Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Back Muscles”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources
PubMed2003

Dynamic stabilization of lumbar motion segments by use of Graf's ligaments: results with an average follow-up of 7.4 years in 39 highly selected, consecutive patients.

BACKGROUND: In recent years considerable effort was undertaken in order to replace rigid lumbar stabilization by soft stabilization in certain instances. The Graf soft system stabilization technique is such an interesting novel alternative to lumbar arthrodesis in the treatment of mechanical low-back disorders. The current retrospective analysis reports the long-term results in 39 consecutive patients treated with Graf's ligaments for painful lumbar instability. METHODS: Young patients with lumbar mechanical disorders resistant to conservative treatment with 1) no or mild facet joint degeneration, 2) minor disc degeneration, 3) well trained low back muscles, 4) pain relief after trial anaesthesia and 5) probatory rigid plastic jacket underwent lumbar ligamentoplasty according to Graf. The patients were assessed clinically and they filled in an extensive questionnaire at an average period of observation of 7.4 years. FINDINGS: After 7.4 years the clinical results in 39 patients were excellent, good, fair, unchanged and worse in 43.6%, 20.5%, 10.2%, 23.1% and 2.6%, respectively. Seven unchanged patients were converted to arthrodesis. In the questionnaire 66.6% reported total disappearance of back pain, in 25.7% it was significantly less and in 7.7% back pain was a bit less. Visual analogue scale for low back pain was 0 in 69.2%, 2.5 in 15.4% and 5 in 15.4% of patients. For leg pain it was nil in 92.3% and 2.5 in 7.7%. INTERPRETATION: Soft system stabilization of lumbar motion segments in young patients with painful mechanical disease resistant to conservative treatment yields favourable long-term results only in a highly selected patient population.

Adolescent↗
PubMed1977

Muscle load and fatigue of film rolling workers.

Effects of locally concentrated loading by repetitive upper limb operations on the musculature were studied in female workers of ages 19--33 rolling photographic film. They repeated rolling and capping of a 35 mm film every 2.5--5 sec during the whole day shift which had a 60 min lunch recess and two 10 min rests. Increase of dull-drowsy symptoms and shoulder complaints was dominant after work, stiff shoulders complaints being divided into 41.6% for prework and 78.7% for postwork. It was characteristic for these workers to have the trapezius muscle showed continuous electromyographic activities in sustaining arms. The average level of the contraction was estimated at about 10--30% of the maximum contraction. Eighty-four per cent of those studied had tenderness at the ascending part of the trapezius, while the same tenderness was found in only 48% of female office workers of the same firm. The operators having low tenderness threshold of 0.6 kg/cm2 or less had stiff shoulders more frequently as well as lower levels of back muscle and upper arm abduction forces than those having no tenderness. It is thus likely that habitual shoulder muscle fatigue is due to repetitive tasks that results in localized tenderness and possibly in occupational hazards.

Adult↗
PubMed1980

Ca2+ and Sr2+ activation: comparison of cardiac and skeletal muscle contraction models.

The mechanism of contraction in rabbit fast-twich, and bovine and rabbit cardiac muscle was examined using functionally skinned fibers, ATPase activity of myofibrils, and cardiac or skeletal troponin-tropomyosin regulated actin heavy meromyosin. The Ca2+ and Sr2+ activation properties for the different measures of contraction were evaluated. (1) Tension in rabbit and bovine cardiac skinned fibers and rabbit cardiac myofibrillar ATPase were activated equally well by either Ca2+ or Sr2+. By contrast, rabbit adductor magnus (fast-twich) skinned fibers required substantially higher [Sr2+] than [Ca2+] for activation, as did rabbit myofibrils from back muscle (fast-twitch). (2) Substantially more Sr2+ than Ca2+ was also required for activation of skeletal muscle actin heavy meromyosin ATPase, controlled by either the skeletal or cardiac troponin-tropomyosin complex, similar to the activation of fast-twitch muscle. (3) The absence of correlation between the divalent cation selectivity properties of actin heavy meromyosin ATPase controlled by cardiac troponin-tropomyosin and cardiac muscle tension or myofibrillar ATPase activation by Ca2+ and Sr2+ suggests that troponin, if primarily responsible for the activation of cardiac muscle, has very different in vivo and in vitro binding properties. (4) The close correlation between percentage of maximal Ca2+- and Sr2+-activated myofibrillar ATPase and tension in skinned fibers strongly justifies the use of myofibrillar ATPase, in contrast to a reconstituted troponin-tropomyosin actin heavy meromyosin ATPase system, as a biochemical measure of contraction.

