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Biomedical subjects

G L Soderberg

Publications and source records attributed to G L Soderberg.

34 records · Page 2Linked to original sources
PubMed1984

Electromyographic analysis of selected muscles during the lateral step-up exercise.

The purpose of this study was to determine electromyographically if significant differences in level of electrical activity in the vastus medialis, rectus femoris, biceps femoris, and semimembranosus/semitendinosus muscles occurred during the concentric and eccentric phases of a 4- and 8-in lateral step-up exercise. Twenty-nine subjects with no pathological condition of the knees participated in the study. The surface electromyograms obtained were processed by linear envelope detectors and normalized, in percentage, to a maximum voluntary contraction of each subject. Within-muscle differences, step height, and contraction type were tested with a two-way analysis of variance. Results revealed that the average values for muscular activity, depending on the height and direction, ranged from 24 percent to 60 percent for vastus medialis, 8 percent to 23 percent for rectus femoris, 3 percent to 9 percent for biceps femoris, and 4 percent to 9 percent for semimembranosus/semitendinosus muscles. All muscles were significantly more active at the 8-in height than at the 4-in height. The concentric phase produced significantly greater activity (p less than .001) than the eccentric phase at each height except for semimembranosus/semitendinosus muscles, where no significant difference existed. The results of this study are discussed with respect to the limited role that the tested hamstrings and quadriceps femoris muscles play in preventing anterior shear of the tibia during the lateral step-up exercise.

Adolescent↗
PubMed1984

Alterations in ankle dorsiflexion torque as a result of continuous ultrasound to the anterior tibial compartment.

Although considerable documentation of the physiologic effects of ultrasound (US) exists, little information is available concerning direct effects of US on muscle, particularly when the US is applied immediately before muscle performance. The purpose of this study was to determine the effect of continuous US to the anterior tibial muscle compartment on ankle dorsiflexion torque assessed immediately posttreatment, at 30 minutes, and at 60 minutes posttreatment. Seventeen healthy subjects were tested performing isometric contractions at dynamometer velocities of 60 and 180 degrees/sec. Subjects first received either a placebo or a 1.5 W/cm2 15-minute US treatment. One week later, the protocol was repeated with the administration of a second treatment. Analysis of variance showed no significant interactions for time and treatment for any contraction; time, for isometric contraction, was the only significant main effect. Follow-up analyses were all nonsignificant for comparisons of pretreatment to posttreatment and posttreatment to 30- and 60-minute intervals within treatment groups. The study concludes that in spite of known physiologic effects, one treatment of US does not have an immediate or latent effect on peak torque.

Adult↗
PubMed1983

Laser etched bifilar fine wire electrode for skeletal muscle motor unit recording.

To selectively record a limited number of skeletal muscle motor unit action potentials, a bifilar fine wire electrode was developed. Two 8 micrometers wires were braided together, a hook formed, and ends insulated. A round beam, pulsed laser, etched a 5 micrometers piece of insulation from each wire near the hooked end. Bipolar recordings from a select number of skeletal muscle motor units were obtained from these two uninsulated 5 micrometers areas. Reactive and capacitative components for each set of electrodes were measured. These electrodes were selective in recording from 3 to 5 single motor unit action potentials at low isometric tension levels.

Electrodes↗
PubMed1983

Comparison of skeletal muscle motor unit discharge characteristics in young and aged humans.

The purpose of this study was to determine the discharge characteristics of motor unit action potentials. Three decades of aged subjects ranging from 60 to 90 yr of age were compared to a group of 20-35 yr olds. Motor unit behavior was described by the interspike interval (ISI) and expressed statistically as a mean, a floating standard deviation (FSD), and a floating serial correlation (FRHO). The 70- to 79-yr-old group tended to have a slow motor unit discharge rate, an increased variability of discharge (FSD) and a negative serial correlation coefficient (FRHO). All three factors describing motor unit discharge behavior possibly suggest substitution of larger motor units for small motor units normally active at low tensions for the 70-79 age group.

Action Potentials↗
PubMed1983

Ultrasound effects on electroneuromyographic measures in sensory fibers of the median nerve.

The purpose of this study was to clarify the available literature and study the influence of ultrasound on the conduction velocity and amplitude of evoked sensory potentials in the median nerve. Thirteen subjects were assigned to either Experimental or Control Groups for ultrasound or placebo treatments. We compared sensory-nerve conduction velocity in the median nerve after 10 minutes of ultrasound treatment at three intensity levels (0.5, 1.0, and 1.5 W/cm2) with sensory-nerve conduction velocity in the median nerve after 10 minutes of placebo ultrasound treatment (0.0 W/cm2). No significant differences were noted between groups at any of the three ultrasound intensity levels, nor were the interaction effects significant. A hypothetical model, based on the available literature, proposes that ultrasound-induced changes in sensory-nerve conduction velocity may not progress in a direct linear fashion relative to the duration of treatment.

Adult↗
PubMed1983

Muscle mechanics and pathomechanics. Their clinical relevance.

This article reviews pertinent mechanical characteristics of the human musculotendinous unit. Contractile and elastic elements of muscle are discussed, primarily in relationship to their length-tension and force-velocity properties. Evidence from a variety of recent studies of muscle function and dysfunction is presented. Clinical implications for physical therapy practice are discussed, and examples of pathological conditions are cited. A primary conclusion reached is that the degree and duration of muscle elongation are important factors in immobilization and important considerations in therapeutic programs.

Humans↗
PubMed1983

An electromyographic analysis of quadriceps femoris muscle setting and straight leg raising.

