This study aims to investigate whether applying blood flow restriction (BFR) during small-sided soccer games (SSG) can help soccer players maintain their passing and dribbling stability when they are fatigued. The study includes 40 young male soccer players. Participants will be randomly divided into two groups:

One group will wear pressurized BFR cuffs on their legs (80% of limb occlusion pressure) during a 4v4 training game.

The other group will act as a control, wearing the same cuffs but without any pressure (0% pressure) during the exact same training game.Both groups will complete a 6-week training program, practicing 3 times a week. Before and after the 6-week period, researchers will test the players' physical and technical skills (such as jumping, passing, and dribbling). Importantly, these tests will be conducted both before and immediately after a tiring 45-minute exercise routine to see which training method is more effective at preventing performance drops caused by fatigue.

This study utilizes a randomized, single-blind, placebo-controlled parallel group design. A total of 40 young male soccer players with systematic training backgrounds will be recruited. Following baseline testing, participants will be randomly assigned to either the BFR-SSG group or the SSG control group.The intervention spans 6 weeks, featuring three standardized 90-minute training sessions per week. The core intervention consists of a 4v4 small-sided game module (4 sets of 4 minutes). During this module, the BFR-SSG group will wear pneumatic cuffs inflated to 80% of their individual Limb Occlusion Pressure (LOP), while the control group will wear uninflated cuffs (0% LOP).Pre- and post-intervention assessments will systematically evaluate physiological adaptations (blood lactate, creatine kinase) , neuromuscular function (Countermovement Jump) , and sport-specific technical stability (Loughborough Soccer Passing Test and a 20m change-of-direction dribbling test). To specifically assess performance under metabolic stress, the technical and neuromuscular tests will be conducted at baseline and immediately following a standardized 45-minute fatigue-inducing protocol (Modified LIST). The primary goal is to quantify the attenuation rate of passing and dribbling performance under fatigue and determine if BFR combined with SSG provides superior chronic adaptations compared to SSG alone

Inclusion Criteria:

• Young male soccer players. Possess a systematic soccer specific training background and maintain a stable competitive state.

Cleared by the Physical Activity Readiness Questionnaire (PAR-Q), confirming that cardiovascular and metabolic systems can tolerate high-intensity physical testing and blood flow restriction interventions.

Exclusion Criteria:

• Any recent history of neuromuscular or musculoskeletal system injuries. Current smoking habit. Consumption of any sports nutrition supplements or drinks that could significantly affect muscle performance or neural excitability (e.g., creatine, caffeine, beta-alanine) within 3 months prior to the start of the study and throughout the experimental period.

Individual participant data will not be shared due to participant confidentiality and institutional data protectionpolicies.

Randomization and group allocation were performed by an independent researcher not involved in data collection or analysis. Group assignments were hidden using coding to ensure that the investigators and outcome assessors remained completely blinded to the intervention conditions throughout the entire study process.