Many of you have read posts that I have linked to before from Katy Bowman who I have a great deal of respect for. Here is one on children and their grasping reflex, and how to encourage their hanging and grasping abilities, which will REALLY help them out later in life. http://breakingmuscle.com/family-kids/katy-bowman-and-biomechanics-human-growth-necessity-monkey-business
Also, here is one on great footwear for children, and why "supportive shoes" are really not such a good idea. We haven't evolved over all these years to be wearing heels and arch support. Get those feet using the ground optimally as a child and as an adult you will be extremely grateful.
It's super fascintating stuff to me, I hope you find it interesting as well.
Along those lines, here's a link to a great article in The Atlantic about children and playing and what has happened to them as a result of the sterile play environments we have created for them in our "new and safe" playgrounds. Not to mention how we feel so unsafe leaving our children to fend for themselves in playgrounds, hovering all the time to keep them safe.