Think of a tennis player who lacks the ability to stop or push off both legs equally; or a soccer player who makes great plays, but only off his right leg; or a basketball player who cuts left with ease, but slows down when going right.
All these situations are great reasons to engage in single-limb [aka unilateral] training. If your moves are predictable—such as always kicking with your left leg, cutting only to the right, or consistently dribbling in the same direction—you will be easy to defend and defeat. Incorporating single-limb training in your program can add new moves to your game, making you unpredictable and tougher to oppose.
Before you begin, ask yourself some easy questions. Which leg do you usually step with or jump off first? Which leg do you typically use to kick a ball? If you are like most athletes, you use one leg more than the other. That’s your dominant leg!
The following unilateral exercises will increase your stability, strength and explosiveness. Make sure to work both legs when performing them.
Single-Leg RDL
DB Step-Up
Single-Leg Physioball Curl
Single-Leg Squat With Foot on Box/Bench
TRX Single-Leg Squat
Most athletes also have one dominant arm. You can see it in the Bench Press when one arm is unable to press a dumbbell with as much force as the other. Again, single limb, or unilateral, training can be of great benefit. The upper bodies of most beginners have strength differentials; once they start resistance training, gaining equal pushing and pulling power in both arms will take time.
Below are some examples of unilateral exercises that can be used to improve single arm function and strength.
Alternate DB Bench Press
Single-Arm Cable Row in Lunge Stance
Single-Arm, Single-Leg Cable Row
Single-Arm DB Press on Physioball
Single-Arm Med Ball Throw
By adding single limb training to your program, you can improve muscle balance, develop the ability to move powerfully in any direction under all playing conditions—making you a bigger threat on the field or court—and reduce the risk of injury. Impressive!
Photo:  fitinthecity.wordpress.com