Journal articles: 'Musculus triceps surae'

1

Shaikhutdinov, I. I., and A. M. Eremeev. "Electroneuromyographic investigations in patients with deforming arthrosis of the hip and knee joints." Kazan medical journal 74, no. 2 (April 15, 1993): 95–97. http://dx.doi.org/10.17816/kazmj64630.

Full text

Abstract:

The changes of the functional state of spinal centers and muscles (musculus quadriceps femoris and musculus triceps surae) are detected, when observing 8 healthy subjects and 16 patients with gonand coxarthrosis. Centers or center-controlled muscles suffer to a large extent depending on the occurrence of the joint affections.

APA, Harvard, Vancouver, ISO, and other styles

2

Peschterliev, N., and N. Natschev. "Korrektur der Spitzfußkomponente beim angeborenen Klumpfuß durch Befreiung des Musculus triceps surae und tibiocalcaneare Distraktion." Zeitschrift für Orthopädie und ihre Grenzgebiete 126, no. 04 (March 18, 2008): 413–15. http://dx.doi.org/10.1055/s-2008-1044460.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Rensing, N., A. Westermann, D. Möller, and H. von Piekartz. "Trainingseffekte eines reaktiven Sprungkrafttrainings bei Handballern in Bezug auf die Sprunghöhe und die Kraftentfaltung des Musculus triceps surae." Sportverletzung · Sportschaden 29, no. 04 (November 18, 2015): 236–43. http://dx.doi.org/10.1055/s-0041-106947.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Waldrop, T. G., and R. W. Stremel. "Muscular contraction stimulates posterior hypothalamic neurons." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 256, no. 2 (February 1, 1989): R348—R356. http://dx.doi.org/10.1152/ajpregu.1989.256.2.r348.

Full text

Abstract:

Recent studies have suggested that the subthalamic locomotor region (STLR) of the posterior hypothalamus is involved in modulating cardiorespiratory responses to feedback from contracting muscles. The purpose of this study was to determine whether neurons in this hypothalamic region alter their discharge frequency during contraction of hindlimb muscles. Stainless steel electrodes were used to record single-unit activity of STLR neurons during static and rhythmic contractions of hindlimb muscles in anesthetized cats. Recordings were also made from neurons in areas outside but surrounding the subthalamic locomotor region. Contraction of the triceps surae muscles was induced by stimulation of the peripheral cut ends of the L7 and S1 ventral roots. Both static and rhythmic contractions of the triceps surae evoked an increase in the discharge rate of the majority of the STLR cells studied. Two types of excitatory responses were observed: 1) abrupt increases in discharge frequency at the onset of muscular contraction and 2) a delayed more gradual increase in firing. Most of the cells that responded to muscular contraction could be activated by mechanical probing of the triceps surae muscles. However, the changes in discharge frequency were unrelated to changes in arterial pressure occurring during muscular contraction. Most of the neurons located outside the STLR were slightly inhibited by or did not respond to muscular contraction. Thus input from contracting muscles exerts predominantly an excitatory effect on neurons in the posterior hypothalamus. These results are consistent with other studies which have concluded that this hypothalamic site is involved in influencing the cardiorespiratory responses to muscular contraction.

APA, Harvard, Vancouver, ISO, and other styles

5

Sánchez-Gómez, Rubén, Carlos Romero-Morales, Álvaro Gómez-Carrión, Blanca De-la-Cruz-Torres, Ignacio Zaragoza-García, Pekka Anttila, Matti Kantola, and Ismael Ortuño-Soriano. "Effects of Novel Inverted Rocker Orthoses for First Metatarsophalangeal Joint on Gastrocnemius Muscle Electromyographic Activity during Running: A Cross-Sectional Pilot Study." Sensors 20, no. 11 (June 5, 2020): 3205. http://dx.doi.org/10.3390/s20113205.

Full text

Abstract:

Background: The mobility of the first metatarsophalangeal joint (I MPTJ) has been related to the proper windlass mechanism and the triceps surae during the heel-off phase of running gait; the orthopedic treatment of the I MPTJ restriction has been made with typical Morton extension orthoses (TMEO). Nowadays it is unclear what effects TMEO or the novel inverted rocker orthoses (NIRO) have on the EMG activity of triceps surae during running. Objective: To compare the TMEO effects versus NIRO on EMG triceps surae on medialis and lateralis gastrocnemius activity during running. Study design: A cross-sectional pilot study. Methods: 21 healthy, recreational runners were enrolled in the present research (mean age 31.41 ± 4.33) to run on a treadmill at 9 km/h using aleatory NIRO of 6 mm, NIRO of 8 mm, TMEO of 6 mm, TMEO of 8 mm, and sports shoes only (SO), while the muscular EMG of medial and lateral gastrocnemius activity during 30 s was recorded. Statistical intraclass correlation coefficient (ICC) to test reliability was calculated and the Wilcoxon test of all five different situations were tested. Results: The reliability of values was almost perfect. Data showed that the gastrocnemius lateralis increased its EMG activity between SO vs. NIRO-8 mm (22.27 ± 2.51 vs. 25.96 ± 4.68 mV, p < 0.05) and SO vs. TMEO-6mm (22.27 ± 2.51 vs. 24.72 ± 5.08 mV, p < 0.05). Regarding gastrocnemius medialis, values showed an EMG notable increase in activity between SO vs. NIRO-6mm (22.93 ± 2.1 vs. 26.44 ± 3.63, p < 0.001), vs. NIRO-8mm (28.89 ± 3.6, p < 0.001), and vs. TMEO-6mm (25.12 ± 3.51, p < 0.05). Conclusions: Both TMEO and NIRO have shown an increased EMG of the lateralis and medialis gastrocnemius muscles activity during a full running cycle gait. Clinicians should take into account the present evidence when they want to treat I MTPJ restriction with orthoses, and consider the inherent triceps surae muscular cost relative to running economy.

APA, Harvard, Vancouver, ISO, and other styles

6

Goulet, C., A. B. Arsenault, D. Bourbonnais, M. F. Levin, and M. Goyette. "Differential effects of tens on the muscular components of the human triceps surae." Electroencephalography and Clinical Neurophysiology 87, no. 2 (August 1993): S86. http://dx.doi.org/10.1016/0013-4694(93)91247-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Willwacher, Steffen, Wolfgang Potthast, Markus Konrad, and Gert-Peter Brüggemann. "Effect of Heel Construction on Muscular Control Potential of the Ankle Joint in Running." Journal of Applied Biomechanics 29, no. 6 (December 2013): 740–48. http://dx.doi.org/10.1123/jab.29.6.740.

Full text

Abstract:

The purpose of this study was to investigate the effect of heel construction on ankle joint mechanics during the early stance phase of running. Kinematic and kinetic parameters (ankle joint angles, angular velocities and joint moments, lever arms of ground reaction force, triceps surae muscle tendon unit lengths, and rates of muscle tendon unit length change) were calculated from 19 male subjects running at 3.3 m/s in shoes with different heel constructions. Increasing heel height and posterior wedging amplified initial plantar flexion velocity and range. The potential for a muscle to control the movement of a joint depends upon its ability to produce joint moments. Runners in this study showed decreased external eversion moments and an increase in eversion range. Maximum eversion angles were not significantly affected by shoe conditions. Without considerable tendon prestretch, joint moment generation potentials of triceps surae and deep plantar flexors might be inhibited due to rapid plantar flexion based on the force–velocity relationship. It could be speculated that increasing ankle inversion at heel strike could be a strategy to keep maximum eversion angles inside an adequate range, if joint moment generation potentials of deep plantar flexors are inhibited due to rapid plantar flexion.

