ABSTRACT
INTRODUÇÃO: A ginástica é o esporte de habilidades fechadas mais antigo e espetacular. Contudo, parâmetros técnicos de execução geralmente são somente ensinados por treinadores experientes. Desta maneira, existe uma lacuna de informações objetivas sobre o desempenho de ginastas (referências cinemáticas). OBJETIVO: No presente estudo, tentamos quantificar movimentos de inversão linear e de hiperextensão durante a execução de flic flacs. MÉTODOS: Foi efetuada uma detecção não invasiva de flic flacs com o auxílio de um instrumento óptico eletrônico 3D. Treze marcadores esféricos retrorreflexivos (1 cm de diâmetro) foram posicionados no corpo de 9 ginastas experientes: maléolos laterais direito e esquerdo, cabeça da fíbula, trocanter maior, acrômio, olecrano, processo estiloide da ulna e vértex. Na mesma sessão e após um período de aquecimento, cada participante executou 15 repetições de flic flacs. Dez repetições forma analisadas, e os trajetos 3D das 13 manobras medidos. RESULTADOS: Em média, os homens obtiveram altura vertical maior (mulheres, 62% da altura; homens, 58%). O alinhamento dos membros inferiores foi homogêneo entre os ginastas: ângulos posteriores de joelho variaram entre 80° e 118°. Nenhuma abdução de membro inferior foi observada: a largura de joelho foi 7 cm menor do que a largura intertrocanter; a largura de tornozelo foi 8 cm menor do que a largura de joelho. Na saída do movimento, o ângulo tronco-coxa apresentou excelente alinhamento corporal, com valores bem próximos de 180°. As mulheres executaram a fase de apoio das mãos com pulsos mais próximos do que os homens (homens, 134% de largura de ombro; mulheres, 121%). CONCLUSÃO: Os resultados podem fornecer informações para melhor conhecimento, definindo assim, a execução de padrão-ouro obtida de ginastas de elite com poucas lesões.
INTRODUCTION: Gymnastics is the most ancient and spectacular closed skills sport. Nonetheless, technical parameters of performance are often taught only by experienced trainers. Thus, there is a lack of objective data about gymnastics performance (kinematics references). OBJECTIVE: In the current study, we tried to quantify linear and hyperextension back movements during performance of backward handsprings. METHODS: A noninvasive detection of backward handsprings was made using a 3D optoelectronic instrument. Thirteen spherical retro-reflective markers (1-cm diameter) were positioned on the body of 9 experienced gymnasts: right and left lateral malleolus, fibular head, greater trochanter, acromion, olecranon, styloid process of the ulna; vertex. In the same session and after a warm-up period, each participant performed 15 repetitions of backward handsprings. Ten repetitions were analyzed, and the 3D tracks of the 13 landmarks measured. RESULTS: On average, men performed longer backward handsprings than women (men, 122% of height; women, 98%); women attained larger vertical height (women, 62% of height; men, 58%). Lower limb arrangement was homogenous among the gymnasts: posterior knee angles ranged between 80° and 118°. No lower limb abduction was observed: knee width was 7 cm smaller than intertrochanter width; ankle width was 8 cm smaller than knee width. At take-off, the trunk-thigh angle presented excellent body alignment, with values very close to 180°. Women performed the handstand phase with closer wrists than men (men, 134% of shoulder width; women, 121%). CONCLUSION: The results may offer data to improve understanding, defining gold-standard execution taken from high level gymnasts with few injuries.
ABSTRACT
OBJECTIVES: Functional orthodontic devices can modify oral function thus permitting more adequate growth processes. The assessment of their effects should include both facial morphology and muscle function. This preliminary study investigated whether a preformed functional orthodontic device could induce variations in facial morphology and function along with correction of oral dysfunction in a group of orthodontic patients in the mixed and early permanent dentitions. MATERIAL AND METHODS: The three-dimensional coordinates of 50 facial landmarks (forehead, eyes, nose, cheeks, mouth, jaw and ears) were collected in 10 orthodontic male patients aged 8-13 years, and in 89 healthy reference boys of the same age. Soft tissue facial angles, distances, and ratios were computed. Surface electromyography of the masseter and temporalis muscles was performed, and standardized symmetry, muscular torque and activity were calculated. Soft-tissue facial modifications were analyzed non-invasively before and after a 6-month treatment with a functional device. Comparisons were made with z-scores and paired Student's t-tests. RESULTS: The 6-month treatment stimulated mandibular growth in the anterior and inferior directions, with significant variations in three-dimensional facial divergence and facial convexity. The modifications were larger in the patients than in reference children. In several occasions, the discrepancies relative to the norm became not significant after treatment. No significant variations in standardized muscular activity were found. CONCLUSIONS: Preliminary results showed that the continuous and correct use of the functional device induced measurable intraoral (dental arches) and extraoral (face) morphological modifications. The device did not modify the functional equilibrium of the masticatory muscles.