BACKGROUND: Little is known about the comparative relationships between knee muscles strength and anaerobic power in weightlifters, basketball and soccer players, popular sports that rely on lower extremity muscles strength. METHODS: Ten weightlifters, 12 basketball and 19 soccer players participated in the study. Concentric peak torque of hamstring (H) and quadriceps (Q) of the dominant (D) and non-dominant leg (ND) was evaluated at 60 and 240°/s. Subjects also performed Wingate Anaerobic Test (WAnT) 48 h after isokinetic measurements. RESULTS: Normalized peak moment of the hamstring (NPMh) of D in soccer players was significantly greater than in basketball players and weightlifters at 60 and 240°/s. At 60°/s, weightlifters presented a greater NPMq when compared to soccer players in D. Significant correlations were observed between NPMq of both legs and peak and mean power at 60 and 240°/s in basketball. In soccer, significant correlations were found between the bilateral NPM of both muscles and the peak and mean power at 240°/s. CONCLUSIONS: Knee flexion strength plays a more decisive role in soccer due to the fast movement pattern while knee extension strength is more important in basketball and weightlifting due to vertical movement patterns.