An adjunct to manipulation in acute low-back pain associated with muscle spasm.
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Back Pain↗
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[Muscle abnormalities on the back of the hand and their differentiation from soft-tissue tumors].
Anomalous muscles at the hand and forearm are described in several studies. They may be confused with ganglia or with other soft-tissue tumours. Two rare cases of atavistic muscles in the area of the back of the hand are described which caused intense pain of the wrist during some months. During the operation an enlongated muscle directly below the extensor tendon, was found which was covered by the extensor retinaculum. It is an extensor digiti brevis manus, which exists in amphibia and is replaced in man by the long tendonous part of the extensor digitorum.
Adult↗
[Musculature as a source of back pain].
Lumbar muscle function is considered to be an important component of chronic low back pain (CLBP). Many studies have documented compromised muscle function in patients with CLBP. Although the mechanism associating muscle insufficiency to CLBP is not clearly understood, it is commonly held that the passive tissues of the spine are increasingly stressed with increasing functional muscle insuffiency. Functional instability of the spine plays a major role in the development of back pain. During the last few years, objective evaluation of the fatigue of back muscles by surface electromyography (EMG) with quantitative spectral techniques, evaluation of fibre type and size of the back muscles and quantifying of postural control of the lumbar spine during different tasks documented the failure of the spine in CLBP patients by a deficit of motor control more objectively. Besides this deficit, many patients show severe psychosocial problems and fear-avoidance beliefs. On this basis, treatment of CLBP with active rehabilitation, which includes educational, psychological, and social components along with the therapeutic exercises, has been increasingly advocated during recent years.
Back Pain↗
An electromyographic study of the trapezius muscle.
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Back↗
Water and electrolyte changes in skeletal and cardiac muscles of rats during prolonged hypokinesia.
The objective of this study was to show that hypokinesia (diminished movement) could affect differently water and electrolyte content in muscles having minimum differences in their function and morphology. To this end, we studied water and electrolyte content in skeletal and cardiac muscles, fluid excretion, electrolyte absorption, and electrolyte levels in plasma, urine and feces of rats during prolonged hypokinesia (HK). Studies were conducted on one-hundred-twenty-six 13-weeks old male Wister rats during a pre-hypokinetic period and a hypokinesia period. Animals were equally divided into two groups: vivarium control rats (VCR) and hypokinetic rats (HKR). Hypokinetic animals were kept in small individual cages which restricted their movements in all directions without hindering food and water intake. Control rats were housed in individual cages under vivarium control conditions. Sodium (Na+) and potassium (K+) absorption, electrolyte and water content in cardiac muscles (right and left ventricle), thigh extensor (quadriceps femoris muscle) and long muscle of the back (biceps femoris muscle), urine volume, and electrolyte levels in plasma and urine and feces did not change in VCR when compared to their pre-hypokinetic levels. The absorption of Na+ and K+, water and electrolyte content in cardiac and skeletal muscles decreased significantly, while urine volume, plasma electrolyte levels and urine and fecal electrolyte excretion increased significantly in HKR compared with their pre-HK values and with their respective vivarium control (VCR). Water and electrolyte content decreased more significantly in skeletal than in cardiac muscles. Water and electrolyte levels decreased more in the thigh extensor and in the right ventricle than in the long muscle of the back, the left ventricle or the septum. Muscles suffering from higher water and electrolyte loss against the background of lower water and electrolyte content show lower water and electrolyte deposition. Lower electrolyte and water content in skeletal than in cardiac muscle shows that water and electrolyte content decreases more in skeletal than cardiac muscles. Skeletal muscle showed lower water and electrolyte content than cardiac muscle indicating that the risk for decreased muscle water and electrolyte content is inversely related to the muscle function and morphology, i.e., the more weight-bearing supporting function and morphology muscles have, the higher the risk for lower muscle water and electrolyte content. It was concluded that the greater muscle function and morphology, the lower electrolyte and water deposition, the higher water and electrolyte losses, and the lower water and electrolyte content.
Animals↗
Back extensor and psoas muscle cross-sectional area, prior physical training, and trunk muscle strength--a longitudinal study in adolescent girls.
