PubMed · 5110505
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C Holland. 1971-09-10. [Morbus Scheuermann].. https://pubmed.ncbi.nlm.nih.gov/5110505/
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This study reports the techniques used by gymnasts to perform the Hecht vault and compares them with techniques used for the handspring somersault vault (Takei and Kim, 1990). Our main aim was to establish how the pre-flight characteristics of the Hecht vault influence post-flight performance. Data were obtained on 27 elite gymnasts performing the Hecht vault at the 1993 Canadian National Championships using two-dimensional video analysis with the direct linear transformation (DLT) technique. The maximum height reached by the mass centre during post-flight was significantly correlated (P < 0.001) with the vertical velocity of the mass centre and the body angle at horse contact. The backwards rotation of the body was significantly correlated (P = 0.015) with the shoulder angle at horse contact. The competition score was significantly correlated (P = 0.043) with the body angle at horse contact and was also related to the maximum height of the mass centre during post-flight. For the Hecht vault, the gymnasts had longer, lower and faster pre-flights with slower rotation at horse contact compared with the handspring somersault vaults.
A new concept is presented for quantifying the variability of iterated human motions and other recurrent biological phenomena. The concept is based on the idea of interpreting the variations occurring in repeatedly executed stereotyped motions as particular realizations of a regular stochastic process with superimposed but infrequently occurring chaotic excursions. Under these premises, the extended transentropy of such a process turns out to be a dimensionless and appropriate quantifier of motion variability. Extended transentropy functions can be used to monitor variability changes during motion execution. The practical applicability and usefulness of the new method is demonstrated by means of an example from gymnastics (the kip on the horizontal bar). Major areas of future applications are expected to be gait analysis, all sports movements, and the objective evaluation of the success rates of certain medical treatment procedures for specific movement disorders.
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