Neuromuscular adaptation in human thenar muscles following strength training and immobilization.

The effects of strength training and limb immobilization on the human thenar muscles were investigated in 11 healthy subjects. One group (n = 6) trained prior to immobilization and a second group (n = 5) underwent immobilization prior to training. Measurements made in the control condition and following the two experimental conditions included voluntary isometric strength, motor-unit counts, motor nerve conduction velocity, reflex potentiation, and isometric twitch-contraction properties.

Unique and common variance in structured interview and Jenkins Activity Survey measures of the type A behavior pattern.

The aim of the present study was to identify factors that account for similarities and discrepancies in classification of Type A and B behavior by the Structured Interview (SI) and by the Jenkins Activity Survey (JAS). Two diverse samples were administered the SI and the JAS. SI questions were coded for content of response and psychomotor behavior during the interview.

Muscle ultrastructural characteristics of elite powerlifters and bodybuilders.

Muscle ultrastructure of a group of subjects possessing extreme hypertrophy was compared with that of a control group which had undergone 6 months of heavy resistance training. Two needle biopsies were taken from triceps brachii of two international calibre powerlifters and five elite bodybuilders. In addition, samples were taken from five healthy volunteers before and after 6 months of training of the elbow extensors.

Challenge-induced cardiovascular response as a predictor of minor illnesses.

Male college students (n = 64) participated in a competitive "TV tennis game" while their heart rate and blood pressure were monitored. Subsequently, their health records were inspected to determine frequency of illnesses. Subjects who responded during the contest with extreme increases in heart rate and diastolic blood pressure were significantly more likely to have frequent minor illnesses than those responding with moderate or low increases.

Cross-Country Skiing: Precautions for Cardiac Patients.

In brief: Cross-country skiing is an attractive winter alternative to walking or jogging, but persons with coronary artery disease must be aware of its high energy costs and make appropriate adjustments. Oxygen costs can be affected by variations in efficiency, arm work, snow, cold temperatures, inclines, altitude, and skier misperceptions. The authors give safety recommendations to reduce the hazards and enable cross-country skiers to enjoy their winter sport.

East pacific rise: hot springs and geophysical experiments.

Hydrothermal vents jetting out water at 380 degrees +/- 30 degrees C have been discovered on the axis of the East Pacific Rise. The hottest waters issue from mineralized chimneys and are blackened by sulfide precipitates. These hydrothermal springs are the sites of actively forming massive sulfide mineral deposits.

Effects of strength training and immobilization on human muscle fibres.

Seven healthy male subjects were studied under control conditions and following 5-6 months of heavy resistance training and 5-6 weeks of immobilization in elbow casts. Cross-sectional fibre areas and nuclei-to-fibre ratios were calculated from cryostat sections of needle biopsies taken from triceps brachii. Training resulted in a 98% increase in maximal elbow extension strength as measured by a Cybex dynamometer, while immobilization resulted in a 41% decrease in strength.

Muscle fiber types and morphometric analysis of skeletal msucle in six-year-old children.

Needle biopsies from the vastus lateralis of 13 six-year-old Swiss children were analyzed for muscle fiber type populations and morphometrical characteristics. No significant differences existed between the males and females for fiber type distribution, maximum oxygen consumption, or any of the ultra-structural parameters investigated. The vastus lateralis muscle consisted of 19.

Interpersonal interaction and cardiovascular response in type A subjects and coronary patients.

The present study tested the hypothesis that Type A subjects respond with greater cardiovascular response than Type B subjects during the structured interview used to assess the Type A pattern. Coronary patients (n = 31) and patient controls (n = 33) were subjected to the interview and a history quiz while ECG and blood pressure were monitored. As predicted, Type A relative to Type B subjects evidenced significantly greater increases in both systolic and diastolic blood pressure, which were sustained over the course of the entire 12-15 minute interview.

The structured interview and questionnaire methods of assessing coronary-prone behavior in male and female college students.

Several self-report measures of type A behavior were compared with the Rosenman and Friedman structured interview method of assessment in male and female college students. The student version of the Jenkins Activity Survey was found to correlate relatively weakly with the interview for both males and females, while scales derived from the Gough and Thurstone inventories showed moderate correlations with interview typing for both sexes. A brief scale derived from a recent reanalysis of the Framingham study correlated with the interview appreciably greater for females than for males.