The association between physical training, low back extensor (erector spinae plus multifidus muscles) and psoas muscle cross-sectional areas (CSA) and strength characteristics of trunk extension and flexion were studied in adolescent girls. A group of athletes (n = 49) (age range 13.7-16.3 years) consisting of gymnasts, figure skaters and ballet dancers was age-matched with non-athletes (n = 17) who acted as a sedentary control group. The CSA of psoas muscles and multifidus plus erector spinae muscles were measured from lumbar axial images by magnetic resonance imaging. Maximal trunk extension and flexion forces were measured in a standing position using a dynamometer and trunk musculature endurance was evaluated using static holding tests. When CSA were adjusted with body mass, the athletes showed significantly greater CSA in both muscles studied (psoas P < 0.001; erector spinae plus multifidus P < 0.05) than the non-athletes. The athletes also had a greater absolute psoas muscle CSA (P < 0.01) and trunk flexion force (P < 0.01) compared to the controls. When the forces were expressed relative to body mass, the athletes were superior both in trunk flexion (P < 0.001) and extension (P < 0.001). There was a significant correlation between muscle CSA and strength parameters, but the force per muscle CSA did not differ significantly between the athletes and the non-athletes. In addition, the athletes showed a better body mass adjusted muscle endurance in trunk flexion (P < 0.05) than the non-athletes. Our study indicated that regular physical training enhances trunk musculature hypertrophy, force and endurance in adolescent girls, and that there is an association between muscle CSA and strength parameters.
Adolescent↗
CT imaging of trunk muscles in chronic low back pain patients and healthy control subjects.
Increasing documentation on the size and appearance of muscles in the lumbar spine of low back pain (LBP) patients is available in the literature. However, a comparative study between unoperated chronic low back pain (CLBP) patients and matched (age, gender, physical activity, height and weight) healthy controls with regard to muscle cross-sectional area (CSA) and the amount of fat deposits at different levels has never been undertaken. Moreover, since a recent focus in the physiotherapy management of patients with LBP has been the specific training of the stabilizing muscles, there is a need for quantifying and qualifying the multifidus. A comparative study between unoperated CLBP patients and matched control subjects was conducted. Twenty-three healthy volunteers and 32 patients were studied. The muscle and fat CSAs were derived from standard computed tomography (CT) images at three different levels, using computerized image analysis techniques. The muscles studied were: the total paraspinal muscle mass, the isolated multifidus and the psoas. The results showed that only the CSA of the multifidus and only at the lowest level (lower end-plate of L4) was found to be statistically smaller in LBP patients. As regards amount of fat, in none of the three studied muscles was a significant difference found between the two groups. An aetiological relationship between atrophy of the multifidus and the occurrence of LBP can not be ruled out as a possible explanation. Alternatively, atrophy may be the consequence of LBP: after the onset of pain and possible long-loop inhibition of the multifidus a combination of reflex inhibition and substitution patterns of the trunk muscles may work together and could cause a selective atrophy of the multifidus. Since this muscle is considered important for lumbar segmental stability, the phenomenon of atrophy may be a reason for the high recurrence rate of LBP.
Adult↗
[Anthropomorphology of the splenius muscles].
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Back↗
[Masticatory muscle activity during exertion of the back].
PURPOSE: The lower jaw is considered to be fixed during body exercise. However, its mechanism remains to be elucidated. The present study investigated masticatory muscle activity during of the back. METHODS: The subjects were 9 healthy dentulous patients. The maximum back strength of the patients was measured with a back-dynamometer. Muscle activities of the temporal, masseter and digastric muscles during exertion of the back and mastication of peanuts were measured. Muscle activities of the temporal and masseter muscle during maximum voluntary clenching and that of the digastric muscles during exertion of resistance against forced mouth opening were also measured, and maximum voluntary muscle activities were obtained. The relative percentage of each masticatory muscle against maximum voluntary activity was calculated from the data obtained, and muscle activities during exertion of the back, mastication of peanuts and maximum muscle activity were compared. RESULTS: Muscle activities of the temporal, masseter and digastric muscles during exertion of back muscles against maximum voluntary muscle activity were 32.1%, 26.4% and 97.4% respectively. Muscle activities of these muscles during mastication of peanuts against maximum voluntary muscle activity were 40.7%, 36.0% and 17.3% respectively. CONCLUSIONS: Muscle activities during exertion of the back were 30% in the temporal and masseter muscle, and approximately 100% in the digastric muscles. The result suggests that the digastric muscles play a key role in fixing the mandible in all masticatory muscles including jaw-opening and closing muscles. People exert back strength not only in sports but also in daily life. This study demonstrates the stronger involvement of the digastric muscles in fixation of the mandible during exercise than during strong clenching. The results are of interest in terms of mandibular position, occlusal contact and the load on the temporomandibular joint (TMJ) since there is no wide mouth opening.
