As i mentioned once before, my sporting love before ultimate was volleyball. Another tip i learned was when preparing to receive serve, you want to stand with your weight forward on the balls of your feet and slightly pigeon toed – that is with your toes slightly pointed in. The reasoning being that your ankle joint provides optimal force moving forward compared to laterally, and it’s even worse when your pushing backwards. So by angling your toes in, if you need to step left, the closer your right foot is to pointing to the left, the more force you can generate in that direction.
Try this: stand facing forward with your feet wider than shoulder width apart. Point your toes forward and bounce back and forth left to right. Now try it with your toes pointed slightly in. And then try it again with your toes pointed out. You should find that you can push off most forcibly when your toes are pointed in and worst with your toes pointed out.
Now, serve receive is a specific moment where you’re static waiting to burst into motion. (Out of curiousity, has anyone ever been taught to do this is tennis or baseball?) Once you’re moving around, it’s not optimal to try maintain a pigeon toed stance. I apply this to ultimate on the mark. I’m not advocating bouncing around pigeon toed, but you can start out on the mark like this if it's not in flow.
The more important thing to keep in mind is to not let your toes start to point out. If you watch a marking drill, you’ll notice that most players will start on the mark with their toes more or less pointed forward (you’ll notice a lot of the worst markers start out with their toes pointed out). As they bounce/shuffle around on the mark, better markers will keep their toes pointed forward and maintain/recover back to this optimal marking stance. For myself, I notice as I fatigue my stance gets wider and my toes start to point out. It is not uncommon to need to lunge to stop a throw, and the further you lunge, the more likely you will open your hips up and that lead foot will turn out. That’s fine. The key is recovering to your optimal marking stance with your toes pointed forward.
This principle of foot angle extends to any lateral movements offensive or defensive. More on that later.