Effects of HOP Stabilization Training on Sport-Specific Fitness Factors in Middle School Fencing Athletes

INTERVENTION: Others(exercise intervention) : This study applies clearly differentiated interventions between the Hop Stabilization group (HG) and the Control group (CG) over a 6‐week intervention period. 1) Experimental Group: Hop Stabilization Training (HOP Stabilization) Duration/Frequency: 6 weeks, 3 sessions per week Session Structure: Each session consists of si Xplyometric‐based hop stabilization drills. For each drill, participants perform 2–4 sets of 6–12 repetitions, with the overall training volume progressed by week (jump contacts). Weekly Training Volume (progression): Week 1: 160 ? Week 2: 200 ? Week 3: 240 ? Week 4: 320 ? Week 5: 320 ? Week 6: 320 Plyometric Drills (examples): Side‐to‐side ankle hops, forward/backward hops, front cone hops, lateral single‐leg hop jumps, standing long jump with lateral sprint, figure‐8 hops, zigzag hops, four‐square hops, double‐cone hops, etc. Landing Mechanics Emphasis (applied throughout all sessions): Maintain proper posture throughout the entire jump sequence Maintain trunk alignment during vertical jumps and minimize excessive lateral/anterior‐posterior sway Use sufficient knee flexion for shock absorption and perform soft landings Achieve stability upon landing before initiating the next hop (rapid yet controlled transition) Supervision/Safety: All sessions are conducted under researcher supervision. If any adverse signs (pain, dizziness, shortness of breath) occur, training is immediately stopped and appropriate rest and actions are provided. 2) Control Group: Usual Training (No Additional Intervention) Duration/Frequency: Participants continue their regular team training for 6 weeks. Key Between‐Group Difference: The control group does not receive the structured hop stabilization program provided to HG. Specifically, CG does not perform the additional 3 sessions/week hop‐stabilization protocol with programmed weekly volume progression, standardized six‐drill structure, and explicit landing‐mechanics instruction. Same Outcome Assessments: Both groups undergo identical pre‐ and post‐intervention assessments (lower extremity strength, ground reaction force, balance, and agility). CONDITION: Diseases of the musculoskeletal system and connective tissue PRIMARY OUTCOME: Lower extremity muscle strength (Peak knee extension and flexion force measured using Kinvent K‐Push) SECONDARY OUTCOME: Agility (Number of touches during a 20‐second Blazepod reaction test) Dynamic balance: Composite score of the Star Excursion Balance Test (SEBT) Ground reaction force (Peak GRF during countermovement jump measured using Kinvent K‐Deltas) Static balance: Center of pressure ellipse area and displacement during single‐leg stance measured using K‐Force Plate INCLUSION CRITERIA: 1, Elite middle school fencing athletes registered with the Korea Fencing Federation 2. Male and female adolescents aged 13–15 years 3. Written informed consent obtained from both the participant and their legal guardian 4. No restrictions on regular training or competition participation within the past 6 months 5. Ability to complete baseline testing and fully participate in the 6‐week intervention program