Influence of Oral Creatine Supplementation of Muscle Torque during Repeated Bouts of Maximal Voluntary Exercise in Man

1. The present experiment was undertaken to investigate the influence of oral creatine supplementation, shown previously to increase the total creatine content of human skeletal muscle (Harris RC, Soderlund K, Hultman E. Clin Sci 1992; 83: 367–74), on skeletal muscle isokinetic torque and the accumulation of plasma ammonia and blood lactate during five bouts of maximal exercise. 2. Twelve subjects undertook five bouts of 30 maximal voluntary isokinetic contractions, interspersed with 1 min recovery periods, before and after 5 days of placebo (4 × 6 g of glucose/day, n = 6) or creatine (4 × 5 g of creatine plus 1 g of glucose/day, n = 6) oral supplementation. Muscle torque production and plasma ammonia and blood lactate accumulation were measured during and after exercise on each treatment 3. No difference was seen when comparing muscle peak torque production during exercise before and after placebo ingestion. After creatine ingestion, muscle peak torque production was greater in all subjects during the final 10 contractions of exercise bout 1 (P <0.05), throughout the whole of exercise bouts 2 (P <0.01), 3 (P <0.05) and 4 (P = 0.057) and during contractions 11–20 of the final exercise bout (P <0.05), when compared with the corresponding measurements made before creatine ingestion. Plasma ammonia accumulation was lower during and after exercise after creatine ingestion. No differences were found when comparing blood lactate levels. 4. There is evidence to suggest that the decrease in the degree of muscle torque loss after dietary creatine supplementation may be a consequence of a creatine-induced acceleration of skeletal muscle phosphocreatine resynthesis. It is postulated that an increased availability of phosphocreatine would maintain better the required rate of ATP demand during contraction. This is supported by the observed lower accumulation of plasma ammonia during exercise after creatine ingestion.

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The effects of phosphocreatine disodium salts plus blueberry extract supplementation on muscular strength, power, and endurance

Journal of the International Society of Sports Nutrition ◽

10.1186/s12970-021-00456-y ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

John Paul V. Anders ◽

Tyler J. Neltner ◽

Robert W. Smith ◽

Joshua L. Keller ◽

Terry J. Housh ◽

...

Keyword(s):

Placebo Group ◽

Exercise Performance ◽

Muscular Strength ◽

Minimal Important Difference ◽

Average Power ◽

Creatine Supplementation ◽

Peak Torque ◽

Before And After ◽

Group A ◽

Percent Decline

Abstract Background Numerous studies have demonstrated the efficacy of creatine supplementation for improvements in exercise performance. Few studies, however, have examined the effects of phosphocreatine supplementation on exercise performance. Furthermore, while polyphenols have antioxidant and anti-inflammatory properties, little is known regarding the influence of polyphenol supplementation on muscular strength, power, and endurance. Thus, the purpose of the present study was to compare the effects of 28 days of supplementation with phosphocreatine disodium salts plus blueberry extract (PCDSB), creatine monohydrate (CM), and placebo on measures of muscular strength, power, and endurance. Methods Thirty-three men were randomly assigned to consume either PCDSB, CM, or placebo for 28 days. Peak torque (PT), average power (AP), and percent decline for peak torque (PT%) and average power (AP%) were assessed from a fatigue test consisting of 50 maximal, unilateral, isokinetic leg extensions at 180°·s− 1 before and after the 28 days of supplementation. Individual responses were assessed to examine the proportion of subjects that exceeded a minimal important difference (MID). Results The results demonstrated significant (p < 0.05) improvements in PT for the PCDSB and CM groups from pre- (99.90 ± 22.47 N·m and 99.95 ± 22.50 N·m, respectively) to post-supplementation (119.22 ± 29.87 N·m and 111.97 ± 24.50 N·m, respectively), but no significant (p = 0.112) change for the placebo group. The PCDSB and CM groups also exhibited significant improvements in AP from pre- (140.18 ± 32.08 W and 143.42 ± 33.84 W, respectively) to post-supplementation (170.12 ± 42.68 W and 159.78 ± 31.20 W, respectively), but no significant (p = 0.279) change for the placebo group. A significantly (p < 0.05) greater proportion of subjects in the PCDSB group exceeded the MID for PT compared to the placebo group, but there were no significant (p > 0.05) differences in the proportion of subjects exceeding the MID between the CM and placebo groups or between the CM and PCDSB groups. Conclusions These findings indicated that for the group mean responses, 28 days of supplementation with both PCDSB and CM resulted in increases in PT and AP. The PCDSB, however, may have an advantage over CM when compared to the placebo group for the proportion of individuals that respond favorably to supplementation with meaningful increases in muscular strength.

