Push Ups on the Pilates Reformer, aka Control Balance Front, or even Control Push Ups on the Reformer, is a great challenge to your Long Stretch and other "tall back" Pilates exercises. Control Balance Front is a great challenge for your entire body and requires more than strength. You need to reach in all directions and endurance to do it! It's easy to make this an arm exercise but you'll feel how much reach you need from your legs. And, how standing in your feet allows you to connect even more to your center. You don't need to do it all but try to keep moving!
Move your arms from your upper back, reach your legs from your center.
Unless you are under 5'1", I highly recommend "gearing" out at least one gear on your Reformer. Place one or two (ideally two) heavy springs on your Reformer. Put your hands on the back edge of the shoulder rests. The straighter your wrists can be the better. Put one foot on the foot bar and then lift up in your center to lift the other foot onto the foot bar. You should be in a "pike" and then press out from your legs and center into a "plank." Your arms should be reaching from your back and your legs reach from your seat.
Start by reaching the arms forward and back. You should feel your arms reaching from the back and pull the carriage back. Do this 2-3x and if it is going well, lift one leg up as you press the carriage out and then close the spring and switch your legs. Repeat 2-3x each side. Then, if that's going great, hold the carriage still in your plank and do 3-5 push-ups without the carriage closing. To dismount you should pike up from your center to close the spring and then step one foot all the way to the floor and then take the other one to the floor.
Be sure to check out more of my online Pilates Reformer exercises. I want to help you continue your Pilates Reformer training!