Changes in muscle activity with exercise-induced fatigue in Thoroughbred horses

2020 ◽  
pp. 1-10
Author(s):  
Y. Takahashi ◽  
K. Mukai ◽  
H. Ohmura ◽  
T. Takahashi
Keyword(s):  
Muscle Activity ◽  
Extensor Digitorum Longus ◽  
Gluteus Medius ◽  
Extensor Digitorum ◽  
Stride Frequency ◽  
Median Frequency ◽  
Propulsive Force ◽  
Triceps Brachii ◽  
Frequency Changes ◽  
Exercise Induced

Understanding the effects of fatigue can provide guidance for training regimens and injury prevention. We have previously reported that the integrated-electromyogram (iEMG) values of the M. gluteus medius and brachiocephalicus decreased with exercise-induced fatigue, whereas those of the M. longissimus dorsi and infraspinatus were not affected. We hypothesised that exercise-induced fatigue would decrease the activities of the muscles associated with propulsive force but not associated with joint stabilisation. Surface EMG recordings of the forelimb muscles (M. triceps brachii, common digital extensor, ulnaris lateralis), and hindlimb muscles (M. semitendinosus, extensor digitorum longus, extensor digitorum lateralis and flexor digitorum lateralis) were conducted on eight Thoroughbreds. Horses galloped on a treadmill (grade, 3%) at a constant speed (12.6-14.8 m/s) until they could not maintain their position with minimal human encouragement (~5 min). The stride frequency, iEMG for a stride and median frequency during muscle discharge were calculated every 30 s. These parameters were compared between the start and end of the test phase for the leading and trailing limbs. The stride frequency (P<0.01) and iEMG values of the M. semitendinosus in both the leading (P<0.01) and trailing limbs (P<0.05) and those of the M. extensor digitorum longus in the trailing limbs (P<0.05) significantly decreased at the end of the test. No median frequency changes were observed in the assessed muscles. Although muscular fatigue itself was not detected, observed fatigue caused by high-intensity exercise resulted in inability to maintain speed, which was associated with decreased iEMG values in the hip extensor muscles that generate propulsive force. In contrast, almost all muscles that stabilise joints were unaffected by fatigue. One exception was the decreased muscle activity observed in the M. extensor digitorum longus of the trailing limb, which may suggest unstable ground contact. Muscle activity changes with fatigue might be associated with muscle functions.

scholarly journals Different sensitivity of miniature endplate currents in rat external and internal intercostal muscles to the acetylcholinesterase inhibitor C-547 as compared with diaphragm and extensor digitorum longus

2009 ◽  
pp. 149-153
Author(s):  
K Petrov ◽  
I Kovyazina ◽  
V Zobov ◽  
E Bukharaeva ◽  
EE Nikolsky ◽  
...  
Keyword(s):  
Cholinesterase Inhibitor ◽  
Extensor Digitorum Longus ◽  
Acetylcholinesterase Inhibitor ◽  
Extensor Digitorum ◽  
Experimental Animals ◽  
Intercostal Muscles ◽  
Limb Muscles ◽  
Exercise Induced ◽  
28 Nm

Derivative of 6-methyluracil, selective cholinesterase inhibitor C547 potentiates miniature endplate currents (MEPCs) in rat external intercostal muscles (external ICM) more effectively than in internal intercostal muscles (internal ICM). Effect of the C-547 on intercostal muscles was compared with those on extensor digitorum longus (EDL) and diaphragm muscles. Half-effective concentrations for τ of MEPC decay arranged in increasing order were as follows: EDL, locomotor muscle, most sensitive = 1.3 nM, external ICM, inspiration muscle = 6.8 nM, diaphragm, main inspiration muscle = 28 nM, internal ICM, expiration muscle = 71 nM. External ICM might therefore be inhibited, similarly as the limb muscles, by nanomolar concentrations of the drug and do not participate in inspiration in the presence of the C-547. Moreover, internal ICM inhibition can hinder the expiration during exercise-induced fast breathing of C-547- treated experimental animals.

