You point your toes down on a Muay Thai knee because it angles the actual kneecap into the target. Toes up, you hit with the soft tissue around the knee. Toes down, you land with the hard, pointed part of the joint — the part that actually does damage.
Small detail. Huge payoff.
Master Toddy breaks this down in the Muay Thai Bible and shows it side by side on the pads. Toes up. Toes down. Toes up. Toes down. You can physically see the angle of the knee change. Toes up still hurts — it's still a knee to the body, and it's still going to bother someone. But toes down sharpens the strike. It tightens the calf into the hamstring and drives the bony point of the knee forward instead of the meaty part.
Here's the cue. Think of your heel going toward your butt. When that heel locks in tight, your toes naturally point down and your knee becomes a spear.
The other reason this matters is safety for YOU. When your toes are flared up and you drive forward, your shin and the top of your foot are exposed. Bang them into an elbow or a hip bone and you'll know about it for a week. Toes down, heel tucked — everything stays protected behind the weapon.
Drill it slow. Catch the knee on a partner's pad or your own hand just to feel the form. Toes down every time. Boring rep after boring rep until it's automatic.
Want the full knee breakdown? See our complete Muay Thai techniques guide. And if you want Master Toddy walking you through every strike in the system, grab The Ultimate Muay Thai Training System.