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PubMed2001

Changes in motor planning of feedforward postural responses of the trunk muscles in low back pain.

Changes in trunk muscle recruitment have been identified in people with low-back pain (LBP). These differences may be due to changes in the planning of the motor response or due to delayed transmission of the descending motor command in the nervous system. These two possibilities were investigated by comparison of the effect of task complexity on the feedforward postural response of the trunk muscles associated with rapid arm movement in people with and without LBP. Task complexity was increased by variation of the expectation for a command to either abduct or flex the upper limb. The onsets of electromyographic activity (EMG) of the abdominal and deltoid muscles were measured. In control subjects, while the reaction time of deltoid and the superficial abdominal muscles increased with task complexity, the reaction time of transversus abdominis (TrA) was constant. However, in subjects with LBP, the reaction time of TrA increased along with the other muscles as task complexity was increased. While inhibition of the descending motor command cannot be excluded, it is more likely that the change in recruitment of TrA represents a more complex change in organisation of the postural response.

Adaptation, Physiological↗
PubMed1976

A fresh look at the intrinsic muscles of the back.

The surgical anatomy of the intrinsic muscles of the back is easy to remember if the approach is systematic. There is a plan to the arrangement which can be easily learned. Without such a plan, the area will always remain a "no-man's land" for physicians and surgeons, even those who deal with many back problems.

Back↗
PubMed1996

The influence of low back pain on muscle activity and coordination during gait: a clinical and experimental study.

Chronic low back pain (CLBP) is a major clinical problem with a substantial socio-economical impact. Today, diagnosis and therapy are insufficient, and knowledge concerning interaction between musculoskeletal pain and motor performance is lacking. Most studies in this field have been performed under static conditions which may not represent CLBP patients' daily-life routines. A standardized way to study the sensory-motor interaction under controlled motor performances is to induce experimental muscle pain by i.m. injection of hypertonic saline. The aim of the present controlled study was to analyze and compare electromyographic (EMG) activity of and coordination between lumbar muscles (8 paraspinal recordings) during gait in 10 patients with CLBP and in 10 volunteers exposed to experimental back muscle pain induced by bolus injection of 5% hypertonic saline. When the results are compared to sex- and age-matched controls, the CLBP patients showed significantly increased EMG activity in the swing phase; a phase where the lumbar muscles are normally silent. These changes correlated significantly to the intensity of the back pain. Similar EMG patterns were found in the experimental study together with a reduced peak EMG activity in the period during double stance where the back muscles are normally active. Generally, these changes were localized ipsilaterally to the site of pain induction. The clinical and experimental findings indicate that musculoskeletal pain modulates motor performance during gait probably via reflex pathways. Initially, these EMG changes may be interpreted as a functional adaptation to muscle pain, but the consequences of chronic altered muscle performance are not known. New possibilities to monitor and investigate altered motor performance may help to develop more rational therapies for CLBP patients.

Adult↗
PubMed1995

Lactate metabolism and hypocarbic hyperventilation. An experimental study in piglets.

Hyperventilation has been reported to increase blood lactate levels. Uncertainty exists as to whether high lactate levels are caused by increased peripheral release or decreased hepatic uptake. Seven piglets were investigated during controlled normoventilation and 13 piglets during controlled hyperventilation. Blood was drawn from catheters in the femoral artery and vein and in the hepatic vein. Blood flow was measured in the femoral artery by an electromagnetic flow meter and in the splanchnic area by indocyanine green extraction. In addition, repeated muscle biopsies from the hind limb and back muscles were taken. The mean PaCo2 was 5.4 in the normoventilated and 3.5 kPa in the hyperventilated group. The average hind limb oxygen uptake was the same in both groups. The arterial blood lactate concentration was significantly higher (P = 0.03) in the hyperventilated group (2.6 mmol.l-1) as compared to the normoventilated group (1.5 mmol.l-1). However, the release of lactate from the hind limb, and the muscular content of lactate were the same in both groups. Similar and unchanged skeletal muscle contents of glucose-6-phosphate, fructose-1,6-diphosphate, alpha-glycerophosphate, pyruvate, citrate and ATP were recorded in both groups. The splanchnic region did not take up or release lactate at normal PaCO2, but released lactate after 120 minutes of hyperventilation. The results indicate that the increased concentration of lactate during hypocarbic hyperventilation was not caused by an increased peripheral release from the skeletal muscles of the pig but could be caused by an altered splanchnic turn-over of lactate.

