Summer exercise program

I admit that I am not an active person.  I would rather sit and read a book than ride a bike, or even take a walk.  My kids (especially Ella) are taking after me in this.  Ella isn't in any organized sports that require lots of practice and hour long games---Taekwondo is good, but it's only 1 hour twice a week. I was also concerned about Amanda's core strength: as I've learned through my exercise class, "They're all core exercises!"  It's important to have good core strength for all aspects of life. So I was trying to think of how we could stay active during the hot summer months when it is easier to stay inside rather than go out into the 100 degree heat.

We go swimming and bike riding.  We can play at the park (although Ella and I bring books =).   But we started a daily exercise program to augment these.  Here's what we do:

• sit ups.  I do 20.  Ella does 30, Luke does 10 and Amanda does 15. 
• pushups.  Ella and I do 30, Amanda and Luke have to do 10 but they have to be really good.  If they're not good, I make them do them again.
• Jump ropes.  I do 100, Ella does 120, Amanda 100.  Luke just learned a few days ago so he does 10, and he's working up to 50.

We're trying to improve all of these numbers over the summer---the theory says that if you do something every day with effort, you will improve.  We'll see if we can demonstrate that over the next few months.