CrossFit® is a competitive sport and fitness modality characterized by multiple physical capabilities and multi-joint movements. This study aimed to analyse and classify variables related to CrossFit® competitors’ specific performance. Fifteen male CrossFit® competitors were selected (n = 15; 30.57 ± 5.5 years; 1.76 ± 0.06 m; 78.55 ± 9.12 kg). Mean values were obtained for body mass index (25.3 ± 2.14 kg/m2), 4 skinfolds, 1 repetition maximum in the squat (137.60 ± 19.65 kg) and the bench press (101.67 ± 10.64 kg), maximum pull-ups (18.87 ± 5.05), sit-ups in 60 s (46.60 ± 4.22), peak power in the countermovement jump (3908.04 ± 423.68 W), VO2max with a shuttle run test (47.70 ± 4.79 ml kg-1·min-1), and time in the Workout of the Day (WOD) “Fran” (337.13 ± 119.19 s) and “Donkey Kong” (417.47 ± 98.44 s) components. Principal component analysis was conducted to classify variables and to select those most related to each new component (“strength and muscle mass”, “adiposity” and “aerobic capacity”). The correlation matrix was analysed, indicating significant correlations between “Donkey Kong” and VO2max (r = -.675; p “ .01), suprailiac skinfold (r = .713; p “ .01) and sit-ups (r = -.563; p “ .05); and between “Fran” and squat (r = -.528; p “ .05). Three important components characterizing CrossFit® competitors were identified: “strength and muscle mass”, low “adiposity” and “aerobic capacity”. Significant relationships between morphofunctional variables and Crossfit® performance were found in Crossfit® competitors.

The aim of this study was to ascertain the differences in kinetic and kinematic profiles between better and poorer performers of the vertical jump within a homogeneous group of trained adults. Fifty rugby players were divided into low scoring (LOW) and high scoring (HIGH) groups based on their performance in the vertical jump. The force, velocity, displacement, and RFD-time curves were analyzed in order to determine the differences between groups. The analysis of the data showed differences in all the patterns of the ensemble mean curves of the HIGH and LOW groups. During the eccentric phase, the differences in the HIGH group with respect to the LOW group were: Lower crouch position, higher downward velocity, and higher force and rate of force development during the braking of the downward movement. During the concentric phase, the HIGH group achieved higher upward velocity, higher force at the end of phase, and a higher position at take-off. The higher jump performances appear to be related to a more effective stretch-shortening cycle function which is characterized by a deeper and faster counter-movement with higher eccentric forces being applied to decelerate the downward movement leading to enhanced force generation during the concentric phase.Abstract Word Count: 198

The purpose of this study was to determine if children exhibit greater variability in center of mass movement and kinetics compared with adults in vertical jumping. Countermovement jumps with arms (CMJA) and without arms (CMJ) performed by 20 female children and 20 female adults were examined using force platform. The data were analyzed using continuous methods to determine differences in variability between groups and between types of jump. Jumping variability was measured by using the average coefficient of variation of the force-, velocity-, displacement-, and rate of force development-time curves across the jump. The analysis indicated that children and adults had similar levels of variability in the CMJ but different levels in the CMJA. In the CMJA, the children had a greater coefficient of variation than adults in force- (20 ± 7% and 12 ± 6%), velocity- (41 ± 14% and 22 ± 9%), displacement- (8 ± 16% and 23 ± 11%) and rate of force development-time (103 ± 46% and 75 ± 42%) curves, as well as in force-velocity relationship (6 ± 2% and 4 ± 2%). The results of analysis suggest that the variability depends on both the level of maturation of the participants as well as the task complexity.

De la Fuente, A. y Gómez-Landero Rodríguez, L.A. (2019). Diferencias motoras en atletas cadetes de taekwondo según nivel competitivo / Motor Differences in Cadet Taekwondo Athletes According to Competition Level.

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