Effectiveness of Closed Kinetic Chain and Core Exercises on Baseball Throwing Distance Among Grade 8 Student-Athletes

Abstract

This study examined the effectiveness of closed kinetic chain (CKC) and core exercises in improving baseball throwing distance among Grade 8 student-athletes. Using a quasi-experimental two-group pretest–posttest design, two intact class sections (n = 26 each) completed an eight-week intervention during MAPEH classes: one performed CKC exercises (squats, push-ups, lunges) and the other core exercises (planks, sit-ups, Russian twists). Throwing distance was measured with a standardized baseball throw-for-distance test. Data were analyzed using descriptive statistics, paired-samples t-tests, and analysis of covariance (ANCOVA) with pretest scores as the covariate, with rank-based transformation applied to meet assumptions. Both groups improved significantly from pretest to posttest (CKC: t = −6.953, p < .001, d = −1.364; Core: t = −5.278, p < .001, d = −1.035), with the CKC group moving from a “Fair” to a “Good” classification and the core group remaining at “Fair.” The ANCOVA showed no significant between-group difference after adjusting for pretest, F(1,49) = 2.822, p = .099, partial η² = 0.054, indicating that the two programs were comparably effective. The findings support Kinetic Chain Theory and the Core Stability Model and suggest that both low-cost, school-deliverable programs can enhance throwing performance in physical education settings.