体力科学
Online ISSN : 1881-4751
Print ISSN : 0039-906X
ISSN-L : 0039-906X
最新号
選択された号の論文の11件中1~11を表示しています
総説
  • 多胡 陽介, 浦田 達也, 芳田 哲也
    原稿種別: 総説
    2022 年 71 巻 4 号 p. 305-318
    発行日: 2022/08/01
    公開日: 2022/07/12
    ジャーナル オープンアクセス

    In this study, we searched the relevant literature for studies involving the number of tackles and wins/losses in a rugby match, the movement of the tackler and ball carrier, the momentum of tackles, the technique and physical fitness of tacklers, and the risk of injury in order to examine the factors contributing to a successful tackle. As a result, it was found that professional players had a higher success rate of tackles than amateur players younger than 20 years of age. However, the number of tackles per match and the relationship between the success rate of tackles and the results of the match differed depending on the competitive level and the country/region. Regarding tackle movements, the success rates of shoulder tackles were higher than those of other types of tackles. High-level players performed shoulder tackles with both shoulders and both hips facing the ball carrier (body position square), with their trunk roughly parallel to the ground. Furthermore, high-level players had a high body mass; thus, they tackled with high momentum (velocity × mass). Regarding physical fitness, high-level tackling techniques required maximum strength and power in the lower and upper limbs, and also improving the maximal aerobic capacity and overall agility may help prevent fatigue and thus positively contribute to successful tackling. This review suggested that young rugby players need to improve their tackling techniques, including adopting a posture with a straight spine and leg-drive, as the risk of concussion among novices was higher than that among experts.

原著
  • 濵野 純, 田中 綾乃, 田畑 泉
    原稿種別: 原著
    2022 年 71 巻 4 号 p. 319-331
    発行日: 2022/08/01
    公開日: 2022/07/12
    ジャーナル オープンアクセス

    The purpose of this study was to examine the risk factors of stress fractures in terms of training distance and intensity in young male Japanese high school long-distance runners. Nine hundred and twenty-five runners from high schools, colleges, and work teams responded to our questionnaire. Our analysis of the questionnaire found that the onset rates of stress fractures in males were 25.0%, 40.2%, and 55.3% in high school runners, collegiate runners, and work team runners, respectively, suggesting that young Japanese long-distance runners are more likely to suffer from stress fractures than European and American runners. Stress fractures occurred in male high school and collegiate runners after training that had increased running distance (24.7% and 33.1%, respectively) or running intensity (17.0% and 9.6%), or both increased running distance and increased running intensity (29.8% and 34.6%), suggesting that an increase in running distance at moderate intensity might be a major risk factor in stress fractures in young male long-distance runners. Data from college and work team runners that ran all three years of high school show that stress fractures are most likely to occur in May of the high school freshman year. These results suggested a need to reconsider training programs for freshmen to prevent stress fractures in young runners.

  • 橋本 峻, 山下 奈瑠美, 谷口 耕輔, 杉田 正明
    原稿種別: 原著
    2022 年 71 巻 4 号 p. 333-343
    発行日: 2022/08/01
    公開日: 2022/07/12
    ジャーナル オープンアクセス

    Sweat contains electrolytes (minerals), therefore, it is necessary to consider its loss through sweat in the fluid replacement strategy in sports. The purpose of this study was to compare the concentration of components in sweat, such as electrolytes (minerals), when endurance exercise is performed in hot and neutral thermal environments. Eight men cycled for 60 min at 55% VO2peak under two envitonment conditions: a hot environment (WetBulb Globe Temperature (WBGT): 29.0±0.2℃; Heat) and a neutral thermal environment (WBGT: 20.5±0.2℃; Con). During exercise, sweat loss, core temperature, and heart rate (HR) were measured, and sweat from the chest, back, and thigh was collected. The core temperature, sweat loss, and HR increased significantly in Heat. The sweat electrolyte concentration was significantly higher in Heat than in Con only for Na. Regarding the amount of electrolyte loss from sweat, Na and K showed a significantly higher value than Con in Heat in comparison of each region, and the total loss amount of three regions in Cu also had a significantly higher value than Con in Heat. In addition, there was no difference in the concentration of Ca and Cu between the regions, but there was a significant difference in the amount of loss. It was concluded that even if there was no difference in the electrolyte concentration in sweat, the amount of electrolyte loss increased in K and Cu in a hot environment, and that there was a site difference in the amount of loss in Ca and Cu.