APA, Harvard, Vancouver, ISO, and other styles

8

Archambault, J. M., T. J. Koh, W. Herzog, and D. A. Hart. "Experimental Animal Model to Study Muscle and Tendon Adaptations to Chronic Loading." Journal of Musculoskeletal Research 02, no. 04 (December 1998): 283–88. http://dx.doi.org/10.1142/s0218957798000287.

Full text

Abstract:

The purpose of this short communication is to present an animal model that: (1) allows for controlled, quantifiable loading of muscle and tendon; and (2) can be used to evaluate the response of musculo-skeletal tissues to chronic loading. A loading apparatus was used to move the rabbit foot through any desired angular position and velocity, while continuously measuring moments about the transverse axis of the ankle. A stimulator was triggered at a pre-set location in the range of motion to produce a contraction of the triceps surae and plantaris muscles. Muscle forces measured with an Achilles tendon force transducer were found to correlate well with externally measured ankle extensor moments. The experimental setup was used to provide cyclic loads to the triceps surae and plantaris muscles and Achilles tendon of 16 rabbits for three loading sessions per week over the period of one to eleven weeks. The experimental model described here is appropriate for the systematic study of the adaptation of muscle and tendon to chronic loading because of the repeatability of the setup and the quantification of tissue loads.

APA, Harvard, Vancouver, ISO, and other styles

9

Bobbert, M. "Dependence of human squat jump performance on the series elastic compliance of the triceps surae: a simulation study." Journal of Experimental Biology 204, no. 3 (February 1, 2001): 533–42. http://dx.doi.org/10.1242/jeb.204.3.533.

Full text

Abstract:

The purposes of this study were to determine the dependence of human squat jump performance on the compliance of series elastic elements (SEEs) of the triceps surae (consisting of the soleus and gastrocnemius) and to explain this dependence. Vertical squat jumps were simulated using an optimal control model of the human musculo-skeletal system. Maximum jump height was found for several values of triceps surae SEE strain at maximum isometric force (ε (0)). When ε (0) was increased from 1 to 10 %, maximum jump height increased by 8 cm. This was partly due to a higher work output of contractile elements (CEs) of the muscles, primarily of the soleus, and also partly to an increased efficacy of converting muscle work to energy contributing to jump height. The soleus produced more work at ε (0)=10 % because, as a result of SEE recoil, the CE covered its shortening range at lower velocity and hence produced more force. Efficacy was higher at ε (0)=10 % because a higher vertical velocity at take-off was achieved with a lower rotational energy of the body segments. This apparent discrepancy was explained by increased angular velocities of the shanks and feet, which have small moments of inertia, and decreased angular velocities of the thighs and trunk, which have larger moments of inertia. This redistribution of segmental contributions to the vertical velocity of the centre of mass was possible because the increased compliance of the triceps surae SEE enhanced the energy-buffering capacity of this muscle group and, thereby, allowed for a higher power output at the ankles. It seems that long compliant tendons in the plantar flexors are an elegant solution to the problem of maximizing jumping performance.

APA, Harvard, Vancouver, ISO, and other styles

10

Cattagni, Thomas, Vincent Gremeaux, and Romuald Lepers. "The Physiological Characteristics of an 83-Year-Old Champion Female Master Runner." International Journal of Sports Physiology and Performance 15, no. 3 (March 1, 2020): 444–48. http://dx.doi.org/10.1123/ijspp.2018-0879.

Full text

Abstract:

Purpose: To examine the cardiorespiratory, muscular, and skeletal characteristics of an 83-year-old champion female master athlete (called DL in this study) who had set multiple world running records in the 80-to-84-year-old age group. Methods: Measures of maximal oxygen uptake, maximal heart rate, maximal isometric torque for knee extensor muscles, thigh and triceps surae muscle volumes, and bone mineral density (BMD) of the proximal femur region were evaluated. Based on previously published equations, physiological age was determined for maximal oxygen uptake, maximal heart rate, and maximal isometric torque. Muscle volumes for the dominant leg were compared with previously published sex- and age-matched data using z scores. For BMD, T score and z score were calculated. Results: DL had the highest maximal oxygen uptake (42.3 mL·min−1·kg−1) ever observed for a female older than 80 years of age, which gave her a remarkable physiological age (27 y). By contrast, she had a physiological age closer to her biological age for maximal isometric torque (90 y) and maximal heart rate (74 y). The z scores for thigh (0.4) and triceps surae (1.1) muscle volumes revealed that DL’s leg muscles were affected almost as much as her sex- and age-matched peers. The T score (−1.7) for BMD showed that DL had osteopenia but no osteoporosis, and the z score (0.7) showed that DL’s BMD was similar to that of females of the same age. Conclusion: This single case study shows that the remarkable cardiorespiratory fitness coupled with intensive endurance training observed in a female master athlete was not associated with specific preservation of her muscular and skeletal characteristics.

APA, Harvard, Vancouver, ISO, and other styles

11

Huyghues-Despointes, Clotilde M. J. I., Timothy C. Cope, and T. Richard Nichols. "Intrinsic Properties and Reflex Compensation in Reinnervated Triceps Surae Muscles of the Cat: Effect of Activation Level." Journal of Neurophysiology 90, no. 3 (September 2003): 1537–46. http://dx.doi.org/10.1152/jn.00718.2002.

Full text

Abstract:

The manner in which activation levels influence intrinsic muscular properties and contributions of the stretch reflex were studied in homogeneous soleus (SOL) and heterogeneous gastrocnemius (G) muscles in the decerebrate cat. Intrinsic mechanical properties were represented by the initial stiffness of the muscle, measured prior to reflex action, and by the tendency of the muscle to yield during stretch in the absence of the stretch reflex. Stiffness regulation by the stretch reflex was evaluated by measuring the extent to which reflex action reduces yielding and the extent to which stiffness depends on background force. Intrinsic mechanical properties were measured in muscles deprived of effective autogenic reflexes using the method of muscular reinnervation. Reinnervated muscles were recruited to force levels comparable to those achieved during natural locomotion. As force declined during crossed-extension reflexes in reinnervated and intact muscles, initial stiffness declined according to similar convex trajectories. The data did not support the hypothesis that, for a given force level, initial stiffness is greatest in populations of predominantly type I motor units. Incremental stiffness (Δ f/Δ l) of both G and SOL increased in the presence of the stretch reflex. Yielding of SOL (ratio of incremental to initial stiffness) substantially decreased in the presence of the stretch reflex over the full range of forces. In reflexive G, yielding significantly decreased for low to intermediate forces, whereas at higher forces, yielding was similar irrespective of the presence or absence of the stretch reflex. The stretch reflex regulates stiffness in both homogeneous and heterogeneous muscles.

