. Due to its power and speed, the kick is the most used technical gesture in Taekwondo to obtain a point. Therefore, explosive strength and related variables are of interest for training control and ...improving technical gestures. The objective of this study was to determine the association between the power developed in the SJ and the CMJ and the power applied in the kicking techniques: Bandal Chagi and Yeop Chagi. In the quantitative, cross-sectional study with a correlational scope, 12 athletes participated, of whom 7 variables related to power in the execution of the SJ and CMJ were measured. Likewise, the power of the kicks was determined using the Electronic Protection Scoring System (PSS). Of the correlations identified between kicks and jumps (SJ, CMJ), the Bandal Chagui kick was associated with a greater number of variables measured in the CMJ and, to a lesser extent, with the SJ; the correlations for both the CMJ and the SJ were less in the Yeop Chagu kick. Therefore, it is concluded that the CMJ is specific in the evaluation of the determining factors in the performance of the aforementioned technical gesture, but not the SJ.
Debido a la potencia y la velocidad, la patada es el gesto técnico más utilizado en el Taekwondo para la obtención de un punto. Por ello, la fuerza explosiva y las variables relacionadas son de interés para el control del entrenamiento y la mejora del gesto técnico. El objetivo de este estudio fue conocer la asociación entre la potencia desarrollada en el SJ, el CMJ y la potencia aplicada en las técnicas de patada: Bandal Chagi, Yeop Chagi. En el estudio cuantitativo, transversal con alcance correlacional, participaron 12 atletas a quienes se les midió 7 variables relacionadas a la potencia en la ejecución del SJ y el CMJ. Así mismo, se determinó la potencia de las patadas mediante el Sistema Electrónico de Puntuación de Protección (PSS). De las correlaciones identificadas entre las patadas y los saltos (SJ, CMJ), la patada Bandal Chagui se asoció con una mayor cantidad de variables medidas en el CMJ y en menor medida con el SJ; las correlaciones tanto para el CMJ y el SJ fueron menos en la patada Yeop Chagu. Por lo que se concluye en la especificidad del CMJ en la evaluación de los factores determinantes en el rendimiento del mencionado gesto técnico, no así del SJ.
La capacidad del salto es una cualidad importante en el ballet clásico. Se ha demostrado que el entrenamiento pliométrico es efectivo en muchos deportes para mejorar el salto vertical. El objetivo de ...este estudio fue evaluar el impacto de 8 semanas de entrenamiento pliométrico sobre la capacidad del salto vertical y petit allegros en bailarinas de ballet clásico. 9 bailarinas (22,4 ± 3,05 años; 167 ± 0,06 cm; 56,1 ± 7,66 kg.; 14,2 ± 2,11 años de experiencia) realizaron 8 semanas de entrenamiento pliométrico. Antes (pre) y después (post) del entrenamiento, se evaluó el CMJ, la altura media de 32 petit allegros, la fuerza G y la eficiencia del salto. En el CMJ y en los petit allegros mejoraron después del entrenamiento (p<.05; 17,4; 14,5 % de cambio). La altura media de los petit allegros también se vio mejorada después del entrenamiento (p<.05: 17,2% de cambio). No se observaron cambios en la fuerza G y en la eficiencia del salto (p>0,05). En conclusión, 8 semanas de entrenamiento pliométrico fueron efectivas para mejorar el CMJ en condiciones de descanso y fatiga y las habilidades específicas de danza en bailarinas de ballet clásico.
La utilización de técnicas de elongación muscular se ha puesto en práctica durante mucho tiempo antes de iniciar actividades físicas para incrementar la activación, aumentar la amplitud articular o ...como parte de técnicas de calentamiento. En los últimos años, ha habido discrepancia a la hora de utilizar elongaciones estáticas (STA), dinámicas o intermitentes (DYN), o no hacerlas (CON) antes de iniciar la sesión de Educación Física. El objetivo de este estudio fue averiguar qué tipo de trabajo de flexibilidad obtendría mejores resultados en el salto con contramovimiento (CMJ) con las variables: índice de fuerza relativa (RSI), altura del salto (HGT) y tiempo de contacto (CT) con una plataforma de contacto. Formaron parte de esta investigación 86 participantes de 16.74 ± 0.19 años, 65.17 ± 30.03 kg y 1.71 ± 0.09 m. Todos los participantes se sometieron de forma aleatorizada a los 3 protocolos, 2 de elongación (STA y DYN) durante 30 segundos y 1 de control sin ninguna elongación (CON). Los resultados mostraron incrementos significativos en el RSI y HGT (p < .001) en la condición de DYN vs. CON y STA. Por otra parte, el CT mostró aumentos significativos en STA con respecto a CON (p < .01) y DYN. A partir de los resultados obtenidos, se podría afirmar que un programa agudo de estiramientos dinámicos podría producir mejoras sobre el salto con contramovimiento (CMJ) en comparación con la ausencia de estiramiento o un mantenimiento de elongación muscular de 30 s.
