Squats are great for strong, lean legs

Squats with Overhead Press

Standing with feet hip width apart, rest a dumbbell on each shoulder with elbows bent and palms facing inwards. Contract the abs and draw your shoulder blades down and together. Keeping the bodyweight towards the heels lower the hips until the knees are bent to a 90% angle, with your butt pushed backwards and your weight over your heels. Inhale as you squat.

Return to the start position exhaling as you do so and extend your arms to press the dumbbelss directly overhead. Bend the arms and return the weights to the starting position. Repeat the combo.

This exercise strengthens the quadsriceps, hamstrings, glutes, front and middle delts.