Landing Kinematics, Sports Performance, and Isokinetic Strength in Adolescent Male Volleyball Athletes: Influence of Core Training

Abstract

Context:Core control and strength are important for reducing the risk of lower-extremity injury. Current evidence on the effect of core training in male adolescent athletes is limited, and other investigations into the effects of core training often emphasized core strength only.Objective:To examine whether core training emphasizing both control and strength of the trunk and hip would improve joint kinematics during landing, sports performance, and lower-extremity muscle strength in adolescent male volleyball athletes.Design:Single group pretest and posttest design.Setting:University laboratory.Participants:Sixteen male participants (age: 13.4 [1] y, height: 167.8 [8.6] cm, mass: 58.6 [13.9] kg, and volleyball experience: 3.8 [1.5] y) from a Division I volleyball team at a junior high school.Main Outcome Measurements:Kinematics of the trunk and lower-extremity during box landing and spike jump landing tasks, volleyball-related sports performance, and isokinetic strength of hip and knee muscles were assessed before and after a 6-week core training program.Results:After training, the participants demonstrated decreased trunk flexion angle (P = .01, Cohen’sd = 0.78) during the box landing task and reduced the maximum knee internal rotation angle (P = .04, Cohen’sd = 0.56) during the spike jump landing task. The average isokinetic strength of hip flexors and external rotators, and knee flexors and extensors also significantly increased (P = .001, Cohen’sd = 0.98;P = .04, Cohen’sd = 0.57;P = .02, Cohen’sd = 0.66;P = .003, Cohen’sd = 0.87, respectively); however, sports performance did not show significant changes.Conclusions:A more erect landing posture following training suggests that the core training program may be beneficial for improving core stability. The long-term effect of core training for knee injury prevention needs further investigation.