In the context of a public health physical fitness (PF) examination in adolescence, a countermovement jump (CMJ) and a squat jump (SJ) are two vertical jump (VJ) tests widely used to evaluate lower ...limb muscle strength and power, respectively. The main criticism of both the CMJ and SJ test is the lack of test standardization. Therefore, the objectives of this review are: (a) to gather information about both jumps; (b) to investigate whether it is possible to identify common procedures referred to in the CMJ and SJ technical execution, and (c) to design standard operating procedures (SOPs) to promote CMJ and SJ standardization in an adolescent population aged 12-18 years.
The review partially adopted the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA). Due to growing attention in monitoring physical health through field tests in recent years, articles were collected using the PubMed, Web of Science, and Scopus databases from January 2009 to July 2019. Original articles in which CMJ or SJ were used to assess the muscular strength in adolescents were eligible for further analysis. Articles written in English was imposed as a limit.
A total of 117 studies met the inclusion criteria. The description of the CMJ and SJ test procedures was different within the literature, with discrepancies in the jump technique, number of jumps, and measurement devices used.
A lack of method standardization for both the CMJ and the SJ test was identified. Based on the literature, SOPs for both VJs were proposed. These are useful in the context of public health PF examination in adolescents, as they facilitate an unbiased comparison of jump performance data between published studies.
The purpose of the present study was to establish the intrasession and intersession reliability of variables obtained from a force plate that was used to quantitate lower extremity inter-limb ...asymmetry during the bilateral countermovement jump (CMJ). Secondarily, a comparison was performed to determine the influence of the jump protocol CMJ with or without an arm swing (CMJ AS and CMJ NAS, respectively) on inter-limb asymmetries. Twenty-two collegiate basketball players performed three CMJ AS and three CMJ NAS on dual force platforms during two separate testing sessions. A majority of variables met the acceptable criterion of intersession and intrasession relative reliability (ICC > 0.700), while fewer than half met standards established for absolute reliability (CV < 10%). CMJ protocol appeared to influence asymmetries; Concentric Impulse-100 ms, Eccentric Braking Rate of Force Development, Eccentric Deceleration, and Force at Zero velocity were significantly different between jumping conditions (CMJAS versus CMJ NAS;
< 0.05). The present data establish the reliability and smallest worthwhile change of inter-limb asymmetries during the CMJ, while also identifying the influence of CMJ protocol on inter-limb asymmetries, which can be useful to practitioners and clinicians in order to effectively monitor changes associated with performance, injury risk, and return-to-play strategies.
Staunton, CA, Stanger, JJ, Wundersitz, DW, Gordon, BA, Custovic, E, and Kingsley, MI. Criterion validity of a MARG sensor to assess countermovement jump performance in elite basketballers. J Strength ...Cond Res 35(3): 797-803, 2021-This study assessed the criterion validity of a magnetic, angular rate, and gravity (MARG) sensor to measure countermovement jump (CMJ) performance metrics, including CMJ kinetics before take-off, in elite basketballers. Fifty-four basketballers performed 2 CMJs on a force platform with data simultaneously recorded by a MARG sensor located centrally on the player's back. Vertical accelerations recorded from the MARG sensor were expressed relative to the direction of gravity. Jumps were analyzed by a blinded assessor and the best jump according to the force platform was used for comparison. Pearson correlation coefficients (r) and mean bias with 95% ratio limits of agreement (95% RLOA) were calculated between the MARG sensor and the force platform for jumps performed with correct technique (n = 44). The mean bias for all CMJ metrics was less than 3%. Ninety-five percent RLOA between MARG- and force platform-derived flight time and jump height were 1 ± 7% and 1 ± 15%, respectively. For CMJ performance metrics before takeoff, impulse displayed less random error (95% RLOA: 1 ± 13%) when compared with mean concentric power and time to maximum force displayed (95% RLOA: 0 ± 29% and 1 ± 34%, respectively). Correlations between MARG and force platform were significant for all CMJ metrics and ranged from large for jump height (r = 0.65) to nearly perfect for mean concentric power (r = 0.95). Strong relationships, low mean bias, and low random error between MARG and force platform suggest that MARG sensors can provide a practical and inexpensive tool to measure impulse and flight time-derived CMJ performance metrics.
The aim of the present study was to compare the effects of countermovement jump (CMJ) and drop jump (DJ) training on the volleyball-specific jumping ability of non-professional female volleyball ...players. For that purpose, 26 female volleyball players (15-32 years) were assigned to either a CMJ (20.4 ± 3.1 years, 171.0 ± 3.0 cm) or a DJ training group (22.0 ± 4.4 years, 168.2 ± 5.0 cm), which performed a six-week jump training (two sessions per week, 60 jumps per session). Each group performed 20% of the jumps in the jump type of the other group in order to minimize the influence of enhanced motor coordination on the differences between groups regarding the improvements of jump performance. Before and after the training, jump height was assessed in four jump types, including the trained and volleyball-specific jump types. Although both training forms substantially improved jump height, the CMJ training was significantly more effective in all jump types (17 vs. 7% on average;
< 0.001). This suggests that, at least for non-professional female volleyball players and a training duration of six weeks, training with a high percentage of CMJs is more effective than one with a high percentage of DJs. We hypothesize that this might be related to the slower stretch-shortening cycle during CMJs, which seems to be more specific for these players and tasks. These findings should support volleyball coaches in designing optimal jump trainings.
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