Efecto de cuatro modelos de secuenciaciones de cargas en las capacidades de fuerza, velocidad, potencia muscular y en el grado de la transferencia sobre la velocidad

Programa de Doctorado en Alto Rendimiento DeportivoEste estudio tuvo como objetivo comparar los efectos de cuatromodelos de entrenamiento de fuerza con secuenciaciones distintas de cargas y ejercicios en las capacidades de fuerza, velocidad, potencia muscular y en el grado de transferencia sobre la velocidad. Setenta y ocho sujetos, militares, miembros de la Brigada de Operaciones Especiales del Ejército Brasileño y moderadamente entrenados en fuerza fueron seleccionados para participar de la investigación. Los sujetos fueron divididos en cinco grupos: ejercicios sucesivos en bloques de 3 semanas (ESB3S: n = 16; edad = 20,11 ± 0,7 años; talla = 172± 4,5 cm; masa corporal = 63,1 ± 3,6 kg); ejercicios de máxima potencia en bloques de 3 semanas (EMPB3S: n = 16; edad = 20,45 ± 0,64 años; talla = 173 ± 4,8 cm;masa corporal = 67,1 ± 9,8 kg); ejercicios simultáneos (Esi: n = 16; edad = 20,27 ± 0,75 años; talla = 171 ± 6,8 cm; masa corporal = 64 ± 8,8 kg); ejercicios sucesivos semanales (ESS: n = 16; edad = 20,36 ± 0,64 años; talla = 171 ± 5 cm; masa corporal = 66,1 ± 8 kg); y grupo control (GC: n = 14; edad = 20,18 ± 0,72 años; talla = 174 ± 6 cm; masa corporal = 66,7 ± 9,8 kg). Con excepción del GC, todos los sujetos realizaron a lo largo de 9 semanas los ejercicios de sentadilla, salto con carga y salto con contramovimiento. Los grupos ESB3S y EMPB3S ejecutaron en las 3 primeras semanas solamente el ejercicio de la sentadilla, seguido respectivamente por entrenamientos de salto con carga (semanas 1-6) y salto con contramovimiento (semanas 7-9). El grupo Esi utilizó el modelo complejo de entrenamiento, ejecutando secuencialmente en todas las sesiones los 3 ejercicios de entrenamiento (sentadilla, salto con carga y salto con contramovimiento). El grupo ESS trabajó alternando semanalmente el tipo de ejercicio realizado semanas 1,4 y 7 sentadilla; semanas 2, 5 y 8 salto con carga; semanas 3, 6 y 9 salto con contramovimiento). Aunque el grupo EMPB3S entrenó utilizando solamente las cargas capaces de producir la máxima potencia media propulsiva, al final del período experimental de 9 semanas, tras 27 sesiones de entrenamiento, todos los grupos entrenaron con el mismo volumen absoluto y la misma intensidad media de cargas. Como conclusión general, la síntesis de nuestro estudio indica que en sujetos moderadamente entrenados en fuerza, los 4 modelos diferentes de secuenciación de los ejercicios utilizados por nosotros (ESBS, ESB3S, Esi y ESS) produjeron resultados semejantes en las capacidades de fuerza, potencia y velocidad. Para estos sujetos, es probable que la carga a la cual se entrena tiene más influencia en las adaptaciones generadas por el entrenamiento de fuerza que los modelos de secuenciación utilizados a lo largo de las 9 semanas de entrenamiento.Universidad Pablo de Olavide. Departamento de Deporte e Informátic

Practices of strength and conditioning coaches in professional sports:A systematic review