Physical therapists routinely advise patients to perform quadriceps femoris muscle setting or straight leg raising or both following knee surgery or trauma from knee injury. Little information exists, however, about the intensity of effort required from knee and hip musculature during the exercises. This study was designed to compare the level of electromyographic activity during maximally resisted straight leg raises with the level during quadriceps femoris muscle setting exercises for the vastus medialis, rectus femoris, gluteus medius, and biceps femoris muscles. Forty healthy young adult men and women performed randomly ordered trials of each exercise in the supine position. Electromyographic activity was recorded from surface electrodes and normalized to values derived from maximal isometric trials. Statistical analysis demonstrated significantly greater (p less than .0001) vastus medialis, biceps femoris, and gluteus medius muscle activity during quadriceps femoris muscle setting. The rectus femoris muscle was significantly more active (p less than .0001) during the straight leg raise. The study demonstrated remarkably different muscle activation levels between the exercises studied and clearly indicates that selection of the exercises needs to be based on the therapeutic objectives.

Adult↗
PubMed1982

An adaptable, multiple plate dynamometer and electromyograph for the study of quadruped postural responses.

An EMG-force measurement system which can be placed inside a sound dampened testing chamber to study subtle postural responses in the standing quadruped is described. The dynamometer is adjustable to accommodate different foot placement strategies and to afford a more natural standing posture. A non-telemeterized method of recording EMG from an unrestrained animal is also discussed.

Animals↗
PubMed1981

Relationship between perception of joint position sense and limb synergies in patients with hemiplegia.

The purpose of this study was to determine if patients with hemispheric brain lesions and subsequent paresis demonstrated a correlation between the perception of joint position sense and the ability to combine component parts of the limb synergies. Twenty-one adult patients with 6-week to 87-month histories of unilateral, hemispheric, paralytic brain lesions were evaluated by each of two tests. The first test evaluated the subject's ability to combine components of the limb synergies. A pilot investigation was performed which established the reliability of the testing instruments. The correlation between the perception of joint position sense and synergy test results, .83, was significant at p less than .01. Implications for therapeutic management of the patient with hemiplegia are discussed.

Adult↗
PubMed1978

A light-emitting diode system for the analysis of gait. A method and selected clinical examples.

The purpose of this study was to design, develop, and test a comprehensive and potentially clinically useful system for the objective evaluation of sagittal-plane motion and temporal and distance factors during gait. A light-emitting diode and a 35 mm single-frame color slide photographic technique were utilized. The method of data collection and reduction produced values that are similar to reports in previous literature. High reliability was shown both within and across investigators testing normal subjects. Across-investigator comparisons when taking angular measurements demonstrated lower reliability. Specific clinical examples are presented to demonstrate the applicability of the light-emitting diode system.

Gait↗
PubMed1978

Electromyographic study of three parts of the gluteus medius muscle during functional activities.

This study was undertaken to determine the onset, duration, and degree of electromyographic activity in the anterior, middle, and posterior segments of the gluteus medius muscle during functional activities. Fine wire electrodes were inserted into each muscle segment. After a triaxial hip electrogoniometer was applied, each of the 10 subjects performed the activities of walking, crawling, stair ascending and descending, shoetying, sitting, and single limb-standing with forward learning. Raw electromyographic records evaluated on the basis of on-off activity provided results showing that the onset, duration, and degree of activity of the three segments was similar for some activities. Results also established that asynchronous activity occurred for selected functional activities, thereby justifying a three-segment conceptual model of the gluteus medius muscle.

Electromyography↗
PubMed1978

Below-knee amputee knee extension force-time and moment characteristics.

This study, utilizing isometric knee extension, was undertaken to determine if significant differences existed between extremities of below-knee amputees and matched normal subjects in minimal time to production of peak force, maximal rate of tension development, and maximal extension moment. Results showed no significant differences for rate of tension development. Significance at the .05 level was established for moments produced by left amputees and their contralateral limb, and right and left limbs of normal subjects. Differences in time to 95 percent of peak force for the amputated leg were also significant when compared to the limb of the matched normal subject. Results indicate that quadriceps tension and rate of tension development are both factors to emphasize in therapeutic programs, particularly for the left knee of the below-knee amputee.

Adolescent↗
PubMed1977

The influence of isometric exercise and passive stretch on hip joint motion.

A method was designed to compare the effects of isometric contractions and passive stretch on modifying joint range of motion in 30 normal men. Subjects were randomly assigned into a control group, a passive stretch group, or an isometric contraction group. Each subject assumed a left sidelying position on the force table. Stabilization was applied to the pelvis and left lower extremity. The cuff, to which the force cable was attached, was applied to the right lower extremity. Force measurements produced by the isometric contractions or passive stretch procedures were stored on computer tape. The results of the mean differences in pelvifemoral angle measurements indicated that both treatment groups significantly increased their range of passive hip flexion with the knee extended when compared to the control group. Comparisons between the two treatment groups indicated that the isometric contraction and passive stretch procedures had significant and similar effects.

Adult↗
PubMedDate not supplied

Muscular function in chronic low-back dysfunction.

The purpose of this study was to use electromyography to determine the level and pattern of muscle activity of the rectus abdominus and T10, L1, and L3 erector spinae muscle in healthy subjects and patients with chronic low-back dysfunction during various postures and activities. Statistically significant differences in erector spinae activities were found between groups for the Valsalva maneuver and for portions of the sit-up exercise. Comparisons between the 4.5-kg and 16-kg lifts completed with bent and straight knees showed few differences during actual lifts, but the patients with chronic dysfunction maintained an increased level of activity when lifts had been completed.

Adult↗