The vipassana retreats are built on Buddhism (though the founder prefers to reformulate it in more secular terms) so it's not surprising that they're aimed towards some notion of nirvana.
At the very least, simple breathing exercises can be super obviously relaxing and mind-clearing. Lots of people do them for just ten breaths. Five minutes is quite a lot from that perspective, so I really think we shouldn't dismiss that kind of duration.
Walking meditation can also help prepare the mind for sitting practice: http://www.insightmeditationcenter.org/books-articles/articl...
Easier said than believed when there's a sixty-year-old woman within view managing just fine without one ^^.
I actually appreciated the discipline of the retreat, I was just physically unprepared for the sitting (too inflexible). I'm open to other techniques, and when I'm alone I don't force myself into an uncomfortable posture. Thanks for the link.
That said, I can't plead ignorance, just overconfidence. Since the retreat, I have lasted no longer than fifteen minutes at a time. I prefer lying down (I'm not tempted to sleep). It actually feels like I'm a worse meditator now than I was before the retreat, though I've been assured that this is a "sign of progress."
Truthfully, after maybe 140 hours of practice, I have doubts about the purported benefits. The ultimate aim, the end of suffering, seems like an impossible and likely undesirable goal. For now, I use it as needed to clear my mind when I need to focus.