Adenosine Triphosphatases↗
PubMed1983

Cloned mRNA sequences for two types of embryonic myosin heavy chains from chick skeletal muscle. I. DNA and derived amino acid sequence of light meromyosin.

Two myosin heavy chain cDNA clones (251 and 110), constructed from chick embryonic skeletal muscle mRNA, were subjected to extensive DNA sequence analysis. A complete description of the DNA sequence of clone 251 was obtained. This 1.5-kilobase pair cDNA sequence specified the COOH-terminal 439 amino acids of the myosin heavy chain, and included the entire 3' nontranslated region. The translated and 3' nontranslated sequences were purine- (64%) and AT-(71%) rich, respectively. The derived amino acid sequence of clone 251 correlated well with sequences obtained by direct amino acid sequencing of adult rabbit back muscle myosin heavy chain protein (87% homology), as well as with cloned myosin heavy chain sequences from other species. Comparison of clone 251 with a partial DNA sequence of clone 110 revealed significant structural differences both in the translated, and 3' nontranslated regions. This data indicates that these two clones represent two distinct myosin heavy chain genes. The protein sequence specified by clone 251 corresponds to the light meromyosin portion of the myosin heavy chain rod. These sequences, like other myosin heavy chain rod sequences, are alpha-helical and exhibit 7- and 28-residue periodicities in the linear distribution of nonpolar, and basic and acidic amino acids, respectively.

Amino Acid Sequence↗
PubMed1999

Sonic hedgehog controls epaxial muscle determination through Myf5 activation.

Sonic hedgehog (Shh), produced by the notochord and floor plate, is proposed to function as an inductive and trophic signal that controls somite and neural tube patterning and differentiation. To investigate Shh functions during somite myogenesis in the mouse embryo, we have analyzed the expression of the myogenic determination genes, Myf5 and MyoD, and other regulatory genes in somites of Shh null embryos and in explants of presomitic mesoderm from wild-type and Myf5 null embryos. Our findings establish that Shh has an essential inductive function in the early activation of the myogenic determination genes, Myf5 and MyoD, in the epaxial somite cells that give rise to the progenitors of the deep back muscles. Shh is not required for the activation of Myf5 and MyoD at any of the other sites of myogenesis in the mouse embryo, including the hypaxial dermomyotomal cells that give rise to the abdominal and body wall muscles, or the myogenic progenitor cells that form the limb and head muscles. Shh also functions in somites to establish and maintain the medio-lateral boundaries of epaxial and hypaxial gene expression. Myf5, and not MyoD, is the target of Shh signaling in the epaxial dermomyotome, as MyoD activation by recombinant Shh protein in presomitic mesoderm explants is defective in Myf5 null embryos. In further support of the inductive function of Shh in epaxial myogenesis, we show that Shh is not essential for the survival or the proliferation of epaxial myogenic progenitors. However, Shh is required specifically for the survival of sclerotomal cells in the ventral somite as well as for the survival of ventral and dorsal neural tube cells. We conclude, therefore, that Shh has multiple functions in the somite, including inductive functions in the activation of Myf5, leading to the determination of epaxial dermomyotomal cells to myogenesis, as well as trophic functions in the maintenance of cell survival in the sclerotome and adjacent neural tube.

Animals↗
PubMed1998

Intramuscular pressure in the erector spinae and intra-abdominal pressure related to posture and load.

