The quadriceps stretches are designed to improve the flexibility of the quadriceps muscles and are important to maintain balance between strength and flexibility.
Most of the muscles that control the movements of the knee are found in the thigh. The four large anterior thigh muscles—rectus femoris, vastus intermedius, vastus lateralis, and vast medialis - are collectively called the quadriceps muscles, and these are the major knee extensors.
Many muscles in the body cross several joints, and thus many of these muscles are able to do several movements. However three of the quadriceps muscles, the vastus muscles, cross only one joint i.e. the knee joint.
The tendons of the four components of quadriceps femoris unite in the lower part of the thigh to form a single strong tendon attached to the base of the patella, and some fibres continue over it to blendwith the patellar ligament. This muscular arrangement allows these muscles to perform only knee extension. These three vastus muscles are strong extensors and sometimes may be sore and tight in front of the knee where the patella bone is located. Muscle tightness due to lack of stretching the quadriceps muscles is most often the cause of this problem.
It is important, however, to have the right balance of strength and flexibility between the opposing muscle groups of the thigh.
Generally the quadriceps muscles more stronger but less flexible than the hamstring muscles. People tend to stretch the hamstring muscles more than the quadriceps muscles, thus creating an imbalance between the two muscle groups. Therefore one must give equal emphasis to stretching of quadriceps muscles as you give to hamstring muscles.
Stretching quadriceps muscles will help you to avoid muscle soreness and tension in these muscles and therefore it is recommended that you include quadriceps stretching in your routine stretching / fitness program.
Following are the quadriceps stretches in different body positions