Back squats, front squats, deadlifts, dumbbell lunges and leg presses, which use weights, are the foundation of any good bodybuilding leg workout. If you don't have access to weights, however, don't throw in the towel just yet. If you train at home, or just don't want to hit the gym, you can still get bigger legs without using weights at all.
Building Muscle 101
Your muscles grow whey they're challenged. When you push the muscle to the point of failure, it breaks down, then rebuilds again to become bigger than before. Your muscles don't actually know if you're using weights or not -- they only respond to how hard you're working. If you can create this muscle breakdown without weights, you're on your way to bigger thighs already.
Body Weight Basics
The best way to build your thighs without weights is to focus on body weight exercises. As a beginner, your body is new to training, so you can use simple exercises such as body weight squats and lunges to bulk up, but as you become more advanced you'll need to do more challenging moves such as pistol squats, split squats or single-leg hip thrusts.
Switch Up Your Cardio
You can use your cardio routine to build your thighs. Curt Pedersen, founder of Stay Fit Central, recommends hill sprints to get your cardio fix and to train your thighs at the same time. Stair sprints work well for this, too. Just find a long hill or a set of stairs, sprint up, walk back down and repeat six to eight times, or until your legs can't take it any longer.
The Good News
Training with heavy weights will always be advocated as the quickest way to build muscle, but when it comes to leg training, body weight training comes a very close second. When squatting, the muscles used in your quads are predominantly slow twitch fibers, meaning they respond best to high reps, suggests strength coach Charles Poliquin on his website. Always take your body weight moves to failure, advises trainer Jimmy Pena on the MuscleMag website and incorporate static moves like wall sits as well as jumps. A sample no-weights thigh routine could involve four sets each of wall sits, jump lunges, single-leg glute bridge raises and stepups, performed twice per week, with each set taken to failure. On one day in between workouts, complete 30 minutes of stair or hill sprints.
The above exercises are all relatively simple to perform but can yield big gains. For the wall sit, assume a squat position with your back resting against a wall and hold the position for as long as you can. For jump lunges, start with your left leg forward and right leg back and then jump up, switching leg positions to land with your right leg forward and left leg back. Single-leg glute bridges involve lying on the floor with one heel resting on a chair and the other leg extended on the floor and lifting your butt up. For step-ups, which are simple, stand in front of a stair or sturdy platform, step up with one leg, bring the other up to meet it and then step back down one leg at a time.