The practices of strength and conditioning (S&C) coaches have been reported in various professional sports. This study aims to comprehensively assess this available evidence to help establish whether theoretical, practical, and evidence-based guidelines align with the practices employed by these experienced S&C coaches. Three databases were searched (PubMed, SPORTDiscus, and Cochrane) until November 2020. Studies surveying the practices of S&C coaches in professional sports using a survey design with common questions, written in English, and published in peer-reviewed journals were reviewed. Eight studies (n = 318 S&C coaches) were finally included. All studies adapted a similar survey, providing a strong basis for comparison between sports. Periodization strategies were widely used (89%), with training volume consistently reduced during the in-season period. Olympic weightlifting was commonly used across sports, except in baseball (29%). Plyometric exercises were predominantly prescribed for speed development (74%) and lower body power (68%), which were mostly programed as complex training (45%) and conducted all year round (52%). Flexibility exercises were mostly performed before practice (83%) for 6–10 min (40%). Physical tests were mainly conducted during the pre-season period (66%), with body composition (86%) being the most used test. S&C coaches generally adhered to current guidelines and research in S&C concerning training prescription and physical testing. Whereas, Intersport differences were also noted and further discussed. Results of this study can be used by S&C coaches to plan, implement, and review their professional practices. Furthermore, may inform the development of general and sport-specific guidelines, and future research in S&C

Reliability and measurement error of tensiomyography to assess mechanical muscle function: A systematic review

Interest in studying mechanical skeletal muscle function through tensiomyography (TMG) has increased in recent years. This systematic review aimed to (a) report the reliability and measurement error of all TMG parameters [i.e., maximum radial displacement of the muscle belly (Dm), contraction time (Tc), delay time (Td), half-relaxation time (1/2 Tr), and sustained contraction time (Ts)] and (b) to provide critical reflection on how to perform accurate and appropriate measurements for informing clinicians, exercise professionals, and researchers. A comprehensive literature search was performed of the Pubmed, Scopus, Science Direct and Cochrane databases up to July 2017. Eight studies were included in this systematic review. Meta-analysis could not be carried out due to the low quality of the evidence of some studies evaluated. Overall, the review of the nine studies involving 158 participants revealed high relative reliability [intra-class correlation (ICC)] for Dm (0.91-0.99); moderate to high ICC for Ts (0.80-0.96), Tc (0.70-0.98), and 1/2 Tr (0.77-0.93); and low to high ICC for Td (0.60-0.98), independently of the evaluated muscles. Additionally, absolute reliability [coefficient of variation (CV)] was low for all TMG parameters except for 1/2 Tr (CV = >20%) while measurement error indexes were high for this parameter. In conclusion, this study indicates that three of the TMG parameters (Dm, Td and Tc) are highly reliable, whereas 1/2 Tr demonstrate insufficient reliability, and thus should not be used in future studies

The bilateral deficit during jumping tasks: Relationship with speed and change of direction speed performance

Research to date has investigated the phenomenon of the bilateral deficit (BLD); however, limited research exists on its association with measures of athletic performance. The purpose of the present study was to investigate the magnitude of the BLD and examine its relationship with linear speed and change of direction speed (CODS) performance. Eighteen physically active and healthy university students performed double and single leg countermovement jumps (CMJ), drop jumps (DJ) and standing broad jumps (SBJ), to calculate the BLD across jump tasks. Subjects also performed 10m and 30m sprints and a 505 CODS test, which were correlated with all BLD metrics. Results showed varying levels of BLD across CMJ metrics (jump height, peak force, eccentric impulse, concentric impulse, peak power), DJ metrics (ground contact time, flight time), and the SBJ (distance). However, a bilateral facilitation (BLF) was shown for jump height and reactive strength index (RSI) during the DJ test. The main findings of the present study were that: 1) a larger BLD in CMJ jump height related to a faster 505 change of direction (COD) (left leg) (r = -0.48; p = 0.04), 505 COD (right leg) (r = -0.53; p = 0.02) and COD deficit (right leg) (r = -0.59; p = 0.01), 2) a larger BLD in CMJ concentric impulse related to faster 505 COD (left leg) (r = -0.51; p = 0.03), 505 COD (right leg) (r = -0.64, p = 0.01) and COD deficit (right leg) (r = -0.60; p = 0.01), 3) a larger BLD in DJ flight time related to a faster 505 COD (left leg) (r = -0.48; p = 0.04). These results suggest that a larger BLD is associated with faster CODS performance, but not linear speed. This highlights the individual nature of the BLD and may support the notion of developing movement competency on one limb for enhanced CODS performance

