What exercises might help me prevent an ACL tear from occurring again?

There are several things you can do through exercise that may help prevent a second ACL injury.  Research shows that a lack of symmetry in single leg balance, strength, and movement biomechanics are strong predictors of someone suffering another ACL injury.  Thus, to prevent this from happening it would be beneficial to include single leg balance training as part of your regular exercise program.  Also, increasing the strength of your quadriceps and hamstrings on the previously injured side is also important.   Finally, focusing on quality technique when performing the exercises is especially important.  Specifically focus on equal weight bearing on both limbs when performing exercises on both legs.  Also, important is keeping your knees aligned over your toes, keeping your toes pointing straight ahead, and making sure to bend your knee and hips when making contact with the ground to best absorb the impact forces.  By including these types of exercises in your regular exercise program you may best prevent the occurence of a second ACL injury.