Soccer is one of the most popular sports in the world with a large number of players under the age of 18. High physical demands, frequent changes in exercise intensity and a large number of movement profiles require optimal physical capacity for both adult and child players in soccer.

Physical Performance Tests (PPT) are used to provide a detailed overview of functional status, to predict injury or to decide on return to sport. Physical performance is assessed using closed or open kinetic chain tests; however, in athletic populations, closed kinetic chain PTs may allow for more comprehensive assessments than open kinetic chain PTs.

The continuity of the kinetic chain is required for biomechanically and kinesiologically correct performance of upper extremity functions during daily life activities. The kinetic chain is a system that enables different body parts to produce and transfer power in coordination. The system creates minimal stress, maximal power generation and transfer in the kinetic chain, thus supporting the movement in the distal segments. In order to ensure minimal loss in power transfer between the extremities and trunk, trunk stabilization with a strong core is required.

Athletic performance can be assessed by functional, agility, speed and power tests involving the extremities or the whole body. According to the kinetic chain theory, a "break in the chain" can lead to a decrease in optimal force production and a decrease in performance. The relationship between balance, strength and endurance parameters can provide a basis for the assessment of injury risks and the development of preventive programs. In the literature, it has been suggested that factors related to strength and functionality of the upper extremity may be related to endurance and performance. The aim of this study was to investigate the relationship between upper extremity performance, balance and core endurance in adolescent soccer players.

Soccer is one of the most popular sports in the world with a large number of players under the age of 18. High physical demands, frequent changes in exercise intensity and a large number of movement profiles require optimal physical capacity for both adult and child players in soccer.

Physical Performance Tests (PPT) are used to provide a detailed overview of functional status, to predict injury or to decide on return to sport. Physical performance is assessed using closed or open kinetic chain tests; however, in athletic populations, closed kinetic chain PTs may allow for more comprehensive assessments than open kinetic chain PTs.

Balance is one of the important factors determining sportive performance. It provides neuromuscular control by integrating central nervous system stimuli from the environment to maintain postural control on unstable surfaces during sports activities. Soccer is often played on unstable surfaces (e.g., jumping on grass, kicking the ball while being blocked by an opponent), and the factors affecting players' balance are greater than in other sports. This suggests that soccer players need to have a more dynamic balance compared to other athletes.

The core is the power center of the body with the abdominal muscles on the front, paraspinal and gluteal muscles on the back, diaphragm on the roof, oblique abdominal muscles on the sides, and pelvic ring on the floor. The core acts as a muscular corset to stabilize the trunk with or without limb movement. Core stability enhances effective control of the trunk and stabilization of posture and provides a fundamental basis for force generation and transmission between the upper and lower extremities.

The continuity of the kinetic chain is required for biomechanically and kinesiologically correct performance of upper extremity functions during daily life activities. The kinetic chain is a system that enables different body parts to produce and transfer power in coordination. The system creates minimal stress, maximal power generation and transfer in the kinetic chain, thus supporting the movement in the distal segments. In order to ensure minimal loss in power transfer between the extremities and trunk, trunk stabilization with a strong core is required.

Athletic performance can be assessed by functional, agility, speed and power tests involving the extremities or the whole body. According to the kinetic chain theory, a "break in the chain" can lead to a decrease in optimal force production and a decrease in performance [16]. The relationship between balance, strength and endurance parameters can provide a basis for the assessment of injury risks and the development of preventive programs. In the literature, it has been suggested that factors related to strength and functionality of the upper extremity may be related to endurance and performance. The aim of this study was to investigate the relationship between upper extremity performance, balance and core endurance in adolescent soccer players.

Inclusion Criteria:

• Athletes between the ages of 13-16
• Be actively playing amateur football for at least 1 year in any football team
• Playing soccer regularly for 60 minutes at least 3 days a week

Exclusion Criteria:

• A shoulder problem in the last three months,
• He plays in the goalkeeper position,
• Not having any disease (cardiac, orthopedic or neurological) that may prevent participation in the study,
• Having circulatory problems such as varicose veins,
• Surgical history in the last 6 months,
• Receiving any other physiotherapy treatment,
• The presence of symptoms such as vertigo,
• Presence of complaints in the musculoskeletal system of the elbow, wrist, hand and trunk and lower extremities

Amateur male soccer players between the ages of 13-16