scholarly journals PO-114 Effects of one-time exhaustive exercise on peripheral drive in rats

2018 ◽  
Vol 1 (4) ◽  
Author(s):  
Mengjiao Chen ◽  
Haojie Huang ◽  
Jiaxin Li ◽  
Ke Li ◽  
Chunhong Teng ◽  
...  
Keyword(s):  
Hind Limb ◽  
Drive Level ◽  
Muscle Group ◽  
Flexor Muscle ◽  
Exercise Time ◽  
Static Contraction ◽  
Flexor Muscles ◽  
Before And After ◽  
Gripping Force ◽  
Exercise Fatigue

Objective In this study, we observed the effects of one-time exhaustive exercise on the grip strength, the time of grabbing, and the changes of the electromyography (EMG) of the hind limb flexor muscles and the flexor elbow muscles of the forelimbs, and revealed the effects of exercise fatigue on the peripheral motor drive level. Methods Male SD rats finished exhaustive fatigue exercise. A one-time exhaustive treadmill exercise fatigue model was established after one-week adaptive training in rats. The model was established by the modified Bedford incremental load motion program of the laboratory. The load is divided into 3 levels: the first stage movement speed 8.2 m/min, exercise time 15 min; second stage speed 15 m/min, exercise time 15 min; third stage speed at 20 m/min, exercise to exhaustion. At the same time, a miniature wireless acceleration sensor (18g) was worn in the tail of the rat to monitor the acceleration change of the running direction of the rat while running on the running platform. Three consecutive parallel experiments were performed using a rat grip tester (BioSEB GS3) to measure and compare the maximal muscle strength changes of the limbs before and after exercise fatigue in rats. Compared the static contraction of the rat muscle before and after exercise fatigue to overcome the length of time and gravity of the rod, and evaluated the muscle endurance after training the rats to learn to grab the rod. The EMG,square root amplitude (maxRMS), frequency domain analysis of EMG median frequency (MDF) and mean frequency (MPF) of the hind limb flexor and the forelimb flexor muscles (EMG) was measured by the Italian BTS FREEEMG ultra-miniature wireless surface electromyography tester to predict peripheral muscle tone and drive level. Results 1) The maximum holding force of the rat in resting state was 68.53 N/Kg, and the gripping force was significantly decreased (p<0.05) and reduced to 25.47 N/Kg after exercise fatigue .2) Exercise fatigue has a significant effect on the static grab time of rats. The rat has a grab time of 287.65s in a quiet state, and can only last for 27.78s after fatigue, and even can hardly maintain static contraction. The maxRMS of hindlimb flexor muscles in rats was significantly lower than that before fatigue (P<0.05) at rest, and there was no difference in forelimb flexor elbow muscle groups. MDF and MDF of forelimb flexor elbow muscle group and hind limb flexor muscle group were significant increased (P<0.05). 4) MaxRMS MDF and MDF of hind limb flexor muscle group and forelimb flexor elbow muscle group were significantly lower than those before fatigue (P<0.05) under the state of grabbing rod. Conclusions The sprinting ability in the running direction,maximum gripping force and grabbing time of the rats decreased significantly after exercise fatigue, revealing that the fatigue of the muscles may cause the decrease of the muscle static contraction ability. The inability of the hind limbs to maintain standing with exercise fatigue may be related to a significant decrease in hindlimb tension, and it was found that there was an explosive discharge and the phenomenon of tonic contraction in the muscles at rest. The muscle endurance and tension of the muscles were significantly reduced, and the contraction frequency of the muscle movement unit decreased significantly after exercise fatigue, causing insufficient peripheral driving level . (NSFC31401018, SKXJX2014014, [email protected]).

