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PubMed1994

[Incidence of complaints about heel-, knee- and back-related discomfort among Danish children, possible relation to short muscles].

Four hundred and fifty-nine children and adolescents from third, sixth and ninth classes in seven schools on Funen were questioned in 1991. Seven percent had complaints from back and knee, and 3% from the heel. When the hamstrings were so short that one knee had an extension deficit gently measured to more than 40 degrees, when the hip was flexed 90 degrees, the incidence of back pain rose significantly to 15%. Furthermore 18% had complaints from the knee and 35% from the heel when the passive range of motion of the foot was less than 0 degrees of dorsiflexion measured with the knee extended. As 75% of the boys and 35% of the girls over age ten have short hamstrings and 13% of both sexes have short Achilles tendons, it is recommended that school children be involved in a daily stretching programme in order to diminish the complaints from the extremities often seen in this group.

Adolescent↗
PubMed2006

Effects of two 4-week proprioceptive neuromuscular facilitation programs on muscle endurance, flexibility, and functional performance in women with chronic low back pain.

BACKGROUND AND PURPOSE: Improving functional performance in patients with chronic low back pain is of primary importance. The purpose of this study was to examine the effects of 2 proprioceptive neuromuscular facilitation (PNF) programs on trunk muscle endurance, flexibility, and functional performance in subjects with chronic low back pain (CLBP). SUBJECTS: Eighty-six women (40.2+/-11.9 [mean+/-SD] years of age) who had complaints of CLBP were randomly assigned to 3 groups: rhythmic stabilization training, combination of isotonic exercises, and control. METHODS: Subjects trained with each program for 4 weeks with the aim of improving trunk stability and strength. Static and dynamic trunk muscle endurance and lumbar mobility were measured before, at the end of, and 4 and 8 weeks after training. Disability and back pain intensity also were measured with the Oswestry Index. RESULTS: Multivariate analysis of variance indicated that both training groups demonstrated significant improvements in lumbar mobility (8.6%-24.1%), static and dynamic muscle endurance (23.6%-81%), and Oswestry Index (29.3%-31.8%) measurements. DISCUSSION AND CONCLUSION: Static and dynamic PNF programs may be appropriate for improving short-term trunk muscle endurance and trunk mobility in people with CLBP.

Adult↗
PubMed2006

The association of physical deconditioning and chronic low back pain: a hypothesis-oriented systematic review.

PURPOSE: Does physical deconditioning (loss of cardiovascular capacity and strength/endurance of paraspinal muscles) exist in patients with chronic low back pain (CLBP) and are treatments specifically aimed to reduce these signs effective? METHOD: Systematic literature search in PUBMED, MEDLINE, EMBASE and PsycINFO until December 2004 to identify observational studies regarding deconditioning signs and high quality RCTs regarding the effectiveness of cardiovascular and/or muscle strengthening exercises. Internal validity of the RCTs was assessed by using a checklist of nine methodology criteria in accordance with the Cochrane Collaboration. RESULTS: There is conflicting evidence that cardiovascular deconditioning is present in CLBP and limited evidence for wasting of the multifidus muscle. No study examined the effectiveness of cardiovascular training specifically. General and lumbar muscle strengthening are equally effective as other active treatments. Only moderate evidence is available for the effectiveness of intensive low back extensor muscle strengthening compared to less intensive strengthening. CONCLUSION: Probably reactivation caused by active treatment and not the reconditioning itself is the important factor in the reduction of disability. Further prospective and evaluative research into the role of physical deconditioning is necessary. It seems more promising to further explore the interplay between biological, social and psychological factors.

Cardiovascular Deconditioning↗
PubMedDate not supplied

The significance of fat and muscle areas in the lumbar paraspinal space: a CT study.

OBJECTIVE: The object of this study was to determine the significance of fat deposition and muscle dimensions on CT in the unoperated lumbar paraspinal space. MATERIALS AND METHODS: Fifty patients were prospectively studied. Paraspinal fat (PSF) and muscle (PSM) areas were correlated with various demographic and anatomical variables in patients with and without low back pain. The fat and muscle areas were derived from a standard CT image using a thresholding technique. RESULTS: Regression equations indicated that the total amount of PSF increases with age and subcutaneous fat area. The PSM area decreases with age. There was no correlation with the other variables examined. CONCLUSION: We conclude that PSF deposition and PSM dimensions on CT are related to patient age and the amount of subcutaneous fat. Paraspinal fat deposition is not a sign of muscle atrophy, and neither parameter is related to low back pain symptoms. Therefore, in patients who have not undergone spinal surgery, PSF and PSM areas are not of clinical or functional significance.