Adenosine Triphosphate↗
PubMed2000

[Lysosomal glycogen storage disease with normal acid maltase (Danon) without apparent cardiomyopathy and mental retardation].

A 29-year-old male who had a past history of mild ECG abnormality of arrhythmia at the age of 14 years, was referred to our hospital because of elevated serum creatine kinase (CK) level. He had never been aware of muscular weakness nor cardiac symptoms. Neurological examination revealed normal muscle strength of all extremities except marked back muscle weakness. He had normal intelligence. On laboratory examination, serum AST, ALT, LDH, aldolase, CK and myoglobin levels were elevated. Both lactate and pyruvate levels were normally responded after an ischemic exercises test. Acid maltase activity was normal in white blood cells. A muscle biopsy obtained from rectus femoris muscle revealed vacuolar myopathy with mildly increased PAS positive material. On electron microscopy, there were autophagic vacuoles scavenging glycogen particles and cytoplasmic debris, and sarcolemmal indentation, compatible with the findings of lysosomal glycogen storage disease with normal acid maltase. This patient had unusual clinical features of absent mental retardation and no apparent cardiomyopathy. Accordingly, mental retardation is probably not necessary to see later onset of cardiac muscle involvement.

Adult↗
PubMed2006

Changes of low back pain after vascular reconstruction for abdominal aortic aneurysm and high aortic occlusion: a retrospective study.

BACKGROUND: The purpose of the present study is to clarify the influence of acute and chronic interruption of blood flow from lumbar arteries as well as the influence of vascular reconstruction on low back pain, back muscles, and lumbar discs. METHODS: Subjects were 34 patients with AAA in whom vascular reconstruction was performed. A second group was comprised of 9 patients with HAO. The presence of low back pain before surgery and at follow-up examination was retrospectively examined in the AAA group and the HAO group to investigate postoperative changes. The CSA and degeneration of the multifidus muscle and the lumbar discs on magnetic resonance imaging were assessed in the AAA group and control group. RESULTS: Low back pain, significant atrophy, or degeneration of the multifidus muscle or degeneration of the lumbar disc did not newly develop after surgery in the AAA group. These results indicated that acute interruption of lumbar arteries did not induce the development or deterioration of low back pain and organic changes in the back muscles or lumbar discs. The frequency of low back pain before surgery was significantly higher in the HAO group than that in the AAA group. However, the frequency of low back pain after surgery did not differ significantly between the 2 groups because low back pain in the HAO group was improved after surgery. CONCLUSION: The finding that low back pain was improved by merely performing treatment for the vascular system might provide support for the presence of vascular backache.

Acute Disease↗
PubMed1996

Correlation of trunk muscle strength with age in children 5 to 18 years old.

OBJECTIVE: To determine the correlation of trunk muscle strength with age in children and the effect of gender on changes in trunk muscle strength. MATERIAL AND METHODS: Strength of the back extensors and back flexors was evaluated in 137 healthy boys and 109 healthy girls who were 5 to 18 years old. Anthropometric determinations of height and weight were done in all study subjects. Maximal back muscle strength was measured with an isometric dynamometer (BID-2000). Standardized positioning techniques were used to allow comparison with the follow-up evaluations. RESULTS: Regression analysis revealed significant increases in trunk strength with increasing age; the strength of the boys began diverging from that of the girls at age 9 to 10 years. Back extensor strength also increased with increasing height and weight, and expected differences were noted between boys and girls. Strength levels ranged from 80 to 774 newtons (18 to 174 lb). Mean back extensor strength in 2-year age intervals ranged from 153 newtons (34.4 lb) in girls 5 to 7 years old to 504 newtons (113.3 lb) in boys 16 to 18 years of age. (Each newton is equal to 0.2248 lb.) CONCLUSION: Results of this study demonstrated that age, height, and weight are all important predictors of trunk strength in children, and the effects of these factors are modulated by gender.

Adolescent↗
PubMed2006

[A histological innovative study of Balb/c mouse tooth germ transplanted to nude mouse in vivo].

