RESUMO
Karate athletes strategically use lower-limb techniques in combat, with the roundhouse kick (mawashi geri) being highly effective in kumite. To quickly improve the technical performance before training or competitions, conditioning activities (CAs) are often utilized. Recently, Whole-Body Vibration (WBV) has emerged as a potential conditioning activity (CA). This study aimed to analyze the acute effects of WBV as a CA on the performance of the mawashi geri. The sample included sixteen male karate athletes. The study had a familiarization and two experimental sessions: one with WBV and the other without (NWBV), conducted randomly and counterbalanced, each preceded and followed by a mawashi geri assessment on a force platform. During the CA intervention, the participants performed four sets of isometric half-squats on a vibration platform at a frequency of 26 Hz and an amplitude of 4 mm in the WBV condition, while the platform was off in the NWBV condition. A significant reduction in the mawashi geri attack phase time was observed under the WBV condition [pre: 0.31 ± 0.03 s; post: 0.30 ± 0.03 s] compared to the NWBV condition [pre: 0.31 ± 0.04 s; post: 0.32 ± 0.03 s] (p = 0.02). However, no differences were noted regarding the impact force or other kinetic variables between the conditions. Therefore, WBV did not increase the performance of the kinetic and kinematic variables of the mawashi geri in karate athletes, but it is possible that there is a positive effect on attack time, suggesting that further studies with different vibration protocol configurations would be beneficial.
RESUMO
AbstractIntroduction Footwear is no longer just an accessory but also a protection for the musculoskeletal system, and its most important characteristic is comfort.Objectives This study aims to identify and to analyze the vertical ground reaction force in barefoot women and women with unstable shoes.Methodology Five women aged 25 ± 4 years old and mass of 50 ± 7 kg participated in this study. An AMTI force plate was used for data acquisition. The 10 trials for each situation were considered valid where the subject approached the platform with the right foot and at the speed of 4 km/h ± 5%. The instable shoe of this study is used in the practice of physical activity.Results The results showed that the first peak force was higher for the footwear situation, about 5% and significant differences between the barefoot and footwear situation. This significant difference was in the first and second peaks force and in the time of the second peak.Conclusion The values showed that the footwear absorbs approximately 45% of the impact during gait.
ResumoIntrodução O calçado deixou de ser acessório e tornou-se uma proteção para o sistema musculoesquelético, tendo como principal objetivo o conforto.Objetivo O presente estudo tem como objetivo verificar e analisar a componente vertical de reação do solo em mulheres descalço e com calçado instável.Metodologia Participaram deste estudo cinco mulheres com idade de 25 ± 4 anos e massa de 50 ± 7 kg. Para a aquisição dos dados foi utilizado plataforma AMTI. Foram consideradas válidas 10 tentativas de o sujeito abordar a plataforma com o pé direito e na velocidade de 4 km/h ± 5%. O calçado instável deste estudo foi utilizado na prática de atividade física.Resultados Os resultados apresentaram que o primeiro pico de força foi maior para a situação calçado, cerca de 5%, e diferenças significativas entre a situação descalço e com calçado para o primeiro pico de força, segundo pico de força e tempo do segundo pico de força.Conclusão Verificou-se que o calçado absorve aproximadamente 45% do impacto durante a marcha.