Intervention of 4 weeks, with two weekly sessions, in which the intervention will be carried out during the training, these sessions having a duration of 10 minutes. During the performance of the intervention, they will perform 3 sets of 15 repetitions of squats in a 25º inclined plane, performing the eccentric phase of the squat in a time of 4 seconds, the concentric phase in 3 seconds, and a rest of 15 seconds between series.

Intervention of 4 weeks, with two weekly sessions, in which the intervention will be carried out during the training, these sessions having a duration of 10 minutes. During the performance of the intervention, they will perform 3 sets of 15 repetitions of squats in a 25º inclined plane, performing the eccentric phase of the squat in a time of 4 seconds, the concentric phase in 3 seconds, and a rest of 15 seconds between series.

The athletes will perform an intervention of 4 weeks, with two weekly sessions, in which the intervention will be performed during the training, with these sessions lasting 10 minutes. During the performance of the intervention, they will perform 3 sets of 15 repetitions of squats in a 25º inclined plane, performing the eccentric phase of the squat in a time of 4 seconds, the concentric phase in 3 seconds, and a rest of 15 seconds between series. This intervention will be performed adding 50% of his OR as external load during the first two weeks, 55% of his MR during the third week, and 60% of his MR in the fourth week of the intervention. During the exercise you can help the physiotherapist who will accompany you to perform the concentric phase without load.

The assessment of the cross-sectional area of the patellar tendon will be assessed by ultrasound measurement. The player must be in the supine position, with the lower limbs resting on a wedge while maintaining a knee flexion of 15-20º. The physiotherapist will make a measurement with the transversal axis of the ultrasound, 1 cm distal to the lower pole of the patella, and with the longitudinal axis to 0.5cm distal of the same pole. In spite of performing the measurement of both lower limbs, only the data of the cross-sectional area of the patellar tendon of the dominant lower limb used by the athlete during the landing of the jump while playing will be analyzed. The unit of measurement will be the centimeter. A higher score in the post-treatment evaluation indicates an improvement in the cross-sectional area of the patellar tendon.

The assessment of the pain threshold to the pressure of the patellar tendon will be quantified using a digital algometer. During the measurement, the subject will remain in the supine position, maintaining a knee flexion of 15-20º supported by a wedge. The physiotherapist will apply the algometer directly on the lower edge of the patella, towards the proximal side of the tendon. As in the previous test, despite evaluating the pressure threshold in both lower limbs, only the result of the dominant lower limb will be counted. This test is quantified on a 0-100 points scale, where a higher score will indicate a greater perception of pain under pressure.