Relationship Between Arm Muscle Strength, Hand Flexibility, and Football Throw-In Performance in Vocational School Students

Abstract

The football throw-in is often treated as a routine restart, yet recent tactical and biomechanical research indicates that it can become an attacking weapon when distance, release quality, and legality are optimized. Evidence explaining the physical foundations of this skill at the school level, especially in Southeast Asia, remains limited. This study examined the correlation between arm muscle strength, hand flexibility, and throw-in performance among male students at SMK Negeri 1 Tenggarong Seberang, Indonesia. A quantitative correlational design was used with 30 students randomly selected from a population of 130 participants in the school's physical education program. Arm muscle strength was assessed through a standardized push-up test, hand flexibility through goniometric wrist-hand range-of-motion measurement, and throw-in performance through legal throw-in distance based on the IFAB procedure. Data were analyzed using descriptive statistics, Pearson product-moment correlation, multiple correlation, and an F test at alpha .05. The results showed that there were very strong positive correlations between throw-in performance and arm muscle strength (r = .932) and between throw-in performance and hand flexibility (r = .918). The combined relationship was also very strong (R = .938; F = 98.396, p < .05), indicating that both variables together explained about 88% of the variance in throw-in distance. The study's novelty lies in examining strength and flexibility simultaneously among adolescent football players in an Indonesian vocational school context. The results confirm that upper-limb force production and distal joint mobility function as an integrated physical profile that underpins effective throw-in execution and supports age-appropriate upper-body strength and mobility training as part of football skill development.