PORPOSE: This study aimed to investigate the relation between cardiorespiratory fitness(CRF) and physical activity, especially vigorous physical activity, in Japanese middle-aged and elderly men. METHODS: Eighty-five men aged 30-69 years participated in this study. CRF was assessed by measuring the maximal oxygen uptake based on weight (VO2max/wt) in an incremental test on a bicycle ergometer. METs·h/week was measured as the parameter of physical activity by using accelerometers. We defined the amount of physical activity higher than 3 METs as “Physical activity ; PA”in this study. Then, PA was divided into “Moderate physical activity ; MPA”(higher than 3 METs and below 6 METs)and “Vigorous physical activity ; VPA”(higher than 6 METs). RESULTS : CRF was positively correlated with PA(r=0.318, P<0.01), MPA(r=0.230, P<0.05), and VPA(r=0.301, P<0.01) and negatively correlated with age(r=-0.607, P<0.001), BMI(r=-0.369, P<0.01), and waist circumference(WC)(r=-0.486, P<0.001). After adjusting for age and WC, the multiple regression analysis revealed that PA was positively correlated with CRF(P<0.01). VPA was positively correlated with CRF(P<0.05) after adjusting for age, WC, and MPA. MPA was not correlated with CRF in the case of adjusting for age and WC. CONCLUSION : This study suggested that physical activity higher than 3 METs was positively associated with cardiorespiratory fitness independently of age and waist circumference, and particularly vigorous physical activity may contribute to increased cardiorespiratory fitness in middle-aged and elderly men. Thus physically active life with maintenance of adequate waist circumference may help to prevent age-related decline in cardiorespiratory fitness.
Purpose: The purpose of this study was to determine the relationship between 20m shuttle run (20mSRT) performance and a substantial increase in waist circumference (WC) with aging in Japanese middle-aged adults. Methods: One hundred and fifty-six Japanese middle-aged adults (40-64 yrs; 40 males, 116 females) participated in this study. Baseline data on 20mSRT, height, weight, WC, alcohol habit, smoking habit and the use of medication were collected from 2003 to 2004. Follow-up data on height, weight and WC were collected in 2008. The 20mSRT results were divided into gender-specific quartiles. A logistic regression analysis was used to predict a substantial increase in the WC (5 cm or more) during the follow-up. Results: During the follow-up, 44 people had a substantial increase in the WC. Independently from sex, age, height (baseline), weight (baseline), WC (baseline), alcohol habit, smoking habit and the use of medication, the highest quartile of 20mSRT was significantly associated with significantly lower odds ratio of a substantial increase in WC (OR: 0.07, 95%CI: 0.01-0.36) in comparison to the lowest quartile of 20mSRT. Furthermore, after additional adjustment for change in weight during follow-up, the highest quartile remained significantly predictive of a substantial increase in the WC, with odds ratio of 0.07 (95%CI: 0.01-0.39). Conclusions: These results indicate that the 20mSRT performance is a significant predictor of a substantial increase in the WC with aging in Japanese middle-aged adults.
The purpose of this study was to compare the motor control against the passive force between an ascend phase (AP) and a descend phase (DP), and to investigate the effect of a subject's athletic experience on it. Thirty-four subjects participated in the experiment, and they were classified into an athlete group and a control group. We used a kinetic-equilibrating (K-E) task. Result of K-E task depends on the kinesthesia, because subjects are required to maintain their balance against a passive force under conditions of limited visual and aural feedbacks. Therefore, subjects were instructed to resist the passive force. Their performance was evaluated using parameters such as absolute error, position fluctuation, and variable error that were calculated from position data. Significantly higher values on DP than AP for each parameter in the control group were found. However, the values of both AP and DP were similar in the athlete group. It was suggested that the athlete group could perform the same level of motor control against passive force between AP and DP, although it was more difficult in DP than in AP for the control group.
Background: Understanding the long-term effects of environment on health behavior is important for the promotion of population-based physical activity. Purpose: The purpose of this study was to examine the relationship between perceived environment and active commuting among Japanese adults. Methods: Internet-based cross-sectional survey were conducted to 3,000 Japanese adults aged 30-59 years. Seven sociodemographic attributes (gender, age, marital status, employment status, living status, educational attainment and household income), type of commute and International Physical Activity Questionnaire Environment Module were assessed by self-administered questionnaire. Results: Of all respondents to the survey, 2,032 (mean age: 43.8±9.2, male: 62.5%) were employed. Those who use an active commute were 1,401 (68.9%). In both genders, high residential density (male: OR=2.28, female: OR=3.08), good access to shops (OR=2.03, 3.06), public transportation (OR=1.65, 3.78), recreational facilities (OR=1.31, 1.44), presence of sidewalks (OR=1.42, 1.77), crossroads (OR=1.87, 1.76), having a destination (OR=1.84, 2.34), and not having household vehicles (OR=15.13, 41.24) were associated with an active commute. The results indicated some gender differences. Among male, the presence of a bicycle lane and good aesthetics was positively associated with the active commute, while traffic safety was negatively associated. On the other hand, crime safety was associated with the active commute in female. Conclusion: The results indicate that perceived environment was associated with the active commute among Japanese adults.
The purpose of this study was to investigate the changes on mechanical work of the lower limb joints during baseball pitching in a simulated game. One male college baseball pitcher threw 15 pitches in an inning for 9 innings (135 pitches) in an indoor pitcher's mound with two force platforms. Rest time between innings was 6 minutes. Three-dimensional positions of 47 reflective markers attached to subject were tracked by an optical motion capture system (Vicon Motion System 612, Vicon Motion Systems) with eight cameras (250Hz). For subject 75 fastball pitches (1st, 3rd, 5th, 7th, and 9th innings) were chosen for analysis. As the main results, the hip joint extension absolute and negative work of the stride leg decreased with increasing the number of pitches. The ankle joint extension absolute and negative work of the stride leg increased with increasing the number of pitches. These results suggest that the hip joint extension torque of the stride leg was needed to maintain for higher performance in baseball pitching.
Circadian rhythms are approximate 24-hour biological cycles that synchronize the timing of an organism's behavior and physiology to daily environmental changes. This endogenously generated temporal coordination has been experimentally shown to provide an adaptive advantage by enhancing an organism's ability to anticipate daily changes in light, temperature and humidity etc. The molecular mechanism responsible for generating circadian rhythms is a highly conserved gene regulatory network composed of transcriptional-translational feedback loops referred to as the Core-Clock. In mammals, the proteins encoded by Core-Clock genes, Bmal1 and Clock, dimerize to drive transcription of Period and Cryptochrome and the protein products of these genes down-regulate BMAL1 and CLOCK function. BMAL1:CLOCK heterodimers also transcriptionally regulate a group of genes referred to as clock-controlled genes which are believed to be necessary for maintenance of normal cell physiology. In this review, the bases of the circadian rhythms regulation in the central/peripheral tissues are discussed. Particular emphasis has been placed on understanding of circadian regulation of skeletal muscle structure and function. Recently, tissue-specific circadian transcriptome including MyoD1, which is the well-known myogenic lineage regulator, were identified in skeletal muscle. Understanding the molecular, physiological and biophysical mechanisms through which the Core-Clock genes and the tissue-specific circadian transcriptome maintain skeletal muscle structure/function is of great significance with broad translational implications associated with chronic disease, metabolic failure and disuse.