RESUMO
The aim of this study was to examine the effects of a traditional resistance training scheme on the relative strength (RS), relative peak-force (RPF), strength deficit (SDef), and vertical jump and sprint abilities in elite young soccer players. Thirty-five under-20 soccer players from two professional clubs were assessed before and after a 4-week competitive period. One team performed 12 sessions of a structured resistance training program and the other maintained their regular soccer-specific training and competitive routines. Resistance training sessions consisted of half-squat and jump-squat exercises at intensities of 30-80% of the one-repetition maximum. Both teams performed pre- and post-measurements in the following order: (1) countermovement jump (CMJ), (2) 20-m sprint, and (3) half-squat one-repetition maximum to determine the RS, RPF, and SDef. A two-way analysis of variance was used to test for group x time interaction among variables. Effect sizes (ES) and 95% confidence intervals (CI) were also calculated. Group x time interactions were demonstrated for RS ([ES [95%CI] = 1.21 [0.57; 1.85], P = 0.001), RPF (ES [95%CI] = 1.18 [0.52; 1.80], P = 0.001), SDef (ES [95%CI] = 0.86 [0.01; 1.71], P = 0.04), and CMJ (ES [95%CI] = 0.64 [0.28; 0.99], P = 0.001); whereas a non-significant interaction was observed for 20-m sprint performance (ES [95%CI] = 0.02 [-0.32; 0.36], P = 0.85). Traditional strength-power oriented training resulted in improved maximum strength performance and CMJ ability but, paradoxically, increased the SDef. As a consequence, stronger athletes are not necessarily able to use greater percentages of their peak-force against relatively lighter loads.
RESUMO
In the present study, we analysed the validity and reliability of a new tool designed to assist the measurement of maximal upper-limb strength in rock climbers in a specific way, named MBboard. The MBboard consists of an artificial small climbing hold affixed to a wooden board, which is connected to any cable-motion strength equipment to determine the maximum dynamic strength (MBboard-1RM). Ten male rock climbers (Rock Climbing Group, RCG = 10) and ten physically active men (Control Group, CG = 10) performed, on three separate occasions, a familiarization session with procedures adopted during MBboard-1RM testing and two experimental trials (i.e., test and retest) to determine the construct validity and reliability of the MBboard during unilateral seated cable row exercise. In the first trial, the electromyographic activity (EMG) was recorded from the flexor digitorum superficialis. The self-reported climbing ability was also recorded. The RCG had superior performance (i.e. 37.5%) and EMG activity (i.e. 51%) in MBboard-1RM testing when compared with the CG (p < 0.05). There was a significant correlation between the MBboard-1RM results and climbing ability (r > 0.72, p < 0.05). Intraclass correlation coefficient analysis revealed good reliability within trials (ICC > 0.79, p < 0.05). These findings suggest that the MBboard is a valid and reliable tool to assess rock climbing-specific maximal strength. The validity of MBboard-1RM appears to be related to the finger flexor muscles activation, probably reflecting the specific adaptations resulting from long-term practice of this sport discipline.
RESUMO
La fuerza y la potencia muscular han sido valoradas en el contexto deportivo o de la salud, con el propósito de determinar su grado de desarrollo; sin embargo, la evidencia de la relación que pude existir entre ellas es escasa y contradictoria. El objetivo del estudio fue identificar la relación entre diferentes manifestaciones de fuerza y de potencia muscular. 37 hombres y 13 mujeres, con edades entre 19 y 23 años, participaron en el estudio. Se evaluó, en miembros superiores e inferiores, la fuerza isométrica, dinámica y la potencia y se midió talla, peso e índice de masa corporal (IMC). No se identificaron diferencias estadísticamente significativas entre los valores de fuerza prensil (FP) de la mano derecha e izquierda (p<0,414). La potencia máxima de miembros superiores (PMMS), se obtuvo con una carga del 4,0%. Se observaron buenas correlaciones (0,608**-0,869**), entre: FP y potencia máxima de miembros superiores (PMMS) e inferiores (PMMI); fuerza máxima isométrica del tren inferior (FMII) y potencia media fase propulsiva en press pecho (PMPP); fuerza máxima en media sentadilla (1RMS) con fuerza máxima en press pecho (1RMP), potencia media fase propulsiva en media sentadilla (PMPS) y velocidad media propulsiva en press pecho (VMPP); RMP con PMPP, PMMS, PMMI y PMPS; PMMS con PMMI, PMPS y PMPP; PMMI, con PMPS y VMP en media sentadilla (VMPS); salto con contra movimiento (CMJ) con el salto sin contra movimiento SJ ; VMPS con PMPS; PMPSP con PMPP; PMMS con CMJ; VMPP con PMMS; y PMPP con CMJ.
Strength and muscular power have been evaluated in the sports or health context to determine their degree of development, however evidence of the relationship between these two muscular manifestations is limited and contradictory. The aim of the study was to identify the relationship between different manifestations of strength and muscular power. Thirty-seven men and thirteen women aged between19 and 23 years participated in this study. We assessed the power and the isometric and dynamic strengthin upper and lower limbs; and size, weight and body mass index (BMI) were measured. No significant differences were identified between prehensile force (PF) values of left and right hand (p-value<0.414). The maximum power of upper limbs (PMMS) was obtained with a4.0% load. Good correlations were observed (0.608**-0.869**) between: PF and maximum power of upper limbs and lower limbs (PMMI); the maximum isometric force of the lower train (FMII) and the mean power propulsive phase in chest press (PMPP); the maximum force in half squat (1RMS) with maximum force in chest press (RMP), the mean power propulsive in half-squat (PMPS) and the mean propulsive velocity in the chest press (VMPP); the RMP with PMPP, PMMS, PMMI and PMPS; the PMMS with PMMI, PMPS and PMPP; the PMMI with PMPS and the VMP in half squat (VMPS); the counter movement jump (CMJ) with squat jump (SJ); the VMPS with PMPS; the PMPSP with PMPP; the PMMS with CMJ; the VMPP with PMMS; and finally, the PMPP with CMJ.