Background: Volleyball players constantly perform vertical jumps, the higher the height of the jump is better sports performance of these players. Several methods have been tested to improve jumping performance in these players. It will be investigated the addition of electrical stimulation and phototherapy to jump training in volleyball athletes. DESIGN: randomized controlled trial. METHODS: This study will be conducted with 36 male athletes volleyball with minimum experience of 12 months sport. Will be randomized and assigned to 3 groups (control group, NEMES group and group phototherapy). All 36 healthy volleyball athletes who passed the initial selection and agreed to participate in the study, conduct a muscle strength and jump training program, which is held in both legs simultaneously. The 12 healthy athletes electrical stimulation group will perform the same training program described above, but strength training is associated with electrical stimulation. The 12 healthy athletes participating in the phototherapy group will undergo a phototherapy protocol before performing the strength and jump training. All selected participants will undergo an assessment of muscle strength of knee extensors and evaluate the jump. These evaluations were baseline, 6 weeks and 8 weeks after baseline.

Background: Volleyball players constantly perform vertical jumps, the higher the height of the jump is better sports performance of these players. Several methods have been tested to improve jumping performance in these players. It will be investigated the addition of electrical stimulation and phototherapy to jump training in volleyball athletes.

DESIGN: randomized controlled trial METHODS This study will be conducted with 36 male athletes volleyball with minimum experience of 12 months sport. Will be randomized and assigned to 3 groups (control group, NEMES group and group phototherapy).INTERVENTION All 36 healthy volleyball athletes who passed the initial selection and agreed to participate in the study, conduct a muscle strength and jump training program, which is held in both legs simultaneously. The training will be held in a period of six weeks with frequency of three times a week, totaling 18 training. The interval between one session and another will be 24 hours.

STRENGTH TRAINING To conduct the training all 36 healthy athletes, carry out heating in stationary bike for six minutes. After heating, the individuals are positioned in the extension machine with the knee joint positioned at 60 ° of flexion and hip at 75 ° flexion, which will perform 10 repetitions of maximal voluntary isometric contraction (MVIC), and the isometric contraction time will be 10 seconds and the rest time between repetitions of 30 seconds.

JUMPING TRAINING After the training the leg extension 36 individuals remain at rest for 5 minutes before starting the jump training. One type of jumps will be trained, countermovement jump (SCM). SCM in the participant will begin the movement of an upright standing position, with the knees fully extended, the volunteer will bend your knees up to about 90 ° before starting the movement up the jump. In each jump training individuals hold five sets of 10 repetitions with one minute intervals between each series.

ELECTRICAL STIMULATION The 12 healthy athletes electrical stimulation group will perform the same training program described above, but strength training is associated with electrical stimulation, medium frequency current (1kHz), Burst duration equal to 2ms with, modulated at 70Hz, cycle Work 10% T-on and T-10 seconds off and 30 seconds intensity used will vary according to the capacity and tolerable for each individual will be recorded for later analysis. The stimulated muscle group will be the quadriceps muscle, with two self-adhesive electrodes 8x13 cm (area of 104cm2). An electrode is placed in the rectus femoris muscle region with a distance of 20 cm from the anterior superior iliac crest and the other is positioned on the oblique vastus muscle region with a distance of 5 cm from the superior pole of the patella.

PHOTOTHERAPY The 12 healthy athletes participating in the phototherapy group will undergo a phototherapy protocol before performing the strength and jump training. Phototherapy will be conducted through a cluster with 03 diodes with 850nm wavelength and the following parameters: Power 50mW diode, diode energy by 2J, power per point of 6J, totaling 36J per member. The irradiation time is 40s by point in the continuous mode. The laser is applied in stationary manner in touch and perpendicular to the skin. The application sites will be six points on the belly of the quadriceps muscles bilaterally.

Evaluation and monitoring All selected participants will undergo an assessment of muscle strength of knee extensors and evaluate the jump. These evaluations were baseline, 6 weeks and 8 weeks after baseline.

The maximum isometric muscle strength of the knee extensors will be quantified using a hand dynamometer. To evaluate the ability of the jump was performed Jump and Reach Test. The maximum amount of countermovement jumps will be performed for 2 minutes. The overall impression will be assessed by scale of perceptation of the overall effect.

Inclusion Criteria:

• Healthy volunteers;
• volleyball players;
• gender male;
• non-smoking;
• aged between 17 and 18;
• weight within 15% variation limit of normal weight for male athletes, taking into account height and physique.

Exclusion Criteria:

• smoking volunteers;
• history of alcohol or substance abuse;
• diagnosis of cardiac, renal, gastrointestinal, hepatic, pulmonary, neurological, psychiatric, hematological or metabolic disorders; that are not available to participate in all stages of the study.