The Evaluations of the Muscle Activity During “Momi” by Using the Different Immersed Bamboo in Water to Making Kyo-Uchiwa (Japanese Paper Fan)

2013 ◽  
Author(s):  
Porakoch Sirisuwan ◽  
Chieko Narita ◽  
Tetsushi Koshino ◽  
Hisanori Yuminaga
Keyword(s):  
Muscle Activity ◽  
Latissimus Dorsi ◽  
Biceps Brachii ◽  
Gluteus Medius ◽  
Triceps Brachii ◽  
Flexor Carpi Radialis ◽  
Japanese Paper ◽  
Bending Process ◽  
The Difference ◽  
Extensor Carpi Radialis

The aim of study is to evaluate whether altering the bamboo moisture by immersed bamboo in water on 4-hour and 3 -day that would affect the muscle activity during separated bamboo by bending process. Moreover, thirteen muscles which bilateral side of Pectoralis major, Biceps brachii, Triceps brachii, Latissimus dorsi, Gluteus medius and only right side of Rectus abdominis, Extensor carpi radialis longus and Flexor carpi radialis were recorded. As a result, the bilateral side of Biceps brachii, right side of Extensor carpi radialis longus and Flexor carpi radialis, left side of Triceps brachii showed the difference quite clearly. When the craftsman was bending the bamboo he was necessary more effortful by these muscles activity on the 4-hour immersed bamboo in water than the 3-day. The scanning electron microscopy (SEM) photographs showed the fracture characteristic of 2 subjects that the adhesive of bamboo fiber decreased when increased moisture.

Atrophy and growth failure of rat hindlimb muscles in tail-cast suspension

1984 ◽  
Vol 57 (5) ◽  
pp. 1472-1479 ◽  
Author(s):  
S. R. Jaspers ◽  
M. E. Tischler
Keyword(s):  
Extensor Digitorum Longus ◽  
Weight Bearing ◽  
Growth Failure ◽  
Dry Weight ◽  
Extensor Digitorum ◽  
Muscle Size ◽  
Sprague Dawley ◽  
Triceps Brachii ◽  
Suspension Model

Atrophy and growth failure of muscle in a tail-cast suspension model were evaluated in hindlimbs of female Sprague-Dawley rats. Based on measurements of food consumption, animal growth rate, urinary excretion of urea and ammonia, and muscle size, 6 days seemed to be the optimum duration of suspension for studying muscle unloading. After 6 days, the soleus, plantaris, and gastrocnemius muscles from suspended animals were 27, 10, and 11% smaller (P less than 0.05), respectively, than those from tail-casted weight-bearing animals. The extensor digitorum longus and tibialis anterior muscles were unaffected by suspension (less than or equal to 6 days) while the triceps brachii hypertrophied (8%, P less than 0.05). Wet weight-to-dry weight ratios were smaller in the plantaris (-0.19, P less than 0.05) and gastrocnemius (-0.19, P less than 0.05) muscles from suspended rats. In the plantaris, this difference coincided with a higher protein concentration (+12 mg/g, P less than 0.001). In vitro measurements of protein metabolism in the soleus muscles of suspended rats showed both slower protein synthesis (P less than 0.05) and faster protein degradation (P less than 0.05), whereas these processes were unaltered in the extensor digitorum longus muscles.

scholarly journals Myostatin dysfunction impairs force generation in extensor digitorum longus muscle and increases exercise-induced protein efflux from extensor digitorum longus and soleus muscles

2015 ◽  
Vol 40 (8) ◽  
pp. 817-821 ◽  
Author(s):  
Juozas Baltusnikas ◽  
Audrius Kilikevicius ◽  
Tomas Venckunas ◽  
Andrej Fokin ◽  
Lutz Bünger ◽  
...  
Keyword(s):  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Muscle Size ◽  
Wild Type ◽  
Protein Loss ◽  
Muscle Properties ◽  
Longus Muscle ◽  
Generating Capacity ◽  
Contraction Times ◽  
Exercise Induced