  • 岩田 理沙, 河村 拓史, 細川 由梨, 張 黎栗, 鈴木 克彦, 村岡 功
    原稿種別: 原著
    2022 年 71 巻 4 号 p. 345-353
    発行日: 2022/08/01
    公開日: 2022/07/12
    ジャーナル オープンアクセス

    To investigate the factors affecting the rate of improvement in endurance exercise performance following pre-cooling with ice slurry, we focused on individual physical characteristics and thermoregulatory capacity. Twenty-four healthy adults (12 males and 12 females) ingested 7.5g kg-1 of either ice slurry at -1°C (ICE) or control water at 20°C (CON) before cycling at 55% VO2max and continued cycling until the rectal temperature reached 38.5°C or untill exhaustion in a hot environment (controlled at 38°C, 40% relative humidity). The relationship between the rate of improvement in exercise performance and physical characteristics and thermoregulatory factors (changes in rectal temperature, the rate of rectal temperature increase, whole body sweat loss, mean metabolic heat production, and heat storage) was investigated. No correlation was noted between the rate of improvement in exercise performance and physical characteristics and heat storage. On the other hand, the rate of improvement in exercise performance showed significant correlations with changes in rectal temperature (r = -0.497), the rate of rectal temperature increases during exercise (r = -0.784), whole body sweat loss (r = 0.407), and mean metabolic heat production (r = -0.436). The rate of inhibition of sweating and the rate of increase in metabolic heat production by ice slurry ingestion during exercise have been suggested to be related to the rate of improvement in exercise performance. On the other hand, there was no relationship between body composition or VO2max and the rate of improvement in exercise performance.

  • 小泉 潤, 泉 主馬, 大家 利之
    原稿種別: 原著
    2022 年 71 巻 4 号 p. 355-365
    発行日: 2022/08/01
    公開日: 2022/07/12
    ジャーナル オープンアクセス

    It has been suggested that inspiratory muscles fatigue impairing blood flow to the active limb muscle via respiratory muscle metaboreflex. The purpose of this study was to investigate the effects of inspiratory muscle fatigue on exercise performance and muscle tissue oxygenation in high-intensity exercise takes about 3.5~5min. Eleven healthy males subjects performed two conditions of constant-load exercise to exhaustion (TTE) on a cycle ergometer at 100% of maximal oxygen uptake. The two conditions—inspiratory muscle fatiguing (IMF) and non-fatiguing (PLA) —which had different intensity inspiratory resistance breathing (IRB) were performed before exercise. Muscle tissue oxygenations were measured by deoxyhemogrobin (HHb), oxygen saturation index (StO2) from right vastus lateralis during TTE. All data were analyzed from nine subjects whose inspiratory muscle were fatigued by IRB in IMF. Results: TTE was significantly shorter in IMF compare to PLA (244±31s vs. 268±38s, p<0.05). HHb was significantly higher and StO2 was significantly lower in IMF than in PLA (p<0.05). Conclusion: High-intensity exercise completed in 3.5~5 minutes, it was suggested that inspiratory muscle fatigue reduced the oxygen deriver to active limb muscle, resulting in decrease exercise performance. Improving function of inspiratory muscles, such as in inspiratory muscle training, may improve oxygenation of the active limb muscle and enhance exercise performance.

ノート
  • 幸 篤武, 玉瀬 友美, 中山 美香
    原稿種別: ノート
    2022 年 71 巻 4 号 p. 367-372
    発行日: 2022/08/01
    公開日: 2022/07/12
    ジャーナル オープンアクセス

    Phase angle, calculated as the arc-tangent of the reactance-to-resistance ratio in bioelectrical impedance analysis, represents skeletal muscle quality, and is suggested to be an indicator of sports ability and physical fitness. However, it is unclear whether phase angle is related to physical fitness in early childhood in Japanese subjects. The purpose of this study was to examine the cross-sectional relationship between physical fitness and bioelectrical impedance analysis-based phase angle in 6-year-old Japanese children. The subjects were 85 kindergarten students who participated in a physical fitness test and body composition assessment in 2017, 2018 or 2019, in the third year of kindergarten. Fitness tests included grip strength, standing long jump, and 25 m run. A multi-frequency composition analyzer was used for body composition analysis, and the phase angle of the left half of the body was acquired at 50 kHz. Statistical analysis was performed using a general linear model to calculate the regression coefficient of phase angle for physical fitness. Phase angle correlated significantly with the standing long jump and 25 m run. The regression coefficient (±standard error) of phase angle in the standing long jump in the fully adjusted model was 5.098 ±2.264 (p<0.05), and that in the 25 m run was -0.179 ±0.088 (p<0.05). There was no significant correlation between phase angle and grip strength. These results suggest that phase angle based on bioelectrical impedance analysis might be related to lower limb muscle function and running ability in 6-year-old Japanese children.

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