Exercise specific to a particular part can help give you relief in terms of pain if any or build muscle. In some cases, one can loose that extra fat on a particular part like waist, chest, thighs etc...

If you get muscle cramp in the back of your thighs, you need to work this out. This exercise stretches the hamstring and thus relieves pain in thighs. Some hamstring exercises need great care while practising as these are prone to injuries due to strecting and twisting.

Lie on your back, knees bent, feet flat.

Grasp one leg at a time just above the knee and hold the leg at a right angle with the body.

Holing the leg out at arm's length, slowly straighten the knee.

Hold the leg as straight as you can as you count to ten.

Note

This exercise is risky for those who have unstable knees. This exercise is not recommended for those who have problem called "Back-Knee". In this problem, the curves back when person stand up. It's easy to overstretch and be sore with this exercise.

Straight Leg Raise

This exercise strengthens the muscles that bend the hip and straighten the knee.

Lie on your back, knees bent, feet flat.
Straighten one leg. Tighten the muscle on the top of that thigh and straighten the knee as much as possible.
Keeping the knee straight, raise your leg one to two feet (about 50 cm) off the ground. Do not arch your back.
Hold your leg up and count out loud for ten seconds.
Relax. Repeat with the other leg.