Techniques Used by Elite Gymnasts in the 1992 Olympic Compulsory Dismount from the Horizontal Bar

1999 ◽  
Vol 8 (3) ◽  
pp. 207-232 ◽  
Author(s):  
Yoshiaki Takei ◽  
Hiroshi Nohara ◽  
Mamoru Kamimura

The purpose of this study was to identify the mechanical factors that are crucial to a successful double salto backward tucked dismount from thehorizontal bar. The subjects were 35 American and 43 Japanese gymnasts competing in their respective 1990 national gymnastics championships. A 16-mm camera, placed with its optical axis parallel to the horizontal bar and operating at 100 Hz, was used to record the performances of the subjects. Significant correlations indicated that a large vertical velocity at bar release, which ensures great height and long time of flight, is important. Successful performance is also likely when efforts are made to (a) achieve the tightest tuck position during the salto backward near the peak of flight, (b) extend the body rapidly and fully early in rotation before the vertical body position is reached well above the bar, (c) maintain the extended body position during the remainder of the flight to display body style for virtuosity bonus points, and (d) simultaneously prepare for a controlled landing on the mat.

1992 ◽  
Vol 8 (2) ◽  
pp. 87-110 ◽  
Author(s):  
Yoshiaki Takei

The purpose of this study was to identify the mechanical factors that are crucial to successful performance of blocking and body control for salto forward and kickout in the handspring and salto forward tucked vault. A 16-mm camera operating at 100 Hz was used to record the performances. The subjects were 51 male gymnasts participating in the 1988 Olympic Games. It was hypothesized that some mechanical factors identified in the model were significantly correlated with successful performance of blocking and body control for salto forward and kickout as rated by the judges. Significant correlations indicated that a large horizontal velocity at touchdown on horse is an important prerequisite for effective blocking and subsequent performance of postflight. The results also indicated that the body’s moment of inertia should be minimized by assuming the full tuck position just before or near the peak of flight, which maximizes the time and height available for executing the kickout in midair. The small angular speed of body rotation due to early kickout and the long-held extended body position as it travels a large horizontal distance are not only effective in the expression of artistic amplitude for virtuosity points but are also crucial for control in landing.


1989 ◽  
Vol 5 (1) ◽  
pp. 1-25 ◽  
Author(s):  
Yoshiaki Takei

The purpose of this study was to determine mechanical factors, through development of the deterministic model, that govern successful performance of the handspring vault. The subjects were 40 elite male gymnasts participating in the 1987 Pan American Games. A motion-picture camera placed with its optical axis at right angles to the runway was used to record the subjects’ performances. Significant correlations indicated that the following were important determinants for success: (a) large horizontal velocity and angular momentum at takeoff from board, (b) shorter time of preflight and smaller relative height of takeoff in preflight, (c) large horizontal breaking force and large vertical force exerted as well as a large loss of angular momentum during horse contact, and (d) large vertical velocity of takeoff from horse. Significant correlation of “on-horse” factors with the judges’ scores indicated that the more the gymnast focused on horse contact and the more vertical the direction of his effort at takeoff, the better the final result. A significant negative correlation revealed that the less the height of CG at touchdown on mat, the more points awarded by judges. This relationship was almost entirely a consequence of the landing angle.


1990 ◽  
Vol 6 (1) ◽  
pp. 29-55 ◽  
Author(s):  
Yoshiaki Takei

The purposes of this study were (a) to determine the mechanical factors associated with successful performance of women’s handspring vault and (b) to contrast the findings to those of men to gain insight for improvement of performance. The subjects were 24 female gymnasts in the 1987 Pan American Games. Significant correlations indicated that the following were important determinants for successful results: (a) large horizontal velocity (VH) and distance of hurdle; (b) large vertical velocity (Vv) at touchdown (TD) on board, a large change of Vv on board, and a short time of board contact; (c) large VH and Vv at takeoff (TO) from board; (d) short time of horse contact; (e) large VH and Vv at TO from horse; (f) high body CG at TO from horse; and (g) great distance and height and a long time of postflight. Comparisons revealed that women had significantly smaller VH and Vv at TD on horse and departed from it with significantly smaller VH and Vv than men. This resulted in significantly less height and distance as well as a shorter time of postflight for women even after adjusting for horse height and subject physique.


