Changes in countermovement jump biomechanics following an eight-week static stretching program in adolescent male basketball players

This study aimed to investigate the eff ects of an eight-week static stretching program consisting of four exercises on countermovement jump (CMJ) biomechanics in 21 adolescent male basketball players aged 11–14 years. The stretching protocol was performed after the fi nal training session of the day, four times per week for eight weeks. Two exercises were performed in a standing position and two in a seated position. Each exercise was repeated 3 times and held for 30–40 seconds, depending on the athlete’s individual tolerance, with a 30-second rest interval between repetitions. CMJ performance was assessed using a Bertec force platform with a sampling frequency of 1 kHz. Following the eight-week intervention, signifi cant changes were observed in several braking-phase variables, including average braking force, average braking power, average braking velocity, braking impulse, peak braking velocity, and countermovement depth. Propulsive duration, propulsive impulse, vertical stiff ness, and time to stabilization also changed signifi cantly, while relative peak power decreased. No signifi cant changes were observed in jump height, absolute peak power, or maximum rate of force development. These fi ndings suggest that the intervention was associated with changes in countermovement strategy and selected braking- and propulsive-phase variables, while maximal jump performance remained largely unchanged. The reduction in time to stabilization may indicate a change in post-landing stabilization; however, landing technique and neuromuscular control were not measured directly.