scholarly journals Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans

2009 ◽  
Vol 296 (4) ◽  
pp. R1078-R1087 ◽  
Author(s):  
Andrew M. Jones ◽  
Daryl P. Wilkerson ◽  
Jonathan Fulford
Keyword(s):  
Creatine Supplementation ◽  
Knee Extensor ◽  
Superconducting Magnet ◽  
Moderate Intensity ◽  
Resonance Spectroscopy ◽  
Subsequent Recovery ◽  
Cr Content ◽  
Before And After ◽  
First Time ◽  
Resting Muscle

We hypothesized that increasing skeletal muscle total creatine (Cr) content through dietary Cr supplementation would result in slower muscle phosphocreatine concentration ([PCr]) kinetics, as assessed using 31P magnetic resonance spectroscopy, following the onset and offset of both moderate-intensity (Mod) and heavy-intensity (Hvy) exercise. Seven healthy males (age 29 ± 6 yr, mean ± SD) completed a series of square-wave transitions to Mod and Hvy knee extensor exercise inside the bore of a 1.5-T superconducting magnet both before and after a 5-day period of Cr loading (4× 5 g/day of creatine monohydrate). Cr supplementation resulted in an ∼8% increase in the resting muscle [PCr]-to-[ATP] ratio (4.66 ± 0.27 vs. 5.04 ± 0.22; P < 0.05), consistent with a significant increase in muscle total Cr content consequent to the intervention. The time constant for muscle [PCr] kinetics was increased following Cr loading for Mod exercise (control: 15 ± 8 vs. Cr: 25 ± 9 s; P < 0.05) and subsequent recovery (control: 14 ± 8 vs. Cr: 27 ± 8 s; P < 0.05) and for Hvy exercise (control: 54 ± 18 vs. Cr: 72 ± 30 s; P < 0.05), but not for subsequent recovery (control: 41 ± 11 vs. Cr: 44 ± 6 s). The magnitude of the increase in [PCr] following Cr loading was correlated ( P < 0.05) with the extent of the slowing of the [PCr] kinetics for the moderate off-transient ( r = 0.92) and the heavy on-transient ( r = 0.71). These data demonstrate, for the first time in humans, that an increase in muscle [PCr] results in a slowing of [PCr] dynamics in exercise and subsequent recovery.

Caffeine counteracts the ergogenic action of muscle creatine loading

1996 ◽  
Vol 80 (2) ◽  
pp. 452-457 ◽  
Author(s):  
K. Vandenberghe ◽  
N. Gillis ◽  
M. Van Leemputte ◽  
P. Van Hecke ◽  
F. Vanstapel ◽  
...  
Keyword(s):  
Intermittent Exercise ◽  
Creatine Supplementation ◽  
Knee Extensors ◽  
Caffeine Intake ◽  
Resonance Spectroscopy ◽  
Experimental Conditions ◽  
Before And After ◽  
And Performance ◽  
Exercise Fatigue ◽  
Voluntary Contractions

This study aimed to compare the effects of oral creatine (Cr) supplementation with creatine supplementation in combination with caffeine (Cr+C) on muscle phosphocreatine (PCr) level and performance in healthy male volunteers (n = 9). Before and after 6 days of placebo, Cr (0.5 g x kg-1 x day-1), or Cr (0.5 g x kg-1 x day-1) + C (5 mg x kg-1 x day-1) supplementation, 31P-nuclear magnetic resonance spectroscopy of the gastrocnemius muscle and a maximal intermittent exercise fatigue test of the knee extensors on an isokinetic dynamometer were performed. The exercise consisted of three consecutive maximal isometric contractions and three interval series of 90, 80, and 50 maximal voluntary contractions performed with a rest interval of 2 min between the series. Muscle ATP concentration remained constant over the three experimental conditions. Cr and Cr+C increased (P < 0.05) muscle PCr concentration by 4-6%. Dynamic torque production, however, was increased by 10-23% (P < 0.05) by Cr but was not changed by Cr+C. Torque improvement during Cr was most prominent immediately after the 2-min rest between the exercise bouts. The data show that Cr supplementation elevates muscle PCr concentration and markedly improves performance during intense intermittent exercise. This ergogenic effect, however, is completely eliminated by caffeine intake.

