I've read that squats and lunges are primarily Hamstring/Glute exercises. But I tend to feel them much more in my quads. Is this indicative of a form issue, or an imbalance in the strength of my quads vs hamstrings?
The barbell squat is primarily a quadricep exercise. Secondary muscle groups include glutes, hamstrings, lower back, and even abs.
The best way to target your quads during a barbell squat is to keep your feet at shoulder width with your toes pointing out a little bit to avoid putting unnecessary pressure on your knees.
If you want to activate your glutes and hamstrings, take a wider stance and perform a deeper squat (to parallel or just below). I wouldn't recommend going any lower than that until your know that your form is really nailed down. Performing a full squat (hamstrings touching your calves) with improper form can put a lot of strain on your knees.
Lunges usually activate your glutes a lot more than a standard barbell squat, but it depends on how you perform them. If you're not feeling glute activation and you want to feel it more, there are two things you can experiment with:
- The length of your stride. Experiment with the distance between your feet to target your muscles differently.
- The angle at which you complete the concentric portion of the movement. If you lean forward during your lunge, you will put more weight and emphasis on your quads. Leaning forward is common in this exercise because the quadricep is the strongest muscle in the leg and transferring the load to the quads makes the movement easier to complete. If you keep your spine vertical throughout the movement, you should notice a lot more glute and hamstring activation.
If you are really looking into building your hamstrings and glutes though, you should look into performing Romanian Deadlifts.