Gary, my legs don't sink when I swim. A little speed and momentum helps. Plus, not to focus on the down beat when kicking, but a little up swing of the opposite leg. Drawing in on the abs and engaging the glutes, plus moving the legs from the hip joint vs the knees all help. The spine needs to be straight and not bowing. Kicking when doing drills can be a challenge but good help stabilize the body.

Thanks for the response! I should have said despite the fact that your flutter kick is not very propulsive rather than that your legs sink like mine. I never thought about the up swing of the opposite leg. I’ll try this at my next practice on Tuesday morning. I am drawing in my abs and moving the legs from the top of the hip bone instead of the knees. My prone glide is decent so I think my spine is straight.

Do you have any tips on how to keep legs from sinking while doing this drill? When I do this drill on my right side, which is my weak side, it feels like I'm losing my balance and I'm about to swallow the pool.