The purpose of this study was to evaluate the effects of clothing made of a new material that is, the polyester staple containing the ceramics and to reflect the solar heat load on physiologi-cal responses during rest, exercise (50 %V0_2max) and recovery on a cycle ergometer. Six young female subjects exposed their back to an artificial solar heat load of an intensity of 680 kcal/m2/h with an air temperature of 30°C. The data were compared to those obtained by wearing clothing made of cotton material. The results were as follows. The cardiac output and oxygen consumption obtained at the end of recovery were increased by solar heat load when the subjects wore cotton material. However, these values showed no significant increase when the subjects wore solar heat reflecting clothing. Furthermore, the cardiac output at the end of submaximal work and recovery were higher for the cotton material compared to the heat reflecting clothing in the solar heat load. The increase of cardiac output for the cotton material may show the increase of skin blood flow for the body heat dissipation. Those results suggest that the solar heat reflecting clothing may decrease the physiological strain like a blood redistribution for the body heat dissipation during exercise in summer sunlight.

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Relative humidity (R. H), vapour pressure (Psk) and evaporation rate (Esk) of the human skin surface were measured at 29 points by an evaporimeter at 25°C, 28°C, 31°C, 34°C and 37°C of air temperature (Ta), with 35±10 % R. H and the air velocity of less than 0.2 m/s. The skin temperatures and the body weight loss were also measured by thermography and electronic balance. Ten healthy female subjects aged 22-34 years, wearing brassiere and shorts, took a supine and a prone posture during experiment. Comparisons of the obtained Esk with the previous results of other studies showed that there were no definite differences among the measuring methods of Esk, while it is ascertained that the calibration of the results to some standard values such as weight loss were more important to get accurate values of Esk. Distribution patterns of Esk were almost the same in the insensible zone but they remarkably changed in the sweating zone. According to the regression analysis of Esk and Ta, 9-9 regions were classified into the following 9 groups which showed similar values and changes of Esk with the air temperature : 1) face, 2) front upper trunk, 3)back upper trunk, 4) front lower trunk, 5) back lower trunk, 6) arm, 7) Ieg, 8) hand and foot and 9) palm, sole and axilla. These results were discussed in relation to the contributing factors such as the number and the capacity of the sweat gland, the regional skin temperature and the pressure-sweat response and also in relation to the skin wettedness.

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The visual recognition (i.e., Iegibility) of moving object was studied. The numerical letters were mainly used as the objects. The influences of (1) directlon of the movement, (2) thickness of line of letter (i.e., stroke width), and (3) design of letter to the visual recognition were measured. From these measurements, the optimal numerical letters were proposed in the first step of the study, which were called as llvIAL(initial most optimal arabic letters). The visual recognition of both moving letters IMAL and letters JIS ( Japan industrial standard) employed for motionless state was compared for both the moving and the motionless states. In the presentation for motionless state, Ietters JIS showed iower error rate, but the statistical significance was not proved, while in the presentation for horizontally moving state letters IMAL showed better visual recognition than letters JIS with the significant level of 5 %. Therefore, the useful numerical letters for moving state could be designed in the study. Moreover, the visual recognition of letters IMAL was evaluated for various moving velocities. The optimal moving velocities for both letters IMAL and JIS were found.

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The effects of chronic hypoxia on muscle fiber distribution were investigated in 10-week-old male Wlstar rats. Samples of the soleus ahd the plantaris muscles were extracted after the animals were exposed to normobaric hypoxia (l0 % O₂) for 4 weeks. Histochemical myosin-based classification of skeletal muscle fibers was used. There was no evidence of transforma-tion between different flber types in either muscles. These results differ from those of previous studies. The rats used in those studies were younger, and it is difficult to distinguish the conversion of fiber types that occurs during normal development from other factors. These data suggest that chronic hypoxia does not affect muscle fiber type in adult rats.

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The detection of dampness in hygroscopic materials has been investigated both by subjective tests and by the application of a model of the physical mechanisms involved. Subjects were asked to rate the degree of dampness of a range of materials of different moisture contents after a short period of contact with the inner forearm. Skin and fabric inner surface temperatures were recorded. It was found that highly hygroscopic wool fabrics were perceived as being dryer and maintained a higher temperature at the skin surface than polyester, a less hygroscopic fabric, during fabric-skin contact. A physical model of the sorption/desorption process in hygroscopic materials has been developed from knowledge of fibre sorption klnetics and used to study the physical processes which take place at the skin-fabric interface during transient contact. These predictions agree well with the subjective responses and the measured temperatures.

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The purpose of this study was to compare the energy expenditure during submaximal front crawl (Fr) and breast stroke (Br) swimming. Six male college swimmers performed submaximal and maximal exercise tests in both styles in a swimming flume. In submaximal exercise tests, they swam at the following given velocities for 5 min, Br : 0.3, 0.5 and 0.7 m/sec ; Fr : 0.3, 0.5. 0.7 and 0.9 m/sec. In maximal exercise tests, following submaximal swimming at 0.9 m/sec in Br and 1.1 m/sec in Fr, swimming velocity was increased progressively by 0.1 m/sec every I min until the subjects reached to voluntary exhaustion. Vo_2max obtained from the maximal swimming tests in Br and Fr were 4.27 and 4.18 l/min, respctively. And there was no significant difference between these two values.

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The purpose of this study was to compare the intramuscular and the intravascular events in relation to energy metabolism during progressive arm exercise. Twelve healthy untrained Japanese males participated in this study as subjects. They performed wrist flexion in a ramp incremental load of 0.14 Wlmin until exhaustion. ³¹P-MR spectra were obtained from wrist flexor muscle before and throughout the exercise. Venous blood was also sampled from antecubital vein with one minute interval during the exercise, and a change in plasma lactate concentration (La) was observed. Intracellular pH (pH) was calculated from a chemical shift between phosphocreatine (PCr) and inorganic phosphate (Pi) of the ³¹P-MR spectra. Change in pH showed a threshold behavior during exercise. Threshold points at decline in pH (pHT), increase in Pi/PCr (PT), and increase in La (LT) were determined by piecewise linear regression analysis of minutes-by-minutes data. Mean values of pHT, PT and LT were 43.0, 42.5, and 24.8% of maximal work rate, respectively. LT was significantly smaller than pHT and PT. This result suggests that lactic acidosis has already existed when pH is kept at resting level, and pHT reflects the capacity of remaining intracellular biochemical homeostasis, which might be one of the physiological indices of muscle fatigue.

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Dapartment of Ergonomics. Kyusyu Institute of Design / Dapartment of Ergonomics. Kyusyu Institute of Design / Dapartment of Ergonomics. Kyusyu Institute of DesignThe aim of this research was to investigate the influences of the menstrual cycles of women on temporary threshold shift (TTS) and to compare the results with TTS of men. The subjects were, after 5 min rest, exposed to 100dB of continuous white noise for 8 min. The audiometry with a 4000 Hz test tone was done in the 45-min recovery process. In the three phases of the menstrual cycle. TTS tended to be lower in postovulatory phase than in preovulatory phase and during menstruation. The male TTS was higher than that of the female in all phases of menstrual cycle.

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