Myostatin dysfunction promotes muscle hypertrophy, which can complicate assessment of muscle properties. We examined force generating capacity and creatine kinase (CK) efflux from skeletal muscles of young mice before they reach adult body and muscle size. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of Berlin high (BEH) mice with dysfunctional myostatin, i.e., homozygous for inactivating myostatin mutation, and with a wild-type myostatin (BEH+/+) were studied. The muscles of BEH mice showed faster (P < 0.01) twitch and tetanus contraction times compared with BEH+/+ mice, but only EDL displayed lower (P < 0.05) specific force. SOL and EDL of age-matched but not younger BEH mice showed greater exercise-induced CK efflux compared with BEH+/+ mice. In summary, myostatin dysfunction leads to impairment in muscle force generating capacity in EDL and increases susceptibility of SOL and EDL to protein loss after exercise.

Exercise-induced alterations in skeletal muscle myosin heavy chain phenotype: dose-response relationship

1999 ◽  
Vol 86 (3) ◽  
pp. 1002-1008 ◽  
Author(s):  
Haydar A. Demirel ◽  
Scott K. Powers ◽  
Hisashi Naito ◽  
Michael Hughes ◽  
Jeff S. Coombes
Keyword(s):  
Exercise Training ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Extensor Digitorum Longus ◽  
Citrate Synthase ◽  
Extensor Digitorum ◽  
Control Group ◽  
Sprague Dawley ◽  
Skeletal Muscle Myosin ◽  
Exercise Induced

This study investigated the effects of exercise training duration on the myosin heavy chain (MHC) isoform distribution in rat locomotor muscles. Female Sprague-Dawley rats (120 days old) were assigned to either a sedentary control group or to one of three endurance exercise training groups. Trained animals ran on a treadmill at ∼75% maximal O2 uptake for 10 wk (4–5 days/wk) at one of three different exercise durations (30, 60, or 90 min/day). Training resulted in increases ( P < 0.05) in citrate synthase activity in the soleus and extensor digitorum longus in both the 60 and 90 min/day duration groups and in the plantaris (Pla) in all three exercise groups. All durations of training resulted in a reduction ( P < 0.05) in the percentage of MHCIIb and an increase ( P < 0.05) in the percentage of MHCIIa in the Pla. The magnitude of change in the percentage of MHCIIb in the Pla increased as a function of the training duration. In the extensor digitorum longus, 90 min of daily exercise promoted a decrease ( P < 0.05) in percentage of MHCIIb and increases ( P < 0.05) in the percentages of MHCI, MHCIIa, and MHCIId/x. Finally, training durations ≥60 min resulted in an increase ( P < 0.05) in the percentage of MHCI and a concomitant decrease ( P < 0.05) in the percentage of MHCIIa in the soleus. These results demonstrate that increasing the training duration elevates the magnitude of the fast-to-slow shift in MHC phenotype in rat hindlimb muscles.

Postexercise hypotension causes a prolonged perturbation in esophageal and active muscle temperature recovery

2006 ◽  
Vol 291 (3) ◽  
pp. R580-R588 ◽  
Author(s):  
Glen P. Kenny ◽  
Ollie Jay ◽  
Wytek M. Zaleski ◽  
Mark L. Reardon ◽  
Ronald J. Sigal ◽  
...  
Keyword(s):  
Temperature Profile ◽  
Recovery Period ◽  
Peak Oxygen Consumption ◽  
Muscle Temperature ◽  
Triceps Brachii ◽  
Active Muscle ◽  
Bilateral Knee ◽  
Collateral Artery ◽  
Postexercise Recovery ◽  
Exercise Induced