Isokinetic Strength After ACL Reconstruction: Influence of Concomitant Anterolateral Ligament Reconstruction

2021 ◽  
pp. 194173812110054
Author(s):  
Benoit Gillet ◽  
Yoann Blache ◽  
Isabelle Rogowski ◽  
Grégory Vigne ◽  
Bertrand Sonnery-Cottet ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Ligament Reconstruction ◽  
Knee Extensor ◽  
Anterolateral Ligament ◽  
Flexor Muscle ◽  
Knee Flexor ◽  
Strength Recovery ◽  
Flexor Muscles ◽  
Knee Muscle ◽  
Knee Muscle Strength

Background: To reduce the rate of anterior cruciate ligament (ACL) graft rupture, recent surgeries have involved anterolateral ligament reconstruction (ALLR). This reconstruction procedure harvests more knee flexor muscle tendons than isolated ACL reconstruction (ACLR), but its influence on knee muscle strength recovery remains unknown. This study aimed to assess the influence of ALLR with a gracilis graft on the strength of the knee extensor and flexor muscles at 6 months postoperatively. Hypothesis: The additional amount of knee flexor harvest for ALLR would result in impairment in knee flexor muscle strength at 6 months postoperatively. Study Design: Retrospective cohort study. Level of Evidence: Level 2. Methods: A total of 186 patients were assigned to 2 groups according to the type of surgery: ACL + ALLR (graft: semitendinosus + gracilis, n = 119) or isolated ACLR (graft: semitendinosus, n = 67). The strength of the knee extensor and flexor muscles was assessed using an isokinetic dynamometer at 90, 180, and 240 deg/s for concentric and 30 deg/s for eccentric contractions and compared between groups using analysis of variance statistical parametric mapping. Results: Regardless of the surgery and the muscle, the injured leg produced significantly less strength than the uninjured leg throughout knee flexion and extension from 30° to 90° for each angular velocity (30, 90, 180, and 240 deg/s). However, the knee muscle strength was similar between the ACL + ALLR and ACLR groups. Conclusion: The addition of ALLR using the gracilis tendon during ACLR does not alter the muscle recovery observed at 6 months postoperatively. Clinical Relevance: Although more knee flexor muscle tendons were harvested in ACL + ALLR, the postoperative strength recovery was similar to that of isolated ACLR.

Motor projection patterns to the hind limb of normal and paralysed chick embryos

Development ◽  
1982 ◽  
Vol 72 (1) ◽  
pp. 269-286
Author(s):  
N. G. Laing
Keyword(s):  
Spinal Cord ◽  
Cell Death ◽  
Hind Limb ◽  
Muscle Volume ◽  
Chick Embryos ◽  
Relative Contribution ◽  
Hind Limbs ◽  
Lateral Motor Column ◽  
Before And After ◽  
Major Period

Counts were made of the number of motoneurons innervating the hind limbs of 10-day normal and paralysed chick embryos whose right hind limb buds had been subjected to varying degrees of amputation prior to innervation. The number of motoneurons on the intact sides of the paralysed embryos was found to be similar to the number present in normal embryos prior to the major period of motoneuron death. Since it has previously been shown that paralysis does not increase the number of motoneurons generated, this means that normal motoneuron death was largely prevented in the paralysed embryos. There were differences in the distributions of motoneurons in the rostrocaudal axis of the spinal cord between normal and paralysed embryos. Therefore, cell death does not eliminate a uniform fraction of motoneurons throughout the rostrocaudal extent of the chick embryo lumbar lateral motor column. It is also argued that there are differences in the relative contribution of the various lumbosacral levels to different parts of the limb, e.g. the shank, before and after the period of cell death. In both normal and paralysed embryos there was a linear relationship between the volume of limb muscle which developed after amputation and the number of motoneurons surviving in the spinal cord. There was no evidence of a ‘compression’ of motoneurons into the remaining muscle either after amputation alone or after amputation combined with paralysis. Motoneurons are therefore rigidly specified for certain parts of the limb. The relationship between motoneuron number and muscle volume on the amputated side differed from that of the intact side. For a similar increase in muscle volume there was a smaller increase in motoneuron number on the intact sides. This suggested a parallel to the paradoxically small increase in motoneuron number that occurs on the addition of a supernumerary limb.

