The purpose of this study was to determine the metabolic equivalents (METs) for scooter exercise (riding a scooter, scootering) and to examine the energy expenditure and the heart rate response, so ...that the results can be used in health promotion activities. Eighteen young adults (10 males and 8 females) participated in scootering on a treadmill at three different speeds for six minutes each. Before, during, and after the exercise, pulmonary ventilation, oxygen uptake (VO2), carbon dioxide product, respiratory exchange ratio (R), and heart rate (HR) were measured. These measurements kept steady states from the 3rd to 6th minute of each different speed session. The MET values acquired during scootering at 80 m·min−1, 110 m·min−1, and 140 m·min−1 were 3.9, 4.3, and 5.0, respectively. Calculated using VO2 (ml·kg−1·min−1)×4.0+R, the energy consumption for scootering at each speed was 67.0±10.6, 73.3±10.2, and 84.8±7.9 cal·kg−1·min−1, respectively. The regression equation between scootering speed (X, m·min−1) and VO2 (Y, ml·kg−1·min−1) is Y=0.062X+8.655, and the regression equation between HR (X, beats·min−1) and VO2reserve (Y, %) is Y=0.458X−11.264. These equations can be applied to both females and males. Thus, scootering at 80 to 140 m·min−1 might not be sufficient to improve the cardiorespiratory fitness of young male adults similar to the participants, but it may contribute many healthy benefits to most female adults and even male adults, and improve their health and fitness at the faster speeds.
Energy Expenditure in Maximal Jumps on Sand Muramatsu, Shigeru; Fukudome, Akinori; Miyama, Motoyoshi ...
Journal of PHYSIOLOGICAL ANTHROPOLOGY,
2006, 2006-Jan, 2006-00-00, 20060101, Volume:
25, Issue:
1
Journal Article
Peer reviewed
Open access
The purpose of this study was to comparatively investigate the energy expenditure of jumping on sand and on a firm surface. Eight male university volleyball players were recruited in this study and ...performed 3 sets of 10 repetitive jumps on sand (the S condition), and also on a force platform (the F condition). The subjects jumped every two seconds during a set, and the interval between sets was 20 seconds. The subjects performed each jump on sand with maximal exertion while in the F condition they jumped as high as they did on sand. The oxygen requirement for jumping was defined as the total oxygen uptake consecutively measured between the first set of jumps and the point that oxygen uptake recovers to the resting value, and the energy expenditure was calculated. The jump height in the S condition was equivalent to 64.0±4.4% of the height in the maximal jump on the firm surface. The oxygen requirement was 7.39±0.33 liters in S condition and 6.24±0.69 liters in the F condition, and the energy expenditure was 37.0±1.64 kcal and 31.2±3.46 kcal respectively. The differences in the two counter values were both statistically significant (p<0.01). The energy expenditure of jumping in the S condition was equivalent to 119.4±10.1% of the one in the F condition, which ratio was less than in walking and close to in running.
Antigen-presenting, major histocompatibility complex (MHC) class II-rich dendritic cells are known to arise from bone marrow. However, marrow lacks mature dendritic cells, and substantial numbers of ...proliferating less-mature cells have yet to be identified. The methodology for inducing dendritic cell growth that was recently described for mouse blood now has been modified to MHC class II-negative precursors in marrow. A key step is to remove the majority of nonadherent, newly formed granulocytes by gentle washes during the first 2-4 d of culture. This leaves behind proliferating clusters that are loosely attached to a more firmly adherent "stroma." At days 4-6 the clusters can be dislodged, isolated by 1-g sedimentation, and upon reculture, large numbers of dendritic cells are released. The latter are readily identified on the basis of their distinct cell shape, ultrastructure, and repertoire of antigens, as detected with a panel of monoclonal antibodies. The dendritic cells express high levels of MHC class II products and act as powerful accessory cells for initiating the mixed leukocyte reaction. Neither the clusters nor mature dendritic cells are generated if macrophage colony-stimulating factor rather than granulocyte/macrophage colony-stimulating factor (GM-CSF) is applied. Therefore, GM-CSF generates all three lineages of myeloid cells (granulocytes, macrophages, and dendritic cells). Since > 5 x 10(6) dendritic cells develop in 1 wk from precursors within the large hind limb bones of a single animal, marrow progenitors can act as a major source of dendritic cells. This feature should prove useful for future molecular and clinical studies of this otherwise trace cell type.
