The purpose of this study was to examine reaction times and ground reaction force in different vertical jumps. Fifteen healthy adult males were given the following tasks ; “Jump as quickly as ...possible when a lamp lights, and then touch the target in succession”. The participants jumped vertically ; (1) with a counter movement jump (CMJ), (2) after relaxing and bending both knees as in the technique from old Japanese martial (Hiza-nuki J) (3) hop and jump (HJ) and (4) from a static squatting position (SJ). The parameters were reaction time, maximum vertical ground reaction force and maximum vertical ground reaction force per weight. Results are summarized as follows ; 1. The reaction time in Hiza-nuki J was the shortest except for SJ. 2. The maximum vertical ground reaction force and the maximum vertical ground reaction force per weight in Hiza-nuki J and HJ were larger than CMJ and SJ. 3. There were correlations between HJ and CMJ (r = 0.677, p < 0.05), SJ and HJ (r = 0.701, p < 0.05) in the reaction time. 4. There were correlations between Hiza-nuki J and HJ (r = 0.662, p < 0.05) in the maximum vertical ground reaction force. 5. There were correlations between SJ and CMJ (r = 0.643, p < 0.05) in the maximum vertical ground reaction force per weight. 6. There were negative correlations between the reaction time and the maximum vertical ground reaction force, CMJ (r = -0.736, p < 0.05), Hiza-nuki J (r = -0.615, p < 0.05), SJ (r = -0.543, p < 0.05). There were negative correlations between the reaction time and the maximum vertical ground reaction force per weight, CMJ (r = -0.741, p < 0.05), Hiza-nuki J (r = -0.671, p < 0.05), SJ (r = -0.640, p < 0.05). As the reaction time shortens, the maximum vertical ground reaction force and the maximum vertical ground reaction force per weight tend to increase except for HJ. In conclusion, the results of this study indicate that Hiza-nuki J is a movement that helps jump the quickest, compared with the other movements. In addition, Hiza-nuki J, CMJ, and SJ showed a tendency that the shorter the reaction time, the larger the ground reaction force becomes.
This study aimed to examine the relationships between changes in the center of pressure (COP) during static one leg standing posture and lower limb isokinetic muscle strength. Subjects included 15 ...healthy young males (height 174.6±7.9cm, body weight 71.2±7.2kg, age 36.7±9.6years). Significant correlations (r = |0.56 - 0.66|) were found between COP parameters (outer area, execution area, and pass length per unit area) during one leg standing posture with open eyes and leg isokinetic muscle strength (hip flexion : 60 deg/sec) during the first interval (0-30 sec) and the second interval (30-60 sec). Increased hip flexion strength may suppress the increase of COP in the beginning of one leg standing posture. Significant correlations (r = 0.60 - 0.62) were found between the one leg standing balance test with closed eyes and leg isokinetic muscle strength (hip flexion : 60 and 180 deg/sec). In conclusion, hip flexion strength may contribute to stable one leg standing posture regardless of whether the eyes are closed or opened.
The purpose of this study was clarify characteristic of “T-style shooting” (TS) applied to the long shot of basketball through a movement analysis. Comparing with the ordinal style (OS) of it, the ...investigation revealed the following regarding TS : (1) The success rate at the 9.25m point was higher, but not different at 8.25m. (2) The movement time was significantly shorter (p＜0.05). (3) The average values of the projecting angle and the initial velocity of the ball were higher (p＜0.05). (4) The shift of the body's center of gravity (BCG) during catching and releasing the ball was larger (p＜0.05). (5) The speed of shifting BCG for the vertical direction when the ball was released was faster (p＜0.05). (6) The time between the movements the ball was released and BCG reached the highest position was longer (p＜0.05). That is, it was observed that in TS the ball was released at a moment while BCG was moving up fast before reaching the top. Other features observed in TS were (7) a reaction movement to move the ball front to backward was observed immediately before setting, (8) the EMG during TS was different from OS. Conclusively, it is clear that TS is a shooting technique to efficiently use reaction movement of the four limbs and the characteristic of muscle power output.
A Study of Quick Jump Movement Irie, Shirou; Nakada, Masakatsu; Mimura, Yuki ...
Journal of Kanagawa Sport and Health Science,
2010, Volume:
43
Journal Article
Open access
The purpose of this study was to clarify the characteristic of quick Hiza-nuki J (knee relaxing jump) in detail on the movement time, comparing the jump duration of Hiza-nuki J with that of a counter ...movement jump (CMJ). In addition, it examined the maximum vertical ground force per weight and the relationships with the extension muscular strength of three lower limb joints at every movement phase of the jump. Results are summarized as follows: 1. The jump duration of two jumps of CMJ and Hiza-nuki J did not have the significant difference, but had a correlation (r ＝ 0.844, p ＜ 0.05 s), 2. As for the maximum vertical ground force per weight of CMJ and Hiza-nuki J, Hiza-nuki J was significantly larger (p ＜ 0.05). Further, both had a meaningful correlation (r ＝ 0.611, p ＜ 0.05), 3. Between the maximum vertical ground force per weight and jump duration of CMJ and also between those of Hiza-nuki J, there was no meaningful correlation. 4. There was no correlation between time at every movement phase of Hiza-nuki J and jump duration, 5. In movement times of CMJ and Hiza-nuki Jump from the beginning to leaving floor, and time of PPT and PPTB, there was a meaningful correlation for relationships with the maximum vertical ground force per weight, 6. For between jump duration and the lower limb extension muscular strength of CMJ, there was a meaningful correlation between muscular strength of the knee joint extension of 300 degrees/second (r ＝ 0.632, p ＜ 0.05) and the foot joint extension of 60 degrees/second (r ＝ 0.634, p ＜ 0.05). Also, there was a meaningful correlation between jump duration and knee joint extension of 300 degrees/second in Hiza-nuki J (r ＝ 0.654, p ＜ 0.05), and 7. In the relationships of time in the movement phase of CMJ and Hiza-nuki J and lower limb extension muscular strength, there was a meaningful correlation only between PT of Hiza-nuki J and muscular strength of the foot joint extension 60 degrees/second (r ＝ 0.619, p ＜ 0.05). Hiza-nuki J was the jump method that secured the jumping height at the same level as CMJ by the movement time when Hiza-nuki J was quick, and possible usability was suggested to be more effective than by ball game sports.
