Best way to get exercising is to have some of your friends join you. If your friends can't join you, then think about doing small amounts of exercises. It is not the 10 km that needs running - but each 50 meters of the 10 km. And sometimes you kids can join you in this by making it a game.
Just walking the dog is a great start, jogging with friends while you catch up and when the kids are at school, playing some sports with the kids -badminton, tennis, bouncing the ball. Yoga and stretches in front of the tv...not too hard!
I like Asian mums - in Tokyo I saw 2 Japanese mums bicycle their toddlers to the park, lay a blue blanket in the middle of the grass, sit and chat while toddlers explored, stumbled and picked themselves off the grass - a lovely time ...
or 2 mums here take their kids for a stroll - mums stop and wait for small kids walking - have a nice chat, everyone gets fresh air, exercise, social contact, a good time - go home and the kids are exhausted and sleep - excellent
the idea of single mum alone stay at home running after every screaming command from bored don't-know-what-to-do kids also stuck at home because it's 'safer' (not) is just crazy-making for me... get out, go for a stroll, talk to the neighbours, get incidental healthy exercise and tire the kids out too so you get some adult time to yourself while they sleep !
I am the sor of person that like putting up memos, photos, where I can see them. So lately, I've pinned this message on my mirror in my own handwriting: "If you are not going to aerobics today, when do you think you will go?"
I laugh when I look at it, but it does do the trick for me. 'Coz if not today, I think I will also not do it 'tomorrow'.