Evaluación de factores de riesgo de lesión del ligamento cruzado anterior en jugadores de fútbol de alto nivel / Evaluation of risk factors for anterior cruciate ligament injury in high-level male football players

El objetivo del presente estudio es la detección de factores de riesgo de lesión de ligamento cruzado anterior (LCA) en jugadores de fútbol profesionales al comienzo de la pretemporada. Treinta y cinco jugadores de fútbol de alto nivel fueron analizados mediante un sistema de análisis del movimiento y 2 plataformas de fuerzas. Se analizó el ángulo de rodilla en el plano frontal (valgo-varo) y las fuerzas verticales de reacción de ambas extremidades durante la fase de aterrizaje del drop jump. Se determinó el coeficiente de correlación intraclase. La significación estadística fue considerada para p < 0,05. Se encontraron diferencias significativas entre la extremidad más fuerte y la débil en el impulso excéntrico (32,4 Ns; IC 95%, 22,9-41,8 Ns; p < 0,05) y en el impulso concéntrico (14,4 Ns; IC 95%, 9,8-19,1 Ns; p < 0,05). El 31,4% de los futbolistas presentaron valores de falta de balance entre extremidades superior al 15%, y el 14,2% de los jugadores aterrizaron con un ángulo de rodillas en el plano frontal mayor a 20°. La metodología propuesta en el presente estudio ha demostrado ser fiable y sensible en la detección de factores de riesgo asociados a la lesión del LCA

Anterior cruciate ligament (ACL) injury is one of the most serious time-loss injuries in football. The purpose of the present study is to evaluate risk factors of ACL injuries in high-level football players during the preseason. Thirty-five high-level players were captured by a video movement analysis system and a two-force platform. Frontal plane knee angle and vertical force were measured during the landing phase of the drop jump. Intraclass correlation coefficient was determined to assess test-retest reliability, and α level of 0.05 was considered statistically significant. There were significant differences between the stronger and weaker leg in eccentric (32.4 Ns; 95% CI; 22.9-41.8 Ns; P < 0.05) and concentric impulse (14.4 Ns; 95% CI, 9,8-19,1 Ns; P <0.05). Additionally, 31.4% of the subjects obtained a lower limb strength imbalance higher than 15%. Furthermore, 14.2% of the subjects obtained a frontal plane knee valgus angle higher than 20°. Findings of the present study are particularly significant as a functional deficit higher than 15% and an increased in valgus motion at the knee suggests an altered muscular control of the lower extremity. Furthermore, results confirmed that the test proposed in this study is reliable and sensitive to identify ACL injury intrinsic risk factors in high level male football players in order to introduce the necessary preventive measures

Efecto de los pantalones compresivos en la amplitud articulary el rendimiento en el salto vertical / Compression shorts effects in the hip range of motion and in vertical jump

Objetivo: Este estudio pretende determinar si la compresión provoca cambios mecánicos en el movimiento y se producen incrementos del rendimiento deportivo. Material y métodos: Participaron en el estudio 8 sujetos de sexo masculino ([mediana ± DE] edad: 25,6 ± 10,3 años, talla: 177,9 ± 2,9 cm, peso: 71,9 ± 7,4 kg). Se evaluó la amplitud articular pasiva mediante tres pruebas: Thomas, Ridge y flexión de cadera con la pierna estirada, y la amplitud articular activa durante el salto vertical. Los valores del ROM fueron determinados utilizando un sistema de videografía 2D. La altura del salto y la fuerza máxima realizada durante la impulsión se utilizaron para comparar el rendimiento. Cada una de las pruebas se realizó utilizando pantalones de compresión (tejido indesmallable por urdimbre, 57% poliamida y 43% elastómero), mallas de lycra convencionales y ropa interior como caso control, mediante un método aleatorio balanceado. Resultados: No se observaron diferencias significativas entre las tres condiciones en los dos parámetros de rendimiento. En cambio, se observó que la compresión limita significativamente la amplitud articular de la cadera, disminuyendo la extensión y la flexión máxima durante la valoración pasiva y la flexión máxima durante la valoración activa. Conclusiones: Los pantalones compresivos actúan en la misma línea que los vendajes funcionales, no varían el rendimiento de la actividad deportiva pero restringen la movilidad de las articulaciones afectadas por la compresión. Esta limitación puede tener efectos profilácticos al prevenir lesiones cuando se excede súbitamente el límite articular individual(AU)

Objective: The purpose of this study was to asses whether compression affects movement mechanics and increases sport performance. Material and methods: Eight subjects participated in the study ([mean±SD] age: 25.6±10.3 years, height: 177.9±2.9cm, weight: 71.9±7.4kg). Passive range of movement was evaluated by means of Thomas, Ridge and hip flexion with straight leg tests. The active range of movement was assessed during vertical jump. Values were determined using 2D analysis. Jump height and peak force applied during impulse phase were used for performance comparison. Tests were performed in three different conditions, using compression shorts (warp knitted fabric 57% Polyamide and 43% Elastan), standard lycra shorts and underwear as a control using a balanced, randomised design. Results: There were no significant differences between the three conditions in the performance parameters, whereas compression significantly limited the hip range of motion (ROM) during either passive or active evaluations. Conclusions: Compression garments act as functional bandages, allowing normal functional movement but restricting ROM. These limitations could have prophylactic effects, preventing injuries when suddenly exceeding the limit of individual joints(AU)

Vertical jump assessment on volleyball: a follow-up of three seasons of a high-level volleyball team.

This is a longitudinal descriptive study whose purpose is to assess the physical state of male volleyball players competing at the international level, comparing their jump heights during 3 different seasons. National team sample relies upon trainer decisions, and it was different every season. There were 23, 15, and 13 players in the first, second, and third years, respectively. Subjects underwent a vertical test protocol consisting of rocket jump, squat jump (SJ), countermovement jump (CMJ), CMJ with arms (CMJa), and spike jump (DJb) at the preparation period of the national team season. In 2007, an extra evaluation was performed during the competitive period. A contact mat was used for the assessment. An increase of jump height was observed over the years, with SJ and DJb increasing significantly (FSJ = 5.4; FDJb = 4.7; p < 0.05). The elasticity index decreased significantly between 2007 and 2008 (FEI = 8.5; p < 0.05), whereas arm utilization index and approach index increased, but this increase was not statistically significant. A significant increase in SJ and DJb was also observed between the 2 tests performed in 2007, whereas a nonsignificant increase was observed for CMJ and CMJa. The results indicate a better performance of explosive strength, elastic-explosive strength, and reflex-elastic-explosive strength and a better use of arms during jumps.