APA, Harvard, Vancouver, ISO, and other styles

12

Rebelatto, José Rubens. "Influência da prática regular de futebol sobre a elasticidade da cadeia muscular cinética reta posterior de jovens." Fisioterapia Brasil 6, no. 6 (March 18, 2018): 444. http://dx.doi.org/10.33233/fb.v6i6.2038.

Full text

Abstract:

No presente estudo foi realizada a avaliação da elasticidade da cadeia muscular cinética reta posterior (CRP) de jovens futebolistas (n = 100) pertencentes às categorias juvenil e amador (16 a 25 anos) de duas escolas de futebol da cidade de Salamanca (Espanha), estabelecendo uma comparação com os resultados obtidos em uma população (n = 37) de estudantes universitários (grupo controle), de idade cronológica similar, e que não praticavam o esporte regularmente. Foi avaliado o grau de elasticidade da musculatura isquiotibial e do tríceps sural de ambos os membros inferiores, utilizando-se o teste de elevação da perna estendida (EPR) e o método do zero. Para a medida da flexibilidade global da CRP foi utilizado o método sit and reach. Os dados foram analisados com o programa estatístico SPSS (análise descritiva, Test T- Student e coeficiente de Pearson). Os resultados revelam que, quando comparados com o grupo controle, os praticantes de futebol apresentaram elasticidade superior da musculatura isquiotibial e elasticidade inferior da musculatura do triceps sural. Em relação à elasticidade global não foram encontradas diferenças estatisticamente significativas. Palavras-chave: cadeia muscular, futebol, elasticidade isquiotibial.

APA, Harvard, Vancouver, ISO, and other styles

13

Kuno, M., Y. Hirano, and M. Myashita. "699 THE EFFECT OF INITIAL MUSCULAR LENGTH ON ELECTRICAL ACTIVITY OF TRICEPS SURAE DURING MAXIMAL VOLUNTARY PLANTAR FLEXION." Medicine & Science in Sports & Exercise 26, Supplement (May 1994): S125. http://dx.doi.org/10.1249/00005768-199405001-00701.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Hill, J. M., J. G. Pickar, M. D. Parrish, and M. P. Kaufman. "Effects of hypoxia on the discharge of group III and IV muscle afferents in cats." Journal of Applied Physiology 73, no. 6 (December 1, 1992): 2524–29. http://dx.doi.org/10.1152/jappl.1992.73.6.2524.

Full text

Abstract:

The reflex pressor response evoked by static muscular contraction is widely believed to be caused by the stimulation of group III and IV afferents. Although the specific nature of the contraction-induced stimulus to these thin-fiber afferents is unknown, they are thought to be stimulated in part by a condition arising from a mismatch between blood supply and demand in the exercising muscle. Hypoxia, a condition found in skeletal muscle during such a mismatch, may stimulate these afferents. We have therefore tested the hypothesis that perfusion of the triceps surae muscles with hypoxic blood stimulates group III and IV afferents in barbiturate-anesthetized cats. We found that 3–3.5 min of hypoxia with the triceps surae muscles at rest significantly (P < 0.05) increased the average discharge rate of contraction-sensitive group IV afferents but had no effect on the average discharge rate of contraction-sensitive group III afferents. Hypoxia had only trivial effects on the discharge of contraction-insensitive group III and IV afferents. Hypoxia stimulated 4 of 11 contraction-sensitive group IV afferents and 2 of 13 contraction-sensitive group III afferents. The responses of the afferents stimulated by hypoxia were small in magnitude. Hypoxia with the muscles at rest appeared to have no effect on either hydrogen or lactate ion concentrations in the femoral venous blood. In addition, hypoxia increased the responses to contraction in only 3 of 22 group III and 4 of 21 group IV afferents tested. We conclude that muscle tissue hypoxia is a minor stimulus to afferents that sense a mismatch between blood supply and demand during static contraction.

APA, Harvard, Vancouver, ISO, and other styles

15

Haouzi, Philippe, Janeen M. Hill, Brock K. Lewis, and Marc P. Kaufman. "Responses of group III and IV muscle afferents to distension of the peripheral vascular bed." Journal of Applied Physiology 87, no. 2 (August 1, 1999): 545–53. http://dx.doi.org/10.1152/jappl.1999.87.2.545.

Full text

Abstract:

This study was undertaken to test the hypothesis that group III and IV afferents with endings in skeletal muscle signal the distension of the peripheral vascular network. The responses of these slowly conducting afferents to pharmacologically induced vasodilation and to acute obstruction of the venous drainage of the hindlimbs were studied in barbiturate-anesthetized cats. Afferent impulses arising from endings in the triceps surae muscles were recorded from the L7 and S1 dorsal roots. Fifteen of the 48 group IV and 3 of the 19 group III afferents tested were stimulated by intra-aortic injections of papaverine (2–2.5 mg/kg). Sixty-two percent of the afferents that responded to papaverine also responded to isoproterenol (50 μg/kg). Seven of the 36 group IV and 2 of the 12 group III afferents tested were excited by acute distension of the hindlimb venous system. Four of the seven group IV afferents responding to venous distension also responded to papaverine (57 vs. 13% for the nonresponding). Finally, we observed that most of the group IV afferents that were excited by dynamic contractions of the triceps surae muscles also responded either to venous distension or to vasodilatory agents. These results are consistent with the histological findings that a large number of group IV endings have their receptive fields close to the venules and suggest that they can be stimulated by the deformation of these vascular structures when peripheral conductance increases. Moreover, such a mechanism offers the possibility of encoding both the effects of muscle contraction through intramuscular pressure changes and the distension of the venular system, thereby monitoring the activity of the veno-muscular pump.

APA, Harvard, Vancouver, ISO, and other styles

16

Hayward, L., U. Wesselmann, and W. Z. Rymer. "Effects of muscle fatigue on mechanically sensitive afferents of slow conduction velocity in the cat triceps surae." Journal of Neurophysiology 65, no. 2 (February 1, 1991): 360–70. http://dx.doi.org/10.1152/jn.1991.65.2.360.

Full text

Abstract:

1. Group III and IV muscle afferents have been shown to be sensitive to both mechanical stimuli and metabolic and thermal changes in muscle. To establish the potential role of slowly conducting muscle afferents in regulating motor output during fatigue, we recorded from mechanically sensitive group III and nonspindle group II afferents originating in the triceps surae in barbiturate-anesthetized cats. We evaluated the response of these afferents to tetanic muscle contraction, stretch, and surface pressure, before, during, and after fatigue. 2. Our results show that muscle fatigue both increases spontaneous discharge in these mechanically sensitive afferents and sensitizes their response to muscle stretch, surface pressure, and, in a few instances, muscle contraction. These fatigue-induced changes typically occurred after 5-10 min of submaximal fatiguing stimulation. 3. During recovery from muscle fatigue, several contraction-sensitive free nerve endings, which had become sensitized to contractions during fatigue, remained sensitized after 20-30 min of rest. 4. The results of this study provide support for the hypothesis that fatigue-induced excitation of slowly conducting afferents is significant in mediating fatigue-induced inhibition of motoneuron output. However, our finding that the discharge of many slowly conducting mechanoreceptor afferents declines during the initial phase of fatigue argues against a primary role for these afferents in mediating the initial decline in motoneuron rate that is so prominent in fatiguing maximum voluntary muscular contraction.

