The aim of this study was to investigate the bilateral strength asymmetry of the knee extensors and flexors, to determine the imbalance difference between the two legs, and to investigate the effect of 6 weeks of Pilates exercises on the strength of the hamstring muscles and the balance imbalance during the preparation process. In this study, a total of 23 professional soccer players were divided into two groups. Group 1 (soccer+Pilates) was asked to continue their routine soccer training (n=12), while group 2 (soccer) was asked to perform Pilates exercises for 25-30 minutes 3 days per week in addition to soccer training (n=11). After the athletes were anthropometrically measured (height, weight and BMI) and eccentric knee flexor muscle strength was determined using the NordBord (ValdPerformance, Australia) hamstring device, Pilates exercises were performed on the mat for 6 weeks prior to pre-season training and the same tests were performed again after the pre-season training period. Data were analyzed using the SPSS 24 package program at a significance level of p