Effect of the Rotational Speed of a Long Jump Rope in a Person Turning the Rope on Heart Rate and Oxygen Uptake

The purpose of this study was to clarify the effect of different rotational speeds on the heart rate (HR) and oxygen uptake of a person turning a long jump rope. The subjects consisted of six healthy Japanese males who volunteered to participate in the study. They were asked to turn a long jump rope. The measurement was set at three rotational speed conditions: 70, 90 and 110 rpm. The measurement indexes were HR, oxygen uptake, rating of perceived exertion and blood pressure. The 90 and 110 rpm conditions demonstrated significant HR increases from the first to the third minute of the 3-minute exercise compared with the 70 rpm condition. The 110 rpm condition showed significant HR increases from the first to the third minute compared with the 90 rpm condition. The 90 and 110 rpm conditions demonstrated significant oxygen uptake increases from the first to the third minute compared with the 70 rpm condition. The 110 rpm condition showed significant oxygen uptake increases from the first to the third minute compared with the 90 rpm condition. The changes in the HR and oxygen uptake of the rope turner were dependent on the rotational speed of the long jump rope

Effects of Irregular Mealtimes on Social and Eating Jet Lags among Japanese College Students

College students’ social and eating jet lags and chronotypes may be related to irregular eating habits. Therefore, we examined the relationship between social and eating jet lags, chronotypes, variability in first and last mealtimes, and non-eating duration, as well as the effects of snacking between dinner and bedtime on social and eating jet lags, chronotypes, and mealtime variation. A total of 1900 Japanese male college students were recruited in this study. Mean wake-up time, bedtime, sleeping time, first and last mealtimes, snacks between meals, non-eating duration, the midpoint of non-eating duration, social and eating jet lags, and chronotype were calculated. Standard deviations in first and last mealtimes, the midpoint of non-eating duration, and the coefficient of variation in non-eating duration were used to evaluate mealtime variations. Mealtime variations were significantly associated with social and eating jet lags, chronotype, the midpoint of non-eating duration, and the difference in first and last mealtime between school holidays and class days. Chronotype and the midpoint of non-eating duration were significantly delayed with increased snacking after dinner. Mealtime variations were significantly lower in those who avoided snacking than in those who did not. Thus, social and eating jet lags and chronotypes are associated with sleep habits and mealtime irregularities