The gym-shorts drawstring trick HN keeps resharing turns out to be the Lapp knot

First Class Amateur's rip-cord knot

The video is a 40-second demonstration from the channel First Class Amateur: tie your gym-shorts drawstring so it cinches tight, then pull one free end and the whole thing releases like a rip-cord, ready to resize without untying anything. It holds on slippery, flat cords that a normal bow slides straight out of. The one catch, several viewers confirmed, is that the two ends finish at uneven lengths, leaving one long dangly side.

It isn't a new trick, it's the Lapp knot

The first thing the thread did was strip away the mystique. A commenter who read the video's own description noted that it names the knot: the *Lapp knot*. Others recognised the mechanism on sight. The author of the *Effective Pandas* series called it a sheet bend; another reader pinned it more precisely as a slipped sheet bend, the quick-release cousin of a join sailors have used for generations.

The deeper fix: you're probably tying a granny knot

Then came the reversal that made the fancy knot almost beside the point. The reason bows fail, an engineer in the thread argued, usually has nothing to do with which knot you picked:

"99% of all loose ties are due to people doing a granny knot instead of a square knot."

The fix is a decades-old HN favourite: tie the second half of your ordinary bow in the opposite direction, turning an unstable granny into a flat, secure reef knot. One commenter credited that single correction with changing how he ties everything. There is an illustrated guide to the granny-knot mistake that has been passed around here for years.

Where the rip-cord knot goes wrong

The adjustability that sells the Lapp knot is also its weak point. kazinator, who maintains the TXR language, suspected the very loop that lets you pop the clamp loose "also makes it less secure than the standard knot." At least one person lived that: a user whose shorts cinched into a knot he couldn't work loose gave up on it and went back to the Ian Knot he already used for shoelaces.

A rival camp skipped rope entirely. One reply would ditch the knot altogether: use a cord lock, shorten the drawstring, and you never lose an end into the waistband. Against all of it, a reader familiar with traditional Afghan pants offered the knot's best case, that those garments arrive with a waist 75 to 100 inches around, and a fast, adjustable, fully releasable drawstring is the only thing that makes them wearable.

For most people the takeaway isn't an exotic knot to memorise. It's a five-second correction to the one they already tie every morning, and the small jolt of a 40-second video teaching a grown adult something their shoelaces have been getting wrong for thirty years.