A well defined and developed body is important for the overall health and look of a body. How many times have you seen a guy with a big upper body and tooth pick legs. This not only looks bad, it can lead to injuries and cause stress on the knees and hamstring injuries. Leg exercise helps with the overall development of your body. You should devote an equal amount of time performing leg exercises as you do your upper body. To achieve a well defined, strong, and balanced legs you must incorporate several leg exercises. Your leg exercise workout must have different exercises from different angles to develop all the parts for your Legs. Developing strong legs is crucial to preventing injuries to other muscles during exercises.
To get the best results you need to do 6-10 reps of each leg exercise. Choose a weight that you can do up to 10 for three sets. Once you can do 10 then move to a higher weight for maximal results. You can build up your Leg muscles by doing a variety of leg exercises with and without weight.
Choose at least 2 exercises from The Entire Thighs and Quadriceps group. Always do leg curls for hamstrings. Every week or so change exercises within each group.

Here are a group of the best leg exercises

Entire Thighs

Leg press
Sitting on a leg press machine, position your feet together against the crosspiece about should-width apart and toes pointed slightly outward. Grasp the handle grips or sides of the seat. Bend your knees and lower the weight as far as possible without changing the position of your hips. Do not lower the weight so far that your hips start to curl up off the seat! Then slowly push the weight back up using your heels, not your toes. Do not lock your knees at the top, but rather take the weight to just before lock. Then being to lower the weight again SLOWLY. You can change your foot positions to vary the angle on the muscle.


Squat

This is the best leg exercise for size, power, and overall development of your leg, it can also be the most dangerous. Make sure you have proper form when performing this exercise.

Hack squat
Step up with dumbbells

Place a barbell on your shoulders like you would if you were doing Barbell Squats. Step up onto a flat bench with your left leg. Then step up with your right leg so you are now standing on the bench. Step down with your left leg, then your right leg. Repeat, starting with your right leg this time. Be careful not to fall! Use lighter weights. Can also be done with two dumbbells in your hands instead of a barbell

Quadriceps

Dumbbell lunges


Place a barbell on your shoulders like you would if you were doing Barbell Squats. Step up onto a flat bench with your left leg. Then step up with your right leg so you are now standing on the bench. Step down with your left leg, then your right leg. Repeat, starting with your right leg this time. Be careful not to fall! Use lighter weights. Can also be done with two dumbbells in your hands instead of a barbell

Leg extension
Using a leg extension machine, sit in the seat and hook your feet under the padded bar. Adjust the pad and/or the seat so that your knees hang off the end of the seat and the footpad rest on the lowest part of the shins. Grasp the handles on the machine or the edges of the seat to keep your hips from lifting up as you perform the exercise. Extend your legs until knees are straight, making sure you remain seated flat on the machine. Raise the weight all the way, lock and hold briefly, then slowly lower the weight back to the starting position. Get the full range of motion and feel the muscle being worked during the entire movement. Do not SWING the weight up!

This is the best leg exercise for toning the quads an adding strength around the knees.


Lateral Squat
Double leg power jump

Cross your arms over your chest. With your head up and your back straight, position your feet at shoulder width. Squat down until your upper thighs are parallel, or lower, to the floor. Jump straight up in the air as high as possible, using thighs like springs. Immediately squat down and jump again. Can also be done with a barbell on your upper back or with dumbbells hanging at your sides.


Hamstrings

Leg Curl

Lie face down on a leg-curl machine and hook your heels under the roller pad. Your legs should be stretched out straight so that the pads rest on the back of your ankles. Grasp the handles under the bench for support. Remaining flat on the bench, curl your legs up until your hamstrings are fully contracted. Release and lower the weight slowly back to the starting position. Concentrate on using a full range of motion and do not SWING the weight up. You can point your toes to intensify the burn in your hamstrings.

This is probably the best leg exercise for your hamstring area