I am not a SAHM but I was one before I returned to work and I do have an 17 month old and a lot of SAHM friends.
Have you tried a run in the stroller? Mine loves it. She gets a snack cup (filled with grapes and berries) and a toy that she only gets in the stroller (an obnoxious cell phone toy). When I run sprints, we yell WHEEE! and she laughs. And sometimes she cries because she doesn't want to be in there and I explain (to her uncomprehending wee one brain) that this hour is mommy's hour. My BFF did this with her LO since she was tiny and her child is three now and still whines but knows this is "mommy's time".
As far as yoga, I can't recommend the YMCA enough! They provide 2 hours of free childcare with a membership every day. The kids like "Kids Club" and it's a well deserved break from each other. Plus, you're being a role model for your child about fitness and exercise. Of course, not everyone can afford the Y so if that's the situation, I would move the yoga to before the LO wakes and try running with her/him.
You got this, mom!