Elevation of Creatine in Red Blood Cells in Vegetarians and Nonvegetarians After Creatine Supplementation

2004 ◽  
Vol 29 (6) ◽  
pp. 704-713 ◽  
Author(s):  
Vanessa M. Maccormick ◽  
Lisa M. Hill ◽  
Lauren Macneil ◽  
Darren G. Burke ◽  
Truis Smith-Palmer
Keyword(s):  
Young Women ◽  
Blood Cells ◽  
Creatine Supplementation ◽  
Control Group ◽  
Creatine Transporter ◽  
Cr Content ◽  
Supplementation Period ◽  
Significant Difference ◽  
Before And After ◽  
Cr Uptake

The purpose of this study was to examine the effect of a 5-day creatine (CR) supplementation period on red blood cell (RBC) CR uptake in vegetarian and nonvegetarian young women. Blood samples were collected from lacto-ovo vegetarians (VG, n = 6, age 21.8 ± 1.9 yrs) and nonvegetarians (NV, n = 6, age 21.7 ± 1.9 yrs) before and after a 5-day CR loading period (0. 3 g CR/kg lean body mass/day), and from a control group of nonvegetarians (NV, n = 5, age 22.0 ± 0.7 yrs) who did not supplement with creatine. RBC and plasma samples were analyzed for the presence of creatine. Significant increases (p < .05) in RBC and plasma CR levels were found for vegetarians and nonvegetarians following supplementation. The initial RBC CR content was significantly lower (p < .05) in the vegetarian group. There was no significant difference between vegetarians and nonvegetarians in final RBC CR content, suggesting that a ceiling had been reached. As the uptake into both muscle and RBC is moderated by creatine transporter proteins, analysis of the uptake of CR into RBC may reflect the uptake of CR into muscle, offering an alternative to biopsies. Key words: plasma, erythrocyte, loading

scholarly journals Effect of high and low glycaemic index recovery diets on intramuscular lipid oxidation during aerobic exercise

2008 ◽  
Vol 99 (2) ◽  
pp. 326-332 ◽  
Author(s):  
Michael I. Trenell ◽  
Emma Stevenson ◽  
Karola Stockmann ◽  
Jennie Brand-Miller
Keyword(s):  
Vastus Lateralis ◽  
Insulin Response ◽  
Glycaemic Index ◽  
Moderate Intensity ◽  
Resonance Spectroscopy ◽  
Moderate Intensity Exercise ◽  
Carbohydrate Ingestion ◽  
Before And After ◽  
Wet Weight ◽  
Intramuscular Lipid

Intramyocellular lipid (IMCL) and plasma NEFA are important skeletal muscle fuel sources. By raising blood insulin concentrations, carbohydrate ingestion inhibits lypolysis and reduces circulating NEFA. We hypothesised that differences in the postprandial glycaemic and insulin response to carbohydrates (i.e. glycaemic index; GI) could alter NEFA availability and IMCL use during subsequent exercise. Endurance-trained individuals (n 7) cycled for 90 min at 70 % V˙O2peak and then consumed either high GI (HGI) or low GI (LGI) meals over the following 12 h. The following day after an overnight fast, the 90 min cycle was repeated. IMCL content of the vastus lateralis was quantified using magnetic resonance spectroscopy before and after exercise. Blood samples were collected at 15 min intervals throughout exercise and analysed for NEFA, glycerol, glucose, insulin, and lactate. Substrate oxidation was calculated from expired air samples. The 90 min cycle resulted in >2-fold greater reduction in IMCL in the HGI trial (3·5 (sem 1·0) mm/kg wet weight) than the LGI trial (1·6 (sem 0·3) mm/kg wet weight, P < 0·05). During exercise, NEFA availability was reduced in the HGI trial compared to the LGI trial (area under curve 2·36 (sem 0·14) mEq/l per h v. 3·14 (sem 0·28) mEq/l per h, P < 0·05 respectively). No other differences were significant. The findings suggest that HGI carbohydrates reduce NEFA availability during exercise and increase reliance on IMCL as a substrate source during moderate intensity exercise.

scholarly journals Effect of 2-Weeks Ischemic Preconditioning on Exercise Performance: A Pilot Study

2021 ◽  
Vol 3 ◽  
Author(s):  
Daichi Tanaka ◽  
Tadashi Suga ◽  
Kento Shimoho ◽  
Tadao Isaka
Keyword(s):  
Confidence Interval ◽  
Ischemic Preconditioning ◽  
Effect Size ◽  
Exercise Performance ◽  
Knee Extensor ◽  
Whole Body ◽  
Moderate Intensity ◽  
Control Group ◽  
Cycling Test ◽  
Before And After

