RESUMEN
Information on daily physical activity is essential for determining daily nutritional demands and devising physical conditioning programs. In order to obtain reliable information on daily physical activity, it is necessary to record the activity in some way. Up to now, however, such data have been collected using retrospective questionnaires and observation, and by measurement of heart rate over extensive periods. These methods are too cumbersome and expensive.<BR>The purpose of the present study was to develop a new device for recording physical activity in the form of an actogram. A pedometer was used to record the physical activity, and a microswitch was set inside the pedometer to convert the pedometer count into an electric signal, since it is advantageous to process the data by computer. The pedometer count was recorded in the IC memory of a computer with a 32-kbyte. The memorized pedometer count was fed into the personal computer through an interface, and after processing it was displayed as an actogram representing the activity pattern and the amount of physical activity.<BR>The new device developed in this study could serve as a practical tool for recording the quantity and time course of physical activity during daily life, since it is small (110mm×70 mm×30 mm) and light (170g), less expensive and also convenient to handle.
RESUMEN
The relationship between daily physical activity and physical fitness in female college students was investigated. Sixteen female college students who regularly took exercise two or three days per week were selected for the active group. Seventeen female college students who seldom took exercise and had not taken part in any kinds of sports activities while at high school were selected for the inactive group. Physical fitness tests and incremental loading maximal cycling exercise tests were undertaken by all subjects. Gas expired during the cycling exercise was collected in a Douglas bag, and ventilation, oxygen uptake and respiratory quotient were measured for each exercise load and in the last few minutes of the exercise test. Electrocardiographic data were also obtained during the test. Heart rate during daily activities in each subject was recorded continuously throughout the day using a heart rate recorder. Daily energy expenditure was estimated from the continuous recordings of heart rate using the linear relationship between heart rate and oxygen consumption obtained in the maximum incremental exercise test. Mean number of strides taken by each subject during da ily activities was also obtained using a pedometer for one week.<BR>The results can be summarized as follows.<BR>1) Maximal oxygen uptake and total score in the physical fitness test averaged 37.8 m<I>l</I>/ kg/min and 27.8 points, and 30.1 m<I>l</I>/kg/min and 22.5 points for the active and inactive group, respectively. The inter-group differences in these parameters were significant.<BR>2) The mean values of daily energy expenditure and strides taken during daily activity were about 2400 kcal/day and 14000 strides/day, and 1800 kcal/day and 7000 strides/day for the active and inactive group, respectively. The differences between the groups for these two values were also significant.<BR>3) The difference in daily energy expenditure between the two groups was 580 kcal and the difference in total strides per day was 7000 strides.<BR>4) These results indicate that both daily physical activity and physical fitness in the inactive group were lower than those in the active group. Furthermore, it was proved that the level of physical fitness in female college students is closely related to their daily physical activity.