If you want to add more power to your golf swing, you should take practice swings on the opposite side. Doing this will strengthen your muscles, which may be needed to help you clear a water hazard. You will experience noticeable differences in the power of your swing if you do this.
Practice your running form. Your feet should always hit the ground directly under your body, not in front of, or behind you. Your toes should be the way you propel yourself forward, not the ball of your foot or the heel. Getting running form correct is the best way to maximize your running potential.
If you want to be a better tennis player, enhance your ability to change your focus quickly from far away to near by. This simulates the same focus it takes to hit a ball, and then react to a ball hit by your opponent. Soon you will be beating your opponent with ease!