Try using your deep core muscles to stabilize yourself as the train stops and starts
While sitting and without changing the position of your pelvis, draw your belly button slightly toward your spine while also “zipping” up through your lower abdominals. This should feel like you are engaging the muscles that would lie underneath the zipper of your pants.Trish McAlaster/The Globe and Mail
For a harder challenge, try the exercise while standing and see if you can keep your balance.Trish McAlaster/The Globe and Mail