| Research Purpose: The purpose of the study is to show the rationality of rowers' stroke rhythm by using the ratio of drive and recovery to reveal the coordination of the relationship between upper, lower limbs and trunk, and evaluate the external characteristic of stroke movement, this paper analysis the body joints angle; to show the characteristics of muscle force and evaluate whether the rowing technique style is good or not by means of body joints' angular velocity.Methods: By using SONY VCR(MODEL: PC 350E) at the speed of 25fps to track and scan rowers' stroke movement of the half-way stage who attended the 2008 Olympic Games. This paper analyzes rowing technique in a stroke cycle by using method of 2D SIMI°Motion 7.50 Analysis System.The results show that:1. It is not only an important symbol of proper rowing technique but an important factor of improving the rowing performance to master the stroke rhythm and correctly control and properly apply in training and competition.2. In one stroke cycle, there exists significant difference among elbow joints range of activities in both pin-side of male and female single-oar rowers, but the difference of off-side lies in wrist range of activities. Both male and female sculls rowers have big difference among wrist range of activities. Women's arms are weaker than men's both in single-oar and sculls, so they mainly depend on the extension of the knee as much as possible to improve the driving efficiency. Both male and female rowers have low leaning forward or backward angles while rowing. 3. There are five popular rowing styles in the driving process according to the cluster analysis of the pantomime external characteristics parameters, such as the phase sequence of knee joint, trunk and elbow angle change.4. There are six rowing styles in the driving process according to the cluster analysis of the limb muscle producing force characteristics parameters, such as the phase sequence of wrist, elbow, shoulder, hip, knee joint and trunk maximal angular velocity.Rowers of style 1 (knee joint→hip joint→trunk→shoulder joint→elbow joint→wrist) and style 2 (knee joint→hip joint→trunk→elbow joint→shoulder joint→wrist) are in line with the principles of biomechanics, so we make use of skill of big joints' action before small joints while overcoming lager resistance and producing tremendous speed. Style one is used commonly and in style two, rowers' muscles of upper arm and forearm are more powerful, especially when rowers produce force actively. 52 single-oar rowers use these two styles, which accounts for 92.86 percent. 40 sculls rowers use these two styles, which account for 71.43 percent.5. There are five rowing styles in the recovery process according to the cluster analysis of the limb muscle producing force characteristics parameters, such as the phase sequence of wrist, elbow, shoulder, hip, knee joint and trunk maximal angular velocity.Rowers' action sequence of style 1 (wrist→elbow joint, shoulder joint, trunk, which arrive at the same time→hip joint→knee joint), style 2 (wrist→elbow joint→shoulder joint→trunk→hip joint→knee joint) and style 3 (wrist→elbow joint→shoulder joint→hip joint→knee joint→trunk) is reasonable. In recovery process, joint moving sequence is not absolute. It is the medium and small joints (wrist) that exert first, then the big joint take action. Style 1 is used widely, while style 2 is better. 35 single-oar rowers use these two styles, which account for 62.50 percent. 41 sculls rowers use these two styles, which account for 17.86 percent. 10 single-oar rowers using style 3 is only applicable to them, which account for 17.86 percent.6. In driving phase, the difference is not obvious in the recovery-to-drive ratio, which is from the limb muscle producing force characteristics. The recovery-to-drive ratio in style 2 is smaller than in other styles because paddle into water is much faster in the end of the recovery process. Style 3 suits single-oar rowers. Some rowers adopted more trunk's torsion that can increase the scope of driving and extend time, so the recovery-to-drive ratio is bigger. Thus, the ratios exist great difference in these two styles.
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