Definition
The quadriceps (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius) are the primary knee extensors and critical for squatting, lunging, sprinting, and jumping. The rectus femoris also flexes the hip, making it active in both squats and leg raises. Deep squats and leg presses are the foundation of quad development.
Real questions
What's the best quad exercise?
The barbell back squat or Bulgarian split squat — both allow heavy loads through a full range of motion.
Why do my knees hurt when I squat?
Usually from insufficient warm-up, valgus collapse (knees caving in), or quad dominance from neglecting posterior chain work.
Stack with
Put it to work
Coach Foster builds your program around quadriceps and the rest of the fundamentals, shaped to your body and your week.