This is funny! Really it is! This would be a perfect training for me.
The fact is that you WILL wear out from exhaustion at some point, and anyone with any combat training knows it will come fast. So the fact that you can lift weights won't help you much, if at all, as you will wear out faster.
I'll be conservative and say I can last 30 minutes (but I can surely last an hour).
Lifting weight won't help you one bit, as you will wear out even faster if you use lots of force.
I will have no problem lasting the 30 minutes, as I am actually aikidoka.
Aikido mainly uses the enemy's strength, or at least tries to minimize the use of your own force.
With 5 years old, it will be cake, I know that already. During training, when in combat with even 15 years old boys, I was very careful not to break anything on them.
Actually, I can knock at least one of them for good just by rolling to evade. I know because during one training, I made a roll to recover from a technique, but I accidentally bumped into someone, and knocked her out. I barely felt her. Fortunately, she recovered, but couldn't continue the session.
If I'm tired, I can protect with one of them, while locking him up with one hand.
Anyway, 30 minutes would be a basic training, where I could break arms, wrists and necks (if they fall bad, which I will provoke) at my leasure. I'll be very conservative and say I can take one out every 15 seconds (actually, it will go faster than that).
If the 5 years old don't faint when they have their limbs broken or if they don't kill themselves while landing on the head, I can still take them out by choking them, as I need only one arm to lock one child.
But I would not like to kill children, just breaking their limbs would be painful enough.
Normally, when they see the first ones flying head first to the ground after a kaiten nage or udekime nage, or screaming from a nikyo or a kotegaeshi, or smashing into each other, or have broken arms, wrists, collarbones or necks, which are all very probable when you don't know how to roll AND the techniques applied on you, the others would stop coming at me altogether, feeling the danger (one manifestation of Ki).
Think Steven Seagal without all the punches or kicks, in far less skillful though (he's far higher level in aikido, a level I won't ever reach), and perhaps you can imagine the slaughter.
So I say I can take out 120 5 years old easily in one half hour, and that is conservative.
BTW I'm 80+ kg (I think that's 170+ pounds) and I can send flying my normal aite that have the same weight easily. Aikido allows me to escape from 3 adversaries like these while they're holding me strongly, so I know for a fact that 5 years old won't ever be able to keep their hands on me if I don't want to.
