ABSTRACT
A simple exercise test with vertical jumping was developed for children. The vertical acceleration wave form of back was measured with strain gauge type transducer. After amplification and rectification, the signal of positive acceleration was converted to frequency with voltage-to-frequency converter (VFC) and VFC signals were decoded by a digital counter. The digital output was normalized by gravitational value and defined as physical activity rate. 10 young males and 24 schoolchildren jumped at several frequencies and oxygen uptake, physical activity rate and heart rate were measured. Also 28 children under school age jumped arbitrary and heart rate and physical activity rate were recorded. The results showed that the oxygen uptake per body weight had good correlation to the physical activity rate (r=0.95) . Although heart rate was significantly different with ages, physical activity rate which was defined as an index of exrecise test, was no significant difference with ages and weights (α<0.05) . The results indicated that this jumping test was helpful to make exercise stress test for younger children.
ABSTRACT
A system for making prolonged measurements of oxygen uptake without the use of mask or mouthpiece is described. A subject wears a hood through which air is drawn by a exhaust pump located on the end of hoses. The flow rate of main stream is measured by a pulsed wire flowmeter located between flexible hose and rigid hose. The flow rate is essentially constant during a run. One sample pump bypasses small amount of mixed air from the main stream. The other pump draws the room air. Two sample pumps operate alternatively at 2 min interval. The sample gas is dried by passing through molecular sieve desiccant and is delivered to in-line oxygen analyzer. Both signals of flow rate and oxygen concentrations of room air and mixed air are converted to digital quantities and then stores in memory devices at 5 min interval. All measuring devices were assembled to small package which the subject carries on his back. The weight was about 7 kg. The memory chip is removed from the device after experiment and oxygen uptake is estimated by connecting the memory chip to a microcomputer. This measurement compared favorably with measurement with Douglas bag collection and gas analysis.