Summary

On the beginning and on the end of a 13 weeks lasting strengthtening, the energy expenditure was examined in 15 trained athletes. A half of the athletes (A) trained in a traditional manner by weight-lifting of dumb-bells, whose weight corresponded to 90–95% of maximum weight, which the athletes were able to lift (concentric contraction). The other half (B) trained only by weight lowering of dumb-bells, whose weight corresponded to 145–150% of the maximum lifted weight (eccentric contractions).

This type of both concentric and eccentric strengthtening led to equal strength increasements in both lower and upper limbs.

Towards the end of the training, the energy expenditure, needed for one dumbbell lifting decreased from the initial 6.0−5.3 kcal, while the energy expenditure, needed for one dumb-bell lowering changed from the initial value of 4.7−4.0 kcal. The energy expenditure, related to kg body weight and to kg load weight decreased from the initial value of 0.68−0.40 cal/kg/kg dumb-bell weight in lifting and from 0.36−0.21 cal/kg/kg dumb-bell weight in lowering. The ratio of dumb-bell lifting to lowering increases from the initial value of 1.87 to 1.94 at the end of the training.

Both oxygen uptake for all the experiment and (especially) oxygen debt decreased towards the end of training in spite of the fact, that the weight load increased substantially.

Strengthtening, using eccentric contractions, is more advantageous from the point of view of the energy expenditure when compared with strengthtening using concentric contractions, as follows from our experiments. Since it leads to equal strength increasements as a training using concentric contractions, it may be used as a further mean of a controlled strengthtening.

Summary

Electronic techniques of motion analysis have been used to evaluate the effects of a restricted diet on travel and manipulation components of motion. 13 subjects were tested at regular intervals during the 3 phases of the experiment: (a) a 21-day control period, (b) a 24-day period of maintenance on a 1000 calorie, all-carbohydrate diet, and (c) a 21-day recovery period. 2 conditions of pacing were employed: a 10-minute period of continuous performance at a “normal” or “comfortable” pace, and a 2-minute period of continuous performance at a “maximum” pace. The results of the study may be summarized as follows: 1.

Travel times increase significantly during food restriction under both conditions of pacing.

No significant change in manipulation times attributable to food restriction is evident under either condition of pacing.

A significant work decrement is apparent only in manipulation movevements under maximum pacing.

Work decrements do not change significantly as a function of nutritional deficit for either motion component.

Summary

The Harvard step test (modified for women) and a modified AAHPER test battery were performed by 144 White and Coloured student teachers, of whom 45 were students of physical education (PE). The rapid fitness index (RFI) was calculated for the Harvard step test and a composite criterion of fitness was derived from the results of the seven tests which comprise the AAHPER test battery.

For men and for women there was a highly significant correlation between the two estimates of physical fitness (RFI and AAHPER criterion) and a good correlation between the criterion and each of the individual AAHPER tests, the highest being with the standing broad jump. The correlation between RFI and individual AAHPER tests was poor in men but good in women. In both sexes the highest correlation was with the 600-yard run.

In general, both men and women PE students were fitter than their controls but there was no consistent difference between White and Coloured students in the results of the fitness tests although the White men and women were taller and heavier. The observed differences are probably not due to race but to different degrees of physical activity.

Summary

18 high school age males were matched to form two groups. Three test sessions were scheduled to investigate the effect of vitamin supplementation on the delay of the onset of fatigue. Each test session consisted of ten 50-yard dashes. The vitamin supplement consisted of 100 mg of thiamine, 8 mg of riboflavin, 5 mg of pyridoxine, 25 mg of cobalamin, 100 mg of niacinamide, and 30 mg of pantothenic acid. It was concluded that the drug supplementation reduced the fatigue incurred during a test session. The drug components of thiamine and pantothenic acid, the amounts of which different from previous studies, are discussed in respect to their role in the TCA cycle.

Summary

54 subjects were given a standardized elbow flexion exercise consisting of holding the arm flexed at 90 ° against the pull of a 20 lb. weight while in a recumbent position. Measurements were obtained on apparent weight of the arm and on upper arm and forearm circumferences during a period of 10 min. prior to exercise and 20 min. after exercise.

The immediate post-exercise upper arm circumference was 1 percent greater than the resting level (t = 10.3) and the lower arm circumference was also 1 percent greater (t = 12.3). The circumferences gradually returned toward the pre-exercise resting level during the 20 min. of recovery period. However, they had not completely returned at this time. The upper arm circumferences lost only 65 percent of the increase. The forearm circumference lost 75 percent.

The time after exercise required for the apparent arm weight to return to within 5 percent of the level of resting was between 8 and 9 min. The subject's failure to relax appears to prevent the arm from manifesting its full apparent weight during the early stages of rest and recovery. To secure data on apparent weight by the method described, therefore entails a rest period of at least 10 min.

Zusammenfassung

Die zunehmende Technisierung des menschlichen Lebens bringt für immer mehr Berufe ungewohnt große Verantwortung mit sich. Da ein hoher Prozentsatz von Unfällen infolge menschlicher Schuld auf akute Versagenszustände — nicht dagegen auf einen konstitutionellen oder dauernden Mangel an Eignung für eine bestimmte Tätigkeit — zurückzuführen ist, wird bei Personen in entsprechenden Stellungen grundsätzlich eine fortlaufende Überwachung des allgemeinen aktuellen Leistungsniveaus in Erwägung gezogen. Akuter inspiratorischer O₂-Mangel erscheint hierfür geeignet, da über Hypoxieresistenz und menschliche Leistungsbreite bereits praktische luftfahrtmedizinische Erfahrungen vorliegen, der Wirkungsmechanismus weitgehend geklärt ist und Applikation sowie Dosierung verhältnismäßig einfach und gefahrlos sind.

