First - to qualify myself. I am not a mechanic’s coach. However, I have worked with reviewing rehab pitchers and listening to enough people who are professionals in the fields of medical and physical specifics, to pass on these comments.
I’m going to address your remarks and question relative to the pivot foot and its position during a pitcher’s choreography only.
- Stability on the pitcher’s mound, regardless of his/her beginning posture - windup or set, is critical to everything that follows. Hence, where and how a pitcher stands is the foundation to address first. If a pitcher is standing in a hole, and the majority of pitchers performing before him/her, are right handed pitchers, and they dig a hole deliberately and/or push off with the ball of the pivot foot, then the hole will be angled on an incline, slanting toward third base. Hence, when a pitcher drives forward to deliver, most, if not all, of his/her body’s weight will be shifted off center - thus planting the stride foot to the pitcher’s right side, thus forcing the pitcher to throw across himself/herself.
-Some pitchers get into a habit of changing their initial pivot foot position, just prior to the leg lift, by sliding the pivot foot along the rubber, then lifting the stride leg. For most pitchers who are not fully matured in their muscular development, this shifting presents some problems. First- it requires the balancing system of the body to “re-think” a starting point - balance wise, and second - it changes the pitcher’s expectations of where the body is going to land while going down the mound. These alterations can be ever so slight, but, not slight enough to avoid real control issues 60 ft. away. I’ve seen some pitchers that have no real issues with this conduct of the pivot foot, while others have remarkable improvements when they don’t move their pivot foot prior to the leg lift.
Ok, now to address your question more directly. When your walking, your normal gait, is to lead with the heel of one foot, and the back foot normally balances and puts energy to that gait with the ball of that foot. So, your upright position is mobile and balanced. In all honestly, there’s not much to think about here. To take this one step further, take a look at a sprinter. These people can really move, and while doing so, they’re always in a forward upright position.
Pitchers on the other hand, move forward -BUT, they have to go with the upper body’s movement, all the while turning (rotating) and managing both legs in a way that allows the upper body (shoulders & arms) to complete a pitch. So, the back leg and foot have to be accustomed to allowing a lot of flexibility for a lot of fluidity in the rest of the body, going down a incline at the same time.
So try this - on a flat surface, play a simple game of catch by stretching out your stride leg, and then use a walking posture with your back leg by standing on the ball of your back foot. Then, increase the stride of your front leg, slowly, a bit at a time, until you’ve reached the best distance that you can. NOTICE any stiffness in your upper body, any strain on the lower back - lumbar, and any stiffness in the base of your neck. Also take note of any restriction in your throwing posture. By that I mean can you follow through without fighting the restrictions of “going with the throws”.
Now do the same game of catch, but this time, place the instep of your back foot, facing the player that catching with you. Keep that foot position while gong through your entire throwing routine - but as you throw, collapse on the instep of the back foot, DON’T turn and push off with the ball of the foot.
Take notice at how relaxed your back leg is and how it doesn’t restrict/pull on the rest of the body to keep it upright. Also, your ability to rotate easier and quicker, increase in your stride, and your overall ability to control who your throwing at and where.
Why is the above possible? Well, when the leg muscles of your back leg are turn laterally, instead of directly in line with a walking posture, those leg muscles are more relaxed and relieve other muscles to move more freely.
I hope I’ve given you some reasons for understanding how and why the body is constructed and functions in he way that it does, sometimes. Also, the more you understand how and why he human body is designed to function and how not, the better you’ll be at improving your quality of life and your game.