Improving Sprint Performance In Soccer: Effectiveness Of Jump Squat And Olympic Push Press Exercises

Training at the optimum power load (OPL) is an effective way to improve neuromuscular abilities of highly trained athletes. The purpose of this study was to test the effects of training using the jump squat (JS) or Olympic push-press (OPP) exercises at the OPL during a short-term preseason on speed-power related abilities in high-level under-20 soccer players. The players were divided into two training groups: JS group (JSG) and OPP group (OPPG). Both groups undertook 12 power-oriented sessions, using solely JS or OPP exercises. Pre-and post-6 weeks of training, athletes performed squat jump (SJ), countermovement jump (CMJ), sprinting speed (5, 10, 20 and 30 m), change of direction (COD) and speed tests. To calculate the transfer effect coefficient (TEC) between JS and MPP OPP and the speed in 5, 10, 20, and 30 m, the ratio between the result gain (effect size [ES]) in the untrained exercise and result gain in the trained exercise was calculated. Magnitude based inference and ES were used to test the meaningful effects. The TEC between JS and VEL 5, 10, 20, and 30 m ranged from 0.77 to 1.29, while the only TEC which could be calculated between OPP and VEL 5 was rather low (0.2). In addition, the training effects of JS on jumping and speed related abilities were superior (ES ranging from Small to large) to those caused by OPP (trivial ES). To conclude, the JS exercise is superior to the OPP for improving speed-power abilities in elite young soccer players.11

The effect of load placement on the power production characteristics of three lower extremity jumping exercises

The purpose of this study was to compare the power production characteristics of the jump squat (JS), hexagonal barbell jump (HEXJ), and jump shrug (JShrug) across a spectrum of relative loads. Fifteen resistance-trained men completed three testing sessions where they performed repetitions of either the JS, HEXJ, or JShrug at body mass (BM) or with 20, 40, 60, 80, or 100% of their BM. Relative peak power (PPRel), relative force at PP (FPP), and velocity at PP (VPP) were compared between exercises and loads. In addition, power-time curves at each load were compared between exercises. Load-averaged HEXJ and JShrug PPRel were statistically greater than the JS (both p < 0.01), while no difference existed between the HEXJ and the JShrug (p = 1.000). Load-averaged JShrug FPP was statistically greater than both the JS and the HEXJ (both p < 0.001), while no statistical difference existed between the JS and the HEXJ (p = 0.111). Load averaged JS and HEXJ VPP were statistically greater than the JShrug (both p < 0.01). In addition, HEXJ VPP was statistically greater than the JS (p = 0.009). PPRel was maximized at 40, 40, and 20% BM for the JS, HEXJ, and JShrug, respectively. The JShrug possessed statistically different power-time characteristics compared to both the JS and the HEXJ during the countermovement and propulsion phases. The HEXJ and the JShrug appear to be superior exercises for PPRel compared to the JS. The HEXJ may be considered a more velocity-dominant exercise, while the JShrug may be a more force-dominant one

Centesimal Age and Relative Age Effect in Elite Futsal Players

International Journal of Exercise Science 13(6): 329-341, 2020. To investigate centesimal age (CA) and relative age effect (RAE) in elite male futsal players their date of birth and court-position were accessed through the official FIFA website. The absolute and relative frequency distributions of player births were quantified by quartiles and semesters. The two-way ANOVA and the Chi-Square analysis were applied to check for possible differences. The results showed a mean CA of 27.76 ± 4.11 years with no differences for both playing positions and competitions. In addition, no significant differences were found between quartiles or between semesters. The results suggest that elite male futsal athletes reach optimal competitive performance close to 27 years. Neither playing position nor geographical location may affect RAE, which seems to not affect the competitive performance (ranking) of elite male futsal players. These findings may help practitioners to understand the RAE phenomenon in futsal. In conclusion, being born in the early months of the year appears not to be important to successful performances in futsal. Overall, futsal athletes take about two decades to achieve their best performance. Coaches and researchers should consider the implementation of long-term training strategies (»20 years) to progressively and effectively develop young futsal players