Horizontal Plyometric Training and Sprint Mechanics in Early-Adolescent Track-and-Field Athletes

Inclusion Criteria: * Male early-adolescent track-and-field athletes aged 12-13 years. * Active participation in a municipal or community-based athletics training program in Antioquia, Colombia. * Minimum recent experience in athletics training according to the records of the local training program. * Ability to complete sprint testing, jump testing, and the planned plyometric training sessions. * Written informed consent provided by a parent or legal guardian. * Written or documented assent provided by the minor participant. Exclusion Criteria: * Current musculoskeletal injury, pain, or medical restriction that prevents sprinting, jumping, or participation in plyometric training. * Any cardiovascular, neurological, orthopedic, or other health condition contraindicating high-intensity physical exercise. * Failure to complete baseline or post-intervention assessments. * Absence from a substantial portion of the intervention sessions, according to the predefined adherence criteria. * Participation in another structured training or research intervention that could substantially affect the outcomes during the study period.