant and changes in u...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1994.sp003749
更新日期:1994-03-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? Exercise can stimulate brown adipose tissue (BAT) with subsequent increase in uncoupling protein 1 expression and mitochondrial biogenesis. In that case, do BAT-specific Hox genes modify BAT functioning and cause uncoupling protein expression changes due to exerc...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP089114
更新日期:2020-12-28 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? Dexmedetomidine has a capacity for sedation, anti-anxiety and analgesia with minimal suppression of respiratory function; what is its role in neuropathic pain and what is the involvement of miRNAs? What is the main finding and its importance? Dexmedetomidine atte...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP088596
更新日期:2020-09-01 00:00:00
abstract:NEW FINDINGS:What is the topic of this review? One of the major unanswered questions in physiology is that of how breathing matches metabolic rate. Venous chemoreceptors seem to have been dismissed since the 1960s. What advances does it highlight? New evidence shows that their apparent dismissal needs reappraisal. The ...
journal_title:Experimental physiology
pub_type: 杂志文章,评审
doi:10.1113/EP086561
更新日期:2017-12-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? Calcium is an important second messenger in eccrine sweating; however, whether modulation of extracellular Ca(2+) and Ca(2+) entry has the capacity to modulate sweat rate in non-glabrous human skin has not been explored. What is the main finding and its importanc...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2013.076547
更新日期:2014-02-01 00:00:00
abstract::Experiments were performed to investigate, in the normal and acutely inflamed rabbit knee joint, the role of prostaglandins in the regulation of joint blood flow, measured by laser Doppler flowmetry, as well as their modulation of sympathetic vasoconstriction. Close intra-arterial injection of prostaglandin E2 (PGE2) ...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1994.sp003745
更新日期:1994-01-01 00:00:00
abstract::The hallmark of epithelial cells is their functional polarization. It is those membrane proteins that are distributed differentially, either to the apical or to the basal surface, that determine epithelial physiology. Such proteins will include 'pumps', 'channels' and 'carriers', and it is the functional interplay bet...
journal_title:Experimental physiology
pub_type:
doi:10.1113/expphysiol.2007.037523
更新日期:2008-03-01 00:00:00
abstract::Mechanical properties of the vascular smooth muscle from normal and dystrophin-deficient (mdx) mice were examined. Changes in resting and developed tensions in response to stretch were recorded in isolated portal vein. The vascular segments were elongated in 5 % increments of the 'in situ' length (Lr) up to 1.30Lr. Th...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:
更新日期:1999-09-01 00:00:00
abstract::Oscillations in the cardiovascular system have been observed in patients with periodic breathing. It is not clear whether these are driven by primary oscillations in the respiratory system or whether an intrinsic cardiovascular instability is required, as previous studies with subjects performing voluntary periodic br...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:
更新日期:2000-11-01 00:00:00
abstract::The effects of two different feeding regimes on the 24 h profiles of maternal and fetal plasma cortisol and adrenocorticotrophic hormone (ACTH) concentrations were studied in eight pregnant ewes between 123 and 144 days of gestation. Once daily-fed ewes (n = 4) received 1 kg of lucerne-chaff at 11.00 h, and multi-fed ...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1991.sp003488
更新日期:1991-03-01 00:00:00
abstract::Increased fetal lung expansion, induced by tracheal obstruction (TO), is a potent stimulus for fetal lung growth, but rapidly reduces surfactant protein (SP) mRNA levels. Our aim was to determine the time course for the re-expression of the surfactant proteins in fetal lung tissue following the release of a TO and to ...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/eph8602088
更新日期:2001-01-01 00:00:00
abstract::The physiological mechanisms contributing to sex differences following myocardial infarction (MI) are poorly understood. Given the strong relationship between sympathetic nerve activity (SNA) and outcome, we hypothesized there may be a sex difference in SNA responses to MI. In anaesthetized, open-chest male, female an...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2012.065615
更新日期:2012-09-01 00:00:00
abstract::Gastric motility was recorded from ferrets chronically prepared with an antral strain gauge. In fasted animals, antral motility showed cycles of activity and quiescence typical of the migrating motor complex (MMC) with a period of 44.7 +/- 6.1 min (n = 4). Anaesthesia with pentobarbitone sodium (50 mg/kg) disrupted th...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.1990.sp003448
更新日期:1990-09-01 00:00:00
abstract:NEW FINDINGS:What is the central question of this study? Although peripheral blood haematopoietic stem and progenitor cells are potentially important in regeneration after acute myocardial infarction, their self-renewal ability in the post-acute phase has not yet been addressed. What is the main finding and its importa...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/EP086643
更新日期:2018-01-01 00:00:00
abstract::This study examined whether left ventricular function was reduced during 3 h of semi-recumbent ergometer cycling at 70% of maximal oxygen uptake while preload to the heart was maintained via saline infusion. Indices of left ventricular systolic function (end-systolic blood pressure-volume relationship, SBP/ESV) and di...
journal_title:Experimental physiology
pub_type: 杂志文章
doi:10.1113/expphysiol.2006.035089
更新日期:2007-03-01 00:00:00
abstract::The dorsal horn of the spinal cord plays an important role in transmitting information from nociceptive primary afferent neurones to the brain; however, our knowledge of its neuronal and synaptic organisation is still limited. Nociceptive afferents terminate mainly in laminae I and II and some of these contain substan...
journal_title:Experimental physiology
pub_type: 杂志文章,评审
doi:10.1113/eph8702351
更新日期:2002-03-01 00:00:00