Wipe and flexion reflexes of the frog. II. Response to perturbations

1993 ◽  
Vol 69 (5) ◽  
pp. 1736-1748 ◽  
Author(s):  
J. L. Schotland ◽  
W. Z. Rymer
Keyword(s):  
External Load ◽  
Hind Limb ◽  
Joint Angle ◽  
Activity Level ◽  
Temporal Organization ◽  
Emg Activity ◽  
Relative Timing ◽  
Before And After ◽  
Movement Segment ◽  
Initial Movement

1. To evaluate the hypothesis that the neural control of sensorimotor transformations may be simplified by using a single control variable, we compared the movement kinematics and muscle activity patterns [electromyograms (EMGs)] of the frog during flexion withdrawal and the hind limb-hind limb wipe reflex before and after adding an external load. In addition, the flexibility of spinal cord circuitry underlying the hind limb-hind limb wipe reflex was evaluated by comparing wipes before and after removal of one of the contributing muscles by cutting a muscle nerve. 2. The kinematics of the movements were recorded using a WATSMART infrared emitter-detector system and quantified using principal-components analysis to provide a measure of the shape (eigenvalues) and orientation (eigenvector coefficients) of the movement trajectories. The neural pattern coordinating the movements was characterized by the latencies and magnitudes of EMGs of seven muscles acting at the hip, knee, and ankle. These variables were compared 1) during flexion withdrawal and the initial movement segment of the limb during the hind limb-hind limb wipe reflex in both unrestrained movements and in movements executed when a load equal to approximately 10% of the animal's body weight was attached to a distal limb segment and 2) during the initial movement segment of the wipe reflex before and after cutting the nerve to the knee flexor-hip extensor, iliofibularis. 3. Addition of the load had no discernible effect on the end-point position of the foot during either reflex. However, during the loaded flexion reflex, the ankle joint did not move until after the hip and knee joints had moved to their normal positions. This delayed flexion of the ankle was accompanied by large increases in the magnitude of EMG activity in two ankle muscles that exceeded the levels found during unrestrained movements. Significant changes in the temporal organization of the EMG pattern accompanied the change in joint angle relations during flexion withdrawal. 4. Despite the addition of an external load, all animals successfully and reliably removed the stimulus during the wipe reflex, and the relative timing of both the EMG pattern and joint angle motion was preserved. 5. Immediately after section of the nerve to a single muscle (iliofibularis), all animals successfully and reliably removed the stimulus during the wipe reflex. The relative timing of muscle activation was preserved, accompanied by a reduction in the activity level of gluteus magnus, a muscle with action reciprocal to iliofibularis.(ABSTRACT TRUNCATED AT 400 WORDS)

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.

Effect of unweighting on skeletal muscle use during exercise

1995 ◽  
Vol 79 (1) ◽  
pp. 168-175 ◽  
Author(s):  
L. L. Ploutz-Snyder ◽  
P. A. Tesch ◽  
D. J. Crittenden ◽  
G. A. Dudley
Keyword(s):  
Lower Limb ◽  
Weight Bearing ◽  
Muscle Group ◽  
Mr Images ◽  
Cross Sectional ◽  
Quadriceps Femoris Muscle ◽  
Before And After ◽  
Exercise Induced ◽  
The Right ◽  
Femoris Muscle

Exercise-induced spin-spin relaxation time (T2) shifts in magnetic resonance (MR) images were used to test the hypothesis that more muscle would be used to perform a given submaximal task after 5 wk of unweighting. Before and after unilateral lower limb suspension (ULLS), 7 subjects performed 5 sets of 10 unilateral concentric actions with the quadriceps femoris muscle group (QF) at each of 4 loads: 25, 40, 55, and 70% of maximum. T2-weighted MR images of the thigh were collected at rest and after each relative load. ULLS elicited a 20% decrease in strength of the left unweighted QF and a 14% decrease in average cross-sectional area (CSA) with no changes in the right weight-bearing QF. Average CSA of the left or right QF showing exercise-induced T2 shift increased as a function of exercise intensity both before and after ULLS. On average, 12 +/- 1, 15 +/- 2, 18 +/- 2, and 22 +/- 1 cm2 of either QF showed elevated T2 for the 25, 40, 55, and 70% loads, respectively, before ULLS. Average CSA of the left but not the right QF, showing elevated T2 after ULLS, was increased to 16 +/- 2, 23 +/- 3, 31 +/- 7, and 39 +/- 5 cm2, respectively. The results indicated that unweighting increased exercise-induced T2 shift in MR images, presumably due to greater muscle mass involvement in exercise after than before unweighting, suggesting a change in motor control.

scholarly journals Effect of Temporomandibular Joint Mobilization on Neck Pain and Function in Patients with Chronic Non-Specific Neck Pain

