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ANGULAR VELOCITIES OF PERFORMER'S BODY SEGMENT
DR. H.J. BIESTERFELDT, JR . i' GYMNAST" RESEARCH EDITOR
Athletics Department- SIU Arena Carbondale. Illinois 62901 USA •.....................................
A Cinematographic Analysis of a Back Uprise to a Handstand on the Parallel Bars Comments on the ABSTRA CT by Larry Svihlik: The study does not purport to give a thorough .analysis of the movement, in how small part due to unavailability of adeq uate computer analysis facilities. It is the view of this editor that as a rule, studies that do not include total linear and angular momentum calcu l ations as a rule give too little information to do us much good. Without these, we do not discover the ACTUAL effects of various body actions, but instead the apparent effects on body position .
larrv W. Svihlik M.A. in Physical Education, 1973. 36 p.
Mankato State College, Mankato, Minnesota This study was undertaken to analyze a back uprise to a handstand on the parallel bars. Motion pictures were taken of the skill. Measurements were made from enlargements of the exposed film from which the data were gathered. The subject showed partial but rapid hip extension prior to the hip-flick action that started nine degrees past the vertical on the downswing. Following the hip-flick action, the body was. moved into a slight arch. The ankles of the subject were raised upward in a rotary manner during the backswing of the skill. The elbows and shoulders generated high angular velocities by extension and flexion as the body swung to a handstand position.
The abov e study was completed in order to illustrate bod Y " act ions " to the neophyte gymnast o r gymnast ic coach . Comparison of execution techniques were not attempted in this st ud y. A lso no attempt was made by the author to mea sure kineti c energy, potential energy stored in the parallel bars or u pward or horizontal momentum . Only angular ve locities of bodY segments and center of gravity ca lculations were record e d for this study. Below is the table of ·angu lar velocities of th e performer's body seg ments during the execution of thi s skill. Positive angu lar Jb
5-6 9-10 13-14 17-18
-379.74 -253 . 16 +316.45 +189.87 +316 . 45
25 - 26 33-34
00 . 00 +253.16 -12 6.58
37-38 41-42 45-46 ·t9-50
00.00 +506.32 -319. 74 -506 .32
53 - 5 4 +189.87 -189 . 87
00.00 -189.87 -25 3.16 +126 .58
57-58 61-62 65-66
+379 . 74 -253 . 16
69-70 73 -74 77-78 81-82
+ 63. i9 +379.74 +316.45 00.00
+189.87 +126 .58 63 . 29 00 . 00
+126.58 +126.58 +189.87 + 63.29
00.00 -443 .03 +632.91
-189 .87 +632 .91 -506.32
00.00 - 63.29 - 63.29
+379.74 +253.16 +506 . 32
+506.32 +253.16 +506.32
+253.16 +l89.87 - 63.29
+632.91 -126.58 +379.74
+253.16 00.00 + 63.29
89-90 93-94 97-98 101-102 105-106 109-110 113-114 116-117
+ 63.29 +379.74
-632.91 +253.16 + 63.29 - 63 . 29 +506 . 29
velocities in dicate tha t subject was in the process of extending the body segments about that joint. A negative an gular ve locity indicate a flexing action about that joint. . During the execut ion of thi s ski ll , it was observed that the performer' s bodY segments exhibited unpatterned ang ular veloc iti es. The performer was co nstantly compensating for rapid extension of one body segment by a slower extension o r flexion of another joint. Thi s was done to maintain balance throughout the performance of the skill. In the illustration, frame 33-34, the hip joint exhibited flexion. This flex ion of the hip joint shortened the radius of rotation thereby increasing angu lar ve locity. (The bodY moved faster in a rotary manner.) Eight frames later, frames 41-42, the hip explosive ly extended at a high angular velocity. This " hip-flick " aCtion, frames 33-42, helped to initi ate addit ional momentum of the body which enabled it to swing to a handstand. The mom entum ·o f this " hip-flick" action caused the body to assume a slightly arched pos iti on . also flexion of the knee joint occurred- for .2686 of a second. The knee joint flex ion and slight arch of the body shortened th e rad iu s of rotat ion and added to the body' s upward swing.
Recommendations 1. A blurring of b ody segments in certain portions of the sk ill was ob se rved. A ca mera speed of 128 frames per second (instead of 64) could help alleviate this problem. 2. More subjects o f different body types could be used for a study of thi s type. 3. A co mparat ive study of execution techniques of this skill cou ld b e undertaken . 4. Computor program analysis cou ld be used in o rd er to gather more data on this skill. 5. Cinematographic studies on parallel bars involving a ba ck uprise as a main component of the sk ill co uld be resea rched. By doing so, a back uprise may be resea rched more thoroughlY.
CORRECTION I n setting the type for a recent research article, we accidentally failed to include the second author. Article appeared on p . 44 of the October 1974 issue, and correct title and authors are as follows: COMPARISON OF THE BODY DIMENSIONS OF JAPANESE, HUNGARIAN AND AMERICAN GYMNASTS by Richard C. Nelson and Brian W. Bergemann Biomechanics Laboratory, Penn State University, University Park, Penna.
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