PURPOSE: To observed the changes of the developed mouse's dental germs after transplanting into nude mouse and find some theoretical foundation for establishing an innovative experimental model. METHODS: Eight tooth germs from four 5th day postnatal Balb/c mice were transplanted to the back muscles of the adult nude mice. At seventh and fourteenth day after grafting, the germs were collected, fixed, demineralized, dehydrated, and embedded in wax. Serial sections of 5 microm thick were made following the routine methods, stained with haematoxylin-eosin dying solution, and observed under a light microscope. The mandibular first molars were taken out from the 12th and 19th day postnatal mouse. Serial sections of 5 microm thick were made following the routine methods, then compared with the germs after graft. RESULTS: All implantations were located in the superficial muscles with abundant capillary vessels. The dental germs could further developed after grafting under the microscope, but slower than dental germs self-development. The layer of dentin was thin, plenty of dentin with disorganized dentin tubule formed after grafting. Although the location of Hertwig's epithelial root sheath hardly moved, the roots developed further. The floor of pulp chamber could form and the pulp chambers were shrinking. The degree of calcification in the area of root increased very clearly. The inflammatory reaction was found at 7th day while hardly noted at 14th day after grafting. CONCLUSIONS: It suggests that late development of mouse tooth germs could further develop after heterotopic transplantation within the superficial muscles of the nude mouse. This model is useful for study of tooth root development in short time.

Animals↗
PubMed2006

Cut-points to prevent low back injury due to force exertion at work.

Force exertion is related to low back injuries (LBI). This paper critically reviews the literature concerning cut-points for back force exertion, presents available guidelines in a concise manner, and identifies areas that need further research. The studies reviewed were grouped according to the criteria used to set the cut-point values. Most often cut-points differ than concur. The approach considering physiological, psychophysical, epidemiological, and biomechanical aspects of back force exertion meets the most known criteria and presents the lowest common denominator of instantaneous load for lifting tasks. Further experimental and epidemiological studies in peak load and cumulative exposure are necessary. Compound indices should also be developed for pushing, pulling, and carrying. Future indices should consider electromyographically determined fatigue, differential viscoelastic properties of tissues, aging, and the cross sectional area of back muscles. We hope that this paper contributes to a more systematic appraisal of back force exertion at work.

Alberta↗
PubMed1981

[Electromyographic validation of exercise for physical conditioning].

This study attempted to investigate on ten male subjects the intensity of muscular activity during the execution of various physical fitness exercises. Each subject executed thirteen exercises of different types which were selected because of their popularity in physical fitness programs. The various exercises involved muscles of the shoulder, elbow, knee and hip joints as well as abdominal and back muscles. The electrical activity of four muscles for each joint or muscular area was investigated by surface electromyography. The statistical analysis showed that the various exercises solicitated the participation of the same muscles at a given joint or muscular area. However, the intensity of solicitation, varied significantly between the various exercises. The results imply that the selection of various exercises should be carefully considered by physical fitness instructors.

Abdominal Muscles↗
PubMed1998

MyoD and Myf-5 define the specification of musculature of distinct embryonic origin.

Mounting evidence supports the notion that Myf-5 and MyoD play unique roles in the development of epaxial (originating in the dorso-medial half of the somite, e.g. back muscles) and hypaxial (originating in the ventro-lateral half of the somite, e.g. limb and body wall muscles) musculature. To further understand how Myf-5 and MyoD genes cooperate during skeletal muscle specification, we examined and compared the expression pattern of MyoD-lacZ (258/2.5lacZ and MD6.0-lacZ) transgenes in wild-type, Myf-5, and MyoD mutant embryos. We found that the delayed onset of muscle differentiation in the branchial arches, tongue, limbs, and diaphragm of MyoD-/- embryos was a consequence of a reduced ability of myogenic precursor cells to progress through their normal developmental program and not because of a defect in migration of muscle progenitor cells into these regions. We also found that myogenic precursor cells for back, intercostal, and abdominal wall musculature in Myf-54-/- embryos failed to undergo normal translocation or differentiation. By contrast, the myogenic precursors of intercostal and abdominal wall musculature in MyoD-/- embryos underwent normal translocation but failed to undergo timely differentiation. In conclusion, these observations strongly support the hypothesis that Myf-5 plays a unique role in the development of muscles arising after translocation of epithelial dermamyotome cells along the medial edge of the somite to the subjacent myotome (e.g., back or epaxial muscle) and that MyoD plays a unique role in the development of muscles arising from migratory precursor cells (e.g., limb and branchial arch muscles, tongue, and diaphragm). In addition, the expression pattern of MyoD-lacZ transgenes in the intercostal and abdominal wall muscles of Myf-5-/- and MyoD-/- embryos suggests that appropriate development of these muscles is dependent on both genes and, therefore, these muscles have a dual embryonic origin (epaxial and hypaxial).

