定量分析高、中、低架的水平推拉力

A Quantitative Analysis on Horizontal Pushing Force and Pulling Force of High, Medium and Low Frames

弓步的高度由步长和大小腿的尺度而定。前小腿的倾斜度对架高也有影响。上体的倾斜度对重心的位置有影响。本文用平面刚体模型对高、中、低架弓步作了力学分析。分析表明,弓步越低,水平推力越大。推(拉)力的计算基于两种临界条件:拔根或打滑。功架的稳定度用稳定角来度量。架子越高,稳定度越差,但灵活性越高。架子越低,稳定度越高,但灵活性越差。前小腿和上体的前倾增加弓步的推力。力学分析表明,中架弓步兼顾了多方的优势。杨澄甫宗师的弓步照片证实了这一点。弓步适合于发出向前的推力,数学运算证明了太极拳的"发劲如放箭"。坐步适合于发出向后的拉力,上体后仰增加坐步的拉力。数学运算证明了太极拳的"引进落空"。分析表明,坐步越低,水平拉力越大。类似地中架坐步兼顾了多方的优势。杨澄甫宗师的坐步功架证实了这一点。

The height of a bow stance is related to step length, calf length and thigh length. The obliquity of the front calf also affects the frame height, while the obliquity of the upper part of the body affects the position of the center of gravity. This article uses planar rigid body model to conduct a mechanical analysis on the bow stance in high, medium and low frames. The analysis indicates that, the lower a bow stance is, the bigger its horizontal pushing force can be supplied. The calculation of the pushing(pulling) force is based on two critical conditions: uprooting or slipping. The stability of a kung fu frame is measured by the stable angle. The higher the frame is, the poorer the stability is, but the higher the flexibility becomes. The lower the frame is, the higher the stability is, but the poorer the flexibility becomes. The forward inclination of the front calf and the upper part of the body can increase the pushing force in a bow stance. The mechanical analysis shows that a medium-frame bow stance has taken into account the advantages of many aspects. The picture of Master Yang Chengfu's bow stance confirms this point. The bow stance is fit for releasing a forward pushing force, and the mathematical operation has proved the phrase of "discharging the force like shooting an arrow" in taijiquan(tai chi chuan, a kind of traditional Chinese shadow boxing). The sit stance is fit for releasing a backward pulling force, for leaning back the upper part of the body can increase the pulling force in a sit stance. The mathematical operation has also proved the phrase of "luring the opponent's force inside to breaking it down or collapsing it" in taijiquan. The analysis indicates that, the lower a sit stance is, the bigger the horizontal pulling force can be supplied. Similarly, a medium-frame sit stance has taken into account the advantages of many aspects. The picture of Master Yang Chengfu's sit stance confirms this point as well.