Adipose Tissue↗
PubMed1975

[Statics and dynamics after total hip arthroplasty. An electromyographic study (author's transl)].

The weightbearing of the hip of 147 patients after total prosthesis operation was controlled by the two wages method. In most of them the weightbearing becomes normal in a few months after the operation. In 39 patients with 48 total prostheses an electromyographic examination of the erectores trunci and the glutaei as well as the quadriceps of both legs in standing and walking was performed. In standing the patients demonstrate an hyperactivity of the paravertebral muscles and glutaei before as well as after the operation. They cannot find the normal standing posture with its typical lack of activity of the back, pelvis or leg muscles. In standing on one leg as well as in walking the innervation of the glutaei is diminished. In many cases it becomes normal after the total hip operation. Only in 1/3 of the cases we can observe a fully normal electrical activity of the glutaei with the classical "fan sign" which corresponds to the normal rotation of the pelvis during the stand phase. The erectores trunci demonstrate before and after the operation the same anomalies of innervation.

Aged↗
PubMed1998

Extensor truncal dystonia: successful treatment with botulinum toxin injections.

Patients with truncal extension dystonia, manifested by involuntary back arching, often associated with pain and severe motor disability, have not consistently responded to pharmacologic agents. We evaluated 4 women and 1 man (mean age, 41.8 years; dystonia duration, 9.8 years) with severe idiopathic (2 patients) or tardive (3 patients) truncal and cervical dystonia. Using electromyographic guidance, we injected botulinum toxin into the paravertebral muscles of the lumbar region in four to six sites using 25-50 U per site. We reevaluated patients 2-4 weeks after injection. The mean dose of botulinum toxin into back muscles was 210 U (range, 150-300 U). By blinded videotape evaluation, objective improvement was found in three patients with a mean truncal dystonia score improving by 37%. Patient evaluation showed improvement in movement ranging from 20-80% (mean, 46%) after botulinum toxin. In all patients with pain as a result of dystonia, there was substantial improvement. None of the patients worsened and no adverse effects occurred. Botulinum toxin injections offer a potent new treatment for truncal dystonia.

Adult↗
PubMed2002

Electrophysiologic evidence for an intersegmental reflex pathway between lumbar paraspinal tissues.

STUDY DESIGN: Electrophysiologic recordings were obtained from a lumbar paraspinal nerve or muscle in the anesthetized cat while electrically stimulating a paraspinal nerve or facet capsule in an adjacent lumbar segment. A variety of approaches were used to demonstrate the reflex nature of both the nerve and the muscle response. OBJECTIVE: The primary purpose of this study was to seek electrophysiologic evidence for the presence of intersegmental reflexes between adjacent lumbar vertebral segments. A second purpose of this study was to confirm a previous procedure used to evoke paraspinal reflexes. This previous work had shown that electrical stimulation of the L1-L2 facet joint capsule elicits electromyographic activity from multifidus muscle one to two vertebral segments caudal to the stimulated facet in a porcine preparation. SUMMARY OF BACKGROUND DATA: Biomechanical approaches have stressed the need for spinal stability to avoid conditions that could give rise to low back dysfunction. It seems reasonable to believe that reflex interactions between vertebral segments contribute to the sensorimotor integration of lumbar paraspinal tissues. It also seems reasonable to believe that alterations or abnormal elicitation of these reflexes could contribute to biomechanical changes associated with low back pain and paraspinal muscle spasm. METHODS: Experiments were performed on 23 alpha-chloralose anesthetized adult cats. In eight cats the L3, L4, and L5 medial branch from each dorsal ramus was exposed and placed on a bipolar hook electrode. In six cats the L4 medial branch was stimulated and a compound action potential was recorded from the L3 medial branch. In three of the six cats the L5 medial branch was stimulated and a compound action potential was recorded from the L3 medial branch. In one cat the L4 medial branch was stimulated and a compound action potential was recorded from the L5 medial branch. In one cat the L3 medial branch was stimulated and a compound action potential was recorded from the L5 medial branch. At the end of each protocol the medial branch was cut just proximal to the stimulating electrode to confirm that the compound action potential was reflexive in nature and not initiated by volume conduction. In 15 cats three approaches were used to confirm that multifidus electromyographic activity evoked by electrical stimulation of a lumbar facet capsule was reflexive in nature: 1) by anesthetizing the site of the sensory endings, i.e., the facet capsule, 2) by injecting lidocaine intrathecally to block neural conduction centrally, i.e., within the spinal canal, or 3) by cutting the afferent pathway, i.e., the medial branch of the dorsal ramus. RESULTS: Electrical stimulation of the medial branch of the dorsal ramus innervating the medial-most lumbar paraspinal tissues evoked a compound action potential in the medial branch innervating the medial-most paraspinal tissues one and two segments away. Stimulating voltages between 2 and 70 V were necessary to evoke the compound action potential. Each compound action potential was reflexive in nature because cutting the lumbar medial branch proximal to its contact with the stimulating electrode abolished each compound action potential. The conduction velocity of the reflex ranged from 3.5 to 6.1 m/sec. Electrical stimulation of a lumbar facet capsule evoked lumbar multifidus muscle electromyographic activity. However, injecting lidocaine intrathecally or transecting the medial branch of the dorsal ramus had no effect on electromyographic activity. Injecting lidocaine into the facet or into the multifidus muscle around the facet joint (near the stimulating electrode) significantly decreased the magnitude of the multifidus electromyography. CONCLUSION: These results indicate that afferent impulses conveyed by the medial branch of the dorsal ramus reflexly altered efferent activity to an adjacent lumbar segment. This intersegmental paraspinal reflex may span at least one or two vertebral segments. The data suggest that electrical stimulation of the facet joint capsule may not have reflexly elicited multifidus activity because neither chemical interruption (intrathecal lidocaine) nor physical interruption (nerve transection) of the presumed reflex pathway diminished or abolished the electromyographic response. Volume conduction of the stimulating currents likely elicited multifidus activity during electrical stimulation of the facet capsule. When using electrical stimulation of neural paraspinal tissues to evoke reflex muscle activity, appropriate control experiments must be performed to clearly demonstrate the reflexive nature of the response.

