Exactly, because by the time your Husky has got to the end of the lead, it's probably going in excess of 25Mph
This could do one of several things.
1. Yank the retractable handle out of your grip. You now have a loose Husky, which is being chased by a strange bouncing, clattering handle.
This scares the dog into running faster.
2. Break your arm / wrist, with the force of the lead snapping tight. (This has happened)
3. Dislocate your shoulder. (Also happened)
Just a few things to consider, if yours is the kind that likes to suddenly 'Launch' forward whilst on the lead.