Without further ado:
This picture provides one angle on the IO foot. The throw isn’t explicitly IO–which is to say, this could just be a flat throw to the open side–but you’ll note that the foot position forces the knee to follow and wind up in a position which allows a fairly clean follow-through of the arm in front of the leg.
This picture shows essentially the same position as the prior one, but from a slightly different angle. You’ll note the release point, which is both low and well in front of the knee–again, this is not explicitly an IO throw (thought note the slight tilt), but I hope it’s fairly apparent that a throw from a similar position could penetrate a mark for a low-release break.
This picture is a great example of how the IO foot can be applied in game (though the foot block is a perpetual menace for low releases). Check the distance the thrower is able to penetrate from where his pivot foot (and presumably weight) was. Note the direction the foot points, relative to the throwing direction–pretty close to perpendicular*. Any mark within a few feet is a candidate for the step-through, IO forehand break.
*I know I referenced “past perpendicular” in the prior post, and that may have been a bit hyperbolic–I get there sometimes, but it’s more instructive as a cue than a hard-and-fast rule.
I’d love to hear thoughts from people who get by with other stepping/throwing techniques. I know there’s a decent-sized camp that points the foot upfield and releases outside of the knee rather than inside, and I’m curious as to how that plays for making IO breaks in particular.