Deleterious effects of chronic clenbuterol treatment on endurance and sprint exercise performance in rats

2000 ◽  
Vol 98 (3) ◽  
pp. 339 ◽  
Author(s):  
Noel D. DUNCAN ◽  
David A. WILLIAMS ◽  
Gordon S. LYNCH
Keyword(s):  
Exercise Performance ◽  
Sprint Exercise ◽  
Chronic Clenbuterol

Effect of creatine loading on long-term sprint exercise performance and metabolism

2001 ◽  
pp. 814-821 ◽  
Author(s):  
DAVID PREEN ◽  
BRIAN DAWSON ◽  
CARMEL GOODMAN ◽  
STEVEN LAWRENCE ◽  
JOHN BEILBY ◽  
...  
Keyword(s):  
Exercise Performance ◽  
Sprint Exercise

Sprint Exercise Performance

2012 ◽  
Vol 40 (3) ◽  
pp. 174-182 ◽  
Author(s):  
Matthew W. Bundle ◽  
Peter G. Weyand
Keyword(s):  
Exercise Performance ◽  
Sprint Exercise

The Influence of Hot Humid and Hot Dry Environments on Intermittent-Sprint Exercise Performance

2014 ◽  
Vol 9 (3) ◽  
pp. 387-396 ◽  
Author(s):  
Mark Hayes ◽  
Paul C. Castle ◽  
Emma Z. Ross ◽  
Neil S. Maxwell
Keyword(s):  
Heat Stress ◽  
Exercise Performance ◽  
Peak Power ◽  
Team Sport ◽  
Peak Power Output ◽  
Evaporative Heat Loss ◽  
Physiological Strain ◽  
Type Method ◽  
Sprint Exercise ◽  
Full Protocol

Purpose:To examine the effect of a hot humid (HH) compared with a hot dry (HD) environment, matched for heat stress, on intermittent-sprint performance. In comparison with HD, HH environments compromise evaporative heat loss and decrease exercise tolerance. It was hypothesized that HH would produce greater physiological strain and reduce intermittent-sprint exercise performance compared with HD.Method:Eleven male team-sport players completed the cycling intermittent-sprint protocol (CISP) in 3 conditions, temperate (TEMP; 21.2°C ± 1.3°C, 48.6% ± 8.4% relative humidity [rh]), HH (33.7°C ± 0.5°C, 78.2% ± 2.3% rh), and HD (40.2°C ± 0.2°C, 33.1% ± 4.9% rh), with both heat conditions matched for heat stress.Results:All participants completed the CISP in TEMP, but 3 failed to completed the full protocol of 20 sprints in HH and HD. Peak power output declined in all conditions (P < .05) but was not different between any condition (sprints 1–14 [N = 11]: HH 1073 ± 150 W, HD 1104 ± 127 W, TEMP, 1074 ± 134; sprints 15–20 [N = 8]: HH 954 ± 114 W, HD 997 ± 115 W, TEMP 993 ± 94; P > .05). Physiological strain was not significantly different in HH compared with HD, but HH was higher than TEMP (P < .05).Conclusion:Intermittent-sprint exercise performance of 40 min duration is impaired, but it is not different in HH and HD environments matched for heat stress despite evidence of a trend toward greater physiological strain in an HH environment.

Deleterious effects of chronic clenbuterol treatment on endurance and sprint exercise performance in rats

2000 ◽  
Vol 98 (3) ◽  
pp. 339-347 ◽  
Author(s):  
Noel D. DUNCAN ◽  
David A. WILLIAMS ◽  
Gordon S. LYNCH
Keyword(s):  
Cardiac Muscle ◽  
Exercise Performance ◽  
Wheel Running ◽  
Structure And Function ◽  
Muscle Structure ◽  
Sprint Running ◽  
Heart Mass ◽  
Chronic Clenbuterol ◽  
And Function ◽  
Voluntary Wheel

The β2-adrenergic agonist, clenbuterol, has powerful muscle anabolic and lipolytic effects and is used by athletes to improve exercise performance; however, its use in conjunction with different forms of exercise training has received limited attention. Since previous studies have reported that chronic use of other β2-adrenergic agonists has deleterious effects on cardiac muscle structure and function, the aim of the present study was to determine whether chronic clenbuterol administration would reduce the exercise capabilities of rats subjected to long-term treadmill sprint running, endurance swimming or voluntary wheel running training. The effect of clenbuterol treatment on exercise performance in rats was evaluated in three separate studies. Different groups of male rats were assigned to an endurance swimming (2 h/day, 5/7 days, 18 weeks) group, a treadmill sprint running (8×1 min bouts, 1.05 m/s, 20 weeks) group, or a voluntary wheel running (16 weeks) group. In each study, rats were allocated into either a treated group that received clenbuterol (2 mg·kg-1·day-1) in their drinking water or an untreated control group. In each of the three studies, treated rats exhibited a reduction in exercise performance compared with untreated rats. Treated rats ran ∼ 57% less total distance than untreated rats in the voluntary running programme and were unable to complete the swimming and sprinting protocols performed by the untreated rats. In each of the studies, the treated rats exhibited cardiac hypertrophy, with absolute heart mass increased by ∼ 19% and heart mass relative to body mass increased by ∼ 20%. The hearts of sedentary rats treated with clenbuterol exhibited extensive collagen infiltration surrounding blood vessels and in the wall of the left ventricle. The results indicate strongly that chronic clenbuterol administration deleteriously affects exercise performance in rats, potentially due to alterations in cardiac muscle structure and function.