Adult↗
The site of reattachment of the extraocular muscle following hang-back recession.
The use of "hang-back" suspensions has been shown to be an effective means of weakening rectus muscles. The exact position where the muscle reattaches to the globe has, however, been questioned. We performed eight large hang-back recessions on the rectus muscles of cynomolgus monkeys. Eight weeks postoperatively the attachment sites were determined by reexploration. Six of the recessions were within 0.5 mm of the intended site. The muscles were found an average of 0.4 mm anterior to the intended position. These results confirm that the muscle reattaches close to the intended location. Eight exaggerated recessions were similarly performed; these were more variable in the site of reattachment. Only three muscles were reattached within 0.5 mm of the intended site. There was a mean forward reattachment of 1.1 mm. Four of the 16 muscles were found reattached by a pseudotendon rather than directly to the sclera.
Animals↗
Muscle strength, task performance and low back load in nurses.
Poor muscle strength, relative to the physical demands of specific jobs, is considered a risk factor for low back pain. To gain an understanding of the underlying mechanisms, this study questioned whether muscle strength was related to task performance and low back load in nursing tasks. Trunk extension, elbow flexion and knee extension strength were therefore measured in 17 nurses. The independent effects of muscle strength on task duration, jerkiness of effort and L5-S1 torque were investigated as the nurses performed several patient handling tasks. Despite a large variation in muscle strength within the subject population, no effect of strength on task duration, jerkiness or L5-S1 torques was observed. In conclusion, poor muscle strength was found not to be related to increased low back load. If 'weaker' nurses were to be at a higher risk, it would be due to a reduced capability to withstand the mechanical load, rather than to an increased mechanical load.
Adult↗
Intra-abdominal pressure increases during exhausting back extension in humans.
The aim of this study was to investigate in humans the effect of maintained spinal load on the intra-abdominal pressure (IAP), low back kinematics and trunk muscle activity. This study consisted of two endurance tests for the low back muscles performed 3 weeks apart. Nine healthy subjects participated in the study. In the first test (upright-test), the subject had to pull with the back muscles at a constant force in an upright position, and in the second test (incline-test), the subject had to resist a constant forward pulling force while standing with a 45 degrees inclination of the back in relation to vertical. The IAP, rate of perceived exertion and electromyogram (EMG) from the erector spinae, iliocostalis lumborum, rectus abdominus and the external and internal oblique muscles were measured using surface electrodes. There was no significant difference in endurance time between the two tests. Both tests showed a significant increase in EMG amplitude with time for all muscles except the erector spinae muscle. A decrease in the median frequency for the erector spinae muscle was found indicating fatigue, and since no increase in EMG amplitude was found a decrease in force output from the muscle must be assumed. The IAP increased significantly during both tests. There was a considerable variation between the subjects in the size of this development, but the pattern was the same for all subjects. In conclusion it was found that trunk extension until exhaustion initiates an increase in the activity of the abdominal muscles and an increase in the IAP as the low back muscles become fatigued.
Abdomen↗
The effect of lumbar back support tension on trunk muscle activity.
OBJECTIVE: Assess the effect of different controlled lumbar back support tightness levels on trunk muscle activity. DESIGN: Two-way repeated measure design assessing lumbar back support tension and submaximal trunk extension moments on trunk muscle electromyographic activity. BACKGROUND: Biomechanical studies on lumbar back supports often use electromyography (EMG) to assess the affect on trunk muscle activity. However, the lumbar back support may alter the electromyographic signal by changing the electrode-muscle distance. METHODS: Subjects performed trunk extensions at three static submaximal extension moment levels (25%, 50% and 75% MVC) while stabilized at the hips and shoulders, with the back support tensioned to three different tightness levels (44.5, 66.7 and 89.0 N) as well as a no-back support condition. RESULTS: Statistical analysis failed to find a significant effect (P</=0.05) of lumbar back support tension on the average normalized EMG across the 10 trunk muscles sampled. CONCLUSIONS: For static experimental tasks, as long as electrodes are protected from direct contact with the back support, studies assessing the effect of lumbar back supports on the trunk muscles via EMG during static tasks are not subject to confounding due to differences in tensions across subjects. RelevanceThe results of this study suggest that variable tensions from previous studies for static exertions with lumbar back supports do not significantly alter the pick-up volume of protected electrodes.