Action Potentials↗
PubMed1983

The relationship between EMG activity of the Sacrospinalis and reported back discomfort.

Six subjects performed a tapping task during replicated pairs of trials involving three different degrees of forward bend. The first and second trial of each pair was separated by either a 4 min or 1 min rest period. Integrated electromyographic (IEMG) records from the right Sacrospinalis muscle and estimates of back discomfort on a 5 point scale at 1 min intervals were collected. Reported back discomfort did not correlate with I.E.M.G. Increased forward bend and reduced rest interval generally led to increased levels of reported discomfort but not necessarily increased I.E.M.G.

Back Pain↗
PubMed1998

Method and performance: two elements of work technique.

In the present study work technique was viewed in two basic elements: the method of carrying out a work task and the individual performance of the work task. The aim was to investigate how eight selected kinematic, kinetic, electromyographic and psychophysical variables can characterize the two elements of work technique. Twelve female subjects lifted a box using two methods, back and leg lifts, and two different simulated performances, fast and slow lifts. Motions, ground reaction forces, muscle activity in the lower back and perceived exertion were measured. A dynamic biomechanical model was applied. The trunk angular displacement and velocity clearly separated the lift methods. The trunk angular velocities and accelerations, the L5/S1 moments and the EMG variables were closely related to the performances. The work technique varied between the subjects to a greater extent than the individual variability over repetitions of a lift task. A larger inter-individual variability for kinematic variables was mostly shown in leg lifts compared with back lifts. The EMG patterns displayed differences in muscle activation that were not revealed by the kinematic or kinetic patterns. The results imply that separate variables should be used for descriptions of work methods and task performances; for method descriptions ranges of motion seem to be appropriate, for performance descriptions displacement time derivatives and load variables seem to be more useful. Moreover, the inter-individual differences suggest that work technique should be evaluated on an individual level.

Adult↗
PubMed1990

The vestibular nuclei of the cat receive a primary afferent projection from receptors in extraocular muscles.

The vestibular nuclei of adult cat were injected with retrogradely transported tracers, WGA-HRP or fluorescent Diamidino-Yellow. Labelled cells were found in the caudal half of the ipsilateral mesencephalic trigeminal nucleus, in the area where ganglionic cells of the sensory receptors in the extraocular muscles have previously been described. Double labelling experiments were carried out with Diamidino Yellow injected in vestibular nuclei and Fast Blue in extraocular muscles. Some cells in the mesencephalic trigeminal nucleus were found to contain both tracers, providing evidence that vestibular neurons do receive direct afferent signals from extraocular muscles. Therefore, this anatomical demonstration suggests a direct feed-back control between the extraocular muscle receptors and the vestibular nuclei.

