A Total Gym Workouts Question

Any Users of Total Gyms! I have a Kneeling Plank Press Question:

I just started doing these again
and noticed The muscles on the outer sides of my knees and up a bit, (like 4 inches up)
Seem to be getting the brunt of this workout.

Am I doing it right if this is going on?

Please let me know if you can!

Thanks!

2/6/14
Anne