Adult↗
Myofascial origins of low back pain. 2. Torso muscles.
Trigger points (TPs) in muscles of the lower torso associated with the spine are an important cause of low back pain. The quadratus lumborum is the muscle most commonly involved, but TPs located there are often overlooked because of inadequate physical examination techniques. TPs in the lower rectus abdominis refer pain horizontally across the low back, and those in the iliopsoas refer pain in a vertical pattern, parallel to the lumbosacral spine. The pain pattern of TPs in the serratus posterior inferior is noted in the region of the muscle itself.
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Effect of intensive training on the isokinetic strength and structure of lumbar muscles in patients with chronic low back pain.
STUDY DESIGN: This study investigated the effects of the intensive physical rehabilitation program on the trunk and knee extensor muscles in patients with chronic low back pain. At baseline and after 3 months, strength was measured and muscle biopsies were taken. OBJECTIVES: To evaluate the effects of strength exercises on the structure of back muscles. SUMMARY OF BACKGROUND DATA: Rehabilitation designed for chronic low back pain patients improves trunk muscle strength, mobility of the spine, and the patients' functional capacity. The effects of such programs on the structure of back muscles have not been reported previously. METHODS: Thirty patients with chronic low back pain volunteered to participate in the study. Biopsies were taken from the multifidus and vastus lateralis muscles. The sizes of Types 1 and 2 muscle fibers were measured. The peak-torques of isokinetic trunk and knee extension were determined at two different angular velocities. RESULTS: Strength increased by 19-22% (P < 0.05) in trunk extension and by 7-11% (P < 0.05) in knee extension. Type 1 fibers maintained their pre-exercise size. The size of Type 2 muscle fibers in men increased by 11% (P < 0.05) in the multifidus and by 8% (P < 0.05) in the vastus lateralis. In women, the corresponding increases were 11% (P = 0.16) and 11% (P < 0.05). The correlation between the size of Type 2 muscle fibers in the multifidus and the strength of trunk extension improved, especially in men at follow-up. CONCLUSIONS: The results of the present study suggest that training with maximal or submaximal effort may reverse the selective atrophy of Type 2 fibers in the multifidus muscles in men. Intensive training also can significantly increase the trunk extension strength in women, but women may need a longer training period than men to achieve significant structural changes in their back muscles.
Adult↗
The alteration of extraocular muscle arc after hang-back recession in animal experiments.
We did an animal experimental study to investigate the extraocular muscle arc after hang-back recession on horizontal rectus muscles of five dogs. Two tiny sutures using 8-0 nylon were made on the sclera 8-10 mm posterior to the muscle insertion along the upper and lower margins of the right lateral rectus and left medial rectus to compare the altered muscle arc with the original muscle arc. Hang-back recession was performed on the horizontal rectus muscles and three months later we investigated the change in the muscle arc. Four of the 10 muscles operated showed no change, four were displaced upward (mean +/- SD; 1.00 +/- 0.16 mm) and two were displaced downward (1.00 +/- 0.00 mm). The average displacement was 0.60 +/- 0.52 mm. The alteration of muscle arc after hang-back recession thus seems insignificant.
Animals↗
Muscular balance, core stability, and injury prevention for middle- and long-distance runners.
This article is intended to provide an understanding of the importance of core musculature to runners and to offer exercises that will help them achieve desired mobility, stability, muscular balance, and neuromuscular control. Please see Table 1 for an example of how to incorporate these exercises into a periodized training program. It is highly recommended, however, that athletes consult a skilled practitioner to address individual needs and maximize results from a program of this nature.
Abdominal Muscles↗
Electromyographic study of the latissimus dorsi muscle.
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Electromyography↗