Amidines↗
PubMed1991

Comparison of canine skeletal muscle power from twitches and tetanic contractions in untrained muscle: a preliminary report.

Power output and blood flow were determined in dogs for four muscles (gastrocnemius, latissimus dorsi, rectus abdominis, and triceps) to determine effects of choice of muscle, tetany or twitch rates, force loading of the muscle, and blood flow on muscle power output. Total power for a 20-Kg dog was greatest for triceps at 0.77 watts (W) and least for rectus at 0.22 W; power per gram was greatest for gastrocnemius at 5.77 mW/g. Muscle perfusion of latissimus and rectus is greatly decreased by overstretching of the muscle. Overstretching also produces severe, persistent, power loss in latissimus and rectus muscles. Gastrocnemius and triceps tolerate stretching much better. We conclude that power can be improved without causing muscle fatigue by choice of muscle, choice of electrical stimulation parameters, linear geometry for contraction of the muscle, and matching the force load to each individual muscle.

Abdominal Muscles↗
PubMed1985

Characteristics of male fallow deer muscle at a time of sex-related muscle growth.

Muscle characteristics of male fallow deer undergoing neck muscle enlargement as the mating season (rut) approached were studied. Five commercially-raised males were slaughtered prerut and five were slaughtered 11 weeks later, just before the rut began. During this period, increases in individual muscle weight were not the same: two of the three neck muscles studied grew more rapidly than the average, whereas the back and two hind leg muscles grew more slowly. The splenius, the neck muscle that grew the most apparently in response to a rise in plasma testosterone, was studied. Cryosections were cut and stained for myofibrillar ATPase so that the muscle fiber classes--slow oxidative (type I), fast oxidative-glycolytic (type IIA) and fast glycolytic (type IIB)--could be distinguished. The IIB class was absent from the splenius and the occurrence of I and IIA fibers did not change during the period of splenius growth. However, the splenius of fallow deer increased in activity of NADH-tetrazolium oxidoreductase at the fiber peripheries as the rut approached. Further, fiber areas increased markedly during the period of growth, with type I fibers doubling in area and type IIA nearly trebling. Thus, the endocrinal and/or neural changes associated with the rut differentially affected these fiber types, and since type IIA fibers outnumbered type I by nearly 2 to 1, muscle enlargement is clearly dominated by the former class. Fiber areas were normally distributed for both fiber types, prerut and at the start of the rut, and coefficients of variation were similar. These results suggest that all fibers within a type are equally liable to grow during the growth period.

Acclimatization↗
PubMed1986

Muscular contracture as a component of low back pain: evaluation criteria and significance of relaxant therapy.

The measurement of diastasis of the spinous processes and of muscular action potentials by means of bio-feedback equipment is a clinically valid means to evaluate the extent of reflex muscular contracture. The methods were used to study the relaxant effect of pridinol mesylate on the lumbar extensor muscles in subjects with acute low back pain. It was found that pridinol mesylate significantly reduced the contracture of the extensor lumbar muscles in low back pain when given per os or parenterally.

Action Potentials↗
PubMed2005

Spinal manipulation alters electromyographic activity of paraspinal muscles: a descriptive study.

OBJECTIVE: To examine the effect of spinal manipulation on electromyographic (EMG) activity in areas of localized tight muscle bundles of the low back. METHODS: Surface EMG activity was collected from 16 participants in 2 chiropractic offices during the 5 to 10 minutes of the treatment protocol. Electrodes were placed over the 2 sites of greatest paraspinal muscle tension as determined by manual palpation. Spinal manipulation was administered to 8 participants using Activator protocol; the other 8 were treated using Diversified protocol. RESULTS: Electromyographic activity decreased by at least 25% after treatment in 24 of the 31 sites that were monitored. There was less than 25% change at 3 sites and more than 25% increase at 4 sites. Multiple distinct increases and decreases were observed in many data plots. CONCLUSION: The results of this study indicate that manipulation induces a virtually immediate change, usually a reduction, in resting EMG levels in at least some patients with low back pain and tight paraspinal muscle bundles. In some cases, EMG activity increased during the treatment protocol and then usually, but not always, decreased to a level lower than the pretreatment level.

Back↗
PubMed1998

Isokinetic muscle strength after anterior cruciate ligament reconstruction.

