Skip cardio. Doing a lot of cardio exercise actually tends to make the legs thinner. The leg muscles get long and lean instead of large and bulky. Doing a lot of cardio also takes away from energy you could be focusing on weight training, which is the key to building leg muscles.
If you love cardio and don’t want to drop it, try stepping it back a notch. Instead of running 4 times a week, make it 1 or 2. Better yet, try walking or lightly jogging instead, so you can conserve your energy for the weight room.
Train 2 to 3 times a week. Many people think that to build muscle you have to train every day, but that’s not the case. Muscles get stronger when they get small “breaks” in training, and get stronger when they build up again during REST days. So don’t exercise the same muscle groups two consecutive days. Rotate muscle groups so you’re training your arms, back, chest, and other areas on the days you aren’t working out your legs.
Making sure to work out your other muscle groups is important when you’re working on your legs. Don’t neglect the rest of your body!
Work out hard. Make your leg workouts count. They shouldn’t last more than 30 minutes, but those 30 minutes shouldn’t feel comfortable. You want to go all in and maximize the workout, putting a lot of pressure on your muscles so that they break down and build back up stronger.
For each exercise, you should use an amount of weight that you can lift for about 10 reps before you have to stop. If you can lift an amount of weight 15 times without stopping, you aren’t lifting enough. If you can’t lift it more than 5 times without needing a break, you’re doing too much.
Some trainers recommend “training to failure,” which is the practice of repeating an exercise until you can’t do even one more rep. This is said to build up the muscles more quickly, but it can cause injury if done incorrectly. Work with a trainer to figure out which technique is right for you.
Do explosive reps. Each rep should be done explosively and with force, rather than slowly. Bodybuilders have found that working out explosively – quickly and with some force – helps muscles build up faster and bigger. Get through your reps as fast as possible. Time yourself to see how fast you do them, and work toward getting through your routine more quickly as the weeks pass.
Get plenty of rest between workouts. Muscles get stronger during the time between workouts, when the fibers heal and strengthen. That’s why it’s mandatory to get plenty of sleep every night when you’re training heavily. On the days when you don’t work out, let yourself rest. Don’t go on a 10-mile hike or bike all day long – it’s okay to put your feet up and relax.
Weight Training Exercises
Work out your thighs with barbell squats. This is a great exercise for building up those thighs. You’ll need a barbell bearing as much weight as you can lift 8-10 times without needing to put it down. Hold the barbell with both hands over your shoulders. (You can use dumbbells instead if you’d like).
Start with your feet shoulder-width apart.
Bend your knees and squat, moving your butt toward the ground. Keep squatting until your thighs are parallel to the floor.
Push back up and repeat 10-12 times for 3 sets.
Do stiff-legged deadlifts. This works your hamstrings, making them bigger over time. Load a barbell with as much weight as you can lift for 10 reps, and set it in front of you on the ground. 
Stand with your feet shoulder width apart.
Bend at the waist, keeping your legs straight. Grab the barbell with both hands.
Keeping your knees locked, lift the barbell so that it rests against your thighs, then lower it back to the floor.
Repeat 10-12 times for 3 sets.
You can build most of the leg at once.
First go next to a wall with enough space to move your body. Make sure that you are not standing on a slippery surface.
Now lift one of your legs, say, right leg and bend it. Keep your right hand on the wall for support.
Now stand on the toes of your left leg. Keep your body straight.
Now bend your leg as if you are going to take a high jump.
Even when you bend your leg, stand on your toes.
Now lift your body with that leg with moderate speed.
During this entire cycle, stand on your toes and of course on only one leg.
Repeat this for 10 times or even 20 times if you are strong enough. Repeat the same with another leg.
Do it twice a day, like once in the morning and once in the evening to give your legs some rest.
Keep increasing the number of times you lift your body as your legs get stronger.
This is hard at the beginning, but you will get used to it.
This strengthens your calf muscles and most of your thigh muscles and makes them harder.
Do calf raises. This exercise pinpoints your calves, which are notoriously hard to buff up. Hold a barbell or dumbbells over your shoulders. Stand with your feet shoulder-width apart. Raise up on your toes, then set your heels back down on the ground. Repeat 10-12 times for 3 sets.
Do standing leg curls. The leg curl machine allows you to lift weights with your ankles for a total-leg workout. Start by loading as much weight as you can lift for 10 reps or so. Attach the cable to your ankle and place your hands on the support bar. Bend your knee and bring your heel toward your butt to lift the weight, then straighten it back out. Repeat 10-12 times for 3 sets, then switch to the other leg.
Do leg extensions. Load the leg extension machine with the heaviest amount of weight you can lift for 10 or so reps. Sit on the machine with your knees bent and your feet under the lower bar. To lift the weight, straighten your legs, then lower them back to starting position. Repeat 10 – 12 times for 3 sets.
Eating to Build Muscle
Eat high-calorie meals. To get bigger muscles, you need extra fuel. Your meals should be large and high in calories during heavy training periods. The calories you consume, however, should not come from fast food and junk food – eating too much of those will just slow you down. Eat plenty of calories from healthy, whole foods to keep your body feeling powerful.
Eat lean meats, fish, eggs, and dairy.
Nuts, avocados, and whole grains are also great.
Eat tons of fruits and vegetables.
Coconut and olive oil provide lots of healthy calories.
Get lots of protein. The body uses protein to build muscles, so you’ll need extra during this time. Eat beef, pork, chicken, fish, eggs, and cheese. Eat beans, legumes, and tofu for non-animal protein sources.
You can try supplements such as creatine. Studies show that creatine supplements can safely help build up the muscles when taken with daily meals.
Drink plenty of water. Your body will need more water than usual to stay hydrated when you’re training heavily. Water also helps flush toxins from the body and is essential for healthy digestion. Aim to drink at least 10 8-ounce glasses of water every day while you’re training.
Health and Wellness Adviser
David is a health and wellness advisor who assists individuals and corporates in achieving and maintaining optimum wellness by advising them about healthy diets and exercise, as well as methods to cope with stress.