It's all a balancing act, without changing the activities you do you start losing muscle mass in your thirties. The good news with kids is that most love climbing so that can be a great activity to do with them if it's available around where you live and you don't like weight training.

If you already run and ride you're ahead of most, so don't get too paranoid about it!

https://www.health.harvard.edu/staying-healthy/preserve-your-muscle-mass