Cluster Training With Blood Flow Restriction in Competitive 200-m Freestyle Swimmers

This study evaluated whether adding blood flow restriction (BFR) to cluster-based training could improve swimming performance and selected physiological responses in competitive swimmers. Twenty competitive swimmers were assigned using a matched, non-randomized design to either an experimental group performing cluster training combined with BFR or a control group performing the same cluster training without BFR. The intervention lasted 8 weeks, with five training sessions per week. The primary outcome was 200-m freestyle performance time. Secondary outcomes included serum concentrations of fibroblast growth factor-2 (FGF-2) and vascular endothelial growth factor-A (VEGF-A), standing long jump performance, mean 50-m split time during a 150-m swimming test, and repetitions completed during a cadence-controlled Burpee test. The study was designed to determine whether BFR provided additional performance and physiological benefits beyond cluster training alone.

Inclusion Criteria: Competitive 200-m freestyle swimmers aged 17-20 years. At least 2 years of structured swimming training experience. Free from musculoskeletal injury for at least 6 months before enrollment. No previous regular experience with blood flow restriction training. Willing and able to complete the 8-week training intervention and all study assessments. Exclusion Criteria: History of cardiovascular, metabolic, thrombotic, or other vascular conditions that could contraindicate blood flow restriction exercise. Current use of medications known to affect vascular tone or blood coagulation. Musculoskeletal injury or medical condition preventing participation in maximal swimming or dry-land training. Attendance below 85% of the scheduled intervention sessions.