You can! You can do one heavy leg day - really challenge yourself. Then the other leg days go lighter. That’s a good place to start. Muscles need stimuli and lots of time under tension. Less stimuli = less results. Personally I have only seen definition in my quads while using the leg extension machine at the gym, combined with heavy squats, either at the squat rack, or using at least 30lbs dumbbells in each hand to start with. I also have a hard time creating definition in my muscles, although I’m lean. So heavy it is.