An acute bout of ischemic preconditioning (IPC) has been reported to increase exercise performance. Nevertheless, the ineffectiveness of acute IPC on exercise performance has also been reported. Similarly, the effect of a shot-term intervention of IPC on exercise performance remains controversial in previous studies. In this study, we examined the effects of short-term IPC intervention on whole and local exercise performances and its-related parameters. Ten healthy young males undertook a 2-weeks IPC intervention (6 days/weeks). The IPC applied to both legs with three episodes of a 5-min ischemia and 5-min reperfusion cycle. Whole-body exercise performance was assessed by peak O2 consumption (VO2: VO2peak) during a ramp-incremental cycling test. Local exercise performance was assessed by time to task failure during a knee extensor sustained endurance test. A repeated moderate-intensity cycling test was performed to evaluate dynamics of pulmonary VO2 and muscle deoxygenation. The knee extensor maximal voluntary contraction and quadriceps femoris cross-sectional area measurements were performed to explore the potentiality for strength gain and muscle hypertrophy. The whole-body exercise performance (i.e., VO2peak) did not change before and after the intervention (P = 0.147, Power = 0.09, Effect size = 0.21, 95% confidence interval: −0.67, 1.09). Moreover, the local exercise performance (i.e., time to task failure) did not change before and after the intervention (P = 0.923, Power = 0.05, Effect size = 0.02, 95% confidence interval: −0.86, 0.89). Furthermore, no such changes were observed for all parameters measured using a repeated moderate-intensity cycling test and knee extensor strength and quadriceps femoris size measurements. These findings suggest that a 2-weeks IPC intervention cannot increase whole-body and local exercise performances, corresponding with ineffectiveness on its-related parameters in healthy young adults. However, the statistical analyses of changes in the measured parameters in this study showed insufficient statistical power and sensitivity, due to the small sample size. Additionally, this study did not include control group(s) with placebo and/or nocebo. Therefore, further studies with a larger sample size and control group are required to clarify the present findings.

AMP kinase expression and activity in human skeletal muscle: effects of immobilization, retraining, and creatine supplementation

2005 ◽  
Vol 98 (4) ◽  
pp. 1228-1233 ◽  
Author(s):  
Bert O. Eijnde ◽  
Wim Derave ◽  
Jørgen F. P. Wojtaszewski ◽  
Erik A. Richter ◽  
Peter Hespel
Keyword(s):  
Protein Expression ◽  
Vastus Lateralis ◽  
Creatine Supplementation ◽  
Knee Extensor ◽  
Double Blind ◽  
Α Subunit ◽  
Beneficial Effects ◽  
Before And After ◽  
Subunit Expression ◽  
The Right

The effects of leg immobilization and retraining in combination with oral creatine intake on muscle AMP-activated protein kinase (AMPK) protein expression and phosphorylation status were investigated. A double-blind trial was performed in young healthy volunteers ( n = 22). A cast immobilized the right leg for 2 wk, whereafter the knee-extensor muscles of that leg were retrained for 6 wk. Half of the subjects received creatine monohydrate throughout the study (Cr; from 15 g down to 2.5 g daily), and the others ingested placebo (P; maltodextrin). Before and after immobilization and retraining, needle biopsies were taken from the right and left vastus lateralis muscles. In the right leg of P and Cr, immobilization did not affect AMPK α1-, α2-, and β2-subunit expression or AMPK α-subunit phosphorylation status. However, irrespective of the treatment received, retraining increased the degree of α-subunit phosphorylation by ∼25% ( P < 0.05) and increased AMPK α1-subunit expression ( P < 0.05) in both groups. From the start to the end of the study, AMPK subunit protein expression and α-subunit phosphorylation status were unchanged in the contralateral control leg. It is concluded that immobilization-induced muscle inactivity for 2 wk does not alter AMPK α1-, α2-, and β2-subunit expression or α-AMPK phosphorylation status. Furthermore, the present observations indicate that AMPK probably is not implicated in the previously reported beneficial effects of oral creatine supplementation on muscle during immobilization and rehabilitative weight training.

Effect of 1-h moderate-intensity aerobic exercise on intramyocellular lipids in obese men before and after a lifestyle intervention

2015 ◽  
Vol 40 (12) ◽  
pp. 1262-1268 ◽  
Author(s):  
Stephanie Ipavec-Levasseur ◽  
Ilaria Croci ◽  
Stéphane Choquette ◽  
Nuala M. Byrne ◽  
Gary Cowin ◽  
...  
Keyword(s):  
Exercise Training ◽  
Lifestyle Intervention ◽  
Acute Exercise ◽  
Fat Oxidation ◽  
Whole Body ◽  
Moderate Intensity ◽  
Resonance Spectroscopy ◽  
Model Assessment ◽  
Intramyocellular Lipids ◽  
Before And After

