Abstract：
BACKGROUND: Phase angle (PhA) is an indicator of cellular health, function, and integrity. PhA has been considered an indicator of nutritional and health status, but it is uncertain whether it could be used as a fitness or athletic performance indicator.
OBJECTIVE: To analyze the relationship between PhA and the fitness and athletic performance of adolescent boxers and to know whether this association is independent of body composition.
METHODS: Thirty-seven trained youth boxers (15-18 y old) participated in the study. Participants underwent anthropometry and bioelectrical impedance assessments. The following tests were conducted: Fitness-Gram battery; speed, agility, and quickness; ball throws; punch impact force; bench press maximal strength; and vertical and horizontal jumps. Linear regression models were estimated and adjusted by covariates.
RESULTS: The PhA was related to upper-limb strength. Nevertheless, in linear regression models, after adjusting models by body composition, only PhA remained as a predictor of relative maximal strength. The PhA was not a predictor of speed, agility, and quickness; cardiorespiratory fitness; or lower-limb power, in which adiposity was the main predictor of fitness.
CONCLUSIONS: In adolescent boxers, PhA can predict upper-limb maximal strength independently of bioelectrical impedance analysis premises. However, compared with mucle mass, PhA is not a better predictor of upper-limb maximal strength.
OBJECTIVE: To analyze the relationship between PhA and the fitness and athletic performance of adolescent boxers and to know whether this association is independent of body composition.
METHODS: Thirty-seven trained youth boxers (15-18 y old) participated in the study. Participants underwent anthropometry and bioelectrical impedance assessments. The following tests were conducted: Fitness-Gram battery; speed, agility, and quickness; ball throws; punch impact force; bench press maximal strength; and vertical and horizontal jumps. Linear regression models were estimated and adjusted by covariates.
RESULTS: The PhA was related to upper-limb strength. Nevertheless, in linear regression models, after adjusting models by body composition, only PhA remained as a predictor of relative maximal strength. The PhA was not a predictor of speed, agility, and quickness; cardiorespiratory fitness; or lower-limb power, in which adiposity was the main predictor of fitness.
CONCLUSIONS: In adolescent boxers, PhA can predict upper-limb maximal strength independently of bioelectrical impedance analysis premises. However, compared with mucle mass, PhA is not a better predictor of upper-limb maximal strength.
摘要：
背景：相位角（PhA）是细胞健康的指标，函数,和正直。PhA被认为是营养和健康状况的指标，但不确定它是否可以用作健身或运动表现指标。
目的：分析PhA与青少年拳击手的健身和运动表现之间的关系，并了解这种关联是否与身体成分无关。
方法：37名受过训练的青年拳击手（15-18岁）参加了这项研究。参与者接受人体测量和生物电阻抗评估。进行了以下测试：健身克电池；速度，敏捷性,和敏捷；投球；冲头冲击力；卧推最大强度；以及垂直和水平跳跃。线性回归模型通过协变量进行估计和调整。
结果：PhA与上肢力量有关。然而，在线性回归模型中，根据身体成分调整模型后，只有PhA仍然是相对最大强度的预测因子。PhA不是速度的预测指标，敏捷性,和敏捷；心肺健康；或下肢力量，其中肥胖是健康的主要预测因子。
结论：在青少年拳击手中，PhA可以独立于生物电阻抗分析前提来预测上肢最大强度。然而,与粘液团相比，PhA不是上肢最大力量的更好预测指标。
目的：分析PhA与青少年拳击手的健身和运动表现之间的关系，并了解这种关联是否与身体成分无关。
方法：37名受过训练的青年拳击手（15-18岁）参加了这项研究。参与者接受人体测量和生物电阻抗评估。进行了以下测试：健身克电池；速度，敏捷性,和敏捷；投球；冲头冲击力；卧推最大强度；以及垂直和水平跳跃。线性回归模型通过协变量进行估计和调整。
结果：PhA与上肢力量有关。然而，在线性回归模型中，根据身体成分调整模型后，只有PhA仍然是相对最大强度的预测因子。PhA不是速度的预测指标，敏捷性,和敏捷；心肺健康；或下肢力量，其中肥胖是健康的主要预测因子。
结论：在青少年拳击手中，PhA可以独立于生物电阻抗分析前提来预测上肢最大强度。然而,与粘液团相比，PhA不是上肢最大力量的更好预测指标。