APA, Harvard, Vancouver, ISO, and other styles

17

Huyghues-Despointes, Clotilde M. J. I., Timothy C. Cope, and T. Richard Nichols. "Intrinsic Properties and Reflex Compensation in Reinnervated Triceps Surae Muscles of the Cat: Effect of Movement History." Journal of Neurophysiology 90, no. 3 (September 2003): 1547–55. http://dx.doi.org/10.1152/jn.00719.2002.

Full text

Abstract:

Effects of prior motion on ramp stretch responses of reflexive and areflexive muscles were measured in decerebrate cats. Soleus and gastrocnemius muscles were rendered areflexive by reinnervation a minimum of 9 mo before the terminal experiments. The introduction of a shortening phase prior to the ramp stretch increased the normalized initial stiffness of muscles and decreased the tendency to yield of the reinnervated muscles as compared with the case in which muscles contracted isometrically prior to stretch. Yielding was compensated by reflex action for all amplitudes of prior shortening in soleus and gastrocnemius muscles. The comparison of responses of untreated and reinnervated muscles indicated that the contribution of reflex action progressively declined with the amplitude of prior shortening as the extent of yielding diminished. In soleus muscle, during a variable delay period of isometric contraction interposed between shortening and lengthening force generation, initial stiffness and yielding returned to levels seen with isometric contractile history. However, these attributes recovered at different rates, suggesting that distinct processes are responsible for initial stiffness and yielding. Yielding was compensated for by reflex action regardless of the length of the interposed delay or of the amplitude of the prior shortening. These and previous findings indicate that the stretch reflex regulates muscular stiffness for a wide range of conditions. This regulation apparently arises from complementary mechanical properties of intrafusal and extrafusal muscle.

APA, Harvard, Vancouver, ISO, and other styles

18

Wakeling, James M., and Benno M. Nigg. "Modification of soft tissue vibrations in the leg by muscular activity." Journal of Applied Physiology 90, no. 2 (February 1, 2001): 412–20. http://dx.doi.org/10.1152/jappl.2001.90.2.412.

Full text

Abstract:

Vibration characteristics were recorded for the soft tissues of the triceps surae, tibialis anterior, and quadriceps muscles. The frequency and damping of free vibrations in these tissues were measured while isometric and isotonic contractions of the leg were performed. Soft tissue vibration frequency and damping increased with both the force produced by and the shortening velocity of the underlying muscle. Both frequency and damping were greater in a direction normal to the skin surface than in a direction parallel to the major axis of each leg segment. Vibration characteristics further changed with the muscle length and between the individuals tested. The range of the measured vibration frequencies coincided with typical frequencies of impact forces during running. However, observations suggest that soft tissue vibrations are minimal during running. These results support the strategy that increases in muscular activity may be used by some individuals to move the frequency and damping characteristics of the soft tissues away from those of the impact force and thus minimize vibrations during walking and running.

APA, Harvard, Vancouver, ISO, and other styles

19

Camargo, Marcela R. de, Carolina Lundberg, Leila S. Saita, Geruza P. Bella, Simone M. Serradilha, and Regina C. T. de Souza. "Treadmill training effects on duration of gait stance and muscular degree in hemiplegic cerebral palsy children." Brazilian Journal of Motor Behavior 7, no. 2 (July 27, 2012): 1–8. http://dx.doi.org/10.20338/bjmb.v7i2.185.

Full text

Abstract:

The aim of this study was to evaluate if gait training on treadmill is effective to decrease the support time in paretic limb, investigating associations between this variable and the lower limb muscle strength degree, after treadmill training. For this, we invited eight children aged between six and 14 years old, diagnosed with hemiparetic cerebral palsy. Gait was recorded and transformed in frames, with which were obtained each limb phase of stance duration. Muscle strength was evaluated manually and graded by a specific scale. Then, children underwent gait training on a treadmill for 20 sessions, twice a week. At the end of sessions, walking and strength were revalued. In data analysis we used non-parametric analyses with Wilcoxon and Spearman linear correlation tests. Significant differences were found for stance time, in both limbs, after treadmill training. Correlation test showed significant inverse association, after training, between triceps surae and iliopsoas muscles strength and the stance time percentage of non-impaired limb. Gait training on a treadmill was effective, resulting muscle strength gains and stance duration reducing, thus improving ambulation quality.

APA, Harvard, Vancouver, ISO, and other styles

20

Pain, Matthew T. G., and John H. Challis. "High Resolution Determination of Body Segment Inertial Parameters and Their Variation Due to Soft Tissue Motion." Journal of Applied Biomechanics 17, no. 4 (November 2001): 326–34. http://dx.doi.org/10.1123/jab.17.4.326.

Full text

Abstract:

This study had two purposes: to evaluate a new method for measuring segmental dimensions for determining body segment inertial parameters (BSIP), and to evaluate the changes in mass distribution within a limb as a consequence of muscular contraction. BSIP were calculated by obtaining surface data points of the body under investigation using a sonic digitizer, interpolating them into a regular grid, and then using Green’s theorem which relates surface to volume integrals. Four skilled operators measured a test object; the error was approximately 2.5% and repeatability was 1.4% (coefficient of variation) in the determination of BSIP. Six operators took repeat measures on human lower legs; coefficients of variation were typically around 5%, and 3% for the more skilled operators. Location of the center of mass of the lower leg was found to move up 1.7 cm proximally when the triceps surae muscles went from a relaxed state to causing plantar flexion. The force during an impact associated with such motion of the soft tissue of the lower leg was estimated to be up to 300 N. In summary, a new repeatable and accurate method for determining BSIP has been developed, and has been used to evaluate body segment mass redistribution due to muscular contraction.

APA, Harvard, Vancouver, ISO, and other styles

21

Rotto, D. M., and M. P. Kaufman. "Effect of metabolic products of muscular contraction on discharge of group III and IV afferents." Journal of Applied Physiology 64, no. 6 (June 1, 1988): 2306–13. http://dx.doi.org/10.1152/jappl.1988.64.6.2306.

Full text

Abstract:

Static muscular contraction has been firmly established to reflexly increase cardiovascular and ventilatory function. Although group III and IV fibers with endings in muscle have been shown to comprise the afferent arm of this reflex arc, little is known about the nature of the contraction-induced stimulus causing the activation of these fibers. This stimulus has often been suggested to be a metabolic product of muscular contraction. We have therefore recorded the impulse activity of group III and IV afferents with endings in the triceps surae muscles of barbiturate-anesthetized cats while we injected into the femoral artery substances believed to be metabolic products of muscular contraction. We found that lithium and sodium lactate (400 mM; 1 ml) had little or no effect on the discharge of group III and IV afferents. Likewise, monobasic sodium phosphate (20 and 400 mM; 1 ml) and 2-chloroadenosine (50–100 micrograms) had only trivial effects on the discharge of these afferents. By contrast, lactic acid (25 and 400 mM; 1 ml) and arachidonic acid (0.5–2.0 mg) caused significant increases in the activity of group III and IV afferents. Most of the excitatory effect of arachidonic acid on the discharge of the afferents was prevented by indomethacin, a cyclooxygenase inhibitor. We conclude that of the substances tested in our experiments, lactic acid and some cyclooxygenase products, such as prostaglandins and thromboxanes, are the most likely to be responsible for any metabolic stimulation of group III and IV afferents during muscular contraction.

