Epiphany is correct. I do it 4-6 times a day, and if you know what you're doing it's not difficult.
Why are you 'stretching' for the pedals in the first place? A proper seating position would allow you to fully displace either pedal without shifting your butt in the seat. We operate with two different seat types, the two-adjustment variety and the single-adjustment type, and it doesn't make any difference if you set up your seating position correctly. We have pilots from about 5'3" to 6'6" and none of the couple dozen among us has a problem, to my knowledge, and certainly nothing like a plurality. Even in our older frames, two pumps is sufficient.
Lower back pain, about 95 times out of 100, means that your abdominal muscles are out of condition, though I realize that most helicopter pilots would rather wear a neoprene corset at work and blame it on the machine. To do otherwise might necessitate missing the first pint of the evening and having word get out they might be getting a bit of exercise.