Wait until your baby is able to hold her head up without assistance and can bear weight on her legs before putting her into a jumper. (verywellfamily.com)
Not being able to move, or put weight on my leg for 6 months, took an emotional and physical toll on my body. (healthcentral.com)
There are many ways that you can increase the resistance that you use by holding dumbbells as well as using weights on your legs when doing leg raises etc.. (x-size.com)