APA, Harvard, Vancouver, ISO, and other styles

22

Wilson, L. B., D. Andrew, and A. D. Craig. "Activation of Spinobulbar Lamina I Neurons by Static Muscle Contraction." Journal of Neurophysiology 87, no. 3 (March 1, 2002): 1641–45. http://dx.doi.org/10.1152/jn.00609.2001.

Full text

Abstract:

Spinal lamina I neurons are selectively activated by small-diameter somatic afferents, and they project to brain stem sites that are critical for homeostatic control. Because small-diameter afferent activity evoked by contraction of skeletal muscle reflexly elicits exercise-related cardiorespiratory activation, we tested whether spinobulbar lamina I cells respond to muscle contraction. Spinobulbar lamina I neurons were identified in chloralose-anesthetized cats by antidromic activation from the ipsilateral caudal ventrolateral medulla. Static contractions of the ipsilateral triceps surae muscle were evoked by tibial nerve stimulation using parameters that avoid afferent activation, and arterial blood pressure responses were recorded. Recordings were maintained from 13 of 17 L7 lamina I spinobulbar neurons during static muscle contraction, and 5 of these neurons were excited. Three were selectively activated only by muscle afferents and did not have a cutaneous receptive field. Spinobulbar lamina I neurons activated by muscle contraction provide an ascending link for the reflex cardiorespiratory adjustments that accompany muscular work. This study provides an important first step in elucidating an ascending afferent pathway for somato-autonomic reflexes.

APA, Harvard, Vancouver, ISO, and other styles

23

Wenning, Markus, Marlene Mauch, Albrecht Heitner, Johannes Lienhard, Ramona Ritzmann, and Jochen Paul. "Neuromechanical activation of triceps surae muscle remains altered at 3.5 years following open surgical repair of acute Achilles tendon rupture." Knee Surgery, Sports Traumatology, Arthroscopy 29, no. 8 (March 3, 2021): 2517–27. http://dx.doi.org/10.1007/s00167-021-06512-z.

Full text

Abstract:

Abstract Purpose To assess whether the neuromuscular activation pattern following Achilles tendon rupture and repair may contributes to the observable functional deficits in this severe and increasingly frequent injury. Methods In this study, the neuromuscular activation using surface EMG of n = 52 patients was assessed during a battery of functional performance tasks to assess potential alterations of muscular activation and recruitment. We analyzed the injured leg vs. the contralateral healthy leg at a mean of 3.5 years following open surgical repair. The testing battery included isokinetic strength testing, bipedal and single-legged heel-rise testing as well as gait analysis. Results During isokinetic testing, we observed a higher activation integral for all triceps surae muscles of the injured side during active dorsiflexion, e.g., eccentric loading on the injured leg, while concentric plantarflexion showed no significant difference. Dynamic heel-rise testing showed a higher activation in concentric and eccentric loading for all posterior muscles on the injured side (not significant); while static heel-rise for 10 sec. revealed a significantly higher activation. Further analysis of frequency of fast Fourier-transformed EMG revealed a significantly higher median frequency in the injured leg. Gait analysis revealed a higher pre-activation of the tibialis anterior before ground contact, while medial and lateral gastrocnemius muscles of the injured leg showed a significantly higher activation during push-off phase. Conclusions The results of this study provide evidence on the neuromuscular changes 3.5 years following open surgical Achilles tendon repair. These complex neuromuscular changes are manifested to produce the maximum force output whilst protecting the previously injured tendon. The observed alterations may be related to an increased recruitment of type II muscle fibers which could make the muscles prone to fatigue. Level of evidence III.

APA, Harvard, Vancouver, ISO, and other styles

24

Maekawa, Takahiro, Riki Ogasawara, Arata Tsutaki, Kihyuk Lee, Satoshi Nakada, Koichi Nakazato, and Naokata Ishii. "Electrically evoked local muscle contractions cause an increase in hippocampal BDNF." Applied Physiology, Nutrition, and Metabolism 43, no. 5 (May 2018): 491–96. http://dx.doi.org/10.1139/apnm-2017-0536.

Full text

Abstract:

High-intensity exercise has recently been shown to cause an increase in brain-derived neurotropic factor (BDNF) in the hippocampus. Some studies have suggested that myokines secreted from contracting skeletal muscle, such as irisin (one of the truncated form of fibronectin type III domain-containing protein 5 (FNDC5)), play important roles in this process. Thus, we hypothesized that locally evoked muscle contractions may cause an increase of BDNF in the hippocampus through some afferent mechanisms. Under anesthesia, Sprague–Dawley rats were fixed on a custom-made dynamometer and their triceps surae muscles were made to maximally contract via delivery of electric stimulations of the sciatic nerve (100 Hz with 1-ms pulse and 3-s duration). Following 50 repeated maximal isometric contractions, the protein expressions of BDNF and activation of its receptor in the hippocampus significantly increased compared with the sham-operated control rats. However, the expression of both BDNF and FNDC5 within stimulated muscles did not significantly increase, nor did their serum concentrations change. These results indicate that local muscular contractions under unconsciousness can induce BDNF expression in the hippocampus. This effect may be mediated by peripheral reception of muscle contraction, but not by systemic factors.

APA, Harvard, Vancouver, ISO, and other styles

25

Abellaneda, Séverine, Nathalie Guissard, and Jacques Duchateau. "Relation entre les modifications de l’architecture musculo-tendineuse et le développement de la tension pendant l’étirement passif du triceps sural." Kinésithérapie, la Revue 6, no. 53 (May 2006): 29–33. http://dx.doi.org/10.1016/s1779-0123(06)70151-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Koriak, IuA. "Influence of physical training under conditions of 120-day simulated microgravity on contractile properties and musculo-tendinous stiffness of the triceps surae muscle." Fiziolohichnyĭ zhurnal 59, no. 2 (May 15, 2013): 71–84. http://dx.doi.org/10.15407/fz59.02.071.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Hill, J. M., and M. P. Kaufman. "Attenuation of reflex pressor and ventilatory responses to static muscular contraction by intrathecal opioids." Journal of Applied Physiology 68, no. 6 (June 1, 1990): 2466–72. http://dx.doi.org/10.1152/jappl.1990.68.6.2466.

Full text

Abstract:

We have tested the hypothesis that intrathecal injections of opioid peptides attenuate the reflex pressor and ventilatory responses to static contraction of the triceps surae muscles of chloralose-anesthetized cats. We found that before intrathecal injections of [D-Ala2]Met-enkephalinamide (100 micrograms in 0.2 ml), static contraction increased mean arterial pressure and ventilation by 32 +/- 5 (SE) mmHg and 227 +/- 61 (SE) ml/min, whereas after injection of this opioid peptide, static contraction increased mean arterial pressure and ventilation by only 15 +/- 5 mmHg and 37 +/- 33 ml/min, respectively. The attenuation of both the pressor and ventilatory responses to static contraction by [D-Ala2]Met-enkephalinamide were statistically significant (P less than 0.05). Moreover, the attenuation was probably not caused by an opioid-induced withdrawal of sympathetic outflow because [D-Ala2]Met-enkephalinamide had no effect on the pressor and ventilatory responses evoked by high-intensity electrical stimulation of the central cut end of the sciatic nerve. In addition, intrathecal injection of peptides that were highly selective agonists for either the opioid mu- or delta-receptor attenuated the reflex responses to static contraction. Naloxone (1,000 micrograms), injected intrathecally, prevented the attenuation of the reflex responses to contraction by opioid peptides. We speculate that the opioid-induced attenuation of the reflex pressor and ventilatory responses to static contraction may have been due to suppression of substance P release from group III and IV muscle afferents.

