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.

Effects of prolonged voluntary wheel-running on muscle structure and function in rat skeletal muscle

2004 ◽  
Vol 92 (1-2) ◽  
pp. 90-97 ◽  
Author(s):  
Fumihiko Kariya ◽  
Hideki Yamauchi ◽  
Keizo Kobayashi ◽  
Mistuo Narusawa ◽  
Yoshibumi Nakahara
Keyword(s):  
Skeletal Muscle ◽  
Wheel Running ◽  
Structure And Function ◽  
Rat Skeletal Muscle ◽  
Voluntary Wheel Running ◽  
Muscle Structure ◽  
And Function ◽  
Voluntary Wheel

scholarly journals Essential Role of Septin 7 in Skeletal Muscle Structure and Function

2020 ◽  
Vol 118 (3) ◽  
pp. 258a
Author(s):  
Laszlo Csernoch ◽  
Mónika Gönczi ◽  
Zsolt Ráduly ◽  
László Szabó ◽  
Nóra Dobrosi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Essential Role ◽  
Structure And Function ◽  
Muscle Structure ◽  
And Function

scholarly journals Lower leg muscle structure and function are altered in long-distance runners with medial tibial stress syndrome: a case control study

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Joshua Mattock ◽  
Julie R. Steele ◽  
Karen J. Mickle
Keyword(s):  
Lower Leg ◽  
Structure And Function ◽  
Flexor Hallucis Longus ◽  
Plantar Flexor ◽  
Distance Runners ◽  
Long Distance ◽  
Cross Sectional ◽  
Muscle Structure ◽  
Leg Muscle ◽  
And Function

Abstract Background Medial tibial stress syndrome (MTSS) is a common lower leg injury experienced by runners. Although numerous risk factors are reported in the literature, many are non-modifiable and management of the injury remains difficult. Lower leg muscle structure and function are modifiable characteristics that influence tibial loading during foot-ground contact. Therefore, this study aimed to determine whether long-distance runners with MTSS displayed differences in in vivo lower leg muscle structure and function than matched asymptomatic runners. Methods Lower leg structure was assessed using ultrasound and a measure of lower leg circumference to quantify muscle cross-sectional area, thickness and lean lower leg girth. Lower leg function was assessed using a hand-held dynamometer to quantify maximal voluntary isometric contraction strength and a single leg heel raise protocol was used to measure ankle plantar flexor endurance. Outcome variables were compared between the limbs of long-distance runners suffering MTSS (n = 20) and matched asymptomatic controls (n = 20). Means, standard deviations, 95 % confidence intervals, mean differences and Cohen’s d values were calculated for each variable for the MTSS symptomatic and control limbs. Results MTSS symptomatic limbs displayed a significantly smaller flexor hallucis longus cross-sectional area, a smaller soleus thickness but a larger lateral gastrocnemius thickness than the control limbs. However, there was no statistical difference in lean lower leg girth. Compared to the matched control limbs, MTSS symptomatic limbs displayed deficits in maximal voluntary isometric contraction strength of the flexor hallucis longus, soleus, tibialis anterior and peroneal muscles, and reduced ankle plantar flexor endurance capacity. Conclusions Differences in lower leg muscle structure and function likely render MTSS symptomatic individuals less able to withstand the negative tibial bending moment generated during midstance, potentially contributing to the development of MTSS. The clinical implications of these findings suggest that rehabilitation protocols for MTSS symptomatic individuals should aim to improve strength of the flexor hallucis longus, soleus, tibialis anterior and peroneal muscles along with ankle plantar flexor endurance. However, the cross-sectional study design prevents us determining whether between group differences were a cause or effect of MTSS. Therefore, future prospective studies are required to substantiate the study findings.

Respiratory muscle imaging by ultrasound and MRI in neuromuscular disorders

2021 ◽  
pp. 2100137
Author(s):  
Jeroen L.M. van Doorn ◽  
Francesca Pennati ◽  
Hendrik H.G. Hansen ◽  
Baziel G.M. van Engelen ◽  
Andrea Aliverti ◽  
...  
Keyword(s):  
Respiratory Muscle ◽  
Imaging Techniques ◽  
Neuromuscular Disorders ◽  
Respiratory Muscles ◽  
Daily Practice ◽  
Structure And Function ◽  
Muscle Structure ◽  
Respiratory Management ◽  
Technological Developments ◽  
And Function

Respiratory muscle weakness is common in neuromuscular disorders and leads to significant respiratory difficulties. Therefore, reliable and easy assessment of respiratory muscle structure and function in neuromuscular disorders is crucial. In the last decade, ultrasound and MRI emerged as promising imaging techniques to assess respiratory muscle structure and function. Respiratory muscle imaging directly measures the respiratory muscles and, in contrast to pulmonary function testing, is independent of patient effort. This makes respiratory muscle imaging suitable to use as tool in clinical respiratory management and as outcome parameter in upcoming drug trials for neuromuscular disorders, particularly in children. In this narrative review, we discuss the latest studies and technological developments in imaging of the respiratory muscles by US and MR, and its clinical application and limitations. We aim to increase understanding of respiratory muscle imaging and facilitate its use as outcome measure in daily practice and clinical trials.

scholarly journals Effects of Ovariectomy on Skeletal Muscle Structure and Function in Young Female Rats: Protective Effects of the Flavanol (−)‐Epicatechin

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Viridiana Navarrrete ◽  
Marcos Ayala ◽  
Antonio Rodriguez ◽  
Francisco Villarreal ◽  
Israel Ramirez-Sanchez
Keyword(s):  
Skeletal Muscle ◽  
Young Female ◽  
Structure And Function ◽  
Female Rats ◽  
Protective Effects ◽  
Muscle Structure ◽  
And Function
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