Es wird dargelegt, in welcher Weise O₂-Mangel die autonomen Regler beansprucht. An Hand experimenteller Untersuchungen mit einem speziellen Kugeltestgerät nach Brüner, Oxymeterwerten und Bestimmungen von Kreislaufgrößen wird erläutert, daß unter kritischem Sauerstoffmangel die Atmungsregulation einen entscheidenden Einfluß auf den Funktionsabbau innerhalb des Organismus hat. Der zuerst auftretende Verfall der höheren zentralen Funktionen hängt im wesentlichen von der durch die Atmung herbeigeführten intracerebralen Sauerstoffspannung ab. Das allmähliche Erlöschen der koordinierenden corticalen Tätigkeit kann mit Hilfe des Kugeltestgerätes in Abhängigkeit von der Zeit quantitativ verfolgt werden. Die vegetativen Regler von Atmung und Kreislauf sind offenbar durch zahlreiche Stress-Arten verhältnismäßig leicht beeinflußbar; möglicherweise werden sie daher — hinreichend stark belastet — zum Indicator auch für geringere Schwankungen der menschlichen Leistungsbreite.

Summary and Conclusions

Twenty-five young adult male subjects twice squeezed a hand ergograph as rapidly and with as much force as possible, each effort being recorded on fast-moving-paper. A succession of measurements were made along the force-time curves and the data individually fitted to a single component exponential equation. The correlation between maximal force and the time required to reach a criterion value (30 kg.) was high (r= −.85); the stronger the individual the more quickly he reached this goal. On the other hand, the correlation between maximum strength and the rate of change of the contraction was approximately zero (r=−.03), indicating that the pattern of development of muscular force is highly task specific. This supports the concept that such abilities are determined by separate neuromuscular coordination pathways of the central nervous system.

Catecholamines and ketosteroids in urine have been estimated on volunteers under the influence of emotional stress. For this purpose a group of a men watched an unpleasant film program as a test of reactivity of sympathoadrenal system. The following compounds were determinated in urine collected during the experiment: adrenaline, noradrenaline, 3-hydroxy-4-metoxy-mandelic acid, 17-ketosteroids and creatinine.

The results of our investigation proved that adrenaline excretion is a sensitive index of individual responses to psychological stressors and its level in urine corresponds to the degree of emotional arousal. The results are indirectly confirming the observations of other authors suggesting a relationship between the increase of noradrenaline excretion and the sympathoadrenal activity in case of a stressful situation.

Zusammenfassung

Wichtige Transportvorgänge im Organismus werden diskutiert und ihre Gleichungen abgeleitet. Jeder Transportvorgang kann auf ein System von Transportelementen zurückgeführt werden, deren Funktion durch ein Transportsymbol charakterisiert wird. Zu jedem Transportvorgang läßt sich aus den Transportsymbolen ein Schaltbild aufbauen, das den Transportvorgang vollständig beschreibt. Transportsymbole und Schaltbilder sind in Analogie zur Elektrizitätslehre gewählt worden. In Anwendung auf die Stickstoffelimination werden die Betrachtungen verdeutlicht und vertieft.

Summary

18 highly acclimatized Bantu and four different groups of 20 unacclimatized Bantu worked continuously for 4 hours at an oxygen consumption of 1.0 litre/min at 72, 82, 86 and 90 ° Effective Temperatures (E.T.). Rectal temperatures of theacclimatized men plotted against time showed that at 72 and 82 ° E.T., rectal temperatures rise from resting levels to a new steady level of 99.7 ° F within one hour and remain at that level for 4 hours; at 86 ° and 90 ° E.T. new, higher steady levels were reached but it took longer to do so. The steady level of rectal temperature ofunacclimatized men at 72 ° E.T. was higher, 100.1–100.3 °F; at 82 ° E.T. a new, higher level was reached only after 2 hours and at 86 and 90 ° E.T. rectal temperature continued to rise, throughout the period. Sweat rates plotted against time showed the expected maximum value in the second hour with a rapid fall-off thereafter, especially at severe heat conditions. The levels of the unacclimatized men were all lower.

Plots of sweat rates/rectal temperature, based both on the hourly measurements and on the averages for the 4 hours of exposure, show the expected trends which are a) an initial rapid rise in sweat rate with increase in rectal temperature, the “sensitive” zone and b) a fall-off in sweat rate with further rise in rectal temperature, the “saturation” zone. Curves fitted to these plots, with 83% confidence limits, show the following differences between acclimatized and unacclimatized men, a) the slopes of the initial part of the curves are steeper in the acclimatized men b) the origin of the curve of the unacclimatized men is shifted to the right by over 0.8 °F, c) the maximum, or saturation level, of sweat rate in the acclimatized men is much higher, d) the curves of the acclimatized men are significantly different from those of the unacclimatized men (at 5% level).

This test procedure distinguishes sensitively and significantly between acclimatized and unacclimatized men in this particular temperature regulatory mechanism.

These data show that the results are highly reproducible; that a maximum of 4 different air conditions are needed; that a minimum of 3 hours of exposure is required; and that a minimum sample often men is needed at each of the air conditions.