2000 ◽  
Vol 16 (2) ◽  
pp. 180-195 ◽  
Author(s):  
Yoshiaki Takei ◽  
J. Hubert Dunn ◽  
Erik P. Blucker ◽  
Hiroshi Nohara ◽  
Noriyoshi Yamashita

The 25 highest scored Hecht vaults (G!) performed during the 1995 World Championships were compared with those receiving the 25 lowest scores (G2). Hypotheses were: GI would achieve (a) larger kinetic energy at takeoff from the board and the horse, (b) greater displacements of CM and greater forward body rotation in prellight. (c) greater changes in velocities and angular momentum on horse, (d) more rapid, forceful blocking/pushing off the horse, and (e) greater “amplitude” and better “form” during the post-flight than G2. A 16-mm motion picture camera, operating at 100 Hz. recorded the vaults during the compulsory competition. The results of t tests (p < .005) indicated Gl had (a) larger kinetic energy at takeoff from the board and the horse, (b) greater displacements of CM and greater forward body rotation in pre-flight. (c) greater changes in vertical velocity and angular momentum on the horse. greater vertical impulse of high force and short duration exerted on the horse, and greater “amplitude,” greater backward body rotation, and greater body extension in post-flight than G2. In conclusion, successful performance of the Hecht vault is likely when focus is on sprinting the approach, blocking and pushing off the horse rapidly and vigorously downward, and maintaining the fully extended body position throughout the post-night to display “form” or fish-like body position for a virtuosity bonus point and simultaneously to prepare for a controlled landing on the mat.


Author(s):  
Ana Mercedes Vernia-Carrasco

<p><strong>Resumen </strong></p><p>Durante mucho tiempo hemos escuchado las diferentes habilidades que son idóneas para el sexo femenino. Así la profesión de maestro es más aceptada por las mujeres que por los hombres, pudiendo añadir que en general las carreras vinculadas a las Humanidades son preferidas por el género femenino. En nuestro trabajo, y a partir del desarrollo de actividades en el aula de música, detectamos un falso perfil para el futuro maestro de primaria donde, si el docente es hombre, evitará la expresión corporal o el control psicomotriz, cuidando la posición corporal o la lateralidad. Si el docente es mujer, por lo general, realizará actividades donde la voz y el cuerpo sean elementos presentes y el juego signifique una herramienta de aprendizaje.</p><p><strong>Abstract</strong></p><p>For a long time we have listened to the different skills that are suitable for the female sex. Thus the profession of teacher is more accepted by women than men, and may add that in general careers linked to the Humanities are preferred by the female gender. In our work, and from the development of activities in the music classroom, we detect a false profile for the future teacher of primary where, if the teacher is male, avoid body expression or psychomotor control, taking care of body position or laterality. If the teacher is a woman, she will usually do activities where the voice and the body are present elements and the game means a learning tool.</p>


2021 ◽  
Vol 10 (78) ◽  

Playing an instrument requires the body to be in a position against the natural posture of the instrument, and there is a risk of bodily problems that may arise from playing the instrument at any level of the musician's life. With this study, it is aimed to search in detail the physical risk factors that may be caused by the playing an instrument and how to protect from these risk factors, to include theoretical information on the subject, to raise awareness on the subject, and to be a source. In line with the purpose of the study, local and foreign sources related to the subject were reached by using the literature review method. The data obtained in the study were classified in line with the subject and purpose of the study and presented as subject headings. Risky situations that cause physical ailments in musicians playing musical instruments; Overuse, misuse, repetitive movements performed in wrong positions, carrying the weight of the instrument for a long time, the quality of the instrument, the use of unfavorable body position, the technical difficulty of the repertoire, intensive work before the concert, overstrain, performance anxiety, psychological stress caused by the pressure to be perfect. To prevent injuries caused by these negative situations, to give appropriate rest breaks during the study, to warm up the body structures used with physical exercises before to work, to protect personal health, to choose appropriate practical environments, to develop the correct practical habits, to benefit from ergonomic principles, to choose suitable instruments and furniture, It will be helpful to be aware and develop safe equipment handling techniques. Playing an instrument requires the body to be in a position against the natural posture of the instrument, and there is a risk of bodily problems that may arise from playing the instrument at any level of the musician's life. With this study, it is aimed to search in detail the physical risk factors that may be caused by the playing an instrument and how to protect from these risk factors, to include theoretical information on the subject, to raise awareness on the subject, and to be a source. In line with the purpose of the study, local and foreign sources related to the subject were reached by using the literature review method. The data obtained in the study were classified in line with the subject and purpose of the study and presented as subject headings. Risky situations that cause physical ailments in musicians playing musical instruments; Overuse, misuse, repetitive movements performed in wrong positions, carrying the weight of the instrument for a long time, the quality of the instrument, the use of unfavorable body position, the technical difficulty of the repertoire, intensive work before the concert, overstrain, performance anxiety, psychological stress caused by the pressure to be perfect. To prevent injuries caused by these negative situations, to give appropriate rest breaks during the study, to warm up the body structures used with physical exercises before to work, to protect personal health, to choose appropriate practical environments, to develop the correct practical habits, to benefit from ergonomic principles, to choose suitable instruments and furniture, It will be helpful to be aware and develop safe equipment handling techniques.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 963
Author(s):  
Ekaterina S. Dolinina ◽  
Elena V. Parfenyuk