Effect of creatine supplementation on sprint exercise performance and muscle metabolism

1998 ◽  
Vol 84 (5) ◽  
pp. 1667-1673 ◽  
Author(s):  
R. J. Snow ◽  
M. J. McKenna ◽  
S. E. Selig ◽  
J. Kemp ◽  
C. G. Stathis ◽  
...  
Keyword(s):  
Exercise Performance ◽  
Anaerobic Metabolism ◽  
Adenine Nucleotides ◽  
Creatine Supplementation ◽  
Muscle Metabolism ◽  
Cycle Ergometer ◽  
Plasma Metabolites ◽  
Double Blind ◽  
Sprint Exercise ◽  
Cr Content

The aim of the present study was to examine the effect of creatine supplementation (CrS) on sprint exercise performance and skeletal muscle anaerobic metabolism during and after sprint exercise. Eight active, untrained men performed a 20-s maximal sprint on an air-braked cycle ergometer after 5 days of CrS [30 g creatine (Cr) + 30 g dextrose per day] or placebo (30 g dextrose per day). The trials were separated by 4 wk, and a double-blind crossover design was used. Muscle and blood samples were obtained at rest, immediately after exercise, and after 2 min of passive recovery. CrS increased the muscle total Cr content (9.5 ± 2.0%, P < 0.05, mean ± SE); however, 20-s sprint performance was not improved by CrS. Similarly, the magnitude of the degradation or accumulation of muscle (e.g., adenine nucleotides, phosphocreatine, inosine 5′-monophosphate, lactate, and glycogen) and plasma metabolites (e.g., lactate, hypoxanthine, and ammonia/ammonium) were also unaffected by CrS during exercise or recovery. These data demonstrated that CrS increased muscle total Cr content, but the increase did not induce an improved sprint exercise performance or alterations in anaerobic muscle metabolism.

scholarly journals Enhancement of Exercise Performance by 48 Hours, and 15-Day Supplementation with Mangiferin and Luteolin in Men

Nutrients ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 344 ◽  
Author(s):  
Miriam Gelabert-Rebato ◽  
Julia C. Wiebe ◽  
Marcos Martin-Rincon ◽  
Victor Galvan-Alvarez ◽  
David Curtelin ◽  
...  
Keyword(s):  
Exercise Performance ◽  
Ischemia Reperfusion ◽  
Radical Scavenging ◽  
Brain Oxygenation ◽  
Double Blind ◽  
Physically Active ◽  
Sprint Exercise ◽  
Muscle Oxygen ◽  
O2 Extraction ◽  
Radical Scavenging Properties

The natural polyphenols mangiferin and luteolin have free radical-scavenging properties, induce the antioxidant gene program and down-regulate the expression of superoxide-producing enzymes. However, the effects of these two polyphenols on exercise capacity remains mostly unknown. To determine whether a combination of luteolin (peanut husk extract containing 95% luteolin, PHE) and mangiferin (mango leave extract (MLE), Zynamite®) at low (PHE: 50 mg/day; and 140 mg/day of MLE containing 100 mg of mangiferin; L) and high doses (PHE: 100 mg/day; MLE: 420 mg/day; H) may enhance exercise performance, twelve physically active men performed incremental exercise to exhaustion, followed by sprint and endurance exercise after 48 h (acute effects) and 15 days of supplementation (prolonged effects) with polyphenols or placebo, following a double-blind crossover design. During sprint exercise, mangiferin + luteolin supplementation enhanced exercise performance, facilitated muscle oxygen extraction, and improved brain oxygenation, without increasing the VO2. Compared to placebo, mangiferin + luteolin increased muscle O2 extraction during post-exercise ischemia, and improved sprint performance after ischemia-reperfusion likely by increasing glycolytic energy production, as reflected by higher blood lactate concentrations after the sprints. Similar responses were elicited by the two doses tested. In conclusion, acute and prolonged supplementation with mangiferin combined with luteolin enhances performance, muscle O2 extraction, and brain oxygenation during sprint exercise, at high and low doses.

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