Previously the application of stimuli of 600 Hz at adjustable strength applied to a muscle's nerve has been proposed as a means of reducing the muscle's contraction in spastic conditions, or when combined with a second tetanic stimulation, of limiting contraction to smaller, physiologically more relevant motor units in the paralyzed state. The side-effects on muscle spindles of such stimuli as seen in the cat's gastrocnemius are reported. During stimulation axonal impulses followed faithfully for periods running into minutes. After stimulation, a pause in ongoing firing with a duration dependent on stimulus-train length and a two-phased recovery occurred. Responses to dynamic stretch of the muscle were affected as well. The contractions of intrafusal fibers activated in several ways was seen to strongly offset the depression. In a clinical application, nevertheless, short-lived depression of all proprioceptive modalities following stimulation should be expected, with corresponding disturbance on sensory perception and reflex effects.
The purpose of this study was to ascertain if a relationship existed between plasma somatomedin C (SmC) level, as an indicator of growth hormone secretion, and muscle performance. Eighteen community-dwelling men between the ages of 65 and 80 comprised the sample group. Muscle strength, power and endurance were measured isokinetically on the elbow flexors and extensors and on the knee flexors and extensors. No relationship was found between plasma SmC levels and measures of muscle performance (P greater than 0.05). The limitations of this study as well as suggestions for future studies were discussed. Further research is needed to assess the effects of growth hormone on muscle performance.
Motor unit activity was investigated in the biceps brachii of twelve men during concentric (CC) and eccentric (EC) contractions by means of computer aided intramuscular spike amplitude-frequency (ISAF) histograms and surface EMG frequency power spectral analyses. Simultaneous recordings of the intramuscular and surface EMG signals were made during both types of contractions with the elbow joint angle varying from 30 to 150 degrees in reference to a fully extended position. Results demonstrated that r.m.s. amplitude and mean power frequency of the surface EMG were significantly higher during CC, particularly at shorter muscle length; e.g., 259 vs. 131 microV (p less than 0.01) and 102 vs. 91 Hz (p less than 0.05). The intramuscular spike recordings made at 45, 90 and 135 degrees showed greater motor unit (MU) activities during CC along with the presence of MUs with relatively large spike amplitude. The pooled data on the ISAF histograms revealed significantly greater mean MU spike amplitude and frequency during CC as compared to EC; e.g., 439 vs. 108 microV and 16.1 vs. 13.0 Hz at 135 degrees, respectively. These data suggest that EC is associated with much less pronounced MU recruitment and rate modulation due to economical tension development which might be a result of better utilization of elastic energy, particularly those inherent in the actin-myosin cross bridges and also a favorable length-tension relationship under the present experimental conditions.
Twenty-one attention deficit disorder with hyperactivity and seven autistic children were randomly exposed to negatively ionized and ambient atmospheres under rigorously controlled experimental conditions. The negatively ionized condition did not significantly affect measurements of activity level, impulsivity, reality orientation, destructive/constructiveness, attention, or task performance. Significant results might be obtained if subgroups of known hyperserotoninemic autistic and attention deficit disorder children were exposed to negatively ionized conditions.
The purpose of the present study was to determine whether sincere and faked grip strength measurements could be distinguished from one another by the patterns of measurements obtained for the five handle (hand size) positions of the Jamar dynamometer. Healthy subjects were instructed on different trials to give a sincere, maximal effort or to fake weakness of grip. Results were that the patterns did differ for sincere and fake trials, but not as strongly as expected. The recommendation is made that further research be done using patients with upper extremity injury.
Miniature triaxial shoe-borne load cells are used to analyze the normal and a below knee amputee's gait. The gait of an amputee is studied from first step on a temporary pylon to a final "normal" gait on a permanent prosthesis. The amputee's gait is compared to that of the normal subject. The load cells are an effective method of analyzing normal and abnormal gait. For an amputee, it is possible to identify misalignments from the output of the various load cells. This method may also be useful for identifying and correcting problems in the painful below knee stump. These load cells are further used to compute the center of pressure of a normal subject and a below knee amputee. Analysis of the resulting patterns has been found to be extremely useful as a measure of the subject's functional mobility.