Powerful antioxidant α-lipoic acid (LA) exhibits limited therapeutic efficiency due to its pharmacokinetic properties. Therefore, the purpose of this work was to evaluate the ability of silica-based composites of LA as well as its amide (lipoamide, LM), as new oral drug formulations, to control their release and maintain their therapeutic concentration and antioxidant activity in the body over a long time. The composites synthesized at different sol–gel synthesis pH and based on silica matrixes with various surface chemistry were investigated. The release behavior of the composites in media mimicking pH of digestive fluids (pH 1.6, 6.8, and 7.4) was revealed. The effects of chemical structure of the antioxidants, synthesis pH, surface chemistry of the silica matrixes in the composites as well as the pH of release medium on kinetic parameters of the drug release and mechanisms of the process were discussed. The comparative analysis of the obtained data allowed the determination of the most promising composites. Using these composites, modeling of the release process of the antioxidants in accordance with transit conditions of the drugs in stomach, proximal, and distal parts of small intestine and colon was carried out. The composites exhibited the release close to the zero order kinetics and maintained the therapeutic concentration of the drugs and antioxidant effect in all parts of the intestine for up to 24 h. The obtained results showed that encapsulation of LA and LM in the silica matrixes is a promising way to improve their bioavailability and antioxidant activity.


2021 ◽  
Vol 7 ◽  
pp. 205951312098032
Author(s):  
Chenyu Huang ◽  
Rei Ogawa

Introduction: Keloids are pathological scars that are notorious for their chronic and relentless invasion into adjacent healthy skin, with commonly seen post-therapeutic recurrence after monotherapies. Methods: An English literature review on keloid pathophysiology was performed by searching the PubMed, Embase and Web of Science databases, to find out the up-to-date relevant articles. The level of evidence was evaluated based on the included studies with the highest level of evidence first. Results: Keloid morphology, signs, symptoms and the histopathological changes that occur in the local cells and extracellular matrix components are described. The theories on the pathophysiology of keloidogenesis that have been proposed to date are also covered; these include endocrinological, nutritional, vascular, and autoimmunological factors. In addition, we describe the local mechanical forces (and the mechanosignalling pathways by which these forces shape keloid cell activities) that promote keloid formation and determine the direction of invasion of keloids and the body sites that are prone to them. Conclusion: A better understanding of this pathological entity, particularly its mechanobiology, will aid the development of new diagnostic and therapeutic strategies for use in the clinic to prevent, reduce or even reverse the growth of this pathological scar. Lay Summary Keloids are skin scars that are famous for their chronic invasion into healthy skin, with commonly seen recurrence after surgeries. Cells such as lymphocytes, macrophages, mast cells and endothelial cells are involved in keloid growth. Particularly, endocrinological, nutritional, vascular, autoimmunological and mechanical factors actively take part in keloid progression.


Biomolecules ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 79
Author(s):  
Svetlana N. Morozkina ◽  
Thi Hong Nhung Vu ◽  
Yuliya E. Generalova ◽  
Petr P. Snetkov ◽  
Mayya V. Uspenskaya

For a long time, the pharmaceutical industry focused on natural biologically active molecules due to their unique properties, availability and significantly less side-effects. Mangiferin is a naturally occurring C-glucosylxantone that has substantial potential for the treatment of various diseases thanks to its numerous biological activities. Many research studies have proven that mangiferin possesses antioxidant, anti-infection, anti-cancer, anti-diabetic, cardiovascular, neuroprotective properties and it also increases immunity. It is especially important that it has no toxicity. However, mangiferin is not being currently applied to clinical use because its oral bioavailability as well as its absorption in the body are too low. To improve the solubility, enhance the biological action and bioavailability, mangiferin integrated polymer systems have been developed. In this paper, we review molecular mechanisms of anti-cancer action as well as a number of designed polymer-mangiferin systems. Taking together, mangiferin is a very promising anti-cancer molecule with excellent properties and the absence of toxicity.


Author(s):  
Fernanda Mottin Refinetti ◽  
Ricardo Drews ◽  
Umberto Cesar Corrêa ◽  
Flavio Henrique Bastos

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