Ventilation threshold (VET), threshold of decompensated metabolic acidosis (TDMA) and lactate threshold (LT1, LT2) were investigated during incremental bicycle exercise for 20 boys (11.7±0.1 years) and 10 girls (11.2±0.2 years) . Maximum oxygen uptake (VO2max) was measured by treadmill running. There was significant difference between boys and girls in VO2max per body weight, but no signif-icant difference per LBM. Mean values of each threshold (% peak VO2) were as follows. VET was 53.3±2.2%, TDMA was 69.0±2.2%, LT1was 51.8±2.2% and LT2was 72.8±2.2%. These values were not higher than those of previous adult's data. There was no significant difference in lactate and ventilatory parameters between boys and girls, except LT2and LT4mM. In conclusion, it seems that no difference is seen in lactate and ventilatory responses between 9-12 year boys and girls. VET and TDMA by bicycle exercise could be estimated by ventilatory responses in prepubertal children.
Serum creatine kinase (CK) activity and myoglobin (Mb) level showed biphasic changes due to transient weight training. The first peak appeared within one day and the second peak appeared within several days after training. We investigated the characteristics of each peak by measuring the total CK and CK isoenzymes (CK-MM, -MB, -BB) activities. The results were as follows: 1) The first peak of Mb level appeared sooner than that of total CK activity. In two untrained subject, the second peak of total CK activity and Mb level were higher than the first peak. 2) The CK activity within four hours after training was that of CK-MM. CK-MB and -BB activities did not appear immediately after training, but they appeared within one day after training. CK-MB activity showed the highest value on the fifth day, and CK-BB activity was highest on the seventh day. Appearance of CK-BB activity was more apparent in the untrained than in the trained subjects. 3) The mean ratio of CK-MB activity to total CK activity was 5.3 % on the fifth day, and that of CK-BB activity was 2.9 % on the seventh day. These ratios were the highest among ratios in the post-training period. It is suggested that the first peak represents a transient enzyme leakage into the blood stream, as the result of damaged muscles, especially in untrained subjects, while the second peak which appeared within several days after training represents, at least to some extent, the participation of ontogenetic muscle regeneration.
The protein in urine from high-school male students before and after exercise was measured by TONEIN-TP method and ASPRO-GP method. 1. The total protein in urine was measured by using the TONEIN-TP method. In comparison with before physical load, the total protein was increased after physical load. 2. Though ASPRO-GP method is used as the method that determine serum mucoprotein, this time it was made better as the method that determine minute amount of urinary mucoprotein immediately. This method is more available, because it is able to determine more simply and rapidly. 3. The coefficient of correlation between the total protein concentration by the TONEIN-TP method and that add the albumin concentration to the acid soluble glycoprotein concentration by ASPRO-GP method was nice, and they were much almost the same. Increase of urinary total protein after physical load is caused by increase of acid soluble glycoprotein and albumin. 4. From the above results, though TONEIN-TP methvd is effective to measure physical load after exercise, ASPRO-GP method is more effective to measure by increase of mucoprotein.