Definitely the right foot, turns you toward 2nd base so your route is more direct, and you get there faster. No. This is wrong. Why the left foot then? He's right and wrong even though there was no explanation, I was always taught with the left foot as well... When making the turn to 2B, you obviously want the "?" shaped turn, but you want to leaning and dipping your left shoulder to make that turn more sharp. But... The most important thing is which feels more comfortable to you, no need to break stride to round the bag. If a batter prefers the right foot, so be it.