Shoulder Manipulation in Volleyball Players

• Manual therapy (Other): This technique involves a low-amplitude, high-velocity push on the shoulder joints with an additional two-second tension
• Placebo (Other): This technique involves a low-amplitude, high-velocity push on the shoulder joints with an additional two-second tension
• Exercise (Other): The following exercise will be performed:push-ups

Primary outcomes

• Assessment of MVC. [The study will be conducted 3 times: pre-intervention, immediately after the intervention and immediately after training session. Each isometric muscle test lasts 3 seconds.]: Muscle EMG is an assessment of electrical characteristics during the test, the electrical source of which is the muscle membrane potential, and measured in μV.
• Assessment of MVC. [The study will be conducted 3 times: pre-intervention, immediately after the intervention and immediately after training session.Each isometric muscle test lasts 3 seconds.]: Muscle EMG is an assessment of electrical characteristics during the test, which is measured by the repetition frequency of muscle motor unit discharges, which is measured in Hz, at the same time of the test.Time
• Muscle stiffness [The study will be conducted 3 times: pre-intervention, immediately after the intervention and immediately after training session. Each Myoton application lasts 1 sec for one point.]: Muscle stiffness - characteristic resistance to physical contraction, which deforms initially forming. Stiffness (N/m) was calculated as S = amax.mprobe/Δl.

Secondary outcomes

• Assessment of proprioception. [The test will be performed 3 times: pre-intervention, immediately after the intervention and immediately after training session. Each joint measurement will be performed at three settings: 30, 45 and 90 degrees.]: Assessing proprioception is an assessment of the angular position of a joint and then an attempt to reproduce it, measured in degrees.
• Y balance test [The test will be conducted 3 times: pre-intervention, immediately after the intervention and immediately after training session.]: Consists of the volunteer standing on one leg while simultaneously stretching the other lower limb in 3 different directions. These are: anterior, posteromedial and posterolateral.
• Med Ball Throw [The test will be conducted 3 times: pre-intervention, immediately after the intervention and immediately after training session.]: It involves the volunteer sitting on the floor with their legs apart and having to throw a 2 kg ball forward in front of them.
• Close Kinetic Chain Upper Extremity Stability Test [The test will be administered 3 times: pre-intervention, immediately after the intervention and immediately after training session.]: The volunteer assumes a push-up position with their hands 36 inches apart, and their performance is assessed based on how many times in 15 seconds the person can lift one arm and move it across the position they are holding their hand in, and touch the other hand with it.

Sex: Male, ages: 18 Years to 30 Years, accepts healthy volunteers

Inclusion Criteria:

* healthy individuals who are over 18 years old,
* a player from the AZS volleyball league,
* a player who regularly competes in the league,
* expressing informed consent to participate in the study and undertaking to comply with the track regulations and wear a helmet.

Exclusion Criteria:

* lack of volunteer consent,
* previous surgeries of the upper, lower limb and spine,
* other upper limb injuries in the last 6 months,
* pain limiting participation in the study,