Thermoregulatory problems encountered in ice hockey.

Despite the fact that ice hockey is played in lower than normal ambient air temperatures, its intense intermittent nature is such that the athlete encounters hyperthermal problems similar to those of most team athletes. This presentation discusses these problems and offers recommendations by which performance may be improved.

The energy cost of cross-country skiing among elite competitors.

The energy costs of skiing with the diagonal stride technique was investigated in 15 members of the men's and women's national cross-country ski teams and in 5 recreational skiers. Oxygen uptake was measured directly by means of a portable bag-method for each subject during level skiing at 3 different skiing speeds. The oxygen cost of double poling vs.

Mitochondrial volume density in human skeletal muscle following heavy resistance training.

Needle biopsies were taken from triceps brachii of 6 healthy males before and after a 6 month intensive weight training programme. The tissue was sectioned, photographed under a Philips EM200 and subjected to stereological analysis. Cross sectional fibre areas were also calculated from cryostat sections stained for ATPase activity.

Components of the type A coronary-prone behavior pattern and cardiovascular responses to psychomotor performance challenge.

The present study tested the general hypothesis that behavioral attributes most predictive of the incidence of coronary heart disease (CHD) in epidemiological research would also be most predictive of sympathetic autonomic nervous system (ANS) arousal in response to performance challenges. Subjects (n = 50) were challenged to respond rapidly and accurately on three tasks involving either perceptual-motor or cognitive skills, while the experimenter monitored blood pressure, heart rate, and galvanic skin potential. The hypothesis was generally confirmed in that (1) type A subjects showed significantly greater cardiovascular changes indicative of sympathetic ANS arousal than type B subjects, (2) the Rosenman and Friedman structured interview was a better predictor of this arousal than the Jenkins Activity Survey, as is the case in CHD, and (3) the stylistic and behavioral components of the type A pattern (as defined by the structured interview) which are most predictive of CHD were also found to be the best predictors of challenge-induced sympathetic ANS arousal.

Stress effects on affiliation preferences among subjects possessing the type A coronary-prone behavior pattern.

An experiment tested the hypothesis that when subjects who display the Type A coronary-prone behavior pattern are placed under stress, they prefer to wait for the stressful event with others, but desire to work under stress alone. One half of 25 Type A and 25 Type B (non-coronary-prone) subjects were told that they would receive painful electric shock while working on a mental task, while the other one half were told that they would receive subliminal stimulation. Both groups were then given the choice of waiting for the event with others or alone and the choice of working on the task alone, in the company of others, or in a leader-directed group.

Biochemical adaptation of human skeletal muscle to heavy resistance training and immobilization.

Nine healthy subjects were studied under control conditions and following 5 mo of heavy resistance training and 5 wk of immobilization in elbow casts. Needle biopsies were taken from triceps brachii and analyzed for adenosine triphosphate (ATP), adenosine diphosphate (ADP), creatine (C), creatine phosphate (CP, and glycogen concentrations. Training resulted in an 11% increase in arm circumference and a 28% increase in maximal elbow extension strength.

Joint Committee on Aviation Pathology: XVII. Round window tear in aviators.

It is the intent of this paper to draw attention to round window tears with the inherent symptomatology that has, for the first time, been documented in two aircrew members. It is also felt important to emphasize that the condition, regardless of etiology, could be catastrophic to the flying pilot and may be an up-recognized cause of otherwise unexplainable accidents. Not all cases of window tears cause vertigo-but some do.

Physiologic reactions to social challenge in persons evidencing the type A coronary-prone behavior pattern.

Physiologic measures were recorded in Type A1 (n = 10) and Type B (n = 14) subjects while they engaged in a reaction-time task after receiving instructions emphasizing the need for rapid and accurate performance. Although resting levels were not significantly different, Type A's responded with significantly greater increases than B's in both heart rate and systolic blood pressure, suggesting greater sympathetic arousal. A significant baseline difference between the Types in heart rate variability was also observed suggesting greater lability in sympathetic-parasympathetic function in Type A's.

Cubanite: A New Sulfide Phase in CI Meteorites.

Cubanite (CuFe(2)S(3)), previously unobserved in meteorites, has been discovered in two carbonaceous chondrites, Orgueil and Alais. The association of this mineral with low-copper pyrrhotite suggests that it formed in a low-temperature environment on the meteorite parent body.