New Sketch - Drawing my Kids from Real Life

Here's a new sketch of my kids watching TV.  I decided that this year I would do more sketches of them and anyone else that I can get in my sights, so that I can improve my drawing skills.  I read somewhere that the foundation of a good painting is good drawing and I realised that although I sketch regularly in my sketchbook, I don't really do much sketching from real life. I love drawing faces but bodies scare me so I'm going to jump right in and draw them anyway!  It's really good practise because my kids (like most, I'm sure!) almost never keep still and it's a challenge to capture a particular posture. I've also been using magazine images but nothing beats real life really!

I don't have three or four kids, only two, but in this instance my son moved much more than my little daughter so I drew three of him and tried to capture each position he moved into.  What I found most interesting, is how their postures are so familiar to me everytime I look at these drawings, if that makes sense.  It seems as if I've captured some of the essence of each child which makes the drawings all the more successful for me personally.

Have any of you ever drawn kids/people from real life?  How challenging was it?  Please let me know in the comments - thanks!