The 11 + " Warm-Up Program in Female Soccer Players and the Morpho-Physiological Changes Generated after its Implementation

Objective: Use "The 11 +" warm-up program in female players of the National Chilean Sub-17 Football team in order to analyze morpho – physiological variables. The implementation of this training program will generate morpho – physiological changes between players exposed. Federation International Football Association (FIFA) created a training program known as the "11+", designed to amend morpho-functional parameters such as lower extremity alignment, strength, intra, and inter muscular coordination and balance, among others. Subjects: Information indicates that injuries are a serious cause of concern for the soccer clubs and therefore, it is necessary to introduce the prevention programs. Methods: 20 female players of the National Chilean Sub-17 Soccer Team, from 14 to 17 years, who trained from March 2017 to January 2018. The “The 11+” warm-up program was considering an independent variable and thigh circumference, jumping ability, speed and balance are considered dependent variables. We use The STATA 11.1 SE (Statistics / Data Analysis) program for the statistical. Results: After implementing the “The 11+” program, significant changes (p < 0.05) were observed in the morphological variables of thigh circumference and functional speed. Concerning the functional variables of jump and balance, favorable but not statistically significant. Conclusions: Application of the "The 11 +" warm-up program for 3 months in addition to proper training, generated morpho – physiological changes associated with an increase in thigh circumference and an improvement in speed. The practical utility is to improve morpho-physiological characteristics of players in a competitive area and thereby to improve the utility of athletic performance indirectly. Corresponding author: Jaime Hinzpeter, Medical Doctor, University of Chile, Santos Dumont # 999, Santiago Chile, E-mail: jhinzpeter@hcuch.cl

The incidence of ACL injuries is higher in women than in men [2]. In soccer, these lesions are commonly seen with a ratio of 9:1, of which approximately 70% of ruptured ACL injuries are not due to contact [2].
In Chile, no record of neither studies nor statistical data on the number of injuries that occur in male and female soccer players have been found.
European studies indicate that the application or implementation of structured warm-up programs can contribute to the formation and development of the soccer players to such a point that they would be directly associated to a decrease of injuries [22,23,25].

The Federation Internationale de Football Association
(FIFA) created a training program known as the "11+", designed to amend morpho-functional parameters such as lower extremity alignment, strength, intra, and intermuscular coordination and balance, among others [20,22,23,25]. players completed the study. Said players underwent a battery of evaluations before and after the "The 11+" warm-up program was implemented. Some players did not attend the session in which some of the assessments were carried out and due to this factor, the modified SEBT and thigh circumference measurements have not been accurate.

Statistical Analysis
The STATA 11.1 SE (Statistics/Data Analysis) program was used for the statistical analysis of the study. All the data obtained was distributed in a normal manner. The "Student T" test was used in order to identify any changes in the results.

Results
Players initially evaluated were 25 This increase in thigh circumference is associated with an increase in muscle mass (hypertrophy) and thus, greater strength [24]. This condition facilitates greater knee stability during the different external demands it will be exposed to [3] as a result of the different movements that are required during a game ( Figure 1). Therefore, greater knee stability would be helpful in reducing the risk factors for non-contact injuries [18].  Table   1.
Nevertheless, it appears that "The 11+" recommends eccentric muscle strengthening exercises for hamstrings and as the strength is increased, the sprint or race becomes more efficient [24], with less energy being used and an increase in the time period before muscle fatigue occurs. It has been shown that eccentric muscle strengthening decreases the risk of tearing [6,16].
It can be seen that there was a favorable change, however, it is not statistically significant in relation to the variable studied after implementing Moreover, studies conducted by Urabe et al [17,19,26] reported that an increased activation of the quadriceps on hamstrings is a factor that would have an impact on the increase on the risk of a knee injury given that during the post-jump buffer stage, the quadriceps tend to anteriorize the tibia generating an increase in ACL strain, stressing them beyond their capabilities and enhancing their risk of injury. From this, and considering the controversy that exists in the literature stating that the quadriceps is a protective factor against a knee injury [2] or that it can increase the risk of injury of the same [20], it is argued that it is not imperative to only increase the strength of quadriceps and hamstring, but to maintain proper synergy and intra and inter-muscular coordination at the thigh (quadriceps -hamstrings ratio) [2,20,21,27].
The modified SEBT corresponded to one of the functional assessments and included in these   [26,10].

Conclusions
The application of " The 11+" warm-up program