Alejandro Sanz 1, Jose Vicente Sánchez- Alarcos1, Javier Sanz Bayo 1,
Sergi Laredo1 & Florentino Huertas1
1 Faculty of Physical Education & Sport Sciences, Catholic University of Valencia.
Football is a sport with a relatively high injury incidence (Fried & Lloyd, 1992). Previous studies show that the older age category the greater risk of injury (Olmedilla, et at., 2006), observing higher injuries rates during matches than during training (Emery et al., 2005). According to UEFA (Hägglund et al., 2013), the hamstring injuries are the most frequent muscular injury in football, and most these injuries occur during sprint and stretching actions (Cohen et al., 2011). The vast majority of studies are focused on professional soccer, with scarce evidence related to the younger stages of development. The aim of this study was to provide information on the occurrence of hamstring injuries in youth football stages (from U9 to U18), including the role of some contextual variables as position, cause, type and context.
116 Spanish coaches from different ages (U9=27, U12=32, U14=24, U16=20, U18=13) from different clubs of Valencia Region (clubs with more than 20 teams in the different categories of age) completed the online survey about hamstring injuries suffered by the players. Data were analyzed using SPSS. We performed the descriptive and comparative analysis using frequency (N). The significance of the chi square value (χ2) was calculated on number of hamstring injuries by different contextual variables: age (U9, U12, U14, U16, and U18), type (strain distension, heavy-legged- overload, the spasm- contracture, strain-break), cause (Running actions, jump, shoot or passing, others), position (goalkeeper, defender, midfielder, forward, various position) and context (training or match). Statistical significance was accepted at alpha set = .05.
67 hamstrings injuries were documented, showing higher rates at older ages (U16=41% and U18=26%). The most repeated injury was heavy-legged- overload (57%). Distribution of type of injury changes according to the age category, but was significant only on Strain- distension χ2 (gl=3, n=116), p = 0,05 and Heavy-legged- overload, χ2 (gl=3, n=116), p = 0,007. Goalkeepers suffered significantly fewer hamstring injuries (0%) than outfield players (49% forward, 22% midfielder, and defender, 6%. 31% of hamstring injuries appeared during run-acceleration- stop- change of direction, χ2 (gl=8, n=116), p < 0,01. There was no significant difference between the number of injuries occurred during match and training (46% v 41%).
Discussion & Conclusions:
The prevalence of hamstrings injuries in young football is pretty lower compared to professional football, mainly due to the younger age in Grassroots (Schmidt-Olsen et al., 1985). The observed rising in frequency of injuries with the growing could be related to the fact that at these older ages players train during longer sessions, higher intensities and more relevance of results in matches (Olmedilla et al., 2006). While strength and conditioning coaches give a very important role to the preventive training in later stages, perhaps, coaches should to enhance relevance of the prophylactic workloads on previous stages of training. Collection and reflection of injury data would help to identify the risk factors involved in injury occurrence, and based on this data, to establish proposal for treatment and prevention of hamstring injuries in different soccer age categories.
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