2019 ◽  
Vol 2 (19) ◽  
Author(s):  
Edgaras Lapinskas ◽  
Janina Stirbytė
Keyword(s):  
Neck Pain ◽  
Temporomandibular Joint ◽  
Chronic Neck Pain ◽  
Flexor Muscle ◽  
Joint Mobilization ◽  
Movement Characteristics ◽  
Neck Function ◽  
Before And After ◽  
And Function

Background. Neck pain is a common problem, and it includes 30% of 25–29 year olds. The percentage of people over 45 years of age has risen to 50% (Knight and Draper, 2012). Long-term muscle imbalance disrupts body biomechanics. Due to long-lasting pain, the quality of work may decrease, rest can get worse, and mood may change. Purpose. To determine the effect of temporomandibular joint mobilization for neck pain and function in patients who suffer chronic non-specifc neck pain. Methods. The study involved six people with non-specifc chronic neck pain, who were divided into two groups: exercises, and the second group – exercises and mobilization of temporomandibular joint. At the beginning and end of the study, we performed the following tests: deep neck flexor endurance test, visual analogue scale (VAS), goniometry, the amplitude of the temporomandibular joint. Results. In the group of exercises, the pain score after treatment decreased (before – 67 ± 28, after – 14 ± 16.5) the strength and endurance of the deep neck flexor muscle improved (before – 13.7 ± 2.5 s, after – 28.7 ± 6.4 s). The amplitude of all neck movements was improved (p < 0.05), comparing them before and after physiotherapy. The amplitude of the temporomandibular joint improved the movement characteristics: depression, lateral excursions to left and right, protrusion (p < 0.05). Conclusions. Comparing the results after applying different methods of physiotherapy, intensity of pain and neck function parameters did not show significant differences.Keywords: temporomandibular joint, nonspecifc neck pain, mobilization.

The appearance of muscle protein and myofibrils within the embryonic chick limb-bud

Development ◽  
1973 ◽  
Vol 30 (3) ◽  
pp. 673-679
Author(s):  
P. V. Thorogood
Keyword(s):  
Banding Pattern ◽  
Hind Limb ◽  
Muscle Protein ◽  
Ventral Surface ◽  
Ultrastructural Level ◽  
Limb Bud ◽  
Embryonic Chick ◽  
Immunofluorescence Technique ◽  
Flexor Muscles

Myotubes are present in the developing hind limb of the embryonic chick at 5 days. An immunofluorescence technique was used to detect actomyosin within the myotubes. The earliest detectable appearance of this muscle protein was at six days of development, at sites located peripherally beneath the flattened dorsal and ventral surface of the limb. These dorsal and ventral loci are interpreted as representing the primordial extensor and flexor muscles. At the ultrastructural level the cytoplasm of the myotubes contains fibrillar components which are apparently aggregating to form myofibrils. A rudimentary banding pattern can be distinguished.

CHANGES IN THE FLEXOR AND EXTENSOR MUSCLES AT DIFFERENT SPEEDS

2021 ◽  
Vol 27 (7) ◽  
pp. 686-688
Author(s):  
Rui Ma ◽  
Wenyan Li
Keyword(s):  
Knee Joint ◽  
Peak Torque ◽  
Muscle Group ◽  
Lower Limbs ◽  
Flexor Muscle ◽  
Level Of Evidence ◽  
Isokinetic Test ◽  
Extensor Muscles ◽  
Test Velocity ◽  
The Difference

ABSTRACT Introduction: Centrifugal strength is an important element for strength quality. Developing muscle centrifugal strength can effectively increase the stability of lower limbs and reduce the risk of injury. Objective: To explore the characteristics of contractile force of flexor ahods in strength training and rehabilitation training, and the extensor muscles of the knee joint in athletes with different speeds of centripetal force. Methods: The knee joint muscle group of 8 first-level male high jumpers and 8 second-level male high jumpers were tested by isokinetic centrifugal contraction; the angular test velocity was 60 °/s, 120 °/s, 240 °/s, and the indexes included peak torque, relative peak torque (peak torque/body weight), and the peak torque flexural extension ratio. Results: With the centrifugal contraction of the knee joint muscle group (P < 0.05), the second-level high jumpers should increase the ability of the knee flexor muscle group of the take-off leg. In the case of constant velocity centrifugal contraction (P < 0.01), taking off time must be reduced, that is, taking off speed must be accelerated. Conclusions: The difference in the knee joint muscle isokinetic test results is one of the reasons for the difference in knee joint flexor and extensor muscle contractility under the different speed forces of high jumpers. Level of evidence II; Therapeutic studies - investigation of treatment results.