Twenty male college students served as subjects for a study which investigated how artificially-induced ischemia, with and without muscular fatigue, affects the: 1) input/output (IEMG/Force) relationship, and 2) power density spectrum of EMG signals during submaximal static contractions. In the first experiment, subjects maintained constant-force (60% MVC) static handgrip contractions for 55 sec. Following exercise, EMG mean power frequency (MPF) was significantly (P less than 0.05) reduced and EMG amplitude (rmsEMG) was significantly (P less than 0.05) increased. With circulation intact during 5 min recovery, MPF and rmsEMG values returned to pre-exercise levels. With ischemic recovery, MPF remained significantly (P less than 0.05) lower than pre-exercise values, while rmsEMG returned to approximately normal levels. In the second experiment, subjects performed either 3 sec ramp (90 N/sec) or constant-force (40% MVC) contractions immediately before, during the final 3 sec of, and 1, 3, 5 and 10 min after a 10 min tourniquet application. No statistically significant differences (P greater than 0.05) in the IEMG/Force slope coefficients, IEMG/Force ratios or MPF were observed for subjects performing either static ramp or constant-force contractions following temporary ischemia. Results suggest that reduced blood flow may contribute to fatigue-induced EMG changes. However, in the absence of motor activity, ischemia is an insufficient stimulus to cause either increased amplitude or frequency shift of the EMG signal during static contractions.
Visual disability appears to be only one of many visual factors related to traffic accidents. Difficulties in acquisition and selection of necessary visual information from the driving environment seem to be of more significance than has commonly been recognized. Increasing investigation of the visual elements of safe driving environments may be of great benefit to society.
The Association of American Medical College's project panel on the General Professional Education of the Physician (GPEP) and College Preparation for Medicine and its working groups appear to share many values with professionals involved in rehabilitation medicine. The GPEP report stresses that learning about disability or functional status, chronic illness and its impact on the individual, his family and the community, and developing the ability to work as a team with other health professionals are important elements in the education of all physicians.
Fifteen male hemiplegic subjects were tested using the Fugl-Meyer Assessment and Barthel Index to evaluate their level of function. Walking performance using interrupted light photography and postural maneuvers while standing on a force platform were recorded for all subjects. Significant relationships were found among functional assessments, objective measures of walking, postural stability and between sections of the Fugl-Meyer Assessment. The hemiplegic subject's gait was characterized by a lack of symmetry and slow speed. Their area of stability during weight shifting was dramatically smaller than for normal men and was located closer to the non-paretic side. The results of this study lend support to the use of the Fugl-Meyer Assessment and Barthel Index as quantitative measures of hemiplegic patient's function.
Three-months re-education treatment of genuine stress incontinence was given to 26 female outpatients: 22 patients completed the treatment programme and 4 interrupted it for various reasons. The aims of the treatment were both to correct compensatory habits that patients used to conceal or reduce leakage accidents and to give specific education and strengthening of pelvic floor muscles. All patients who completed the three-months treatment definitely improved and 7 were cured. Accordingly a marked reduction or absence of weekly incontinence episodes as well as a reduction of the daily frequency of micturition was observed. On vaginal palpation a clear-cut improvement of pubococcygeous muscle contractility was detectable. Urethral closure pressure profilometry showed significant improvement of functional urethral profile length at rest and of maximal urethral closure present both at rest and during maximal voluntary contraction of the pelvic floor muscles. Micturition cystourethrography, repeated in 15 patients at the end of the treatment, showed a clear-cut improvement of bladder neck suspension defects in all but 2 patients. Follow-up assessments showed that the clinical effects were long-lasting. Possible mechanisms of this re-educative technique are discussed.
To determine the effects of wearing graduated compression stockings (GCS) on the exercise response, twelve high fit males served as subjects in a series of two experiments. The first experiment consisted of six subjects performing two tests of maximal oxygen consumption (VO2 max) on a treadmill with and without GCS. The second experiment consisted of six subjects performing three separate three minute tests on a bicycle ergometer at 110% of their VO2 max. The experimental conditions for the three tests were: GCS worn during the test and recovery (GCS), GCS worn only during the test (GCS-O/O) and no stockings worn during either the test or recovery (NO-GCS). Oxygen consumption (VO2) was measured at rest, throughout the duration of all tests and during recovery in both experiments. Blood samples were obtained at rest and at 5, 15, 30, 45 and 60 minutes post exercise in the first experiment and at rest and at 5, 15 and 30 minutes post exercise in the second experiment for the determination of lactate and hematocrit. The use of GCS in the first experiment resulted in no significant difference in VO2 max, recovery VO2 or plasma volume shifts. Lactate values were lower throughout the duration of the recovery period with the 15 minute values being significantly different with the use of GCS. Significant differences in post exercise blood lactate values were found in the second experiment. The GCS trial resulted in significantly less lactate when compared to the GCS-O/O and the NO-GCS trials. There was no significant difference in post exercise lactate values between the NO-GCS and the GCS-O/O trials. Plasma volume changes were not significantly different among trials. Results of both experiments showed recovery lactate values to be lower with the use of GCS. These lower values are not ascribable to plasma volume shifts but rather appear to be due to an inverse gradient created by the GCS resulting in the lactate being retained in the muscular bed.
