The role of stretching protocols in post-fatigue performance and flexibility among soccer players

This study aimed to compare the efficacy of static stretching (SS), slow dynamic stretching (SDS), and fast dynamic stretching (FDS) on restoring flexibility, balance, and performance following soccer-specific fatigue. Forty male soccer players (age: 21.0 ± 2.4 years) completed the study. Participants performed a soccer-specific fatigue protocol followed by one of four conditions (SS, SDS at 50 bpm, FDS at 100 bpm, and a control condition (CC)). Measures included knee range of motion (ROM) (Modified Thomas and passive knee extension tests), dynamic balance (Y-Balance Test), biomechanics during a countermovement jump (CMJ) (assessed via OpenCap), 20-m sprint speed, and Illinois agility test performance. The findings indicate that the SS condition showed the greatest improvements in knee flexion (d = 0.51-0.98) and extension (d = 0.45-0.52) ROM. The SDS condition demonstrated superior performance in CMJ jump (highest knee flexion increase, lowest knee valgus, fastest take-off time; d = 0.43-1.89), sprint speed (d = 0.57-0.71), and agility (d = 0.80-0.92). Although dynamic balance improved over time, there were no significant differences between the stretching conditions (p > 0.05). Additionally, the FDS protocol resulted in the smallest gains across all measured outcomes, particularly under fatigued conditions. SDS is most effective for enhancing knee joint mechanics, sprint, and agility recovery post-fatigue, while SS is optimal for ROM restoration. Stretching protocol selection should be contingent on the intended recovery outcome. These findings support incorporating such targeted interventions to optimize athletic performance.