We investigated the relationships between the ability to maintain balance in an upright stance and center-of-pressure (COP) dynamic properties in young adults. Included in this study were 10 healthy male subjects in each of two groups with respect to balance ability. Balance ability was evaluated according to the length of time a subject stood on one leg with his eyes closed. The means and ranges of this one-leg balancing time were 17.9 s (3-43 s) and 118.3 s (103-120 s) for the off-balance and balance groups, respectively. The time-varying dis-placements of the COP under a subject's feet during quiet two-leg (normal) standing were measured by an instrumented force platform. Each subject was tested in both the eyes-open and eyes-closed conditions. The COP trajectories were analyzed as fractional Brownian motions according to the procedure of 'stabilogram-diffusion analysis', proposed by Collins and De Luca (1993). The extracted parameters were the effective diffusion coefficients (D) for the short-term (less than about 1.0 s) and long-term intervals, respectively, as well as the Hurst exponents (H) for the short-term and long-term intervals, and some critical-point co-ordinates (i.e., critical mean square displacements and critical time intervals). The off-balance group showed significantly higher values for short-term D, short-term H, and critical mean square displacements than the balance group. No significant differences between the groups were found in the long-term D and H or in the critical time intervals. That is, for the off-balance subjects, an increase in the stochastic activity and positively correlated (persistent) behavior of the postural sway during shorter timescales may cause postural instability. These results suggest that the difference in balance ability for young adults is related to the open-loop (i.e., short-term) control mechanisms but not to the correc-tive feedback (i.e., long-term) mechanisms used to maintain balance in an upright stance.

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For randomly selected 50 villages in Bangladesh, an interview survey with a structured questionnaire was conducted to reveal their perception on the environmental, health and economic conditions at present and for the past 10-year change. The eight following items were analyzed in this paper: air pollution and water pollution, which represent environmental conditions with close relation to health conditions, soil degradation and deforestation, which represent environmental conditions with close relation to economic conditions, epidemic diseases and malnutrition, which represent health conditions, and poverty and jobless, which represent economic conditions. Among the 50 villages, deforestation was most frequently perceived serious at present and worsened in the past 10 years. Of the remaining seven items, those related to economic conditions were more seriously perceived than those related to health and environmental conditions. As revealed by the cluster analysis for the interitem relations, epidemic diseases, which formed the same cluster with the environmental items, were recognized less serious whereas malnutrition, which formed the same cluster with the economic items, was recognized more serious. These findings are useful not only for rural development programs but also for mitigation programs toward health and environmental hazards in Bangladesh.

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We have already presented two studies of the traditional carrier frame, the seita. In our first study, we reported on seita users supporting loads not on the lumbar vertebrae but on the sacrum. In the second study, we showed that carrying a load on the sacrum was efficient in terms of metabolic rate, muscle activity, cadence and subjective responses. The purpose of this study was to verify the effect of carrying a load on the sacrum in terms of gait pattern. We compared the kinetic parameters produced while carrying a load on the sacrum (LOS) with those produced while carrying a load on the lumbar vertebrae (LOLU). Maximum propulsive force and medial impulse were significantly larger in LOS than in LOLV These results suggested that a normal gait pattern was maintained more in LOS conditions than in LOLU conditions. This indicated that seita-fitting was efficient for carrying and transporting loads.

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The aim of this pilot study was to evaluate the accuracy of a simple step-test procedure supplemented by the measurement of heart rate (HR) (STEP 1) to assess the cardiorespiratory capacity i.e., maximal oxygen consumption (O₂max) of Thai workers. The subjects comprised 18 men and 17 women. Their ages varied from 19 to 20 years and all were physically active. The subjects performed three tests, a submaximal incremental cycle-ergometer (CYCLE) test supplemented by HR recordings and respiratory gas exchange, and two step-tests (STEP1 and STEP2). In the STEP1 test HR was recorded continuously. The STEP2 test included the measurements of HR and respiratory gas exchange. For the male subjects the mean difference of the estimated (O₂max) values obtained from the CYCLE and STEP 1 test was 15% (₂max) values were equal when predicted according to the CYCLE and STEP1 tests. The present STEP1 test is not sufficiently accurate to predict the (O₂max) of Thai men. The results of this pilot study need to be confirmed with larger samples of subjects with various backgrounds in terms of individual characteristics and occupations.

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For female workers in a computer factory in Japan, consisting of 41 daytime workers and 74 weekly-rotating shift workers (of whom, 37 each were engaged in, respectively, early-shift work and late-shift work during the survey week), within-day variations in the number of fatigue complaints were elucidated. Based on a repeated questionnaire survey, changes of fatigue complaints in a day were evaluated at three occasions, i.e., just before work, just after work, and before retiring, for three working days and one off day. The occasions of fatigue feelings differed among the three work groups: the complaints were significantly more frequent before work in the early-shift workers, after work in the late-shift workers, and before retiring in the daytime workers. Feeling of fatigue before and after work may be disadvantageous to safety and efficiency of work.

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Recovery cardiac cost (RCC) after short duration high intensity exercise and its relationship with physical and physiological parameters were assessed for 45 sedentary girls aged 10-25. RCC of postpubertal girls were significantly lower than those of prepubertal and just pubertal girls, when expressed in terms of cost in beats above rest. No significant differences were found among the three groups regarding RCC values in terms of % cost above rest. Age and diastolic blood pressure were negatively correlated with RCC both in terms of cost in beats above rest and % cost above rest only in postpubertal group. Pre-exercise heart rate in postpubertal group was negatively correlated with RCC only in terms of % cost above rest. No positive or negative correlation was found between RCC and other parameters under study, in prepubertal and just pubertal groups.

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Although adaptation to hunting-gathering life is a main hypothesis for understanding of the nature of humans, studies directly examining the hypothesis have not been done. In the present study, we used the method of showing a film depicting hunting and housework by African hunter-gatherers to elementary pupils and university students to examine their memories. In pupils and students, males showed higher percentage of correct answers than females for hunting-related questions, and female showed higher percentage for housework-related questions. The results suggest a males' learning bias to hunting and support the hunting-gathering hypothesis.

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