When a single-muscle learned behavior was superimposed upon natural human treadmill locomotion, in previous work, it operated as a self-contained behavioral unit. The new behavior altered some features, however, of ongoing stepping patterns. These findings prompted broader consideration of how individual muscle actions combine to form large, patterned ensembles. Accordingly, the present experiment constructed a larger, double-muscle learned behavior to see if it would compete with natural treadmill locomotion or combine with it harmoniously. A demanding requirement was made for in-phase bilateral EMG and contraction by rectus femoris (RF), in opposition to its natural out-of-phase interlimb pattern. EMG bursts were controlled, through computer-assisted operant conditioning, by a flash shortly after left heel strike. The new, double ensemble was conditioned rapidly, within 1-6 days, for all four adults. Harmonious stepping continued, for the most part, with little alteration in step cycle timings. Leg positioning was modified appreciably, however, pointing to complex neural mechanisms. The evidence argued that operant conditioning can construct fine-grained behaviors and also participate powerfully across the full range of single- and interlimb coordination.

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.

The purpose of this study is to provide a thorough and comprehensive description of the late onset manifestations of poliomyelitis (PM). In addition, unusual findings, seen in the post-poliomyelitis period, have been presented to further increase awareness of the potential diversity of the problem. The scope of PM sequelae is broad. Following a description of acute PM, the various sequelae are addressed categorically. These include neurologic, vascular, orthopedic, respiratory, sleep and psychologic problems; as well as less commonly recognized maladies. Different theories for PM sequelae have been proposed. Thorough electrodiagnostic testing can frequently confirm or negate the clinical impression. The pathophysiology of vascular problems, as well as the correlation between respiratory involvement, sleep disorders, and hypertension, is reviewed. Orthopedic problems and spinal deformities are discussed. Since overuse weakness is frequently present in these patients, the role of slowly progressive non-fatiguing exercise in their rehabilitation is emphasized. Of significance are the emotional concerns demonstrated by this group of patients. Further considerations include those sequelae not readily recognized in relation to PM. A brief overview of present epidemiologic trends in the United States, and the immunologic effects of vaccination, is presented.

Neurogenic heterotopic ossification is a potential sequela of neurological disorders, especially spinal cord injury and head injury. The etiology is unknown. Clinical, radiologic, and bone scan findings are typical. Complications may threaten function. The differential diagnosis is crucial in its early stages. Treatment options include diphosphonates, non-steroidal anti-inflammatory drugs, and surgery. This article has reviewed the literature on neurogenic heterotopic ossification (HO), soft tissue ossification of neurologic disease, including pathogenesis, histology, presentation, diagnosis, natural history, complications, and current treatments.

The present article summarizes 10 years of experience in head injury rehabilitation at Loewenstein Rehabilitation Center. The goal of rehabilitation in head injured patients consists of returning to work and adaptation to: interpersonal consequences of disability; new affective needs; and capacity to attend to financial, legal and bureaucratic matters. The achievement of these goals goes far beyond neurological boundaries in the ordinary narrow sense and needs a neuropsycho-social approach. Neuropsycho-social rehabilitation in head injury has multidimensional clinical aspects. Two problems should be emphasised: a) gross neurological disability (mono, hemi, para and triplegia) found in the presence of good cognitive function (patients easy to rehabilitate) and b) minor neurological disability found in the presence of gross cognitive impairment (patients not easy to rehabilitate). Posttraumatic epilepsy needs general criteria for its management. It is preferable to wait for the first seizure in order to start anticonvulsant treatment, except for 3 at risk conditions: 1) diffuse bilateral injury 2) prolonged coma, and 3) intracerebral hematoma. The first 3 years is the maximum at risk period. The traumatic syndrome consisting of impaired insight and behaviour disturbances is underdiagnosed owing to the absence of neurological signs. The sleep disturbances accompanying head injury are usually underestimated.

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.

Cutaneo-muscular reflexes with short and long latency excitatory phases following digital nerve stimulation were observed in the first dorsal interosseus muscle of the hand in healthy subjects. The short latency reflex was obtained also with the H-reflex method in the flexor carpi radialis muscle, stimulating the median nerve, with a mean latency (+/- SE) of 15.4 +/- 0.5 ms. The height of the subject correlated with the H-reflex latency. The amplitudes of maximal M-response and maximal H-reflex were higher in athletes than in normals. During weak voluntary contraction of the muscle studied the 50% H-reflex amplitude increased and during passive stretching of wrist flexors the resting amplitude of the 50% H-reflex decreased.

Proprioceptive neuromuscular facilitation (PNF) techniques are often used to induce muscle relaxation and increase joint range of motion (ROM). However, the relationship between muscle activation and ROM with PNF is not well understood. The purpose of this study was to investigate the effect of three common PNF stretching techniques on hamstring muscle activation and knee extension. Three PNF techniques: stretch-relax (SR), contract-relax (CR) and agonist contract-relax (ACR) were applied to ten male and female subjects aged 23-36 years who were stabilized to isolate knee extension measurements. Knee joint position and EMG activity from quadriceps and hamstring muscles were computer processed throughout technique application. The results revealed mean hamstring EMG activity increased 8-43% within a given trial of ACR and CR respectively, and did not diminish across trials. SR produced a 11% decrease in mean hamstring EMG activity. ACR produced 3-6% greater knee extension values than CR and SR respectively, in spite of 71-155% greater hamstring EMG activity during ACR. The data suggest that CR and ACR do not evoke sufficient relaxation in muscles opposing knee extension to overcome tension facilitation generated by stretch. Thus, increases in ROM are achieved while the hamstrings are under considerable tension. Such tension increases muscle vulnerability to soreness and strain if stretching continues. The degree of knee extension produced via SR, although 3-6% less than CR and ACR, was achieved during simultaneous reduction in hamstring activity and may be the safer stretching technique.

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.