I came across an interesting article a couple weeks ago that made me question (again) the way I hydrate during Ultra's. Over the last few years I've used primarily handhelds for the following reason:
-I seem to drink more with handhelds since the water is quick and convenient.
-The whole concept seems faster and more streamlined with a handheld.
-Quicker aid stations filling up the handhelds.
-I can easily calculate how much I've had to drink.
-Water belts seem to give me stomach issues with all that weight bouncing and pushing against the abdomen.
-Backpacks are too cumbersome and bulky. Plus hard to access gear.
However this research study indicates that handhelds are less energy efficient then packs. A 6 lb pack was more efficient than a 2 lb handheld! Seems crazy but heck I run barefoot around town nowadays which would have seemed crazy 2 or 3 years ago.
So I still plan on using a handheld but thinking I will use the Nathan running vest more often to carry extra gear. I usually use a pack and handheld for long training runs which seems to work well. I would like to see how a small waist pack compares in their study. I tend to use a single handheld with a small waistpack quite a bit for races and mid range training runs. All just more food for thought when running ultra's. Check out the article for yourself. It's a quick solid read.