APA, Harvard, Vancouver, ISO, and other styles

28

Martín-Llantino, Pedro Javier, César Calvo-Lobo, and Irene Sanz-Corbalán. "Estado actual de la validez y fiabilidad de la valoración ecográfica del tendón de Aquiles." European Journal of Podiatry / Revista Europea de Podología 5, no. 1 (February 14, 2019): 23–30. http://dx.doi.org/10.17979/ejpod.2019.5.1.3542.

Full text

Abstract:

Objetivo: Conocer la validez y fiabilidad de la ecografía musculo esquelética en la valoración del tendón de Aquiles. Conocer los hallazgos ecográficos típicos en el tendón de Aquiles, tanto sano como lesionado.Material y métodos: Se realizó una revisión bibilográfica desarrollando una búsqueda en PubMed que abarcó trabajos desde 1984 hasta el 30 de enero de 2018 Se usaron los siguientes términos: “Ultrasound achilles tendon”, “Ultrasound triceps surae”, “Achilles tendinopathy ultrasound”. Se incluyeron artículos en base a su calidad metodológica, relevancia científica, aportación de una visión novedosa y su utilidad clínica.Resultados: Se encontraron artículos sobre la validez y fiabilidad de la evaluación del tendón de Aquiles, así como de estructuras próximas, con ecografía músculo esquelética. También se encontraron artículos sobre los hallazgos en la imagen del tendón de Aquiles sano y lesionado. Conclusiones: La literatura parece confirmar que la ecografía músculo esquelética es un método valido y fiable para evaluar la tendinopatía aquilea. Existirían diferencias ecográficas entre tendones sanos y lesionados, y no parece diferenciarse éste entre lesión crónica y desgarro interno. El engrosamiento tendinoso y la neovascularización deberían tenerse al diagnosticar la tendinopatía aquilea, pero su simple presencia no determinaría la severidad clínica.

APA, Harvard, Vancouver, ISO, and other styles

29

Koriak, IuA. "Contraction properties and musculo-tendinous stiffness of the human triceps surae muscle and their change as a result of a long-term bed-rest." Fiziolohichnyĭ zhurnal 58, no. 2 (April 24, 2012): 66–79. http://dx.doi.org/10.15407/fz58.02.066.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Grosset, Jean-Francois, Isabelle Mora, Daniel Lambertz, and Chantal Pérot. "Changes in stretch reflexes and muscle stiffness with age in prepubescent children." Journal of Applied Physiology 102, no. 6 (June 2007): 2352–60. http://dx.doi.org/10.1152/japplphysiol.01045.2006.

Full text

Abstract:

Musculo-articular stiffness of the triceps surae (TS) increases with age in prepubescent children, under both passive and active conditions. This study investigates whether these changes in muscle stiffness influence the amplitude of the reflex response to muscle stretch. TS stiffness and reflex activities were measured in 46 children (7–11 yr old) and in 9 adults. The TS Hoffmann reflex (H reflex) and T reflex (tendon jerk) in response to taping the Achilles tendon were evaluated at rest and normalized to the maximal motor response (Mmax). Sinusoidal perturbations of passive or activated muscles were used to evoke stretch reflexes and to measure passive and active musculoarticular stiffness. The children's Hmax-to-Mmax ratio did not change with age and did not differ from adult values. The T-to-Mmax ratio increased with age but remained significantly lower than in adults. Passive stiffness also increased with age and was correlated with the T-to-Mmax ratio. Similarly, the children's stretch reflex and active musculoarticular stiffness were significantly correlated and increased with age. We conclude that prepubescent children have smaller T reflexes and stretch reflexes than adults, and the lower musculoarticular stiffness is mainly responsible for these smaller reflexes, as indicated by the parallel increases in reflex and stiffness.

APA, Harvard, Vancouver, ISO, and other styles

31

Rotto, D. M., J. M. Hill, H. D. Schultz, and M. P. Kaufman. "Cyclooxygenase blockade attenuates responses of group IV muscle afferents to static contraction." American Journal of Physiology-Heart and Circulatory Physiology 259, no. 3 (September 1, 1990): H745—H750. http://dx.doi.org/10.1152/ajpheart.1990.259.3.h745.

Full text

Abstract:

Cyclooxygenase products of arachidonic acid might be some of the substances that accumulate in contracting muscle to cause the reflex increases in arterial pressure and ventilation that are evoked by exercise. Recently, cyclooxygenase blockade has been shown to attenuate the reflex cardiovascular responses to static muscular contraction in anesthetized cats. Group IV afferents are believed to comprise part of the afferent arm of the reflex arc, the activation by which static muscular contraction causes these cardiovascular effects. We therefore examined the effects of indomethacin and aspirin, two cyclooxygenase-blocking agents, on the responses to static contraction of group IV afferents with endings in the triceps surae muscles of anesthetized cats. We found that indomethacin (5 mg/kg iv) decreased the responses to contraction of each of eight group IV afferents tested. Likewise, aspirin (50 mg/kg iv) decreased the responses to contraction of each of four group IV afferents tested. On the other hand, we found that arachidonic acid (2 mg) injected into the femoral artery did not increase the responses to contraction of four group IV afferents that were stimulated by this maneuver. In addition, arachidonic acid injection did not cause any of seven group IV afferents not stimulated by static contraction to become responsive to this maneuver. Nevertheless, arachidonic acid injection with the muscle at rest stimulated five of seven contraction-insensitive and two of four contraction-sensitive group IV afferents. Our data suggest that cyclooxygenase metabolites of arachidonic acid are needed for the full expression of the responses of group IV muscle afferents to static contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

APA, Harvard, Vancouver, ISO, and other styles

32

Hayashi, Naoyuki. "Exercise pressor reflex in decerebrate and anesthetized rats." American Journal of Physiology-Heart and Circulatory Physiology 284, no. 6 (June 1, 2003): H2026—H2033. http://dx.doi.org/10.1152/ajpheart.00400.2002.

Full text

Abstract:

I investigated whether muscular contraction evokes cardiorespiratory increases (exercise pressor reflex) in α-chloralose- and chloral hydrate-anesthetized and precollicular, midcollicular, and postcollicular decerebrated rats. Mean arterial pressure (MAP), heart rate (HR), and minute ventilation (V˙e) were recorded before and during 1-min sciatic nerve stimulation, which induced static contraction of the triceps surae muscles, and during 1-min stretch of the calcaneal tendon, which selectively stimulated mechanosensitive receptors in the muscles. Anesthetized rats showed various patterns of MAP response to both stimuli, i.e., biphasic, depressor, pressor, and no response. Sciatic nerve stimulation to muscle in precollicular decerebrated rats always evoked spontaneous running, so the exercise pressor reflex was not determined from these preparations. None of the postcollicular decerebrated rats showed a MAP response or spontaneous running. Midcollicular decerebrated rats consistently showed biphasic blood pressure response to both stimulations. The increases in MAP, HR, and V˙e were related to the tension developed. The static contractions in midcollicular decerebrated rats (381 ± 65 g developed tension) significantly increased MAP, HR, andV˙e from 103 ± 12 to 119 ± 24 mmHg, from 386 ± 30 to 406 ± 83 beats/min, and from 122 ± 7 to 133 ± 25 ml/min, respectively. After paralysis, sciatic nerve stimulation had no effect on MAP, HR, or V˙e. These results indicate that the midcollicular decerebrated rat can be a model for the study of the exercise pressor reflex.