Abdominal Muscles↗
PubMed2003

Back strength cannot be predicted accurately from anthropometric measures in subjects with and without chronic low back pain.

OBJECTIVES: (1) To develop a multiple regression equation using anthropometric measurements to predict back strength and (2) to estimate the effect of practice on the back strength results and back strength predictions. DESIGN: Comparative study with repeated measures performed on three days. BACKGROUND: The assessment of back muscle relative endurance (% maximal strength) requires the measurement of maximal back strength which is problematic with low back pain patients. METHODS: The back strength (L5/S1 static extension moment), age and 26 anthropometric parameters were obtained from 83 male volunteers [42 healthy subjects and 41 chronic low back pain patients] aged between 20 and 60 years. A subsample of 20 healthy subjects and 20 patients were assessed through three days of testing to evaluate the variations of back strength with practice. RESULTS: The final regression model (n=42 healthy subjects) explained 39% of the variance in back strength. Back strength increased with practice (Day1<Day2 & 3) for both healthy and patients groups. However, the error of prediction of back strength derived from the regression model showed a significant improvement with practice for the patients only. CONCLUSIONS: Back strength cannot be predicted from simple anthropometric measures without important errors. The decrease of the error of prediction obtained for the patient group is indicative of a decreasing influence of psychological factors that are independent of motor learning because the effect of motor learning would have occurred on both groups if present. RELEVANCE: The prediction of back strength would be useful to determine (1) the relative force level of a given exercise or (2) the preinjury back strength. Unfortunately, anthropometric measurements are not enough good predictors of back strength.

Adult↗
PubMed1981

Surgical technique of hemipelvectomy in the lateral position.

Hemipelvectomy is most frequently indicated for sarcoma of the upper thigh, hip, or pelvis. With the patient in the lateral position the incision is made through the anterior abdominal wall, and the iliac vessels are dissected free and divided just distal to the aortic bifurcation. The multiple visceral branches of the internal iliac vessels are divided and ligated to expose the sacral nerve roots deep within the pelvis. The posterior skin flap is dissected free and the gluteus maximus muscle severed from its origin on the sacrum. Back muscles are detached from the wing of the ilium and the psoas muscle with accompanying obturator and femoral nerves is divided. The pelvis begins to open as the symphysis pubis is divided. Next the sacral nerve roots are divided and anterior capsule of the sacroiliac joint. The muscles and ligaments of the pelvic floor are severed including the urogenital diaphragm, levator ani muscle, sacrotuberous ligament, and sacrospinalis ligament. The specimen is released by severing the sacroiliac joint posteriorly. The operative defect is closed by suturing gluteal fascia to inguinal ligament over suction drains.

Amputation, Surgical↗
PubMed1989

Relationship of muscle strength of back and upper extremity with level of physical activity in healthy women.

The objective of this study was to evaluate any correlation between the muscle strength of the upper extremity (appendicular muscles) and that of the back extensors (axial muscles) in postmenopausal women. Back extensor strength and power grip of the dominant hand were measured in 68 healthy postmenopausal women. The level of physical activity was determined according to a scale (score, 0-18) that considered vocational and avocational activities. Statistical analysis demonstrated a significant positive correlation between back extensor strength and power grip (r = 0.46, P less than 0.001) and back extensor strength and level of physical activity (r = 0.37, P less than 0.002). The correlation between level of physical activity and power grip was much less significant (r = 0.25, P less than 0.05) than that between physical activity and back strength. These data suggest that, in healthy individuals, stronger grip may also indicate stronger back extensor muscles. They also demonstrate that physical activity contributes significantly to the back extensor strength and, to a lesser degree, to the strength of the upper extremities.

Aged↗
PubMed1997

Electromyographic amplitude and frequency changes in the iliocostalis lumborum and multifidus muscles during a trunk holding test.

