That kind of stuff doesn't work for me; I can't "outsmart" myself by trying to take ad-hoc self-delivered advice. If I said something like that to myself, my brain would respond "nice try, I'm not that gullible. If quitting after five minutes were a reasonable outcome, then never starting is a reasonable outcome. Why don't I just wait until later?"
If I know it's a trick enough to try it, then I know it's a trick enough to see through it.
Doesn't have to be a trick though. As long as some measurable dent in the pile of work is made, that's infinitely more than none at all, right? One way to make this real is for the first few times, to commit to definitely stop after the short interval decided for. So work out for those five minutes and then stop even when feeling like going longer. This way there's no trick involved. It's about removing the pressure to accomplish a significant dent and allow yourself to feel some satisfaction still, as long as there is a positive contribution. Small steps and all that...
This isn't "outsmarting" yourself, its simply getting past the hardest part. It's difficult to "get off the couch" if I think I'm committing myself to running 10 miles. But I can easily get off the couch to run for 5 minutes. After 5 minutes, I can quit, or keep going. Sometimes I quit, sometimes I keep going.
If I know it's a trick enough to try it, then I know it's a trick enough to see through it.