APA, Harvard, Vancouver, ISO, and other styles

33

Rtail, Raed, Olena Maksymova, Viacheslav Illiashenko, Olena Gortynska, Oleksii Korenkov, Pavlo Moskalenko, Mohamad Nasser, and Gennadii Tkach. "Improvement of Skeletal Muscle Regeneration by Platelet-Rich Plasma in Rats with Experimental Chronic Hyperglycemia." BioMed Research International 2020 (July 13, 2020): 1–9. http://dx.doi.org/10.1155/2020/6980607.

Full text

Abstract:

Herein, the structural effect of autologous platelet-rich plasma (PRP) on posttraumatic skeletal muscle regeneration in rats with chronic hyperglycemia (CH) was tested. 130 white laboratory male rats divided into four groups (I—control; II—rats with CH; III—rats with CH and PRP treatment; and IV—rats for CH confirmation) were used for the experiment. CH was simulated by streptozotocin and nicotinic acid administration. Triceps surae muscle injury was reproduced by transverse linear incision. Autologous PRP was used in order to correct the possible negative CH effect on skeletal muscle recovery. On the 28th day after the injury, the regenerating muscle fiber and blood vessel number in the CH+PRP group were higher than those in the CH rats. However, the connective tissue area in the CH group was larger than that in the CH+PRP animals. The amount of agranulocytes in the regenerating muscle of the CH rats was lower compared to that of the CH+PRP group. The histological analysis of skeletal muscle recovery in CH+PRP animals revealed more intensive neoangiogenesis compared to that in the CH group. Herewith, the massive connective tissue development and inflammation signs were observed within the skeletal muscle of CH rats. Obtained results suggest that streptozotocin-induced CH has a negative effect on posttraumatic skeletal muscle regeneration, contributing to massive connective tissue development. The autologous PRP injection promotes muscle recovery process in rats with CH, shifting it away from fibrosis toward the complete muscular organ repair.

APA, Harvard, Vancouver, ISO, and other styles

34

Nakamoto, Tomoko, Kanji Matsukawa, Nan Liang, Rie Wakasugi, L. Britt Wilson, and Jouji Horiuchi. "Coactivation of renal sympathetic neurons and somatic motor neurons by chemical stimulation of the midbrain ventral tegmental area." Journal of Applied Physiology 110, no. 5 (May 2011): 1342–53. http://dx.doi.org/10.1152/japplphysiol.01233.2010.

Full text

Abstract:

We examined whether neurons in the midbrain ventral tegmental area (VTA) play a role in generating central command responsible for autonomic control of the cardiovascular system in anesthetized rats and unanesthetized, decerebrated rats with muscle paralysis. Small volumes (60 nl) of an N-methyl-d-aspartate receptor agonist (l-homocysteic acid) and a GABAergic receptor antagonist (bicuculline) were injected into the VTA and substantia nigra (SN). In anesthetized rats, l-homocysteic acid into the VTA induced short-lasting increases in renal sympathetic nerve activity (RSNA; 66 ± 21%), mean arterial pressure (MAP; 5 ± 2 mmHg), and heart rate (HR; 7 ± 2 beats/min), whereas bicuculline into the VTA produced long-lasting increases in RSNA (130 ± 45%), MAP (26 ± 2 mmHg), and HR (66 ± 6 beats/min). Bicuculline into the VTA increased blood flow and vascular conductance of the hindlimb triceps surae muscle, suggesting skeletal muscle vasodilatation. However, neither drug injected into the SN affected all variables. Renal sympathetic nerve and cardiovascular responses to chemical stimulation of the VTA were not essentially affected by decerebration at the premammillary-precollicular level, indicating that the ascending projection to the forebrain from the VTA was not responsible for evoking the sympathetic and cardiovascular responses. Furthermore, bicuculline into the VTA in decerebrate rats produced long-lasting rhythmic bursts of RSNA and tibial motor nerve discharge, which occurred in good synchrony. It is likely that the activation of neurons in the VTA is capable of eliciting synchronized stimulation of the renal sympathetic and tibial motor nerves without any muscular feedback signal.

APA, Harvard, Vancouver, ISO, and other styles

35

Cronin, Neil J., Rod S. Barrett, and Christopher P. Carty. "Long-term use of high-heeled shoes alters the neuromechanics of human walking." Journal of Applied Physiology 112, no. 6 (March 15, 2012): 1054–58. http://dx.doi.org/10.1152/japplphysiol.01402.2011.

Full text

Abstract:

Human movement requires an ongoing, finely tuned interaction between muscular and tendinous tissues, so changes in the properties of either tissue could have important functional consequences. One condition that alters the functional demands placed on lower limb muscle-tendon units is the use of high-heeled shoes (HH), which force the foot into a plantarflexed position. Long-term HH use has been found to shorten medial gastrocnemius muscle fascicles and increase Achilles tendon stiffness, but the consequences of these changes for locomotor muscle-tendon function are unknown. This study examined the effects of habitual HH use on the neuromechanical behavior of triceps surae muscles during walking. The study population consisted of 9 habitual high heel wearers who had worn shoes with a minimum heel height of 5 cm at least 40 h/wk for a minimum of 2 yr, and 10 control participants who habitually wore heels for less than 10 h/wk. Participants walked at a self-selected speed over level ground while ground reaction forces, ankle and knee joint kinematics, lower limb muscle activity, and gastrocnemius fascicle length data were acquired. In long-term HH wearers, walking in HH resulted in substantial increases in muscle fascicle strains and muscle activation during the stance phase compared with barefoot walking. The results suggest that long-term high heel use may compromise muscle efficiency in walking and are consistent with reports that HH wearers often experience discomfort and muscle fatigue. Long-term HH use may also increase the risk of strain injuries.

APA, Harvard, Vancouver, ISO, and other styles

36

Kindig, Angela E., Todd B. Heller, and Marc P. Kaufman. "VR-1 receptor blockade attenuates the pressor response to capsaicin but has no effect on the pressor response to contraction in cats." American Journal of Physiology-Heart and Circulatory Physiology 288, no. 4 (April 2005): H1867—H1873. http://dx.doi.org/10.1152/ajpheart.00735.2004.