STUDY DESIGN: Intramuscular pressures in both Erectors Spinae and intra-abdominal pressures were measured during different holding tasks. OBJECTIVES: To investigate the potential for using intramuscular pressure measurements in both Erectors Spinae to better quantitate the role of muscles during different lifting tasks in vivo. SUMMARY OF BACKGROUND DATA: Intramuscular pressure and intra-abdominal pressure were measured previously under isometric and dynamic conditions. However, no previous study systematically has addressed the relation between intramuscular and intra-abdominal pressures and different loads, tasks, and postures. METHODS: Intramuscular and intra-abdominal were measured simultaneously with microtip pressure transducers in 10 healthy volunteers performing 24 different static holding tasks. Tasks included different weights (10 kg and 20 kg), postures (squat or back lift), and positions of the weight. RESULTS: Intramuscular pressures were dependent on posture. Kyphotic back posture produced intramuscular pressures of 120-130 mm Hg, compared with the 10-25 mm Hg produced when volunteers were in the erect position (P < 0.001). Holding a 10-kg weight at the thighs close to the body produced significantly (P < 0.001) lower intramuscular pressures (25-32 mm Hg) than that produced by holding it 25 cm in front of the body (47-56 mm Hg). In all tasks, intramuscular pressures were significantly higher with the 20-kg weight than with the 10-kg weight (P < 0.001). Highest values (> 300 mm Hg) were measured when the 20-kg weight was held in the kyphotic posture above the floor and 25 cm away from the body. CONCLUSIONS: Intramuscular pressure measurements in the erector spinae seem to be a valuable tool for quantitating the role of back muscles during different lifting tasks.

Abdomen↗
PubMed2000

Body mass in lowland gorillas: a quantitative analysis.

Body proportions and tissue composition (e.g., relative contributions of muscle, skin, bone, and adipose to total body mass) were determined through dissection of four adult captive lowland gorillas. The relative contribution of bone varies little among the four animals (10.2-13.4%) despite considerable range in body weights (99.5-211 kg). In tissue composition, three animals have on average 37.3% muscle relative to body mass. Maximum estimates of body fat range between 19.4-44%. Differences in age, sex, and life history events partially explain the observed variation in body proportions and tissue composition among the four animals. Although gorillas are considered extremely sexually dimorphic in body weight and canine size, differences in tissue are not as dramatic as body mass differences suggest. This study found sex differences mostly in the upper body; males have relatively heavier forelimbs, including heavier deltoid, trunk-binding, and deep back muscles compared to the younger female. The old, obese female had one half the muscle tissue of the other three animals (16% vs. 37.3%), and twice the body fat (44%); forelimbs and upper body musculature were relatively well-developed to compensate for the restricted hip-joint movement due to arthritis. Data on the variation in tissue composition and body proportions in gorillas provide a basis for comparison with other hominoids, including humans. For example, compared to highly dimorphic orangutans, gorillas have more muscle, less adipose tissue, lighter forelimbs and heavier hindlimbs. Such analyses complement studies of the skeleton and contribute to our understanding of human evolution and adaptation.

Animals↗
PubMed1986

Characterization of the junctional face membrane from terminal cisternae of sarcoplasmic reticulum.

We have recently described a preparation of junctional terminal cisternae (JTC) from fast skeletal muscle of rabbit hind leg. The fraction differs from other heavy sarcoplasmic reticulum (SR) fractions in that it contains a substantial amount of junctional face membrane (JFM) (15-20% of the membrane) with morphologically well-defined junctional feet structures. In common with other heavy SR preparations, it contains predominantly the calcium pump membrane (80-85% of the membrane) and compartmental contents (CC), consisting mainly of calcium-binding protein (calsequestrin). In this study, a modified procedure for the preparation of JTC from frozen rabbit back muscle is described. The yield is substantially greater (threefold per weight of muscle), yet retaining characteristics similar to JTC from fresh hind leg muscles. Methodology has been developed for the disassembly of the JTC. This is achieved by selectively extracting the calcium pump membrane with 0.5% Triton X-100 in the presence of 1 mM CaCl2 to yield a complex of JFM with CC. The CC are then solubilized in the presence of EDTA to yield JFM. This fraction contains unidirectionally aligned junctional feet structures protruding from the cytoplasmic face of the membrane with repeat spacings comparable to that observed in JTC. The JFM contains 0.16 mumol phosphorus (lipid) per milligram protein. Characteristic proteins include 340 and 79-kD bands, a doublet at 28 kD, and a component that migrates somewhat slower than or equivalent to the calcium pump protein. Approximately 10% of the calcium-binding protein remains bound to the JFM after EDTA extraction, indicating the presence of a specific binding component in the JFM. The JFM, which is involved in junctional association with transverse tubule and likely in the Ca2+ release process in excitation-contraction coupling, is now available in the test tube.

