The 45 Degree LegPress machine is an outstanding compound push exercise to target the quadriceps and glutes. It allows the lower body to move in a motion similar to the squat while supporting the glutes and upper body.
The leg press machine allows you to get the benefits of a barbell squat for developing the quadriceps.Secondarily, it develops the gluteus maximus, hamstrings, and calves. By varying your foot position you can emphasize different muscles. It builds strength in these muscles and you can use it to overcome imbalances, such as when runners have more developed hamstrings than quadriceps.
As you exercise with a leg press, the muscles worked primarily include the quadriceps and hamstrings. You'll also engage your glutes and calves as stabilizer muscles throughout the exercises.