The Simple, No-Equipment Workout You Can Do at Home
Modified Side Plank
If the side plank is too difficult, hold for five seconds, rest for five seconds, and repeat as many times as needed to total 30 seconds. Each time you perform the exercise, try to hold each repetition a little longer, so that you reach your 30-second goal with fewer repetitions.
If that's still too hard, bend your knees 90 degrees and allow your lower legs to rest on the floor as you do the exercise. (Your body will now form a straight line from your knees to your shoulders.)