This study was intended to examine the specific nature and an aerobic value of jumping jacks (Fig. 1) which has a greater movement in shoulders and is easy to perform in standing position without specific skill and equipment and in also a narrow place.
Individual's self-selected (free) tempo in jumping jacks was determined for 92 subjects by administering it for 5 minutes.
The optimal tempo was obtained from measuring energy expenditures on two subjects when they performed five minutes of jumping jacks at each tempo of 50, 60 and 70 times/min and also at one's free tempo. Exercise intensity of jumping jacks as a general endurance activity was determined from energy expenditures and % Vo₂2max of 9 subjects who performed 5 minutes of jumping jacks at 60 times/min. Training effect of jumping jacks was examined on the basis of the changes in Vo₂max and heart rate (jumping jacks at 60 times/min for 3 min) before and after one month of training on 7 subjects who participated 180 jumping jacks at free tempo a day, averagely 6.3 times a week. Subjects were all college male students aged between 18 and 22. Followings are the results obtained in this study.
1) Individual's self-selected (free) tempo in jumping jacks was about 60 times/min.
2) The optimal tempo in jumping jacks determined on the basis of energy expenditure was also about 60 times/min.
3) Oxygen requirement and RMR at the optimal tempo (60 times/min) in jumping jacks were 40.9 ml/kg/min and 12.3, respectively. Percent Vo₂max, Oxygen requirement and RMR in jumping jacks was smaller for persons who have greater Vo₂max/body weight.
4) One month of training by jumping jacks demonstrated significant increases in Vo₂max and Vo₂max/body weight, which were 2.59 to 2.751/min (p<0.01) and 43.5 to 46.1 ml/kg/min (p<0.05), respectively. Significant decreases in heart rate were also observed during and recovery after the exercise.
5) From above results, jumping jacks could be used as an effective general endurance exercise, provided that some necessary modifications should be made according to each individual's fitness level.

　　It usually takes several days to detect slow-growing bacteria by a blood culture system. Moreover, even if the microbial growths are detected in blood samples, they will escape our notice at a microscopic examination using Gram’s stain. Consequently, the results are often regarded as false positive.　　This paper reports case of malignant lymphoma in which bloodstream infection caused by slow-growing spirillum was observed. The patient in chemotherapy for malignant lymphoma, complained of repeated fever. Repeated blood cultures were taken and occasionally positive signals, which mean increased CO2 concentrations in the culture bottle, were detected by BACTEC 9240 (Becton Dickinson). However, routine microscopic examination with Gram’s stain did not detect any bacteria. Thus, the results of BACTEC were thought to be false positive. Thereafter, the bacterial culture period was extended. Finally, a spirillum, suspected of one of Helicobacter species, was observed microscopically. The detected spirillum was regarded as Helicobacter canadensis with 98.08% homology, using polymerase chain reaction with the 16S rRNA method and basic local alignment search tool (BLAST).　　H. canadensis is one of new species isolated from humans with diarrhea. This bacterium is considered to cause a zoonotic infection. There have been some case reports that this bacterium infected immunosuppressive patients, so we should exercise caution against such conditions. Moreover, we should keep vigilant against the spread of slow-growing bacteria when there are discrepancies in findings between blood culture system and microscopic examination. It is useful to extend the culture period to detect such slow-growing bacteria.