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Lactate kinetics in resting and exercising forearms during moderate-intensity supine leg exercise

Journal of Applied Physiology ◽

10.1152/jappl.1993.74.1.435 ◽

1993 ◽

Vol 74 (1) ◽

pp. 435-443 ◽

Cited By ~ 13

Author(s):

P. G. Catcheside ◽

G. C. Scroop

Keyword(s):

Skeletal Muscle ◽

Blood Lactate ◽

Lactate Production ◽

Voluntary Contraction ◽

Moderate Intensity ◽

Arterial Blood ◽

Exercise Period ◽

Leg Exercise ◽

Lactate Removal ◽

Lactate Levels

Arterial blood lactate was elevated by supine leg exercise (20 min at approximately 65% maximal oxygen uptake) in five untrained male subjects, and the contribution to blood lactate removal from passive uptake vs. metabolic disposal was compared in resting and lightly exercising (15% maximal voluntary contraction static handgrip) forearm skeletal muscle. An integrated form of the Fick equation was used to predict venous lactate levels resulting solely from passive equilibration of lactate between incoming arterial blood and the forearm muscles. In the resting forearm, predicted and measured venous lactate levels were closely correlated during the exercise period (r = 0.995, P < 0.001), indicating that lactate removal could be accounted for in terms of passive uptake alone. In the lightly exercising forearm, measured venous lactate levels were higher than both the arterial and predicted venous levels, indicating net lactate production. It was concluded that most of the blood lactate generated by moderate-intensity supine leg exercise is taken up passively and not metabolized by resting skeletal muscle and that the rate of lactate disposal is unlikely to be enhanced in lightly exercising muscle.

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Blood Lactate Levels in Free-Swimming Rainbow Trout (Salmo gairdneri) Before and After Strenuous Exercise Resulting in Fatigue

Journal of the Fisheries Research Board of Canada ◽

10.1139/f76-020 ◽

1976 ◽

Vol 33 (1) ◽

pp. 173-176 ◽

Cited By ~ 42

Author(s):

William R. Driedzic ◽

Joe W. Kiceniuk

Keyword(s):

Rainbow Trout ◽

Blood Lactate ◽

White Muscle ◽

Recovery Period ◽

Lactate Concentration ◽

Blood Lactate Concentration ◽

Strenuous Exercise ◽

Salmo Gairdneri ◽

Before And After ◽

Lactate Levels

Rainbow trout (Salmo gairdneri) were exercised to fatigue in a series of 60-min stepwise increasing velocity increments. There was no increase in blood lactate concentration, serially sampled during swimming by means of indwelling dorsal and ventral aortic catheters, at velocities as high as 93% of critical velocity of individuals. The data show that under these conditions the rate of production of lactate by white muscle, at less than critical velocities, is minimal or that the rate of elimination of lactate from white muscle is equal to its rate of utilization elsewhere. Immediately following fatigue blood lactate level increases rapidly. During the recovery period there appears to be a net uptake of lactate by the gills.

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Skeletal muscle architectural adaptations to marathon run training

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2014-0287 ◽

2015 ◽

Vol 40 (1) ◽

pp. 99-102 ◽

Cited By ~ 7

Author(s):

Kevin Murach ◽

Cory Greever ◽

Nicholas D. Luden

Keyword(s):

Skeletal Muscle ◽

Vastus Lateralis ◽

Pennation Angle ◽

Fascicle Length ◽

Lateral Gastrocnemius ◽

Marathon Training ◽

Architectural Features ◽

Before And After ◽

Recreational Runners ◽

Lactate Levels

We assessed lateral gastrocnemius (LG) and vastus lateralis (VL) architecture in 16 recreational runners before and after 12 weeks of marathon training. LG fascicle length decreased 10% while pennation angle increased 17% (p < 0.05). There was a significant correlation between diminished blood lactate levels and LG pennation angle change (r = 0.90). No changes were observed in VL. This is the first evidence that run training can modify skeletal muscle architectural features.

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Diet-induced obesity accelerates blood lactate accumulation of rats in response to incremental exercise to maximum

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00337.2016 ◽

2017 ◽

Vol 313 (5) ◽

pp. R601-R607 ◽

Cited By ~ 2

Author(s):

Chiao-Nan (Joyce) Chen ◽

Yi-Hung Liao ◽

Shang-Ying Lin ◽

Jun-Xian Yu ◽

Zhen-Jie Li ◽

...

