We are not stronger, we have more stamina. There is a difference
Considering the weight and power in a human leg, a swift kick would seriously harm and probably kill an average macaque. The issue is not strength here.
18kg is the average weight of a 5 year old kid [1]. It’s pretty routine for women in childcare roles to pick up kids for various reasons.
1. https://www.disabled-world.com/calculators-charts/height-wei...