BACKGROUND AND PURPOSE: Muscle endurance is an important variable to measure in the assessment of back muscle function. This study investigated the electromyographic (EMG) activity and fatigue patterns of iliocostalis lumborum and multifidus muscles during a trunk holding test. SUBJECTS: Sixteen male subjects (mean age = 24.2 years, SD = 4.2, range = 20.6-31.9) without low back pain or known pathology were recruited in the study. METHODS: Surface EMG electrodes were used to record the activity of iliocostalis lumborum and mutifidus muscles during a 60-second isometric contraction. To reflect the activity level and fatigue rate of the muscles. EMG amplitude (root mean square [RMS] values) and a frequency variable (median frequency [MF]) were measured. RESULTS: The multifidus muscle displayed a higher level of activity, initial MF, and normalized MF slope than did the iliocostalis lumborum muscle. There was no difference, however, in the normalized RMS slope between the two muscles. The correlations between the normalized MF slope and the RMS slope of the two muscles were nonsignificant. CONCLUSION AND DISCUSSION: This study shows that monitoring frequency changes of the EMG signals may enable therapists to quantify the fatigue changes of individual muscles during the trunk holding test. The higher fatigue rate shown in the multifidus muscle compared with the iliocostalis lumborum muscle may be due to the higher activity level of the multifidus muscle during te trunk holding contraction. This greater activity of the multifidus muscle during the contraction might be explained by the functional differences between these two muscles.

Adult↗
PubMed2004

[Effect of lumbar protective belt on prevention of low back fatigue in personnel during simulated driving].

OBJECTIVE: To observe low back fatigue of subjects before and after simulated driving, and to study the role of the belt used in prevention of low back fatigue of drivers during driving. METHODS: To assess the changes in median frequency (MF), mean power frequency (MPF) of surface electromyogram (SEMG), and flicker frequency, visuognosis persistence of drivers with and without protective belt in simulated driving. RESULTS: There were significant differences in MF [(47.35 +/- 6.07), (39.26 +/- 5.79), (47.21 +/- 6.02), (43.44 +/- 6.26) Hz respectively], MPF [(69.86 +/- 7.08), (59.12 +/- 7.19), (69.86 +/- 7.08), (63.88 +/- 7.49) Hz respectively] between before and after simulated driving without or with the special belt (P < 0.01). But no differences in MF or MPF between without and with the belt before simulated driving were found (P > 0.05). The flicker frequency [(35.64 +/- 2.82), (42.31 +/- 4.68), (35.96 +/- 3.05), (39.79 +/- 3.36) Hz], visuognosis persistence (65.77% +/- 3.94%, 56.83% +/- 5.68%, 65.88% +/- 3.92%, 62.27% +/- 2.91%) had some changes too. CONCLUSION: Simulated diving could induce fatigue of back muscle in drivers. However, the protective belt can effectively prevent low back fatigue of drivers in simulated driving.

Adult↗
PubMed2007

Truncus endurance, hip and ankle mobility and aerobic fitness in 15-year-old Norwegian adolescents in 1968 and 1997.

This study compared the physical performance of adolescents in 1997 and 1968. The material included 1329 15-year-old Norwegian adolescents in Akershus county in Norway in 1968, and 1105 15-year-old adolescents in the same region in 1997. The investigations were supervised by the same conductor on both occasions, and used identical physical tests. The test battery included dynamic endurance of abdominal and low back muscles, hip flexion, ankle dorsiflexion and aerobic fitness. Compared with 1968, low back extension endurance in 1997 was almost 10% lower in both genders, the endurance of the abdominal muscles was 4.8% poorer among boys and 8.1% higher among girls and the ratio between abdominal and low back extension endurance was 11.8% higher among boys and 26.4% higher in girls. Compared with 1968, hip flexion in 1997 was 8.3% higher in girls, while ankle dorsiflexion and aerobic fitness in boys were 15% and 13.4% poorer, and 4.8% poorer and 2.5% higher in girls, respectively. The data indicate a general decline during one generation in physical performance among boys, a decline in low back endurance, truncus balance and ankle mobility among girls and in a higher abdominal endurance among girls.

Adolescent↗
PubMed1993

Development and tissue-specific distribution of mouse small heat shock protein hsp25.

We have investigated the developmental and tissue-specific distribution of the mouse small hsp25 by immunohistology using an antibody that specifically identifies hsp25. Our analysis shows that the relative amount of hsp25 increases during embryogenesis. Through days 13-20 of embryogenesis, hsp25 accumulation is predominant in the various muscle tissues, including the heart, the bladder, and the back muscles. hsp25 is detectable also in neurons of the spinal cord and the purkinje cells. Furthermore analysis of the closely related alpha, B-crystallin shows that in several tissues, including the bladder, the notochordal sheath and the eye lens both proteins are coexpressed. Our studies demonstrate that mammalian hsp25 accumulation is developmentally regulated during mouse embryogenesis and support the view of an important functional role of small heat shock proteins in normal cell metabolism.

Animals↗