Objective: Whether strengthening exercises emphasizing on internal rotators of the knee are more effective in improving shuttle-run agility of the knees with anterior-posterior laxity (AP laxity). Methods: Twenty men with AP laxity of knee were randomly assigned to the three experimental groups in different strengthening modes: plate-loaded squat press (SP), plate-loaded kneeling leg curl with internal rotation (KLCIR), and kneeling leg curl (KLC). Control group with stable knees received no training. Anterior-posterior laxity, shuttle-run agility, and isokinetic strength were evaluated before and after training. Results: Those with AP laxity of knee have poorer performance in the shuttle run test than their contralateral sound side, and this vulnerability is improved after six-week SP or KLCIR training. Isokinetic strength of medial hamstring is increased after KLICR and SP training. The anterior displacement by KT 2000 are decreased among the three training groups. Conclusions: KLCIR, as SP, emphasizing knee internal rotators, enhances both AP laxity and shuttle-run agility. KLCIR can be either an advanced or an alternative mode to SP in the strengthening exercise of knees with AP laxity.