The lock horns position is a typical example of positive force versus positive force. He who is stronger will win the contest (the "Strong Man Principle"). However, no matter how strong you are, your body condition will decline as time goes by and you will meet people stronger than you.
The Taiji Classic said, if the stronger person will always win, what's the point of learning an art (of martial)?
Most martial art schools have their own specific application techniques to overcome the Strong Man Principle.
In Taiji, the Yin Yang Conversion Principle is the answer. Applying the Yin Yang Conversion Principle, a weak party makes use of the strength of the strong party to defeat the latter. It does not mean that a strong body is useless - you still need a strong physical body to support your skill. It's just that muscle strength no longer plays a decisive role here. The weak party and the strong party have equal chances. He who has the higher skill and can apply the yin /yang principle creatively has a higher chance to win.
As a starting point, a taiji practitioner should first go through the "Know Your Own Self" stage to recreate the coordinated body condition. This is the foundation of the art. An internal martial artist builds up a natural body rather than a body with strong muscle power.
Some misinformed internal martial art practitioner over emphaize the importance of "Fa Jing" or "Coherent bodily force". It is correct that after acquiring a natural body, an internal martial artist becomes very powerful as he can utilise coherent bodily force. However, no matter how powerful he has become - he is still a slave of the "Strong Man Principle" if he simply uses his power to defeat a weaker opponent.
A buffalo is strong. We appreciate the strength of a buffalo, but we do not want to act like a buffalo. With the suitable skill, a small boy can control a buffalo by knotting a string to the buffalo's nose. That's where the application techniques come into the picture.
It is not to say that a natural body is not important. A Taiji practitioner will not be able to skillfully apply the Yin Yang Conversion Principle in the absence of a natural body. You will need the flexibility of a natural body to exercise the application technique. With a natural body, a Taiji practitioner is qualified to enter the "Know Others" stage and start learning the Taiji skill.