Every tennis player wants an untouchable serve. It’s a massive weapon that either wins the point outright or sets you up for an easy second shot.
Many young tennis players mistakenly think that to add serve speed they need to swing harder, which can result in serve inaccuracies and potentially cause shoulder problems. Tennis athletes should instead focus on developing lower body strength, core power and shoulder stability—three components that are integral to increasing serve speed.
Incorporate the following four weight room exercises to improve the power and accuracy of your serve.
Overhead Med Ball Slams
Overhead Med Ball Slams develop upper body and core strength with a movement that closely mimics the serve follow-through. This helps you drive through the ball with more force, resulting in increased serve speed.
Med Ball Rotational Throws
The core adds speed to the serve when the body begins perpendicular to the target and unleashes energy by powerfully rotating to finish facing the target. Med Ball Rotational Throws strengthen core rotator muscles in a movement that resembles a game-time serve.
Single-Leg Squat
Most of the power in your serve is actually generated from the legs and hips. Think of a deep knee bend and explosive drive up toward the ball. Develop serve-specific lower body strength and balance with the Single-Leg Squat.
YTWL
The shoulder must be strong and stable to cope with the tremendous force and speed transferred through your body to your arm. The YTWL strengthens shoulder stabilizer and back muscles that keep the joint healthy and strong for a consistent arm swing and improved accuracy.
Source:  Core Performance
Photo:  The Slice