The Importance of Exercise to Prevent Injuries in Athletes

实验性的：Experimental group

Group will carry out the proprioceptive exercise program during 8 weeks at the begining of the season

其他：Proprioceptive exercise program

Group A will carry out two sessions of proprioceptive training per week, in a total of 8 weeks, during the pre-season period (September-October). Each session will last approximately 30 minutes and will include 6 exercises. The execution of the exercises will be supervised by a physiotherapist and a national trainer of athletics.

安慰剂比较：Control group

Control group will continue with their usual training routine

其他：Usual training routine

The subjects of the control group (group B) will be informed so that they do not include any change in their usual training routine.

Knee Joint Position Sense (JPS)

JPSThe JPS is defined as the awareness of the actual position of the limb to quantify proprioception.The method for measuring JPS is to place the joint at a specific target angle and then, after the limb has been moved back to the starting angle, the subject is asked to actively or passively reproduce the target angle. The outcome of the measurement is the absolute error (AE), which is the difference between the true target angle and the reproduced angle

The Y Balance Test (YBT)

The YBT, derived from the Star Excursion Balance Test (SEBT), has been reported to be a valid and reliable measure of dynamic balance; furthermore, the results of the YBT have been reported to be related to lower-extremity impairments and to be predictors of injuries.The YBT instrument has a central raised platform with three pieces of PVC (polyvinyl chloride) pipe in the three directions with a sliding plastic reach indicator that the participant pushes to determine reach distance.The YBT testing protocol assessed absolute reach and normalized distance for each direction, asymmetry between limbs, and composite score. Normalized reach distance is calculated by dividing reach distance by the limb length. Asymmetry is the absolute difference between right and left leg and is determined for each reach direction. The composite score is calculated by summing the reach distance in the three directions, dividing by three times limb length, and multiplying by 100.

The countermovement jump (CMJ)

The CMJ is primarily used to measure an athlete's explosive lower-body power, and has become one of the most frequently used tests by coaches and researchers to indirectly measure power in the lower limbs. CMJ performance is reported as either jump height(centimeters).