Originally Posted by
caloso
Also known as paper-boying.

That looks like a wild segment, but also riders that I would expect to be pounding straight up the hill. Obviously they didn't quite get their gearing right.
Originally Posted by
chaadster
Wow...zig-zagging up a climb is pretty common...up steep ones, anyway. Moreover, the concept should not be that foreign, because as pointed out, it's why switchbacks exist. This is ancient practice, guys...literally.
All that said, the OP should not need to zig-zag up anything but the steepest climbs, which are pretty rare. If they're finding difficulty climbing most hills, perhaps a change in gearing, or even reviewing how to use gears, would be helpful. Thing is, an MTB is typically geared quite low, lower than most road bikes, so I'm a little confused as to why this is being done.
A lot depends on the rider... And, of course, the hill.
If the rider is carrying around an extra 50 pounds or so, it can make the hills that much harder.
Also, cheap MTBs can be as much as 20 pounds heavier than a nice road bike, as well as having more rolling resistance. A lot more to lug up the hills.
I stand a fair amount when hill climbing, so cleats or clips are very helpful. Take that away, and I'll be rapidly dropping gears, and struggling.