This study investigated the effects of concentric and eccentric knee flexor strength training on recovery from sprint training sessions, eccentric strength, and biceps femoris muscle architecture in 30 participants. The participants were randomly assigned to a concentric or eccentric training group and underwent a 5-week training program. Outcomes including strength, sprint performance, muscle architecture, and blood markers of muscle damage were measured before and after training and after two sprint sessions. The results showed that eccentric training led to greater increases in muscle fascicle length but no other differences compared to concentric training. Additionally, neither training mode improved recovery between sprint sessions or affected the relationship between muscle architecture and strength.