Intramyocellular lipids (IMCL) are depleted in response to an acute bout of exercise in lean endurance-trained individuals; however, it is unclear whether changes in IMCL content are also seen in response to acute and chronic exercise in obese individuals. We used magnetic resonance spectroscopy in 18 obese men and 5 normal-weight controls to assess IMCL content before and after an hour of cycling at the intensity corresponding with each participant’s maximal whole-body rate of fat oxidation (Fatmax). Fatmax was determined via indirect calorimetry during a graded exercise test on a cycle ergometer. The same outcome measures were reassessed in the obese group after a 16-week lifestyle intervention comprising dietary calorie restriction and exercise training. At baseline, IMCL content decreased in response to 1 h of cycling at Fatmax in controls (2.8 ± 0.4 to 2.0 ± 0.3 A.U., –39%, p = 0.02), but not in obese (5.4 ± 2.1 vs. 5.2 ± 2.2 A.U., p = 0.42). The lifestyle intervention lead to weight loss (–10.0 ± 5.4 kg, p < 0.001), improvements in maximal aerobic power (+5.2 ± 3.4 mL/(kg·min)), maximal fat oxidation rate (+0.19 ± 0.22 g/min), and a 29% decrease in homeostasis model assessment score (all p < 0.05). However, when the 1 h of cycling at Fatmax was repeated after the lifestyle intervention, there remained no observable change in IMCL (4.6 ± 1.8 vs. 4.6 ± 1.9 A.U., p = 0.92). In summary, there was no IMCL depletion in response to 1 h of cycling at moderate intensity either before or after the lifestyle intervention in obese men. An effective lifestyle intervention including moderate-intensity exercise training did not impact rate of utilisation of IMCL during acute exercise in obese men.

scholarly journals Skeletal Muscle Abnormalities in Girls and Adolescents With Turner Syndrome

2013 ◽  
Vol 98 (6) ◽  
pp. 2521-2527 ◽  
Author(s):  
Greg D. Wells ◽  
Clodagh S. O'Gorman ◽  
Tammy Rayner ◽  
Jessica Caterini ◽  
Sara Thompson ◽  
...  
Keyword(s):  
Physical Activity ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Turner Syndrome ◽  
Muscle Metabolism ◽  
Moderate Intensity ◽  
Resonance Spectroscopy ◽  
Moderate Intensity Exercise ◽  
Atp Production ◽  
Before And After

Context: Turner syndrome (TS) is a chromosomal disorder occurring in approximately 1 in 2500 live births. Individuals with TS report lower levels of physical activity than healthy control (HC) subjects. Cardiorespiratory limitations may contribute to the observed reduction in physical activity. Objective: The objective of this study was to compare muscle metabolism of patients with TS vs HC subjects before and after exercise using exercise testing, magnetic resonance imaging, and magnetic resonance spectroscopy techniques. Design: We hypothesized that girls and adolescents with TS would have muscle metabolic abnormalities not present in the HC population. Setting: The research was conducted at the Hospital for Sick Children in Toronto, Ontario, Canada. Participants: Fifteen participants with TS were age-, activity-, and body mass index Z-score–matched with 16 HC subjects. Main Outcome Measures: 31P magnetic resonance spectroscopy was used to characterize muscle metabolism at rest and after 30 seconds of high-intensity exercise, 60 seconds of moderate-intensity exercise, and 5 minutes of low-intensity exercise. Results: While achieving the same workloads, participants with TS exhibited a greater difference between rest and end-exercise pH compared with HC subjects after 30 seconds (TS, 0.29 ± 0.04; HC, 0.21 ± 0.08; P = .03) and 90 seconds (TS, 0.47 ± 0.22; HC, 0.32 ± 0.13; P = .02) of exercise. During the 5-minute exercise test, similar workloads were achieved between groups; however, ATP production was greater in participants with TS vs the HC subjects via all 3 bioenergetic pathways (total ATP: TS, 0.90 ± 0.34; HC, 0.60 ± 0.25; P = .01). Conclusions: The results of this study suggest that patients with TS exhibit greater anaerobic stress during exercise than HC subjects, which may lead to symptoms of increased muscle fatigue with short bursts of activity. Recovery metabolism after exercise appears to be similar between participants with TS and HC subjects, which is suggestive of normal mitochondrial metabolism and oxygen transport.

