Validation of the iPhone app using the force platform to estimate vertical jump height.

BACKGROUND: Vertical jump performance has been evaluated with several devices: force platforms, contact mats, Vertec, accelerometers, infrared cameras and high-velocity cameras; however, the force platform is considered the gold standard for measuring vertical jump height. The purpose of this study was to validate an iPhone app called My Jump, that measures vertical jump height by comparing it with other methods that use the force platform to estimate vertical jump height, namely, vertical velocity at take-off and time in the air. METHODS: A total of 40 sport sciences students (age 21.4±1.9 years) completed five countermovement jumps (CMJs) over a force platform. Thus, 200 CMJ heights were evaluated from the vertical velocity at take-off and the time in the air using the force platform, and from the time in the air with the My Jump mobile application. The height obtained was compared using the intraclass correlation coefficient (ICC). RESULTS: Correlation between APP and force platform using the time in the air was perfect (ICC=1.000, P<0.001). Correlation between APP and force platform using the vertical velocity at take-off was also very high (ICC=0.996, P<0.001), with an error margin of 0.78%. CONCLUSIONS: Therefore, these results showed that application, My Jump, is an appropriate method to evaluate the vertical jump performance; however, vertical jump height is slightly overestimated compared with that of the force platform.

Los ejercicios preventivos tras el calentamiento ayudan a reducir lesiones en fútbol / Preventive exercises after warming help to reduce injuries in soccer

Las lesiones suponen un gran problema en el fútbol profesional y amateur. La mayoría se localizan en las extremidades inferiores (89,6%), concretamente en: muslo (31.4%), tobillo (12.5%), ingle (10.9%), y en menor medida rodilla y gemelos. Son varios los estudios sobre la eficacia de los métodos para prevenir lesiones; sin embargo, la prevalencia de éstas, sobre todo musculares, sigue siendo alarmante. La Federación Internacional de Fútbol creó el FIFA 11+, que ha demostrado ser eficaz en la prevención de lesiones de rodilla, pero no para lesiones en muslo, ingle... Por ello, el objetivo de este estudio fue comprobar la eficacia de un programa de prevención para reducir lesiones en las extremidades inferiores en el fútbol amateur. Se realizó un seguimiento de un total de 84 futbolistas amateur (GE = 40 jugadores [edad: 23,1 ± 3,8 años] y GC = 44 jugadores [edad: 24,7 ± 4,1 años]). Se registró el número y tipo de las lesiones que se produjeron durante la primera vuelta de la temporada 2015/16. El grupo experimental llevó a cabo un plan preventivo tras el calentamiento, mientras que el grupo control no realizaba ningún trabajo de este tipo. Se registraron un total de 42 lesiones, el 83,4% en las extremidades inferiores, concretamente: muslo (35,7%), tobillo (23,8%), aductores (14,3%), rodilla (4,8%) y gemelos (4,8%). El número de lesiones en las extremidades inferiores fue mayor en el grupo que no realizaba trabajo preventivo (82,9%) que en el grupo que sí lo realizaba (17,1%). Por tanto, incluir un programa preventivo tras el calentamiento ayuda a reducir el riesgo de sufrir lesiones en las extremidades inferiores en futbolistas amateur

Injuries are a major problem in professional and amateur soccer. Most of them occur in the lower limbs (89.6%), specifically in thigh (31.4%), ankle (12.5%), groin (10.9%), and, to a lesser extent, knee and calves. There are several studies focusing on the effectiveness of preventive methods but, nevertheless, the prevalence of injuries, mainly muscular, remains alarming. The International Football Federation designed the program FIFA 11+, which has proven to be effective in preventing knee injuries, but not thigh or groin injuries. Therefore, the aim of this study was to assess the effectiveness of a prevention program to reduce lower extremity injuries in amateur soccer. A total of 84 amateur footballers volunteered to participate (experimental group (GE) = 40 players (age: 23.1 ± 3.8 years) and control (GC) = 44 players (age: 24.7 ± 4.1 years)). The number and type of injuries that occurred during the first phase of the 2015/16 season was recorded. The GE completed a preventive protocol after the warm up, while the GC did not perform any specific work. A total of 42 injuries was recorded, 83.4% of which in lower extremities, specifically: thigh (35.7%), ankle (23.8%), adductors (14.3%), knee (4.8%) and calves (4.8%). The number of injuries in lower limbs was higher in the group that did not perform the preventive work (82.9%) than in the group that performed it (17.1%). Therefore, including a preventive program after warm up helps reduce the risk of injury in the lower limbs in amateur soccer players

Efecto de la fatiga en el ratio isquiotibiales: cuádriceps. Revisión sistemática / The influence of fatigue in hamstrings:quadriceps ratio. A systematic review

Las lesiones deportivas conforman la principal causa por la que el proceso de entrenamiento se ve interrumpido total o parcialmente. Entre los diferentes tipos de lesión que pueden darse en cualquier disciplina deportiva, las lesiones musculares, y más especialmente las que se producen en la musculatura isquiotibial, son las más recurrentes. En este sentido, uno de los indicadores más fiables para cuantificar la descompensación muscular que produce esta lesión es el ratio isquiotibiales: cuádriceps, del cual se diferencian dos tipos: ratio convencional y ratio funcional. El objetivo de esta revisión fue buscar en la literatura científica cómo afecta la fatiga a los valores de ambos ratios que indican el riesgo de sufrir una lesión muscular. Se realizó una búsqueda electrónica en diferentes bases de datos, y un total de trece artículos publicados hasta el 19 de Mayo de 2015 fueron incluidos en el análisis bajo las palabras clave «Hamstrings», "Quadriceps", "Isokinetic", "Peak torque" y "Fatigue". Los estudios analizados revelaron un importante descenso en los valores de ambos ratios, en especial del funcional, tras la realización de diferentes protocolos de fatiga, sobretodo en aquellos que eran más específicos. Este descenso de los valores del ratio se traduce en un mayor riesgo de sufrir una lesión muscular. Además, el descenso en ambos ratios se producía por una disminución en los valores de fuerza de los isquiotibiales, especialmente durante su fase excéntrica. Por tanto, los resultados obtenidos sugieren la implantación de estrategias de prevención enfocadas al retraso de la aparición de la fatiga, especialmente en la musculatura isquiotibial, y en el fortalecimiento de la misma durante la fase excéntrica del movimiento

Sport injuries are considered the main cause of cessation of training process, either completely or partially. Among the different types of injuries that may be produced in any sport disciplines, muscular injuries, and more specifically hamstring injuries, are the most common. For that matter the best indicator for evaluating the muscular risk of this kind of injury produced by a muscular imbalance is the hamstrings: quadriceps ratio, of which two types can be distinguished: functional ratio and conventional ratio. The aim of this study was to search in scientific literature how the fatigue presents an influence in the values of both conventional and functional hamstrings:quadriceps ratio as an injury risk indicator. An electronic search of different databases was carried out and a total of thirteen studies publicated until 19th May 2015 were included in this review. The following keywords were employed: «Hamstrings», «quadriceps», «Isokinetic», “Peak torque» and «Fatigue». Analysed studies showed a significant decrease of both ratios values, but especially functional ratio, after the fatigue protocols application. Besides, a greater decrease of both ratios were noticed when protocols were more specific. This fact means a greatest risk of muscular injury. In addition, the fall in both ratios levels were produced by a decrease in hamstings strength values, in particular during the eccentric phase of movement. Hence, our results suggest that it would be important to develop an injury prevention strategy focused on delay fatigue, specially in hamstrings, as much as possible and improve hamstrings strength during the eccentric phase of movement