At present, it is unclear how caffeine induced alterations in neuromuscular function might affect force production and EMG signal characteristics during isometric exercise. These data suggest that acute caffeine ingestion (7 mg/kg) has no significant effect on force production during a maximal isometric hand grip contraction or endurance during a sustained submaximal contraction. Further, maximal motor unit activation, the relationship between submaximal motor unit activation and subsequent force production, and frequency content of the EMG signal were not significantly altered following caffeine ingestion. These results indicate that although caffeine may be a potential ergogenic aid for some activities, its ingestion may not improve performance in activities requiring strength and/or short-term endurance.
: Theoretical approaches to the understanding of psychological adjustment in spinal cord injury have recently experienced a re-examination which seriously questions the traditional "stage theory" of adjustment. Despite limited empirical validation at best, the stage theory has not only enjoyed an unchallenged popularity amongst rehabilitation professionals but often has been imposed upon new SCI patients as a necessary criterion for hospital discharge. Experienced professionals have also been shown to exaggerate the distress of their SCI patients and these misperceptions tend to progressively worsen with length of clinical experience. The present study replicated and extended this tendency amongst research personnel and their SCI subjects. Staff members tended to over-estimate depression, anxiety, and social discomfort while under-estimating the optimism of their SCI subjects. Recommendations are made for the use of a questionnaire to measure their distress. Also, suggestions are made regarding the potential clinical utility of assessing the contrasting perceptions of distress by SCI patients and significant people in their rehabilitation and social environments.
The aim of this study was to assess the electromyographic (EMG) activity of the middle part of the deltoid and of the supraspinatus muscles in subjects suffering from supraspinatus tendinitis. This experimental group (N = 10) was compared to a control group (N = 10). Each subject performed three isometric contractions for each of four pre- determined levels (5, 20, 35 and 50%) of their maximal voluntary contraction (MVC) during shoulder abduction. These contractions were carried out at angles of 0 degree and 45 degrees of abduction. The EMG signals obtained for each subject were integrated and normalized in a Z score form. Trend analysis, performed on the data of each of the two groups, revealed the existence of a significant (p less than 0.001) linear relationship between the integrated EMG (IEMG) and torque levels for each muscle investigated, at both angles of abduction. Furthermore, in the control group, similar EMG amplitudes were obtained for each muscle at these two angles of abduction. However, in the experimental group, the IEMG of the deltoid muscle showed a significant decrease in activity relative to the activity of the supraspinatus at an angle of 45 degrees of abduction (ANOVA, p less than 0.05). It is suggested that this inhibition of the deltoid reflects a compensatory mechanism. The purpose of this mechanism could be to prevent the compression of the affected supraspinatus tendon between the humeral head and the acromion that could occur while abducting the arm.
Interactions between specific operant conditioning and ongoing treadmill walking have been characterized in several previous investigations of mechanisms that coordinate locomotion. The present study examined a higher walking velocity in which contractile forces and, by inference, reflex behavior, might be more powerful. Two subjects walked on a motor-driven treadmill at 0.90 m/sec. As in past work, at 0.45 m/sec, a conditioning regimen constructed a test operant in the following way. With training, a green light that flashed approximately 200 msec after heel strike on every third step produced, after operant reinforcement, a 100-500 msec electromyographic burst in the rectus femoris (RF) muscle before the end of a 500 msec performance duration. Reinforcement consisted of a tone that sounded after each response and indicated success or failure. Burst durations were shorter than had been typical at a lower treadmill speed, a characteristic that could favor rapid matching of contractile patterns to more rapidly changing conditions. No evidence was gained of interference from stretch reflexes or any other ongoing inborn behavior. The resulting rapid walk was as well coordinated as that seen at lower velocity, to argue for increased emphasis on the role of learning in normal locomotion and to improve pathological walking.
