There are a few other ways that you can build your quads besides just doing traditional squats. You could try doing lunges, which work your quads (as well as your hamstrings and glutes). You could also try doing split squats, which are a bit more challenging than regular squats but will also help build up your quads. Finally, you could try doing single-leg squats, which as the name suggests, you do with just one leg at a time. This helps to make sure that each side of your body is getting an equal workout.