Why You Should Never Lockout

You should generally avoid locking out your joints during exercises because it can shift the load from your muscles to your joints, potentially increasing the risk of injury and reducing the effectiveness of the exercise for muscle growth. When you lock out, particularly in moves like the bench press or leg press, you momentarily take tension off the targeted muscles (such as the chest or quads) and place it on the joint structures (such as the elbows or knees), which may lead to joint strain—especially if performed forcefully or repeatedly.

Maintaining a slight bend at the end of a movement keeps constant tension on the muscle, leading to more effective stimulation and time under tension, which is important for hypertrophy (muscle gain). In some exercises, like triceps pressdowns or leg extensions, locking out is actually required for full contraction, but for compound lifts where joint health is a concern and muscle tension is the goal, not locking out is generally preferred.

However, if you are training for powerlifting, locking out is necessary to meet competition standards, but for general fitness and muscle building, it's safer and often more effective to stop just short of full lockout.