Significance of a Perfect Back
To become truly glorious one must never neglect to achieve perfection in all aspects of the physique and the mind. To have a back worthy of the Gods is indeed a good sign of a healthy mind.
Even though we should all strive for a symmetrical physique of harmony there are other benefits and necessities with having a strong back. Whereas good strong legs are needed for many an endeavour, a strong back is also a must if you want a long term development of the physique as a whole. A good strong back will enable you to achieve true perfection when gazed upon from the front.
The perfection achieved when only seeing a physique from the front is an illusion and highly transitory. The reason for this is a that a long-term development is impossible when not taking into account that the front and back must be in perfect harmony with each other. It is a quite simple truth to be honest, if your back strength is not on par with your push strength you will hurt yourself sooner of later.
So if someone displays a magnificent chest or shoulders yet are lacking a strong back you know that true perfection has not been reached as the individual has not taken into account the long-term implications of neglecting the back. A glorious back enables true perfection and long-term magnificence.
To reach enlightenment you must always look for these relations, not only in regards to the physique but also in a broader sense.
To give another example the ancient Greeks put great emphasis on violence and rhetoric. To be able to wield a spear just as well as to deliver a powerful speech and argument.
The Sword and the Book must work in perfect unison. Being proficient in only one aspect will leave you open to injury, just as neglecting the strength of your back will lead to an inevitable collapse of the front.
Being a scion of martial prowess without being skilled in speech will leave you a barbarian. By the same token a people skilled only in speech, writing and arguments with words will be an easy victim for a martially superior people. History contains plenty of such examples. Rome conquered Greece, the Mongols conquered both high standing China and Persia.