Animals↗
PubMed2001

The effect of timing of a perturbation on the execution of a lifting movement.

Anticipation to the mass magnitude is important in lifting, but underestimation of a mass, in contrast to overestimation, does not cause major movement disturbances. This may be caused by corrections in muscle activity before the object is actually lifted. This study was designed to assess the importance of these corrections during the loading phase for the execution of a lifting movement when the mass is underestimated. Ten subjects lifted a box (1.6 kg), of which the mass was increased by 10 kg without them knowing so. The mass was added either before the box had been lifted from the ground (perturbation before lift-off, PBL) or right perturbation after lift-off (PAL). In the PBL condition back muscle activity was increased before lift-off. Even though this early corrective response could obviously not occur in the PAL condition, the lifting movement was executed without clear problems. In sum, corrections in muscle activity before lift-off are not necessary for adequate correction of a perturbation induced by an unexpected heavier object.

Adaptation, Physiological↗
PubMed2005

Scoliosis correction in an adolescent with a rigid spine syndrome: case report.

STUDY DESIGN: Details of presentation and approach to the treatment of scoliosis in a case of a Rigid Spine Syndrome (RSS). OBJECTIVE: To report on the results of conservative and operative treatment of scoliosis associated with RSS, and, based on this, to propose an assessment and treatment protocol for this condition. SUMMARY OF BACKGROUND DATA: Congenital muscular dystrophies (CMD) are a group of disorders marked by hypotonia at birth and a generally nonprogressive course of muscle weakness. Spinal rigidity is present in a number of patients with CMD. RSS is classified as a CMD, and is characterized by early rigidity of the spine, limb contractures, and restrictive respiratory dysfunction. An approach to the treatment of scoliosis in RSS has not been established. METHODS: Details of history, diagnostic tests, and treatment of an adolescent with RSS associated with progressive scoliosis and cervical spine extension contracture is presented. The role of brace treatment, Botox (Allergan, Inc., Irvine, CA), and details of operative correction, including histology of back muscles, is defined. RESULTS: In this case of RSS with rigid scoliosis nonresponsive to brace therapy and Botox injections, an anterior thoracolumbar spine fusion with instrumentation was successfully performed for correction of the scoliosis, and the cervical spine was addressed through a posterior approach and an occiput-cervical fusion. We outline the details of surgical procedure and restoration of spinal balance in both sagittal and coronal planes. CONCLUSIONS: The chromosomal bases of CMD and characteristic features of RSS, including diagnostic tests, have been reviewed. Surgical intervention with spinal deformity fusion, correction, and instrumentation is indicated in RSS with progressive spinal imbalance not responding to conservative therapy is safe and can give promising results.

Adolescent↗
PubMed1989

[A study of trunk muscle in idiopathic scoliosis].

Isometric and isokinetic parameters related to trunk muscle function in patients with idiopathic scoliosis were measured by Cybex dynamometer with a trunk stabilization system. Activities of the paraspinal muscles were also determined by electromyographic observations. In scoliotic patients some parameters, especially endurance in lateral bending to the concave side of the trunk, were predominant. In electromyographic analysis, neurogenic changes were observed in 25.9% of patients with idiopathic scoliosis. In nonprogressive scoliosis, the mean amplitude of EMG did not differ between the convex and the concave. In progressive scoliosis, however, the mean amplitude of EMG was higher on the convex side than on the concave side. Thus, the compensatory reaction on the curvature of the spine caused higher amplitude of action potential of the back muscles on the convex side than in the concave side. These data suggest that the trunk muscle imbalance is one of the most important factors in the onset and progression of idiopathic scoliosis.

