The Leg Press Machine

The leg press machine is one of my favorite exercises to use when building the quads. Position yourself firmly in the seat by holding on to the handles. Feet shoulder width apart anything wider than that takes the tension off the quads and put a lot of stress on the hip joints. When the weight gets heavy people have a tendency to raise their heels off the plate form, pay close attention so that doesn't occur because the force of the weight shifts to the knees. Keep your head aligned with the torso and avoid contracting the neck/traps muscles. Never fully lock out at the top thus, takes away that spilt second rest during the movement. Avoid using momentum, lowing the weight is more important pushing the weight up be mindful of that. Also when lowing the weight stop when you feel the burn on the upper quads, hamstring/glutes shouldn't engage.
The upper quad is your focus point thats where the power comes from.
The longer the muscle is under tension the greater the results. Recommended 3x4 sets 8 to 10 reps, increase the weight per set.