The purpose of the present study was to investigate the isokinetic muscle strength 6 months after reconstruction of the anterior cruciate ligament (ACL). In order to recommend full-load come-back in sport, sufficient muscle strength may be important. Ninety female elite team handball players (mean 24.1 years) were postoperatively tested with Biodex. The operated limb was compared with the contralateral limb: 82.2% had a hamstring strength of a minimum of 49.6 Nm, corresponding to at least 90% of the non-operated limb, while only 12.2% fulfilled the recommended strength of 117.7 Nm for quadriceps femoris. Patients over 26 years showed significantly lower muscle strength in the operated limb than their younger counterparts. Increased focus on quadriceps femoris muscle strength during rehabilitation may improve the knee function faster after ACL reconstruction.

Acceleration↗
PubMed1997

Muscle fibre size and type distribution in thoracic and lumbar regions of erector spinae in healthy subjects without low back pain: normal values and sex differences.

This study sought to investigate the normal muscle fibre size and type distribution of the human erector spinae, both in thoracic and lumbar regions, in a group of 31 young healthy male (n = 17) and female (n = 14) volunteers. Two percutaneous muscle biopsy samples were obtained under local anaesthesia, from the belly of the left erector spinae, at the levels of the 10th thoracic and 3rd lumbar vertebrae. Samples were prepared for routine histochemistry for the identification of fibre types. Fibre size (cross-sectional area (CSA) and narrow diameter (ND)) was quantified using computerised image analysis. The mean CSA/ND for each fibre type was greater in the thoracic than the lumbar region, but there was no difference between the 2 regions either for percentage type I (i.e. percentage distribution by number), percentage type I area (i.e. relative area of the muscle occupied by type I fibres) or the ratio describing the size of the type I fibre relative to that of the type II. Men had larger fibres than women, for each fibre type and at both sampling sites. In the men, each fibre type was of a similar mean size, whereas in the women the type I fibres were considerably larger than both the type IIA and type IIB fibres, with no difference between the latter two. In both regions of the erector spinae there was no difference between men and women for the proportion (%) of a given fibre type, but the percentage type I fibre area was significantly higher in the women. The erector spinae display muscle fibre characteristics which are clearly very different from those of other skeletal muscles, and which, with their predominance of relatively large type I (slow twitch) fibres, befit their function as postural muscles. Differences between thoracic and lumbar fascicles of the muscle, and between the muscles of men and women, may reflect adaptive responses to differences in function. In assessing the degree of any pathological change in the muscle of patients with low back pain, it seems clear that (1) sex cannot be disregarded and (2) 'atrophied' (using the criteria from other muscles) type II fibres are not necessarily abnormal for the erector spinae, particularly in women.

Adult↗
PubMed2006

A novel micro tensile tester with feed-back control for viscoelastic analysis of single isolated smooth muscle cells.

A novel micro tensile tester was developed to measure the viscoelastic properties of single isolated cells. A specimen cell was held with two glass micropipettes, the tips of which were coated with a urethane resin adhesive. One pipette was rigid and fixed in position, and the other was deflectable and could be moved by a laboratory-made piezoelectric actuator to stretch the specimen. The actuator was made of an originally designed lever mechanism which can magnify the deformation of conventional piezoceramic actuator and allowed for sufficient displacement up to 150 microm. The distance between the two pipette tips was obtained by real-time image processing and kept constant following stepwise stretching with an accuracy of +/-0.1 microm by changing the voltage applied to the piezoceramics under feed-back control. The force applied to the cell was measured by the deflection of a cantilever part of the deflectable pipette. The stress relaxation test was performed for cultured rat aortic smooth muscle cells. The cells were stretched by 75% and their length was kept constant. Viscoelastic analysis with a standard linear solid showed that the relaxation time constant of the isolated smooth muscle cells was 250+/-42 s (n=8, mean+/-S.E.M.) which was over six times longer than that reported for vascular endothelial cells and fibroblasts.

Animals↗
PubMed2004

Muscular and centre of pressure response to sudden release of load in symmetric and asymmetric stoop lifting tasks.

Sudden changes in load during asymmetric lifting may be associated with a particularly high risk of loss of balance and spinal injury. Centre of pressure (COP) motions and electromyographic responses of trunk and lower limb muscles were studied in 10 normal male volunteers during sudden release of 20, 40, 60 and 80N stoop lifting loads in symmetric and asymmetric postures. Similar overall COP responses and muscular response strategies to sudden release of load were seen in both postures, although the asymmetric posture showed a larger medio-lateral COP displacements and greater co-contraction asymmetries. While sudden release of load in asymmetric stoop lifting does not seem to involve a greater risk of fall than symmetric lifting, the muscular response results in more complex and asymmetric loading of the trunk, indicating greater localised segmental loading and therefore increased risk of tissue injury.

Abdominal Muscles↗