We examined the effect of two levels of exercise-induced hypotension on esophageal (Tes) and active and nonactive muscle temperatures during and following exercise. Seven males performed an incremental isotonic test on a Kin-Com isokinetic apparatus to determine their peak oxygen consumption during bilateral knee extensions (V̇o2sp). This was followed on separate days by 15-min of isolated bilateral knee extensions at moderate (60% V̇o2sp) (MEI) and high (80% V̇o2sp) (HEI) exercise intensities, followed by 90 min of recovery. Muscle temperature was measured with an intramuscular probe inserted in the left vastus medialis (Tvm) and triceps brachii (Ttb) muscles under ultrasound guidance. The deepest sensor (tip) was located ∼10 mm from the femur and deep femoral artery and from the superior ulnar collateral artery and humerus for the Tvm and Ttb, respectively. Additional sensors were located 15 and 30 mm from the tip with an additional sensor located at 45 mm for the Tvm measurements only. Following exercise, mean arterial pressure (MAP) remained significantly below preexercise rest for the initial 60 min of recovery after MEI and for the duration of the postexercise recovery period after HEI ( P ≤ 0.05). After HEI, significantly greater elevations from preexercise rest were recorded for Tes and all muscle temperatures paralleled a greater decrease in MAP compared with MEI (all P ≤ 0.05). By the end of 90-min postexercise recovery, MAP, Tes, and all muscle temperatures remained significantly greater after HEI than MEI. Furthermore, a significantly shallower muscle temperature profile across Tvm, relative to preexercise rest, was observed at the end of exercise for both HEI and MEI ( P ≤ 0.05), and for 30 min of recovery for MEI and throughout 90 min of recovery for HEI. No significant differences in muscle temperature profile were observed for Ttb. Thus we conclude that the increase in the postexercise hypotensive response, induced by exercise of increasing intensity, was paralleled by an increase in the magnitude and recovery time of the postexercise esophageal and active muscle temperatures.

Human growth hormone treatment of hypophysectomized rats increases the proportion of type-1 fibres in skeletal muscle

1989 ◽  
Vol 123 (3) ◽  
pp. 429-NP ◽  
Author(s):  
C. M. Ayling ◽  
B. H. Moreland ◽  
J. M. Zanelli ◽  
D. Schulster
Keyword(s):  
Skeletal Muscle ◽  
Fibre Type ◽  
Extensor Digitorum Longus ◽  
Human Growth ◽  
Hormone Treatment ◽  
Pituitary Hormones ◽  
Extensor Digitorum ◽  
Replacement Treatment ◽  
Hypophysectomized Rats

ABSTRACT The studies describe alterations after hypophysectomy in the proportion of the type-1 and type-2 fibres in rat skeletal muscles, and the effects of replacement treatment with pituitary human (h) GH. Cytochemical analysis of myosin ATPase, succinate dehydrogenase and lactate dehydrogenase activities in sections of rat hind limb muscles were used as markers of fibre type and revealed that hypophysectomy reduced the proportion of type-1 fibres by 50% in soleus and in extensor digitorum longus muscles. This reduction in the proportion of type-1 fibres was accompanied by the appearance of transitional fibres (type 2C/1B). Following seven daily injections of hGH (60 mIU/day) to hypophysectomized rats, the proportion of type-1 fibres in both soleus and in extensor digitorum longus was increased with a concomitant reduction in the number of transitional fibres. After 11 days of treatment, all these transitional fibres had reverted back to type-1 fibres. Only hGH was observed to elicit this effect; injections of other pituitary hormones had no effect on the proportions of these transitional fibres. These alterations in fibre type occurred more rapidly than the changes reported after prolonged electrical stimulation of muscle or following extended exercise. These findings suggest that hypophysectomy and GH injection can result in a rapid alteration in the fibre composition of skeletal muscle, which may have important implications in terms of the resistance to fatigue and speed of contraction of the muscle. Journal of Endocrinology (1989) 123, 429–435

scholarly journals Identification in skeletal muscle of a distinct extracellular pool of amino acids, and its role in protein synthesis

1971 ◽  
Vol 121 (5) ◽  
pp. 817-827 ◽  
Author(s):  
R. C. Hider ◽  
E. B. Fern ◽  
D. R. London
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Incubation Medium ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Longus Muscle ◽  
Kinetics Of

1. The kinetics of radioactive labelling of extra- and intra-cellular amino acid pools and protein of the extensor digitorum longus muscle were studied after incubations with radioactive amino acids in vitro. 2. The results indicated that an extracellular pool could be defined, the contents of which were different from those of the incubation medium. 3. It was concluded that amino acids from the extracellular pool, as defined in this study, were incorporated directly into protein.

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