Well, I've been lifting weights and doing cardio for 4 years. I jog for an hour a day, so I have very good endurance. I can squat a solid 450 pounds and I can Bench a solid 250. I also was on my track team and did discus throwing for years in Middle School and High School, so I have a good arm. I am 5' 11" tall. I figure since (credit to Alpha) the average 5 year old is about 50 pounds and 3.7 feet tall, my best strategy would be to lift them by the ankle and swing them.
So, my first priority would be to grab one of the small 5-year-olds (a 30-40 pounder) and swing away, knocking the others to the side as I moved through the crowd to get my back against a corner (assuming a square room) or at least a wall.
Ideally, I could find a second small 5 year old and then be able to wield one in each hand with relative ease. If I could find 2 small ones, given that I do my weight training in repetitions and have quite a bit of endurance, I think I could take out quite a few. The small ones would of course need to be knocked unconscious first, but that would be relatively simple.
Let's say each swing of a 5-year-old was a 90 degree arc. I could swing with each hand. If each 5 year old is 40 pounds, I would estimate that before tiring I could swing them with an extended arm 20 times each. at a 90 degree arc, if they are bunched together, each swing should be able to hit 2 or 3 5-year-olds (we'll estimate 2.5 to be safe).
2 X 20 X 2.5 + 2 (the ones I knocked out in the first place) = 102 5 year olds. However, I believe I would at least have enough energy left to chuck the 2 I was holding as clubs before collapsing in exhaustion and being overtaken. When thrown, they should be large enough to take out an extra 5-year-old each, putting my total at a solid 104 5-year-olds.