Full text

Abstract:

Vanilloid type 1 (VR-1) receptors are stimulated by capsaicin and hydrogen ions, the latter being a by-product of muscular contraction. We tested the hypothesis that activation of VR-1 receptors during static contraction contributes to the exercise pressor reflex. We established a dose of iodoresinaferatoxin (IRTX), a VR-1 receptor antagonist, that blocked the pressor response to capsaicin injected into the arterial supply of muscle. Specifically, in eight decerebrated cats, we compared pressor responses to capsaicin (10 μg) injected into the right popliteal artery, which was subsequently injected with IRTX (100 μg), with those to capsaicin injected into the left popliteal artery, which was not injected with IRTX. The pressor response to capsaicin injected into the right popliteal artery averaged 49 ± 9 mmHg before IRTX and 9 ± 2 mmHg after IRTX ( P < 0.05). In contrast, the pressor response to capsaicin injected into the left popliteal artery averaged 46 ± 10 mmHg “before” and 43 ± 6 mmHg “after” ( P > 0.05). We next determined whether VR-1 receptors mediated the pressor response to contraction of the triceps surae. During contraction without circulatory occlusion, the pressor response before IRTX (100 μg) averaged 26 ± 3 mmHg, whereas it averaged 22 ± 3 mmHg ( P > 0.05) after IRTX ( n = 8). In addition, during contraction with occlusion, the pressor responses averaged 35 ± 3 mmHg before IRTX injection and 49 ± 7 mmHg after IRTX injection ( n = 7). We conclude that VR-1 receptors play little role in evoking the exercise pressor reflex.

APA, Harvard, Vancouver, ISO, and other styles

37

Bojsen-Møller, Jens, Philip Hansen, Per Aagaard, Ulla Svantesson, Michael Kjaer, and S. Peter Magnusson. "Differential displacement of the human soleus and medial gastrocnemius aponeuroses during isometric plantar flexor contractions in vivo." Journal of Applied Physiology 97, no. 5 (November 2004): 1908–14. http://dx.doi.org/10.1152/japplphysiol.00084.2004.

Full text

Abstract:

The human triceps surae muscle-tendon complex is a unique structure with three separate muscle compartments that merge via their aponeuroses into the Achilles tendon. The mechanical function and properties of these structures during muscular contraction are not well understood. The purpose of the study was to investigate the extent to which differential displacement occurs between the aponeuroses of the medial gastrocnemius (MG) and soleus (Sol) muscles during plantar flexion. Eight subjects (mean ± SD; age 30 ± 7 yr, body mass 76.8 ± 5.5 kg, height 1.83 ± 0.06 m) performed maximal isometric ramp contractions with the plantar flexor muscles. The experiment was performed in two positions: position 1, in which the knee joint was maximally extended, and position 2, in which the knee joint was maximally flexed (125°). Plantarflexion moment was assessed with a strain gauge load cell, and the corresponding displacement of the MG and Sol aponeuroses was measured by ultrasonography. Differential shear displacement of the aponeurosis was quantified by subtracting displacement of Sol from that of MG. Maximal plantar flexion moment was 36% greater in position 1 than in position 2 (132 ± 20 vs. 97 ± 11 N·m). In position 1, the displacement of the MG aponeurosis at maximal force exceeded that of the Sol (12.6 ± 1.7 vs. 8.9 ± 1.5 mm), whereas in position 2 displacement of the Sol was greater than displacement of the MG (9.6 ± 1.0 vs. 7.9 ± 1.2 mm). The amount and “direction” of shear between the aponeuroses differed significantly between the two positions across the entire range of contraction, indicating that the Achilles tendon may be exposed to intratendinous shear and stress gradients during human locomotion.

APA, Harvard, Vancouver, ISO, and other styles

38

Pradines, M., I. Masson, C. Giroux, R. Portero, P. Portero, and J. M. Gracies. "Effet d’un an de rééducation intégrant un programme quotidien d’auto-étirements chez des patients hémiparétiques chroniques sur la longueur musculaire et les propriétés passives musculo-tendineuse du triceps sural." Kinésithérapie, la Revue 17, no. 184 (April 2017): 51. http://dx.doi.org/10.1016/j.kine.2017.02.050.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Koryak, Yuri A. "Influence of simulated microgravity on mechanical properties in the human triceps surae muscle in vivo. I: Effect of 120 days of bed-rest without physical training on human muscle musculo-tendinous stiffness and contractile properties in young women." European Journal of Applied Physiology 114, no. 5 (February 8, 2014): 1025–36. http://dx.doi.org/10.1007/s00421-014-2818-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Schmieder, R., S. Jung, D. Kannenkeril, J. M. Harazny, K. Striepe, C. Ott, P. Linz, A. M. Nagel, and M. Uder. "P4993Tissue sodium concentration emerged as a determinant of hypertrophic vascular remodeling in type 2 diabetes." European Heart Journal 40, Supplement_1 (October 1, 2019). http://dx.doi.org/10.1093/eurheartj/ehz746.0171.

Full text

Abstract:

Abstract Background Studies describe a linkage between greater sodium intake and higher incidence of organ damage and cardiovascular end points. Sodium intake is usually assessed by measuring 24-hour urinary sodium excretion, which is prone to high fluctuation. For the assessment of tissue sodium a new technique (23Na-MRI) has been developed. We analyzed whether tissue sodium is linked to vascular remodeling of small resistance vessels in patients with type-2 diabetes. Methods In patients with type 2 diabetes we assessed tissue sodium content and vascular structural parameters of the retinal arterioles, since structural changes of resistance vessels (150–300 μm) can be non-invasively and reliably assessed in the retinal circulation by Scanning Laser Doppler Flowmetry (SLDF). Patients with antidiabetic medication were off the therapy (antihypertensives were kept constant) for 4 weeks. The structural parameters of retinal arterioles assessed were outer- and inner diameter (OD & ID), wall thickness (WT), wall-to-lumen ratio (WLR) and wall cross sectional area (WCSA). Tissue sodium content was assessed non-invasively with a 3.0 T clinical MRI system in each patient. Subject placed their lower legs in the center of a 23Na knee coil and sodium content in skin and muscle (musculus triceps surae) were measured. Results In patients with type 2 diabetes (N=52) we observed a significant correlation between tissue sodium content (muscle and skin) and OD, WT and WCSA and a trend has been noticed between muscle sodium content and ID and WLR. Multiple linear regression analysis demonstrated that tissue sodium content is a significant determinant of hypertrophic vascular remodeling as indicated by increased WT and WCSA, independent of age, gender and 24-hour ambulatory diastolic blood pressure. Correlation coefficients Muscle sodium content (mmol/l) Skin sodium content (mmol/l) OD (μmol) r=0.402, p=0.003 r=0.299, p=0.033 ID (μmol) r=0.265, p=0.058 r=0.202, p=0.154 WT (μm) r=0.402, p=0.003 r=0.313, p=0.026 WLR r=0.247, p=0.078 r=0.171, p=0.230 WCSA (μm2) r=0.417, p=0.002 r=0.322, p=0.021 Conclusion With the novel 23Na-MRI technology, we could demonstrate that high tissue sodium concentration is linked to with hypertrophic vascular remodeling of retinal arterioles. Thus, the reduction of tissue sodium content may emerge as a therapeutic target.

APA, Harvard, Vancouver, ISO, and other styles

41

Clark, William H., Richard E. Pimentel, and Jason R. Franz. "Imaging and Simulation of Inter-muscular Differences in Triceps Surae Contributions to Forward Propulsion During Walking." Annals of Biomedical Engineering, September 8, 2020. http://dx.doi.org/10.1007/s10439-020-02594-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Musculus triceps surae'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles