I saw a movie the other night, this kid had tied a rope to two trees about shoulder height.
He would start on one side duck under from right to left and come back to the right with a leaping hook.
If you had your 16oz gloves on some ankle weights....a vest this could be one hell of a cardio workout, it would also increase your agility to a degree I would believe?
It's a drill you'll find being done in probably most boxing gyms, and probably in some MMA gyms if they're witty. It works your footwork in combination with your overall evasion, your bob and weave as it were.
It's a good workout regardless of gloves or ankle weight or vest. I normally only do it at the end of a workout, because of how much it drains me. Ten minutes workin' around that line and I'll have sweat just pourin' off me, and I'll be about spent after that. Full body workout really, if you're doin' it right and intense. Legs to push off so to move laterally and forward, and to get the elevation change. Core to make slight elevation changes at the waist. Arms to keep your damn hands up. Just a whole body thing, I find.
Although it won't make anyone too much lighter on their feet, if you ask me. The drill's more about getting yourself around the line cleanly and staying balanced. If someone's looking to get faster or lighter feet, a drill like the ones posted above would be time better spent. The dot or circle drills, jump roping, ladder or tire drills, cone hopping, things like that.