Adolescent↗
PubMed1982

[Effect of route and place of minocycline administration on the zootechnical performance of rabbits].

Minocycline administered to rabbits per os or intramuscularly (30 mg/kg) over a period of three days led neither to digestive problems nor mortality. Administration per os left the growth curve unchanged. Intramuscular administration reduced rate of growth, and on the 15th day weight loss compared to controls was 3.2% or 11.7% depending on whether the place of administration was in the back muscles or in the thigh, and this despite a normal food intake. Minocycline did not modify microbial flora and level of ammonia in the caecum. Level of acetic acid was reduced by 50% on the fourth and 15th day after intramuscular administration of minocycline into the thigh. The depressive effect of minocycline on growth remains unexplained.

Administration, Oral↗
PubMed2005

Classification of large array surface myoelectric potentials from subjects with and without low back pain.

An algorithm was developed and tested for differentiating between the spatial distribution of large arrays of surface electromyographic (LASE) data from subjects with and without low back pain (LBP). The surface EMG data from 62 channels were collected from the low back of 161 healthy and 44 acute (less than 6-weeks) LBP subjects in three minimum stress postural positions including standing, 20 degrees of trunk flexion (at hip joint) and standing with arms extended forward holding a 1.36kg (3lb) weight in each hand. These data were statistically analyzed and the spatial distribution of the root mean square (RMS) values was used in a multivariate quadratic discriminant model to reclassify the healthy and acute LBP subjects. The most predictive results were obtained from the 'flexion' group of experiments and correctly reclassified 95.5% (42/44) of the acute LBP subjects and 99.4% (160/161) of the healthy subjects. The success rate of this reclassification based on surface distribution of myoelectric potentials was found to be better than the reported patient classifications based on a smaller set of electrode pairs using fewer subjects [Peach JP, McGill SM, Classification of low back pain with use of spectral electromyogram parameters. Spine 23(10):1998;1117-23; Roy SH, De Luca CJ, Emley M, Oddsson LI, Buijs RJ, Levins JA, Newcombe DS, Jabre JF. Classification of back muscle impairment based on the surface electromyographic signal. J Rehabil Res Dev 34(4):1997;405-14 [review]]. The results indicated the potential of the model for clinical patient classification.

Action Potentials↗
PubMed2002

"Occupational backache" - surface electromyography demonstrates the advantage of an ergonomic versus a standard microscope workstation.

Musculoskeletal symptoms such as low back pain, neck pain, and tension headache are reported by up to 80% of professional personnel involved in daily microscope work. Yet, in striking contrast to the high prevalence of complaints, there is a general unawareness of this issue both in those suffering, and those ordering and designing microscopes. We intend to call attention to this underestimated work-related health hazard and to demonstrate a potential means of prevention. We obtained repeated surface electromyographic (EMG) recordings from the most strained neck, upper limb, and back muscles in 12 healthy volunteers while they were operating a near-to-ergonomic prototype workstation and a conventional microscope, respectively. Mean EMG activity was reduced in all recorded muscles when operating the ergonomic workstation compared to the standard microscope. This improvement became more distinct with sustained work, and was most pronounced in those muscles displaying the highest degree of activity while using the standard microscope. We demonstrate the usefulness of surface EMG recordings to show the advantage of an ergonomically tailored and individually adjustable microscope workstation over a standard microscope. The former allows the operator to maintain a more physiological posture, and may thus prevent the development of cumulative musculoskeletal disorders during prolonged microscope-related work.

Adult↗
PubMed1989

Risk indicators for low back trouble.