Keyword(s):

Blood Lactate ◽

Skeletal Muscles ◽

Incremental Exercise ◽

Monocarboxylate Transporter ◽

Control Group ◽

Treadmill Test ◽

Metabolic Pattern ◽

Before And After ◽

Lactate Levels ◽

Hepatic Proteins

Blood lactate increases during incremental exercise at high-intensity workloads, and limited exercise capacity is a characteristic of obese animals. This study examined whether blood lactate changes in response to incremental exercise is disrupted in obese animals. Muscular and hepatic proteins that are critical in lactate metabolism were also investigated. Rats were randomized to either standard chow (control) or high-fat diet (HFD) groups. All animals underwent an incremental treadmill test after 14 wk of diet intervention. Blood lactate levels were measured before and after the treadmill test. Activities of mitochondrial oxidative phosphorylation and glycolysis were examined in muscle tissues. Proteins in the liver and skeletal muscles that participate in the turnover of blood lactate were determined by Western blot. Running time in the incremental treadmill test decreased in the HFD group, and blood lactate accumulated faster in these animals than in the control group. Animals with HFD had a decreased level of hepatic monocarboxylate transporter 2, the protein responsible for blood lactate uptake in the liver. Skeletal muscles of animals with HFD showed greater glycolytic activity and decreased content of lactate dehydrogenase B, which converts lactate to pyruvate. We conclude that blood lactate accumulated faster during incremental exercise in obese animals and was associated with their decreased exercise performance. Changes in the metabolic pattern of muscles and changes of liver and muscle proteins associated with lactate utilization likely contribute to the abnormal response of blood lactate to incremental exercise in obese animals.

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Effect of short-term exercise training on insulin-stimulated PI 3-kinase activity in human skeletal muscle

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1999.277.6.e1055 ◽

1999 ◽

Vol 277 (6) ◽

pp. E1055-E1060 ◽

Cited By ~ 30

Author(s):

Joseph A. Houmard ◽

Christopher D. Shaw ◽

Matthew S. Hickey ◽

Charles J. Tanner

Keyword(s):

Skeletal Muscle ◽

Insulin Sensitivity ◽

Exercise Training ◽

Kinase Activity ◽

Vastus Lateralis ◽

Maximal Oxygen Consumption ◽

Exercise Bout ◽

Phosphatidylinositol 3 Kinase ◽

Insulin Signal Transduction ◽

Before And After

The purpose of this study was to determine if the improvement in insulin sensitivity with exercise training is associated with enhanced phosphatidylinositol 3-kinase (PI 3-kinase) activity. Nine sedentary men were studied before and after 7 days of exercise training (1 h/day, ≈75% maximal oxygen consumption). Insulin sensitivity was determined with a euglycemic-hyperinsulinemic glucose clamp in the sedentary state and 15–17 h after the final exercise bout. PI 3-kinase activity was determined from samples (vastus lateralis) obtained in the fasted condition and after 60 min of submaximal insulin stimulation during the clamp. After exercise, glucose infusion rate increased ( P < 0.05) significantly (means ± SE, 7.8 ± 0.5 vs. 9.8 ± 0.8 mg ⋅ kg−1 ⋅ min−1), indicating improved insulin sensitivity. Insulin-stimulated (insulin stimulated/fasting) phosphotyrosine immunoprecipitable PI 3-kinase activity also increased significantly ( P < 0.05) with exercise (3.1 ± 0.8-fold) compared with the sedentary condition (1.3 ± 0.1-fold). There was no change in fasting PI 3-kinase activity. These data suggest that an enhancement of insulin signal transduction in skeletal muscle may contribute to the improvement in insulin action with exercise.

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Skeletal Muscle Total Creatine Content and Creatine Transporter Gene Expression in Vegetarians Prior to and Following Creatine Supplementation

International Journal of Sport Nutrition and Exercise Metabolism ◽

10.1123/ijsnem.14.5.517 ◽

2004 ◽

Vol 14 (5) ◽

pp. 517-531 ◽

Cited By ~ 24

Author(s):

Kenneth K.O. Watt ◽

Andrew P. Garnham ◽

Rodney J. Snow

Keyword(s):

Gene Expression ◽

Skeletal Muscle ◽

Alternative Treatment ◽

Creatine Supplementation ◽

Crossover Design ◽

Transporter Gene ◽

Double Blind ◽

Creatine Transporter ◽

Before And After ◽

Total Creatine

This study examined the effect of vegetarianism on skeletal muscle total creatine (TCr) content and creatine transporter (CreaT) gene expression, prior to and during 5 d of Cr supplementation (CrS). In a double-blind, crossover design, 7 vegetarians (VEG) and nonvegetarians (NVEG) were assigned Cr or placebo supplements for 5 d and after 5 wk, received the alternative treatment. Muscle sampling occurred before, and after 1 and 5 d of treatment ingestion. Basal muscle TCr content was lower (P < 0.05) in VEG compared with NVEG. Muscle TCr increased (P < 0.05) throughout the Cr trial in both groups but was greater (P < 0.05) in VEG compared with NVEG, at days 1 and 5. CreaT gene expression was not different between VEG and NVEG. The results indicate that VEG have a lower muscle TCr content and an increased capacity to load Cr into muscle following CrS. Muscle CreaT gene expression does not appear to be affected by vegetarianism.

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