The best thing a working mom can do to stay in shape is to fit in a 20 minute cardio workout that gets your heart rate up and includes intervals. Its better to work out smarter than longer especially if your in a time crunch!
Working Mom's can do a lot of things to stay in shape. One is to get out and PLAY with their kids! Running around a soccer field, tennis court or playground can be fun and keep you moving. Mom's with little one's can grab their jogging stroller and hit the streets! Or, find a friend who also is under time constraints to meet up with at the gym or take a walk/jog 4-5 days a week.
The most important thing for a working mother to do if she wants to stay in shape is to not let her other responsibilities become excuses. Being a great mom, employee, and performing household duties are all important and time consuming. Any mom who does all of that deserves to put aside a block of time to do something for herself too! Fitting in a 30 minute high intensity workout 3 or 4 times a week is very manageable, and will produce super benefits. A mom who does that for herself will have more energy to keep the house running, perform at work, and be a great mother!