Football is one of the most popular sports games of today, requiring players to have high physical fitness. Football players must adequately respond to any challenges and workloads they may find during training or matches. Football players use the dominant foot more than the non-dominant player when striking or adding. Therefore, bilateral asymmetry can be expected. In this study, the iso-kinetic method examined the muscular strength, muscular endurance and fatigue index of the flexors and hip extensors of the dominant and non-dominant legs. The study is retrospective in nature, where access to the database of isokinetic testing of the football players of "HNK Rijeka" at Thallassotherapy Opatija was requested. 56 respondents entered the statistical analysis. In the statistical analysis, a t test was used for the dependent samples between the dominant and non-dominant legs. A statistically significant difference in muscular strength was found between the extensor muscles of the dominant and non-dominant legs (p = 0.023), while in the flexor muscles there was a statistically significant difference at the level (p = 0.049). Until a statistically significant difference in muscular endurance was found between the extensor and flexor muscles dominant to the non-dominant leg. Likewise, no statistically significant difference in fatigue index was found between the extensor and flexor muscles dominant with respect to the non-dominant leg. The hypothesis that both legs are equally used in player activity is rejected, which establishes the existence of bilateral asymmetry. Bilateral asymmetry has a negative effect on players as it increases the risk of injury, which in professional sports is negative for both the player and the club. This indicates that the training process for the development of strength should be evenly focused on both extremities, while the results in muscular endurance and fatigue index justify the type of sport as it requires very good physical fitness.