RESEARCH FOR PATTERNS OF PULLING FORCE CURVE DURING BACK AND WHIP SWING PERFORMANCE ON FLYING RINGS

Abstract

INTRODUCTION When a gymnast performs the back and whip - swing performance on the rings, how did the pulling - force curve change? What was the relationship between this curve and the position and shape of the body? How was the relationship between this curve and the force exerted by the muscles in the performance? METHODOLOGY The high - speed camera, pulling - force sensor and remote EMG meter were simultaneously operated by means by synchronous signal generator for the collection of data. RESULTS The pulling - force values in five movements were 6.30 ± 0.33 (Swing in hanging), 6.59 ± 0.48 (Swing backward to handstand), 7.5 ±.65 (Forward grand circling) respectively as times of a body weight. Therefore the contraction speed of muscle was emphasized, because the force value produced by the body with acceleration acting on rings was larger than that without acceleration. Since the gravity force was constant for one gymnast, the force value mainly depended on the magnitude of the body acceleration (Σ:F=m.a). The larger the acceleration was, the larger the reactive force was. CONCLUSION There were two types of pulling-force curve in back and whip-swing performance of rings. These were single and double peak types. The single peak was caused by back and whip swing without the handstand. Forward grand circling performance was the double peak type. 2. In the double peak curve, the first peak was caused by dropping shoulder, its value was about 4.27 to 4.66 as times of body weight, the second peak value was about 6.30 to 7.50 as times of body weight. This reason was the different value of the muscle force. 3. The maximum value of pulling force curve (the second peak) occurred just behind vertical level. The time behind vertical level in five performances was from 4.50 ms to 13.00 ms. REFERENCES Niu Jianzhuang and Zhou Li, "Study on the Pattern of the Muscles Exerting Force during Back and Whip Swing from Hanging Position in Rings". Chinese Sports Science and Technology, Vol. 28 NO. 8, P17-21, 1992