Front stance has the back leg straight and heel on the ground. Why?

[Buka50 2]

Me too. I faced a Shotokan guy who stood as steady and patient as a rock - make that a boulder. He didn't respond to any of my brilliant tactics. I tried a spinning backfist. His timing was impeccable and landed a simple reverse punch to my kidney. It felt like I got stabbed in the back.

The deep forward stance limits mobility but this guy did fine without that. Typical fighting style of old time Shotokan. The new guys seem to bounce around a lot - very irritating to deal with though it does provide some counter opportunities.

I know I’ve said this before, but that’s okay.
Some Shotokan fighters gave me fits. I always described them thusly - They’d punch a hole right through my body and give the finger to my teammates behind me.

Even when I’d sometimes win, they’d calmly walk to the sidelines and I’d slowly shuffle off with my arms wrapped around my body desperately trying not to moan out loud.

 

[Buka50 2]

A stance is a point of stability between steps. Steps are transitions between stances. That particular front stance can root against force coming in from in front of you, channeling it to the ground through the back leg, or it can drive power from the ground as you move onto the front foot. After the weight is transferred forward, the back leg can be free even if appearing flat on the ground.

Very quotable. Very.

 

[isshinryuronin36 36]

Some Shotokan fighters gave me fits.

I felt a bit intimidated by them. Being young, I was impatient with their lack of movement, standing motionless and was enticed to force the action - a big mistake against a great counter puncher with great timing. Of course, that was their plan. As I matured, I learned not to be too eager to attack and how to avoid counters.

 

[J. Pickard2 1]

We just went over this this week in my classes. There are pros and cons to heel down vs heel up. Power is not driven by the heel, there is no circumstance in any other sport when you are trying to push forward and are taught to use the heal to drive the power forward. Think about it, if you decide to push something really heavy in a forward direction do you dig in with the ball of the foot and lift the heel, or do you dig the heel in? the answer is ball of the foot. So why lock the back leg? Control. Stances aren't supposed to be static, they are snapshots of dynamic movements. They are often practiced static for exercise and to learn to feel the movements, and more often than not, tradition. So now imagine the case when you would step deep, lower your body and punch with the lead arm; if it lands its gonna do a lot of damage, but if your timing is off or your opponent sees it coming it is the perfect setup for your opponent to off balance you, trip you and mess you up. But what if you lock the back leg for a split second at the point of impact? It creates a structure that is difficult to pull or push off balance.

You don't have to take my word for it. Here are 2 simple experiment you can do to prove the concept:
experiment 1) If you have a full wavemaster bag, push it across the floor. a full size wm bag filled with water is about 230-250lbs so it takes some force. Try it once digging in with the ball of the foot and once trying to drive with the heel. One is definitely stronger than the other and easier to move the bag with.
experiment 2) grab a partner of comparable size to you and have them stand one step away from you but just off to the side. Step into a lead arm punch so the punch will end right in front of them so they can grab it and continue to pull you forward and continue the momentum of the punch. Do this twice; the first time keep your back leg bent and heel up. The second time put the heel down and lock the back leg right as they grab your punch and pull.

I can pretty much guarantee that you will have an easier time pushing in exp1 with the ball of the foot and not the heel, and will be harder to off balance in exp2 with the heel down.

TL,DR; heel up pushing with ball of the foot gives you power, heel down leg locked gives you structure but cuts the power short.

 

[Kung Fu Wang146 177]

TLR; heel up pushing with ball of the foot gives you power, heel down leg locked gives you structure but cuts the power short.

Agree!

Heel up - give.

Heel down - take.

 

[Kung Fu Wang146 177]

It's clear that his heel is off the ground when he punch. After the power has been generated from the back leg -> hip -> shoulder -> fist, the heel connection is no longer needed when your body is moving forward.

If your opponent is just 6 inch away from your reach, you will have no option but to lift your back heel in order to gain that extra punching distance.