Proper Technique:
Lie on the floor, face up, and bend one knee to hip level
Grasp the hamstrings with both hands and pull the knee closer to the lateral aspect of the shoulder on the same side of the body
Targeted Muscles
Adductors
Gluteus
RECOMMENDED LINKS
Read about the benefits of a proper warm up routine
http://www.fit-2-hit.com - Blog on Athletic Conditioning & Health
http://www.conditioning-coach.com - Tennis & Conditioning Coach