A general population of 928 men and women aged 30, 40, 50 and 60 years participated in a health survey with emphasis on low back trouble (LBT). In all 135 variables were analysed to identify possible indicators for first-time experience and recurrence or persistence of LBT during a one-year follow-up. Stepwise logistic regression analyses were carried out to identify the most informative combinations of indicators for prediction of LBT. For men, a high risk for recurrence or persistence of LBT was associated with frequent LBT in the past, worsening of the LBT since its onset, sciatica and living alone. For women corresponding risk indicators were: recency of the last LBT episode, waking up during night because of LBT, aggravation of LBT when standing, rumbling of "the stomach" and smoking. The strongest risk indicators for first-time experience of LBT were epigastric pain, daily smoking and low isometric endurance of the back muscles. In addition, hospitalisations for whatever cause and a long distance from home to work showed predictive power for first-time LBT among gainfully employed participants. The results indicate that persons with either recurring or first-time LBT had more health problems and probably lived under a higher psycho-social pressure than those without LBT in the follow-up year.

Adult↗
PubMed1996

Mechanical stress reduction during seated jolt/vibration exposure.

The risk of experiencing low back pain is associated with mechanical factors. Anatomic factors, such as advancing pregnancy, can also place extra mechanical stress on the lower back. Mechanical factors, such as those related to the workplace, can be minimized by ergonomic interventions. A constrained, seated posture, in combination with exposure to whole-body, jolt/vibration can impose significant stresses on the posterior intervertebral disc and can lead to back muscle fatigue. Interventions that reduce the jolt/vibration magnitude and duration of exposure will decrease the mechanical work performed on the intervertebral disc. Such interventions range from jolt/vibration isolating seats and vehicle cabs, to decreasing exposure time and maintaining simple supported postures during ingress and egress. Improvements in seat configuration can reduce the intervertebral disc pressure and the strain on the posterior disc.

Biomechanical Phenomena↗
PubMed2006

Osteoinductive porous titanium implants: effect of sodium removal by dilute HCl treatment.

In a previous study, we observed that chemically and thermally treated plasma-sprayed porous titanium possesses intrinsic osteoinductivity and that bone formation occurs after 12 months in the muscles of beagle dogs. The aim of this study was to optimize the surface treatment and to accelerate the osteoinductivity. Previous studies have reported that sodium removal converts the sodium titanate layer on the surface of an alkali-treated titanium plate into a more bioactive titania layer. In this study, we developed a dilute hydrochloric acid (HCl) treatment for porous titanium, which removed sodium from the complexly shaped porous structure more effectively than conventional hot water treatment. Three types of surface treatments were applied: (a) alkali and heat treatment (AH treatment); (b) alkali, hot water, and heat treatment (Water-AH treatment); and (c) alkali, dilute HCl, hot water, and heat treatment (HCl-AH treatment). The osteoinductivity of the materials implanted in the back muscles of adult beagle dogs was examined at 3, 6, and 12 months. The HCl-AH-treated porous bioactive titanium implant had the highest osteoinductivity, with induction of a large amount of bone formation within 3 months. The dilute HCl treatment was considered to give both chemical (titania formation and sodium removal) and topographic (etching) effects on the titanium surface, although we cannot determine which is the predominant factor. Nevertheless, adding the dilute HCl treatment to the conventional chemical and thermal treatments is a promising candidate for advanced surface treatment of porous titanium implants.

Animals↗
PubMed2006

Classification of longissimus lumborum muscle spindle afferents in the anaesthetized cat.

Recordings have been made from 127 single muscle spindle afferents from the longissimus lumborum muscles of anaesthetized cats. They have been characterized by their responses to passive muscle stretch and the effects of succinylcholine (SCh) and by their sensitivity to vibration. The use of SCh permitted the assessment for each afferent of the influence of bag1 (b1) and bag2 (b2) intrafusal muscle fibres. From this, on the assumption that all afferents were affected by chain (c) fibres, they were classified in four groups: b1b2c (41.9%), b2c (51.4%), b1c (1.3%) and c (5.4%). All the afferents with b1 influence were able to respond one to one to vibration at frequencies above 100 Hz and were considered to belong to primary endings. On the basis of the vibration test, 64% of the b2c type afferents appeared to be primaries and 36% secondaries. Of the units classified as primaries, 41% were designated as b2c and would not therefore be able to respond to dynamic fusimotor activity. The significance of this relatively high proportion of b2c-type spindle primary afferents is discussed in relation to the specialized postural function of the back muscles.

Anesthesia↗