Medical guidelines are presented by which the physician may evaluate a patient for participation in a program of active physical therapy (A.P.T.). A.P.T. system modalities are introduced and defined as: a) isokinetic leg trainer, b) stationary bicycle ergometer, c) outdoor exercise bicycle, and d) Functional Electrical Stimulation (F.E.S.)--Orthosis for ambulation. The physiological responses to these F.E.S. exercise modalities are reviewed. Initial and interim patient evaluations are discussed. The initial patient evaluation includes a history, physical examination, lab tests, and a report summary, all of which culminate in an F.E.S. exercise prescription. The interim patient evaluation is performed for continuation-termination purposes as well as to progress the patient through the various F.E.S. exercise modalities. Specific F.E.S. exercise progression criteria are summarized. The medical criteria are presented with respect to both patient participation in the F.E.S. exercise program and patient monitoring during the exercise itself. Specific medical criteria for patient participation in A.P.T. are organized around eight functional categories: a) level of neurological injury, b) muscular system, c) skeletal system, subdivided into bone criteria and joint criteria, d) cardiovascular system, e) respiratory system, f) urogenital system, g) cutaneous system, and h) psychological system. The medical criteria for patient monitoring during F.E.S. exercise are discussed with respect to: a) cardiovascular monitoring, b) objective patient monitoring, and c) F.E.S. exercise system monitoring. The article concludes with a discussion of informed consent when applied to an emerging treatment modality.
The difficulty in obtaining approval for payment of durable medical equipment by third party payers has impeded the rehabilitation program and discharge planning of many spinal cord patients throughout the country for many years. To gain some insight as to the number and level of patients affected, the kinds of equipment denied, the reasons given for the denial, which third party payers were mostly involved and how the patient and his/her family managed to cope or resolve this problem, a survey was undertaken. Letters were sent to 259 members of the American Spinal Injury Association (ASIA) asking them to list representative cases where requests for equipment deemed necessary were denied. Twenty-eight responses from different institutions were received from sixteen states describing 110 patients and 180 pieces of durable medical equipment denied in 1984 and 1985. Manual wheelchairs, motorized wheelchairs, shower/commode chairs, and environmental control units were the four most common equipment items denied by the third party payers. Government agencies ie., Medicaid, Medicare, Vocational Rehabilitation Departments and State Crippled Children's Services were the most frequent deniers, comprising 54% of the total sample. They were followed by private insurance (31%) and Workman's Compensation (3%). By far, the two most common reasons given for denials were: it was not covered by the insurance policy (38%) and it was not medically necessary (30%). Ninety (90) pieces of equipment (50%) were eventually obtained, most often by charity, or through the patient's family resources.
Kyphosis is commonly associated with ageing and osteoporosis of the spine. This study was conducted to evaluate whether physical fitness and bone mass in post menopausal women, between the ages of 50-60 years, may influence the degree of kyphosis. The level of physical fitness was determined by 1) calculating maximum oxygen uptake, (VO2 max), attained by a graded exercise treadmill test, and 2) evaluating the muscle strength in performing one repetition maximum on the bench press. In vivo neutron activation analysis was used to measure the bone mineral content in the axial skeleton and proximal femurs. It is expressed as Calcium Bone Index (CaBI). The normal range was 1.00 +/- 0.12 (I.S.D.). The degree of kyphosis was measured indirectly by calculation of an index of kyphosis, (I/K), using a surveyor's flexicurve. Individuals with I/K greater than 13 showed a clinically apparent kyphosis. Fit individuals (VO2 max greater than 29 ml/kg/min) had a significantly lower I/K (p less than 0.001) than average persons. Individuals with normal bone mass (CaBI greater than 0.8) also had a significantly lower I/K (p less than 0.05) than those with bone loss. Similarly, subjects who were fit, and had normal bone mass, had a significantly lower I/K (p less than 0.001) than those who were less fit and had bone loss. There was a significant correlation between I/K and VO2 max (p less than 0.02, df 45), I/K and CaBI (p less than 0.05, df 45) and I/K and bench press (p less than 0.05, df 45).(ABSTRACT TRUNCATED AT 250 WORDS)
Thirty-one young women subjects performed four maximal and four submaximal elbow flexion efforts. The strength of each effort was measured using make tests and a hand-held dynamometer. The variability of repeated maximal and submaximal tests was determined by calculating CVs for each subject. Every subject's CV was greater during submaximal than during maximal trials. Furthermore, the mean CV was significantly greater during submaximal trials than during maximal trials. No subject demonstrated a CV greater than 7.5 per cent for maximal trials, but most had CVs greater than 7.5 per cent for submaximal trials. The results suggest that for the subjects tested CVs greater than 7.5 per cent were consistent with feigned weakness. Coefficients of variation above 7.5 per cent were not, however, limited to subjects feigning weakness. Further investigations of strength variability are needed under different conditions before confident judgements can be made about patient performance.