This study examined the contribution of plantar flexion in vertical jumping on sand. Seven healthy young adults performed a plantar flexion without jumping and a vertical jump on a force-platform ...(RS) and on one covered with sand (SS). The vertical force of jumping and that of plantar flexion, the ankle joint range of motion, and the angular velocity were measured. The impulse of the plantar flexion and of the jump were calculated. The impulses of the vertical jump and of the plantar flexion were significantly less for the SS than for the RS (p<0.05). However, between the SS and the RS, there was no statistical difference in the contribution of the plantar flexion, the ankle joint range of motion, and the angular velocity. In conclusion, the contribution of the plantar flexion to vertical jumping on sand would not be distinct from jumping on a rigid surface.
The developmental origin of dendritic cells, a specialized system of major histocompatibility complex (MHC) class II-rich antigen-presenting cells for T-cell immunity and tolerance, is not well ...characterized. Granulocyte-macrophage colony-stimulating factor (GM-CSF) is known to stimulate dendritic cells, including growth and development from MHC class II-negative precursors in suspension cultures of mouse bone marrow. Here we studied colony formation in semi-solid methylcellulose cultures, a classical bioassay system in which GM-CSF induces the formation of mixed granulocyte-macrophage colonies. When colonies were induced from MHC class II-negative precursors, a small subset (1-2%) of typical dendritic cells developed alongside macrophages and granulocytes. The dendritic cells were distinguished by their cytologic features, high levels of MHC class II products, and distinct intracellular granule antigens. By using differential adherence to plastic, enriched populations of the various myeloid cell types were isolated from colonies. Only the dendritic cells stimulated a primary T-cell immune response, the mixed leukocyte reaction, and the potency was comparable to typical dendritic cells isolated from spleen. Macrophages from mixed or pure colonies were inactive as stimulator cells. Therefore, three distinct pathways of myeloid development-granulocytes, macrophages, and dendritic cells-can develop from a common MHC class II-negative progenitor under the aegis of GM-CSF.
The purpose of this study is to examine the cardiovascular and metabolic responses between dynamic and static exercise when a leg press exercise is performed. Seven participants (20–21 yrs) were ...recruited for the experiment. Four modes of dynamic or static leg press exercise were assigned in two combined conditions: a unilateral or a bilateral condition and two exercise intensities with 20% and 40% of maximal voluntary contraction (20% MVC, 40% MVC). The duration of the dynamic exercise and the static exercise at 20% MVC was six minutes, and the static exercise at 40% MVC was three minutes. In the dynamic exercise, ventilation (VE), O2 uptake (VO2), heart rate (HR), and systolic and diastolic blood pressures (SBP, DBP) reached the steady-state after 3 min exercise, while in the static leg press, these responses continued to increase at the end of exercise. The alteration in VO2 mostly depended on both exercise intensity and the one- or two-leg condition during the dynamic leg press, whereas no significant difference in VO2 during the static leg press was found in the four modes. The alterations in rate-pressure product (RPP) depended solely on exercise intensity and leg condition. These findings suggest that the static leg press causes a greater rise in HR, SBP, and DBP. In addition, RPP appears particularly sensitive to experimental modes.
This experiment evaluates the effectiveness of the drag of sand for strength training. Twenty cm depth of quartz sand was placed in a large box and five subjects performed knee extension/flexion ...against the sand drag and on an isokinetic machine at three velocities, 30, 60, and 120 degrees/sec. Electromyograms of vastus laterlis, biceps femoris, and tibialis anterior were taken, and the changes of the knee joint in motion were measured. The exercises with the sand and the machine were similar in the changing velocity and antagonist's activity. The muscle activity with the sand exercise was 30 to 50% less than with the machine. However, the intensity of the exercises with the sand was at a positive level for strength training, especially, the high velocity exercise was similar with the machine exercises. These findings suggest the exercise training using sand resistance can cause the same effect as the isokinetic training.
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