Modulatory effects of nitric oxide on synaptic depression in the crayfish neuromuscular system

2000 ◽  
Vol 203 (23) ◽  
pp. 3595-3602 ◽  
Author(s):  
H. Aonuma ◽  
T. Nagayama ◽  
M. Takahata
Keyword(s):  
Nitric Oxide ◽  
Neuromuscular Transmission ◽  
Procambarus Clarkii ◽  
Synaptic Depression ◽  
Physiological Property ◽  
Muscle Fibres ◽  
Flexor Muscle ◽  
Bath Application ◽  
Flexor Muscles ◽  
Stimulation Of

A characteristic physiological property of the neuromuscular junction between giant motor neurones (MoGs) and fast flexor muscles in crayfish is synaptic depression, in which repetitive electrical stimulation of the MoG results in a progressive decrease in excitatory junction potential (EJP) amplitude in flexor muscle fibres. Previous studies have demonstrated that l-arginine (l-Arg) modulates neuromuscular transmission. Since l-Arg is a precursor of nitric oxide (NO), we examined the possibility that NO may be involved in modulating neuromuscular transmission from MoGs to abdominal fast flexor muscles. The effect of a NO-generating compound, NOC7, was similar to that of l-Arg, reversibly decreasing the EJP amplitude mediated by the MoG. While NOC7 reduced the amplitude of the EJP, it induced no significant change in synaptic depression. In contrast, a scavenger of free radical NO, carboxy-PTIO, and an inhibitor of nitric oxide synthase, l-NAME, reversibly increased the EJP amplitude mediated by MoGs. Synaptic depression mediated by repetitive stimulation of MoGs at 1 Hz was partially blocked by bath application of l-NAME. Bath application of a NO scavenger, a NOS inhibitor and NO-generating compounds had no significant effects on the depolarisation of the muscle fibres evoked by local application of l-glutamate. The opposing effects on EJP amplitude of NOC7 and of carboxy-PTIO and l-NAME suggest that endogenous NO presynaptically modulates neuromuscular transmission and that it could play a prominent role at nerve terminals in eliciting MoG-mediated synaptic depression in the crayfish Procambarus clarkii.

Plasma catecholamines and their effect on blood lactate and muscle lactate output

1984 ◽  
Vol 57 (2) ◽  
pp. 321-325 ◽  
Author(s):  
W. N. Stainsby ◽  
C. Sumners ◽  
G. M. Andrew
Keyword(s):  
Venous Blood ◽  
Plasma Catecholamines ◽  
Muscle Group ◽  
O2 Uptake ◽  
Plantaris Muscle ◽  
Muscle Lactate ◽  
Blood Samples ◽  
Lactate Output ◽  
Before And After

This study was designed to test the hypothesis that epinephrine (E) and norepinephrine (NE) increase net muscle lactate output (L) of in situ gastrocnemius-plantaris muscle group during contractions. Plasma [E] and [NE] were measured before and after the surgical isolation of the muscle and at 10-min intervals during the 60-min experiments. Plasma [E] and [NE] were increased threefold by intravenous infusions of E (n = 3) or NE (n = 3) at a rate of 1.5 micrograms X kg body wt-1 X min-1. Arterial and muscle venous blood samples for O2 and lactate concentrations were also obtained. The infusions began at min 11 and repetitive isometric contractions (4 tw/s) began at min 31. The presurgery plasma [E] and [NE] averaged 0.34 and 0.52 ng/ml, respectively, and rose to 1.12 and 1.19 ng/ml 10 min after surgery. Arterial and venous lactate concentrations (CaL and CvL) increased continuously during E infusion but remained constant during NE infusion. Maximal L during the first 10 min of contractions was significantly increased compared with an identical earlier study without infusions. O2 uptake was not changed by the infusions. It is concluded that E causes CaL to rise and that both E and NE increase maximal net lactate output during contractions.

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