Untersuchungen zur Quantifizierung der Änderung der Skelettmuskeldurchblutung nach Gefäßrevaskularisationen mit einem 99mTechnetiummarkierten Tracer

1990 ◽  
Vol 29 (05) ◽  
pp. 215-220 ◽  
Author(s):  
R. Benning ◽  
K. Nagel ◽  
M. Jugenheimer ◽  
S. Fischer ◽  
S. Worthmann ◽  
...  
Keyword(s):  
Transluminal Angioplasty ◽  
Lower Limbs ◽  
Surgical Patients ◽  
Treadmill Test ◽  
Negative Results ◽  
Clinical Observations ◽  
Before And After ◽  
Comparative Results ◽  
First Time ◽  
Percutaneous Transluminal

A new 99mTc-labelled tracer (99mTc-Sestanriibi) was used for the first time to demonstrate the perfusion of the skeletal muscle. In 16 patients with obstructive atherosclerosis of the lower limbs the change of perfusion of thigh and lower leg was studied with SPECT before and after vascular surgery (n = 11) or percutaneous transluminal angioplasty (n = 5). Comparative results of scintigraphic measurements and clinical observations (ancle-arm pressure, treadmill test) in 10 surgical patients (14 operated legs) showed correct positive or negative results in 86% (12/14).

Superionic Lithium Intercalation through 2 nm x 2 nm Columns in the Crystallographic Shear Phase Nb18W8O69

2019 ◽  
Author(s):  
Kent Griffith ◽  
Clare Grey
Keyword(s):  
High Performance ◽  
Rate Capability ◽  
Block Size ◽  
Lithium Intercalation ◽  
Resonance Spectroscopy ◽  
Complex Metal Oxides ◽  
Battery Electrode ◽  
Crystallographic Shear ◽  
Battery Material ◽  
First Time

Nb18W8O69 (9Nb2O5×8WO3) is the tungsten-rich end-member of the Wadsley–Roth crystallographic shear (cs) structures within the Nb2O5–WO3 series. It has the largest block size of any known, stable Wadsley–Roth phase, comprising 5 ´ 5 units of corner-shared MO6 octahedra between the shear planes, giving rise to 2 nm ´ 2 nm blocks. Rapid lithium intercalation is observed in this new candidate battery material and 7Li pulsed field gradient nuclear magnetic resonance spectroscopy – measured in a battery electrode for the first time at room temperature – reveals superionic lithium conductivity. In addition to its promising rate capability, Nb18W8O69 adds a piece to the larger picture of our understanding of high-performance Wadsley–Roth complex metal oxides.

Trombodynamics Method in the Assessment of Coagulation Parameters in Psychopharmacotherapy of Endogenous Mental Disorders

Psychiatry ◽  
2020 ◽  
Vol 18 (4) ◽  
pp. 16-25
Author(s):  
N. S. Karpova ◽  
O. S. Brusov ◽  
I. V. Oleichik ◽  
M. I. Faktor ◽  
N. S. Levchenko ◽  
...  
Keyword(s):  
Mental Disorders ◽  
Response To Therapy ◽  
Procoagulant Activity ◽  
Coagulation Activity ◽  
Continuous Type ◽  
Chronic Neuroinflammation ◽  
Psychopharmacological Treatment ◽  
Before And After ◽  
First Time ◽  
Schizotypal Disorder

Background: currently, it has been proven that the pathogenesis of endogenous mental disorders is associated with the process of neuroinflammation in the brain of patients. It is also known that chronic neuroinflammation, accompanied by a violation the permeability of the blood-brain barrier. It is accompanied by the activation of platelets that generate procoagulant microparticles, which leads to a disturbance of the hemostasis system, causing an increase in blood clotting in patients. Objective: to investigate the dynamics of procoagulant activity of blood in patients with endogenous mental disorders before and after psychopharmacotherapy.Patients and methods: the study included 185 patients aged 16 to 64 years with the following mental disorders: schizophrenia with attack-like/attack-progressive/continuous type of course (F20.00–2), affective disease (F31.1–5; F32.0–3; F33.0–3), schizotypal disorder with affective fluctuations (F21.3–4). The thrombodynamic test (TD) was performed on T-2 Trombodynamis device according to the manufacturer’s instructions (Hemacore LLC, Moscow, Russia). All patients received standard pharmacotherapy according to their condition.Results: a significant decrease of procoagulant activity of spontaneous clots in the patients’ blood after psychopharmacological treatment is observed. Our data on the positive dynamics of changes in the values of TD test’s indicators in most of the examined patients suggest that a decrease in the coagulation activity of the patients’ blood as a result of treatment may be associated with the anti- inflammatory effect of antipsychotics and antidepressants.Conclusion: for the first time, it was shown that there is a positive dynamic in changing the values of the main parameters of the TD test in most patients with endogenous mental diseases. The results of TD tests can be the basis for monitoring the response to therapy.

Sign in / Sign up

Export Citation Format

Share Document